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Assessing the effectiveness of a large marine protected area for reef shark conservation
... Thus, marine protected areas (MPAs), which offer one potential solution to combat global declines in biodiversity, may not protect species equally: mobile marine animals are unlikely to stay within even very large MPAs (> 150,000 km 2 Conners et al. 2022) and ephemeral ocean processes on which these species rely may only occur within an MPA for part of the year (e.g., Gilmour et al. 2022). Additionally, MPAs are subject to external threats like seabed mining (Amon et al. 2023), illegal fishing (White et al. 2017), and passive fishing strategies (drifting fish aggregation devices; dFADs; Curnick, Feary, et al. 2020). These cumulative threats increase risk to biodiversity, especially within tropical marine ecosystems, where animals connect coral reefs to adjacent terrestrial and pelagic ecosystems (e.g., McCauley, DeSalles, et al. 2012). ...
... In 2023, U.S. President Biden recommended increasing PKMPA's area (Biden 2023). Because of PKMPA's established climate resilience (Fox et al. 2023;Khen et al. 2022) and diverse and abundant highly mobile marine species White et al. 2017;Young et al. 2015), quantification of MPA efficacy within the context of climate change could inform whether MPA expansion could improve regional conservation outcomes on longer timescales. ...
... The brevity of cross-boundary movements may result in overall greater protection. However, being near boundaries could be problematic because, although resources adjacent to MPAs are enhanced (Caselle et al. 2015), fisheries activity may also be higher, and regional enforcement efforts may be limited (Jacoby et al. 2020;White et al. 2017). Longer movements associated with migration and breeding (time scale: weeks to months) that were not captured in this analysis due to tagging limitations can occur during critical life history phases that require transit to, or away from, PKMPA. ...
Large‐scale marine protected areas (LSMPAs; > 1000 km ² ) provide important refuge for large mobile species, but most do not encompass species' ranges. To better understand current and future LSMPA value, we concurrently tracked nine species (seabirds, cetaceans, pelagic fishes, manta rays, reef sharks) at Palmyra Atoll and Kingman Reef (PKMPA) in the U.S. Pacific Islands Heritage Marine National Monument. PKMPA and the U.S. Exclusive Economic Zone encompassed 39% and 54% of species movements ( n = 83; tracking duration range: 0.5–350 days), respectively. Species distribution models indicated 73% of PKMPA contained highly suitable habitat. Under two projected future scenarios (SSP 1–2.6, “Sustainability”; SSP 3–7.0, “Rocky Road”), strong sea surface temperature gradients initially could cause abrupt oceanic change resulting in predicted habitat loss in 2040–2050, followed by an equilibrium response and regained habitat by 2090–2100. Current and future suitable habitats were available adjacent to PKMPA, suggesting that increased MPA size could enhance protection. Our three‐tiered approach combining animal tracking with publicly available remote sensing data and future projected environmental scenarios could be used to design, study, and monitor protected areas throughout the world. Holistic approaches that encompass diverse species and habitat use can enhance assessments of protected area designs. Animal telemetry and remote sensing may be helpful for ascertaining the extent to which other MPAs protect large mobile species in the future.
... In Indonesia, for example, many fishers began targeting reef sharks in the 1990s and 2000s; Jaiteh et al. (2017a) found that most fishers reported dramatic declines in reef shark abundance since the early 2000s, but not in the preceding years. Most reef sharks display a high degree of site fidelity (Barnett et al. 2012, Espinoza et al. 2015, White et al. 2017, making them particularly vulnerable to nearshore fisheries and leading to stark differences in reef shark abundance between pop-ulated and unpopulated Indo-Pacific islands . Despite reported declines in catch, Indo-Pacific trade networks for shark fins have proliferated (Eriksson & Clarke 2015), suggesting that Indo-Pacific reef shark fisheries may be experiencing serial depletion. ...
... Here, we combined data from 2 social-ecological studies (White et al. 2017, Golden et al. 2022 in the Northern Line Islands (Kiribati), with a particular focus on Teraina (Teeraina) Atoll. Fishers on Teraina report declines in catch per unit effort going back to the early 2000s in a fishery comprised of only 17 fishers and 8 motorized boats at the time of initial study (2013). ...
... The data used in this study were collected in the Northern Line Islands and consist of (1) fisher surveys and observations on Teraina Atoll between May and August 2013 as part of related research aimed at characterizing reef shark movement in the Northern Line Islands (White et al. 2017) and (2) Island Council and community member surveys and ecological surveys conducted in 2019 and 2020 as part of a larger study on coral reef fisheries dynamics and community health and nutrition across Kiribati (Golden et al. 2022). We focus on Teraina as a case study, but leverage data from surveys in the broader Line Islands where relevant. ...
Small-scale fisheries are immensely important for the livelihoods, nutrition, and cultural identities of millions of people, but their impacts are less understood than those of industrial fisheries. On the island of Teraina in Kiribati’s Northern Line Islands, sharks have traditionally been harvested only occasionally for cultural purposes. At the turn of the century, growing access to international markets drove sharp increases in harvests, but the fishery remained small, comprising only 17 fishers in 2013, and a ban on commercial shark fishing and trade was implemented in 2016. To understand the possible impacts of this fishery, we interviewed each fisher, obtaining estimates of catch and effort as early as 1983 and validating these estimates with storehouse inventories. We combined these data with previously published tag-recapture data for grey reef sharks Carcharhinus amblyrhynchos at nearby Palmyra Atoll to inform a Bayesian production model for Teraina’s grey reef shark population. Our model suggests that a small number of fishers and motorized boats could plausibly have driven a significant reduction in grey reef shark abundance on surrounding reefs, declining by as much as 75% in as few as 15 yr. Recent ecological and social surveys confirm that shark populations in the Line Islands are likely severely depleted. These results highlight the vulnerability of sharks and other slow-growing marine megafauna to relatively modest small-scale fishing efforts. As few communities, even those that are relatively geographically isolated, remain disconnected from global trade networks, our research suggests a need for management and trade regulations at trans-national scales.
... Collectively, insight from this space-based sensing of fishing vessels has been valuable in myriad ways to marine managers-for example, by identifying risks of overlap between fishers and sharks (White et al. 2017), informing management on the high seas (Dunn et al. 2018), addressing issues of equity and slavery in fisheries , McDonald et al. 2021, and estimating the amount of seabed that has been disturbed by bottom trawling and carbon dioxide released by trawling (Seto et al. 2023, Atwood et al. 2024. One challenge of using these space-based data is that some of the data are proprietary or costly. ...
... At its core, biologging science involves attaching small electronic tags to animals that store data on behavior and oceanographic variables; when at the surface, they then often utilize radio telemetry to transmit data to satellites in order to determine the animals' positions and relay archived tag data on behavior and oceanography back to researchers. Lessons learned from past research have generated many applied benefits, including identifying the habitat requirements of endangered species (e.g., Schofield et al. 2013), providing insights into marine protected area design (e.g., White et al. 2017), and generating information about spatial and temporal distributions of marine megafauna (e.g., Block et al. 2011, Andrzejaczek et al. 2023). In addition, significant advancements in physiology, behavioral research (such as foraging ecology), and spatial habitat analyses that are directly germane to whole-ecosystem management have been made using these tools (Block et al. 2011, Raymond et al. 2015. ...
Advancements in space-based ocean observation and computational data processing techniques have demonstrated transformative value for managing living resources, biodiversity, and ecosystems of the ocean. We synthesize advancements in leveraging satellite-derived insights to better understand and manage fishing, an emerging revolution of marine industrialization, ocean hazards, sea surface dynamics, benthic ecosystems, wildlife via electronic tracking, and direct observations of ocean megafauna. We consider how diverse space-based data sources can be better coupled to modernize and improve ocean management. We also highlight examples of how data from space can be developed into tools that can aid marine decision-makers managing subjects from whales to algae. Thoughtful and prospective engagement with such technologies from those inside and outside the marine remote sensing community is, however, essential to ensure that these tools meet their full potential to strengthen the effectiveness of ocean management.
... Direct threats are associated to targeted fisheries, being part of by-catch, poaching of isolated reefs located in marine protected areas and indirect threats to the destruction of their habitats (Knip et al., 2010), to material and sound pollution (Fernández & Anastasopoulou, 2019), and removal of their prey species (Consales & Marsili, 2021;Dulvy et al., 2021;Heupel et al., 2019;Stevens, 2000). Yet despite the current conservation measures adopted by several countries worldwide to mitigate these anthropogenic effects, many reef shark species are still listed as vulnerable, near threatened, or threatened on the IUCN Red List for endangered species (MacNeil et al., 2020;White et al., 2017). Because all coral reef ecosystems are affected by human activities in one way or another, we have no baseline for what a healthy reef shark population should look like (Ferretti et al., 2018;Hughes et al., 2003;Lecchini et al., 2021). ...
... Reef shark abundance has declined remarkably over the past decades across all coral reefs (MacNeil et al., 2020;Sherman et al., 2023;White et al., 2017). Assessing reef shark population abundance at recovery, increase, or decline is often greatly challenging because we lack spatial and temporal monitoring data on their population dynamics (Latour & Gartland, 2020). ...
Reef shark species have undergone sharp declines in recent decades, as they inhabit coastal areas, making them an easy target in fisheries (i.e., sharks are exploited globally for their fins, meat, and liver oil) and exposing them to other threats (e.g., being part of by‐catch, pollution, and climate change). Reef sharks play a critical role in coral reef ecosystems, where they control populations of smaller predators and herbivorous fishes either directly via predation or indirectly via behavior, thus protecting biodiversity and preventing potential overgrazing of corals. The urgent need to conserve reef shark populations necessitates a multifaceted approach to policy at local, federal, and global levels. However, monitoring programmes to evaluate the efficiency of such policies are lacking due to the difficulty in repeatedly sampling free‐ranging, wild shark populations. Over nine consecutive years, we monitored juveniles of the blacktip reef shark (Carcharhinus melanopterus) population around Moorea, French Polynesia, and within the largest shark sanctuary globally, to date. We investigated the roles of spatial (i.e., sampling sites) and temporal variables (i.e., sampling year, season, and month), water temperature, and interspecific competition on shark density across 10 coastal nursery areas. Juvenile C. melanopterus density was found to be stable over 9 years, which may highlight the effectiveness of local and likely federal policies. Two of the 10 nursery areas exhibited higher juvenile shark densities over time, which may have been related to changes in female reproductive behavior or changes in habitat type and resources. Water temperatures did not affect juvenile shark density over time as extreme temperatures proven lethal (i.e., 33°C) in juvenile C. melanopterus might have been tempered by daily variation. The proven efficiency of time‐series datasets for reef sharks to identify critical habitats (having the highest juvenile shark densities over time) should be extended to other populations to significantly contribute to the conservation of reef shark species.
... The results presented so far suggest that the dispersal abilities of (Barnett et al., 2012;Bonnin et al., 2019;White et al., 2017). When strong IBD is present, it is difficult to attribute a biological meaning to groups identified by clustering algorithms (Meirmans, 2012). ...
... We would have expected the connectivity in each sampled deme to be highly correlated to the distribution of coral reefs in its neighborhood, as it was previously observed in C. melanopterus(Maisano Delser et al., 2019). However, the two species differ in their dispersal behaviors: While gray reef sharks perform longdistance movements of at least ~900 km(Barnett et al., 2012;Bonnin et al., 2019;White et al., 2017), the blacktip reef shark exhibits a range of movement not exceeding ~50 km. ...
Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here, we investigated the evolutionary history of the endangered gray reef shark (Carcharhinus amblyrhynchos) across its range by sequencing thousands of RADseq loci in 173 individuals in the Indo-Pacific (IP). We first bring evidence of the occurrence of a range expansion (RE) originating close to the Indo-Australian Archipelago (IAA) where two stepping-stone waves (east and westward) colonized almost the entire IP. Coalescent modeling additionally highlighted a homogenous connectivity (Nm ~ 10 per generation) throughout the range, and isolation by distance model suggested the absence of barriers to dispersal despite the affinity of C. amblyrhynchos to coral reefs. This coincides with long-distance swims previously recorded, suggesting that the strong genetic structure at the IP scale (F ST ~ 0.56 between its ends) is the consequence of its broad current distribution and organization in a large number of demes. Our results strongly suggest that management plans for the gray reef shark should be designed on a range-wide rather than a local scale due to its continuous genetic structure. We further contrasted these results with those obtained previously for the sympatric but strictly lagoon-associated Carcharhinus melanopterus, known for its restricted dispersal ability. Carcharhinus melanopterus exhibits a similar RE dynamic but is characterized by a stronger genetic structure and a nonhomogeneous connectivity largely dependent on local coral reefs availability. This sheds new light on shark evolution, emphasizing the roles of IAA as source of biodiversity and of life-history traits in shaping the extent of genetic structure and diversity.
... The question of how MPAs can be used to protect chondrichthyans was first addressed over two decades ago (Bonfil, 1999). There is now a growing body of evidence that no-take reserves actually benefit chondrichthyan populations (Garla et al., 2005;Heupel et al., 2009;Goetze and Fullwood, 2012;Knip et al., 2012;da Silva et al., 2013;Bond et al., 2017;White et al., 2017;Juhel et al., 2019;Albano et al., 2021). It was demonstrated that MPAs may be most effective for juveniles due to smaller individuals being more site attached to specific reefs Garla et al., 2005;Pikitch et al., 2005;Robbins et al., 2006;Heupel et al., 2010). ...
... These are very important results for chondrichthyan conservation, as most focus is given to charismatic species, while other species are usually left unprotected despite being constantly caught in fisheries in South Africa (Department of Agriculture, Forestry and Fisheries, 2012;da Silva et al., 2015). These findings are aligned with some of the previous studies confirming the positive effects of MPAs on the conservation of chondrichthyans (Garla et al., 2005;Heupel et al., 2009;Goetze and Fullwood, 2012;Knip et al., 2012;da Silva et al., 2013;Bond et al., 2017;White et al., 2017;Juhel et al., 2019;Albano et al., 2021). Albano et al. (2021) found that sharks significantly benefit from the presence of the large and old De Hoop MPA, however, these authors did not undertake temporal sampling in their study. ...
Chondrichthyans are threatened worldwide due to their life-history traits combined with a plethora of anthropogenic impacts that are causing populations to collapse. Marine Protected Areas (MPAs) are a conservation option, but their efficacy for chondrichthyans is still unclear. Conservation efforts might be challenging especially in developing countries, due to a lack of resources and monitoring and limited data and stakeholder support. Here Baited Remote Underwater Stereo-Video systems (stereo-BRUVs) were deployed inside and outside a small partially protected MPA (Robberg MPA, Western Cape, South Africa) to assess the status of cartilaginous fishes’ assemblages and to investigate the potential benefits derived from the presence of a marine reserve. Overall, 19 chondrichthyan species in 11 different families were observed. Chondrichthyans were observed in 78.5% of the sites and, of these, 89.7% of the MPA sites showed at least one chondrichthyan, while only in the 67.5% of surrounding exploited sites a cartilaginous fish was sighted. The presence of the MPA had a significant effect on the relative abundance of batoids, threatened species and local endemics, with more observations inside the MPA than outside, indicating the potential benefit of marine reserves on species that are more vulnerable to fishing pressure. Relative abundance was generally higher inside the bay than in the exposed area, and both relative abundance and species richness decreased significantly with depth. The analysis of the body length showed that the 35.5% of species had an average body length below maturity length, indicating that the area might be used as nursery ground for different species. This study provides evidence that MPAs, even though small and partially protected, can provide benefits for chondrichthyans, specifically to threatened species, endemic species and lesser-known species. Importantly, different environmental parameters must be considered to maximize the benefits an MPA can provide.
... Moreover, fishing grounds overlapped with rhinoray encounters, which may represent observation bias rather than fishers intentionally targeting those areas, but nonetheless, indicates that rhinorays are present in fishers' usual fishing grounds and are thus at risk from fishing pressure. This aligns with previous research highlighting the broader issue that marine protected areas alone are not a silver bullet solution for shark conservation (Knip et al., 2012;MacKeracher et al., 2019;White et al., 2017). Fisheries management measures are also needed to prevent mortality of sharks both within and beyond marine protected areas (Goetze et al., 2024). ...
The “rhinorays” (giant guitarfish‐Glaucostegidae and wedgefish‐Rhinidae) are a critically endangered group of “shark‐like rays,” which have experienced steep global population declines in the past decade due to overfishing. Their slow life histories and high market value increase the risk of trade‐driven extinction and lead to trade‐offs between conservation objectives and fishers' economic objectives. As such, it is important to understand the social and ecological dimensions of risk to rhinorays to identify feasible conservation interventions. We conducted semi‐structured interviews with 162 small‐scale fishers in Karimunjawa National Park (KJNP), Indonesia. We collected data on fisher interactions with rhinorays, the technical and socio‐economic characteristics of the fisheries, key risks to rhinorays, and potential leverage points for management, including feasible pro‐conservation actions that fishers could engage in. We then constructed a linear model to identify socio‐demographic predictors of fishers' stated willingness to engage in pro‐conservation actions for rhinorays (specifically, willingness to release), to inform the design of future interventions. Our results indicate that socio‐economic factors—fishers' perceived income contribution from catches of rhinorays and formal education levels—were significant predicators of fishers' willingness to release rhinorays. In contrast, awareness of rhinorays threat status was not a significant predictor. These findings are a first step toward understanding barriers and opportunities for engaging fishers in rhinorays conservation in KJNP. Our findings and recommendations also offer lessons learned for other marine conservation interventions at the intersection between small‐scale fisheries management, marine protected areas, and marine megafauna conservation.
... Highly protected LSMPAs can offer ecosystem wide protection and improved ecological connectivity, with highly mobile species afforded extended protection across their ranges (Toonen et al. 2013;White et al. 2017;O'Leary et al. 2018). However, critics argue that some LSMPAs have been strategically placed in areas of low commercial value to help countries meet protection targets with minimal resistance, whilst others question the ability to enforce regulations over such vast spatial scales (De Santo 2020; Collins et al. 2023;Relano and Pauly 2023). ...
The establishment of large-scale marine protected areas (LSMPAs) has emerged as one of the defining trends in ocean conservation over recent decades. To assess the potential benefits of such designations, it is necessary to understand the nature of the threats that have been excluded. Here, we summarise over 25 years of historical catch and effort data for a pelagic longline fishery that formerly operated within the recently designated LSMPA surrounding Ascension Island (UK), using data compiled from logbooks and observer programmes. Licenced fishing by foreign vessels (primarily flagged to Taiwan and Japan) operated intermittently in the Ascension Island exclusive economic zone (EEZ) between 1988 and 2016, with catch peaking at over 5000 t year −1 in the early 1990s. Bigeye tuna (Thunnus obesus) was the dominant species targeted (76% of total catch weight) whilst oceanic sharks (e.g. blue shark Prionace glauca) and other predatory pelagic finfish (e.g. longnose lancetfish Alepisaurus ferox) appear to have presented a sizable bycatch risk, accounting for 37% of total individuals caught in local observer data. The fishery displayed strong seasonality, with two thirds of activity occurring between December and March and was consistently concentrated in the northwest of the EEZ. This distribution closely aligns with recent satellite-derived vessel tracking data which suggests that a regional longline fishing hotspot remains in the high seas area adjacent to the northwest of the Ascension Island MPA. Our results suggest that predatory pelagic fish and sharks will be the most direct beneficiaries of the Ascension Island MPA, although the high mobility of these species may lessen any conservation impacts, given intense the fishing effort in adjacent high seas areas. While illegal fishing remains a potential threat, the spatiotemporal predictability of the historic fishery may be useful in identifying areas of elevated risk for targeted enforcement in this large, remote MPA.
... Walau bagaimanapun, maklumat sedia ada masih belum kukuh kerana lebih banyak data dan kajian empirikal yang diperlukan untuk memahami impak berkaitan dengan taman laut (Pendleton et al., 2018). Antara fokus kajian yang kerap diketengahkan ialah impak taman laut terhadap konservasi marin (White et al., 2017), sosioekonomi (Salleh et al., 2011;Ban et al., 2017;Mizrahi et al., 2018), pelancongan (Lopes et al., 2017;Masud et al., 2017) dan isu berkaitan dengan pengurusan taman laut (Bennett & Dearden, 2014;Masud et al., 2017). Namun, persoalan tentang sejauh mana penerimaan masyarakat tempatan terhadap penubuhan taman laut setelah penubuhannya masih kurang diketengahkan. ...
Pulau Tioman adalah salah satu daripada 42 buah pulau taman laut yang terdapat di Malaysia. Pewartaan taman laut bertujuan meningkatkan sumber perikanan negara melalui pengurusan, pemeliharaan dan pemuliharaan biodiversiti serta ekosistem sumber marin secara efektif di kawasan-kawasan tersebut. Namun, sejauh mana penerimaan masyarakat setempat terhadap penubuhan taman laut serta keberkesanannya untuk memastikan kelestarian sumber perikanan masih menjadi satu persoalan. Sehubungan dengan itu, kajian ini dijalankan untuk mengumpul maklumat bagi menjawab persoalan tersebut dengan menggunakan pendekatan kuantitatif. Pengumpulan data kajian telah dilaksanakan melalui tinjauan menggunakan soalan kaji selidik terhadap penduduk di tujuh buah kampung di Pulau Tioman. Penemuan kajian menunjukkan bahawa penduduk Pulau Tioman mempunyai kebergantungan yang tinggi pada sumber perikanan apabila kebanyakan daripada mereka menangkap ikan untuk dijadikan sumber makanan. Selain itu, penerimaan penduduk Pulau Tioman terhadap penubuhan taman laut agak sederhana, namun mereka mengakui kepentingannya dalam usaha pelestarian sumber perikanan. Kajian mendapati tahap penerimaan penduduk terhadap taman laut mempunyai hubungan yang signifikan dengan kepentingan dan keberkesanan pengurusannya. Oleh itu, usaha untuk memperkasakan kesedaran serta keberkesanan pengurusan taman laut hendaklah diteruskan dan dibuat penambahbaikan dari semasa ke semasa.
... Large MPAs effectively protect populations of reef sharks (e.g., (Dwyer et al., 2020;White et al., 2017)) that are declining worldwide (Robbins et al., 2006;Graham et al., 2010;Ferretti et al., 2018). However, the ecological consequences of shark loss, or conversely recovery, on coral reefs remain unclear, as there is conflicting evidence in the literature for shark driven trophic cascades (e.g., (Casey et al., 2017;Desbiens et al., 2021;Rizzari et al., 2014a;Ruppert et al., 2013;Houk and Musburger, 2013;Sandin et al., 2008;Roff et al., 2016;Ruppert et al., 2016)) where many studies have been conducted in systems with low shark abundance or where gradients of shark abundance coexist with fishing pressure on lower trophic levels. ...
Large marine protected areas (MPAs) will likely multiply worldwide to address accelerating biodiversity loss. Coral reefs are an especially at-risk ecosystem, but our understanding of whether and how large MPAs will benefit reef recovery from disturbances remains limited. Here, we evaluate how fishes influence coral reef recovery and if there are cascading trophic interactions in the fish community that influence recovery. We combine i) a meta-analysis of previous research evaluating how fishes affect coral reef succession, ii) field surveys of sharks, fishes, and benthic cover, and iii) a 2.5-year coral recruitment experiment of caged, uncaged, and partially caged settlement tiles in a remote and large MPA, in the Chagos Archipelago. In both our meta-analysis and field experiment, we found variable effects of fishes on coral recruitment with no overall significant effect, but strong control by fishes on the developing benthic communities, where fishes promote crustose coralline algae and reduce macroalgae. Within the Chagos, fishes had a positive effect on corals in protected microhabitats but a negative effect on exposed surfaces, leading to an overall neutral effect from fishes. Although meso-predatory fish abundance was negatively correlated with shark abundance, these top-down effects did not cascade down the food web through herbivores and corallivores to coral recruitment and benthic succession. Thus, our results suggest that within this large MPA, herbivores are important in limiting algae during recovery and there are compensatory responses to the loss of benthic feeding fishes and sharks, with implications for coral reef persistence in the face of global change.
... savage man-eaters that already exist on social media (Johnson et al., 2023), is necessary to promote shark ecotourism among youngsters and the public. The fact that the majority of kids think Marine Protected Areas (MPAs) would help with shark protection also shows how effective MPAs are in managing resources, as has been demonstrated elsewhere (Albano et al., 2021;White et al., 2017). However, further research is required to determine which regions are scientifically viable before shark MPAs may be established (van Zinnicq Bergmann et al., 2022;). ...
The significant increase in shark catches has made shark conservation a global problem. Although several studies on sharks have been conducted in Ghana, there is a dearth of information on the use of educational approaches for shark conservation. This study aimed to assess schoolchildren's knowledge of sharks and shark fisheries, attitudes toward shark conservation, and the factors that affected their knowledge and attitudes. From March to April 2023, two basic schools from the Western region of Ghana were visited. These schools were two Primary and Junior High Schools. From these schools, 99 students were given questionnaires to fill out with the help of a local teacher. According to the survey , more than 60% of students were aware of sharks' predatory function in the ecosystem but oblivious to their ecological significance. From the study, schoolchildren demonstrated a fair amount of understanding of shark fisheries and fishing in Ghana due to their proximity to the fishing community. However, the misunderstandings that some of these children hold about sharks may lead to poor participation in shark conservation activities. Correlation analysis between knowledge and attitude indicated an increase in knowledge about sharks would increase the attitude of children towards shark conservation. Therefore, it is crucial to incorporate shark conservation topics into the curriculum of these children, establish shark conservation groups, and engage them in citizen science projects to foster their desire for shark conservation.
... However, in many cases, there is insufficient monitoring of elasmobranchs within MPAs to fulfil such data needs, with information often being inferred from local perceptions of success (MacKeracher et al., 2018), estimates of individual movements in relation to MPA size (Dwyer et al., 2020;White et al., 2017) or comparisons of fish size inside and outside MPAs (Karvolic et al., 2021). Distinguishing the causal effect of spatial fishery restrictions from other sources of variability in population dynamics is also difficult without comparable data from both before fishery restrictions were established and for comparable unprotected areas out with the MPA (Guidetti & Claudet, 2010). ...
While elasmobranchs are often a designated feature in Marine Protected Areas, there are few studies that have evaluated the effectiveness of spatial fishery restrictions on their recovery.
Here we examine the effectiveness of fishery restrictions on the critically endangered flapper skate, Dipturus intermedius , based on changes in their abundance, demography and survival rate.
Trends in local abundance at two sites within the Loch Sunart to the Sound of Jura Marine Protected Area (LStSJ MPA), were contrasted with that in surrounding waters off the west of Scotland where fishing remains unrestricted. Survival rate was estimated using a multi‐state model of capture mark recapture data, and spill‐over from the LStSJ MPA was considered from tag‐recapture rates between the two LStSJ MPA study areas and a further site south of the LStSJ MPA.
In contrast to the wider trend across adjacent waters, skate abundance increased, especially for young juveniles, following the introduction of fishing restrictions in the LStSJ MPA. This increase could be explained by a reduction in juvenile and adult mortality as population growth rates following fishing restrictions were markedly higher than estimated in a pre‐restriction study of one site.
Limited exchange of skate between the two study areas within the LStSJ MPA and a southern site beyond the LStSJ MPA indicated a low rate of spill‐over.
This study demonstrates that spatial fishery restrictions have the potential to benefit populations of elasmobranchs which have a high site‐fidelity, but their wider conservation benefit may be partly confounded by a high level of residency.
... Similarly to ecosystems, a number of studies showed generally positive conservation outcomes on species, even if on occasions mediated by avoided habitat degradation (Gillingham et al. 2015;White et al. 2017;Cazalis et al. 2020). In their literature review, Coetzee et al. (2014) found that species' abundance, assemblage abundance and richness were higher in PAs for invertebrates (arthropods), reptiles, birds and mammals, but similar to controls for plants. ...
This book addresses the effectiveness of existing protected areas in conserving the diversity of genes, species and ecosystems on land and at sea. The book synthetizes the main biodiversity conservation outcomes of protected areas in the 2010-2019 decade, drawing on a systematic literature review of scientific publications and case studies from around the world demonstrating successes and failures. It provides region-specific results for land and sea ecosystems as well as for developed and developing countries. It also reviews current methodological approaches used to assess protected area effectiveness. The work is timely, since there is growing concern on the global biodiversity crisis among researchers, government organizations and the general public, as demonstrated by the 2030 targets established by the UN Sustainable Development Goals for Life Below Water (SDG 14) and Life On land (SDG15). The book is written in an easy and enjoyable style using numerous pictures, tables and graphs to make the content more engaging and understandable. The main intended audiences of the book are academics, from post-graduate students to university lecturers, and senior researchers in the fields of biodiversity conservation, sustainable development and environmental policy, as well as protected area managers and practitioners.
... Advances in big data processing, machine learning and vessel tracking data are revolutionizing the ability to provide data on fishing activity at high spatial and temporal resolution. These data now underpin numerous attempts to characterize global industrial fishing activity 3,91,139 , examine its overlap with target and non-target species 140,141 , assess conservation actions [142][143][144] and reveal illegal fishing 97 . Similar approaches have also demonstrated successful applications to small-scale fisheries 145,146 . ...
Food production data — such as crop, livestock, aquaculture and fisheries statistics — are critical to achieving multiple sustainable development goals. However, the lack of reliable, regularly collected, accessible, usable and spatially disaggregated statistics limits an accurate picture of the state of food production in many countries and prevents the implementation of effective food system interventions. In this Review, we take stock of national and international food production data to understand its availability and limitations. Across databases, there is substantial global variation in data timeliness, granularity (both spatially and by food category) and transparency. Data scarcity challenges are most pronounced for livestock and aquatic food production. These challenges are largely concentrated in Central America, the Middle East and Africa owing to a combination of inconsistent census implementation and a global reliance on self-reporting. Because data scarcity is the result of technical, institutional and political obstacles, solutions must include technological and policy innovations. Fusing traditional and emerging data-gathering techniques with coordinated governance and dedicated long-term financing will be key to overcoming current obstacles to sustained, up-to-date and accurate food production data collection, foundational in promoting and monitoring progress towards healthier and more sustainable food systems worldwide.
... The designation of Marine Protected Areas (MPAs) is commonly used in the protection of vulnerable cetacean species to aid population recovery (Taylor, Suckling, & Rachlinski, 2005). However, the success of a fixed-area conservation zone depends on the inclusion of a high proportion of the range and ecologically relevant habitat of the population of interest (Hooker & Gerber, 2004;Cañadas et al., 2005;White et al., 2017). Conservation management is therefore increasingly challenging for highly mobile populations, due to the lack of knowledge on temporal and spatial distributions, which is exacerbated by the relatively small coverage of coastal MPAs (Wilson, 2016). ...
Coastal bottlenose dolphin populations are highly vulnerable due to their small population sizes and proximity to human activities. Long‐term studies in the UK have monitored populations protected within Special Areas of Conservation (SACs) since the 1990s, but a small community of bottlenose dolphins inhabiting the coastal waters of southern England has received much less attention. The English Channel is one of the most heavily impacted marine ecosystems worldwide and increasing anthropogenic pressures pose a severe threat to the long‐term viability of this population. Conservation measures to protect these animals have been hindered by a lack of knowledge of population size, distribution and ranging behaviour. This study aimed to fill these knowledge gaps. A citizen science sighting network yielded 7458 sighting reports of bottlenose dolphins between 2000 and 2020. Resightings of identified individuals were used to estimate abundance, distribution, and ranging behaviour. Social structure analysis revealed a discrete interconnected group of animals in shallow coastal waters, which did not appear to mix with conspecifics identified further offshore. A Bayesian multi‐site mark–recapture analysis estimated that this population comprises around 48 animals (CV = 0.18, 95% HPDI = 38–66). These dolphins ranged between North Cornwall and Sussex, with an average individual range of 530 km (68–760 km). Areas of high‐modelled habitat suitability were found to overlap with high levels of anthropogenic pressure, with pollution and boat traffic identified as the most pervasive threats. Although adult survival rates indicated that the population was relatively stable from 2008 to 2019 (0.945 (0.017 ± SE)), the small population size implies a significant risk to their long‐term viability and resilience to environmental change. By highlighting the most deleterious anthropogenic activities and regions of conservation significance, our results will be useful for developing management policies for threat mitigation and population conservation, to protect this vulnerable group of dolphins.
... Given the extensive exploitation of giant guitarfish (Family: Glaucostegidae) and wedgefish (Family: Rhinidae) in both the Java Sea (Yuwandana et al. 2020) and Indonesia in general (Kyne et al. 2019a(Kyne et al. , 2019b, effective management will be needed to prevent local population decline or extinction (Dulvy et al. 2017). On the basis of the results and available knowledge, authors consider KJNP (see BTNKJ, Profil Kawasan Taman Nasional Karimunjawa at https://tnkarimunjawa.id/ profil/index) as one of the last strongholds (White et al. 2017;MacKeracher et al. 2019) for both groups of species in Java Sea. ...
... Given the extensive exploitation of giant guitarfish (Family: Glaucostegidae) and wedgefish (Family: Rhinidae) in both the Java Sea (Yuwandana et al. 2020) and Indonesia in general (Kyne et al. 2019a(Kyne et al. , 2019b, effective management will be needed to prevent local population decline or extinction (Dulvy et al. 2017). On the basis of the results and available knowledge, authors consider KJNP (see BTNKJ, Profil Kawasan Taman Nasional Karimunjawa at https://tnkarimunjawa.id/ profil/index) as one of the last strongholds (White et al. 2017;MacKeracher et al. 2019) for both groups of species in Java Sea. ...
Context
Giant guitarfish (Family: Glaucostegidae) and wedgefish (Family: Rhinidae) (Critically Endangered, IUCN Red List and CITES Appendix II) are highly exploited throughout their distribution because of their highly valued fins in the international market. Both are commonly caught as bycatch or secondary valuable catch in the Java Sea, including in Karimunjawa National Park, Central Java, Indonesia.
Aims
Assess the presence and relative abundance of giant guitarfish and wedgefish species in Karimunjawa National Park and adjacent waters.
Methods
Data were collected using baited remote underwater video (BRUV) surveys across 40 sites, covering multiple zonation areas and depth ranges. All species were identified to the species level and their relative abundance was tested with one-way PERMANOVA based on sites, zonation areas and depths.
Key results
Two target species, Glaucostegus typus and Rhynchobatus australiae, were present in the study area with a maximum number of 3 and 6 and relative abundance of 0.0048 and 0.0096 respectively, over 477 BRUVs and 623.9 h of videos. Their presence during the study was not affected by sites, zonations or depth.
Implications
The presence and relative abundance of both G. typus and R. australiae were low, which may be a result of decades of overfishing, and have provided the first information to the urgency of managing the species in the areas.
... Quantifying the species' movement patterns is essential for the design of targeted conservation strategies Gallagher et al. 2021). With the global decline of shark populations accessible to fisheries, and the continuing threat of illegal, unreported, and unregulated fishing (Porcher and Darvell 2022;Worm et al. 2024), the establishment of Marine Protected Areas (MPAs) has emerged as a cornerstone of shark conservation efforts (White et al. 2017). However, the effectiveness of these measures hinges on a deep understanding of reef shark movement patterns, which can vary seasonally and with habitat (Papastamatiou et al. 2009(Papastamatiou et al. , 2010. ...
One challenge in studying the natural behaviour of wild animals is the requirement of detailed observations spanning extended periods of time, which is particularly difficult in the case of sharks. As a result, remote sensing technologies are increasingly employed in which the data received is considerably simplified. In this study, 475 blacktip reef sharks (Carcharhinus melanopterus) were identified using direct underwater observation. Subsequent sightings of these sharks were recorded at various locations along the north shore of Mo'orea Island over a period of 6.5 years. The key factors influencing their movements were found to be the reproductive season and the lunar phase. Additionally, a tendency to avoid turbulent regions was observed, particularly by mature females. Notably, significant variations existed among individuals; while some sharks left their ranges for only two weeks twice a year for mating and parturition, others were frequently absent, sometimes for months at a time. It was also observed that juveniles displayed high mobility prior to settling into a home range around the ages of three to four. Understanding such movements will be useful in the future in the planning of MPAs and other conservation strategies.
... Vessel positioning data broadcast from onboard Automatic Identification System (AIS) equipment have been leveraged for identifying areas where highly migratory sharks overlap with elevated levels of fishing effort (31)(32)(33). These approaches have also detected cases where fishing activities occurred inside marine protected areas (34,35). Remotely sensed fisheries monitoring thus represents an alternative source of data to traditional fisheries management methods such as the historical reliance on data reporting, which can be characterized by taxonomic uncertainty, a lack of geolocation data, and a general underreporting of catch (27,(36)(37)(38). ...
Marine protected areas are increasingly touted for their role in conserving large marine predators such as sharks, but their efficacy is debated. Seventeen "shark sanctuaries" have been established globally, but longline fishing continues within many such jurisdictions, leading to unknown levels of bycatch mortality levels. Using public data from Global Fishing Watch and Regional Fisheries Management Organizations, we quantified longline fishing within eight shark sanctuaries and estimated pelagic shark catch and mortality for seven pelagic shark species. Sanctuary mortality ranged from 600 individuals (Samoa) to 36,256 individuals (Federated States of Micronesia), equivalent to ~5% of hypothesized sustainable levels for blue sharks to ~40% for silky sharks, with high mortality levels in the Federated States of Micronesia, Palau, and the Marshall Islands. Unsustainable mortality rates were exceeded for silky sharks in two sanctuaries, highlighting a need for additional stock assessments and implementation of bycatch reduction measures. Big data integration workflows represent a transformative tool in fisheries management, particularly for data-poor species.
... Marine reserves are characterized by fostering the growth and reproduction of fishes (Roberts and Hawkins 2000), but these areas provide limited protection for highly migratory species (White et al. 2017). The scalloped hammerhead is known to migrate between the aggregation sites at Darwin and Wolf, Cocos and Malpelo (Bessudo et al. 2011;Ketchum et al. 2014b;Nalesso et al. 2019), and apparently with seamounts located off these islands that have been suggested may also represent potential aggregation sites (Chávez et al. 2020;Cambra et al. 2021;Ladino et al. 2022). ...
The Eastern Tropical Pacific (ETP) is one of the last regions where large aggregations of the critically endangered scalloped hammerhead shark (Sphyrna lewini) can still be observed. In this regard, we comparatively assessed the seasonality in S. lewini’s relative abundance within three marine protected areas (MPAs) of the ETP and explored its relationship with environmental factors such as temperature. Abundance standardization via generalized linear mixed models revealed that Galapagos Islands (Ecuador) held an overall higher relative abundance of S. lewini when compared to Cocos Island (Costa Rica) and Malpelo (Colombia). The greatest relative abundance was observed from June to October for Cocos, followed by Galapagos (January, September, and November) and Malpelo (December, February, and March). Our results suggest that S. lewini observed relative abundances are significantly affected by water temperature and years (all three sites), and by the seasons, dive schedule, visibility and moon phase (to a lesser extend). This research contributes to the understanding of the temporal and spatial fluctuations of S. lewini at oceanic aggregation sites to improve the decision-making tools for the integral regional climate-smart management of the species. We recommended future studies to model the effect of climate change in the abundance at aggregation sites and potential distribution shifts across the ETP.
... Much of the research on reef-associated sharks to date has, therefore, focussed on quantifying aspects of horizontal space use such as habitat associations, movement networks and home ranges (e.g. Donaldson et al. 2014, Espinoza et al. 2015b, White et al. 2017. ...
Vertical space use informs the ecology and management of marine species, but studies of reef-associated sharks often focus on horizontal movements. We analysed the vertical movements of silvertip sharks Carcharhinus albimarginatus using pop-up archival tags deployed on 7 individuals in the Chagos Archipelago, central Indian Ocean. The sharks changed depth predictably with water column thermal structure, moving deeper with seasonal increases in mixed layer depth while occupying a narrow ambient water temperature range around ~27°C. At shorter timescales, higher resolution data from 5 tags showed that silvertip shark depth varied cyclically with surface light levels, increasing during daylight and on nights around the full moon. This matches the diel vertical migrations of many fish species, suggesting that the sharks’ light-driven depth changes might relate to foraging. While most vertical movements (>98%) were within the mixed layer, deeper dives to 200-800 m occurred approximately every 3 d. High-resolution data from one recovered tag showed the shark ascending deep (>200 m) dives in 2 sharply defined phases, initially fast then slow. Analysis of dive profiles against dissolved oxygen (DO) data suggested that the shark may have ascended rapidly to escape low DO levels at depth, then reduced its ascent rate by 50-80% once DO levels increased. While a small sample, the electronic tags deployed in this study revealed the silvertip sharks’ predictable use of mixed layer waters, narrow thermal range and apparent intolerance of hypoxic conditions. These characteristics may exacerbate the species’ vulnerability as oceanic warming and shoaling oxygen minimum zones modify vertical habitat availability.
... Little is known about how the constant forward motion of some shark species might alter potential attachments on the fin, and the highly migratory behavior of some shark species that are the focus of tracking studies makes it challenging to document how different tags and geolocators behave on the fins after long time periods. However, satellite-linked geolocators offer an opportunity to remotely collect shark movement data (Hammerschlag et al. 2011), which can help to design efficient conservation measures (e.g., White et al. 2017). A thorough understanding of the movement behavior of Great Hammerheads is needed for efficient conservation of this species (Gallagher and Klimley 2018). ...
Objective:
Sharks face a high risk of injuries throughout all life stages and are therefore expected to show a good wound closure capacity.
Methods:
Here, the wound closure of one major injury and one minor injury to the first dorsal fins of two free-ranging, mature female Great Hammerheads Sphyrna mokarran is described macroscopically.
Result:
The sharks showed complete wound closure of single, clean-cut lacerations measuring 24.2 and 11.6 cm in length after an estimated 323 and 138 days. These estimates were based on the observed closure rate and visual confirmation of a complete wound closure upon multiple resightings of the same individuals. Additionally, the posterior lateral displacement of fin-mounted geolocators within the fin and outside of the fin without causing external damage was documented in three additional Great Hammerheads.
Conclusion:
These observations supplement findings about wound closure capabilities in elasmobranchs. The documented geolocator displacement furthers the discussion about the safe use of these geolocators to track shark movements but also has implications for future tagging studies.
... Entretanto, apesar dos potenciais benefícios dos santuários (Ward-Paige & Worm, 2017), seu tamanho e sua localização em áreas remotas acabam ampliando ainda mais os já grandes desafios para a efetividade dessas áreas supostamente protegidas, considerando as dificuldades para as ações de fiscalização e monitoramento. Diante disso, uma vez que estejam estabelecidos formalmente, entre os aspectos mais importantes para o sucesso dos santuários, estão: (1) considerar os fatores socioeconômicos durante a etapa de planejamento, (2) conhecer a abundância das espécies visando o monitoramento da efetividade, (3) avaliar as capturas incidentais (fauna acompanhante) e (4) incorporar medidas de gestão pesqueira, como restrições de artefatos de pesca, limites de captura e a proibição temporária de pescarias (Vianna et al., 2016, White et al., 2017, Ward-Paige, 2017, Mizrahi et al., 2019, Birkmanis et al., 2020. (Rosa & Moura, 1997, Freitas et al., 2006, Wetherbee et al., 2007. ...
... Entretanto, apesar dos potenciais benefícios dos santuários (Ward-Paige & Worm, 2017), seu tamanho e sua localização em áreas remotas acabam ampliando ainda mais os já grandes desafios para a efetividade dessas áreas supostamente protegidas, considerando as dificuldades para as ações de fiscalização e monitoramento. Diante disso, uma vez que estejam estabelecidos formalmente, entre os aspectos mais importantes para o sucesso dos santuários, estão: (1) considerar os fatores socioeconômicos durante a etapa de planejamento, (2) conhecer a abundância das espécies visando o monitoramento da efetividade, (3) avaliar as capturas incidentais (fauna acompanhante) e (4) incorporar medidas de gestão pesqueira, como restrições de artefatos de pesca, limites de captura e a proibição temporária de pescarias (Vianna et al., 2016, White et al., 2017, Ward-Paige, 2017, Mizrahi et al., 2019, Birkmanis et al., 2020. (Rosa & Moura, 1997, Freitas et al., 2006, Wetherbee et al., 2007 Apesar da existência de estudos abordando diferentes aspectos da biologia dos elasmobrânquios no interior de AMPs brasileiras (e.g. ...
... Daily positions were used to calculate 50% (core use area) and 95% (home range) kernel utilization distributions (KUDs) (Worton, 1989) of Atlantic blue marlin using the R package adehabitatHR version 0.4.19 (Calenge, 2006). Kernel utilization distributions are a commonly used tool to describe the habitat use of marine animals from tracking data (Walli et al., 2009;White et al., 2017). The smoothing parameter (h) was estimated using the ad hoc method ("href"), which assumes a bivariate normal distribution. ...
Knowledge of blue marlin, Makaira nigricans, movement patterns across a range of spatiotemporal scales is important for understanding the ecology of this epipelagic fish, informing responsible management strategies, and understanding the potential impacts of a changing ocean climate to the species. To gain insight into movement patterns, we analyzed data from 66 blue marlin satellite-tagged between 2001 and 2021 throughout the North Atlantic. We recorded migrations connecting west and east Atlantic tagging locations, as well as long-term residency within small sub-regions. Blue marlin showed a pattern of latitudinal migration, occupying lower latitudes during cooler months and higher latitudes in warmer months. Diving data indicate blue marlin primarily inhabited a shallow vertical habitat with deeper diving associated with higher sea surface temperatures and dissolved oxygen content. Consistent patterns in diel vertical habitat use support the hypothesis that these fish are visual hunters, diving deeper during the day, as well as dawn, dusk, and full moon periods. The wide-ranging movements of blue marlin indicate that traditional spatial management measures, such as static marine reserves, are unlikely to be effective in reducing the fishing mortality of this species. Longer tag deployment durations are required to delineate its annual and multi-annual migratory cycle.
... There is still limited evidence on the rate at which shark populations can rebound from over-exploitation in protected areas. However, recent studies show promising results in places such as Ashmore Reef in Western Australia (Speed et al., 2018) and U.S. Palmyra Atoll National Wildlife Refuge (White et al., 2017). One of the biggest challenges to shark protection is their mobility. ...
Bycatch of non-target species is a pressing problem for ocean management. It is one of the most concerning issues related to human-wildlife interactions and it affects numerous species including sharks, seabirds, sea turtles, and many critically endangered marine mammals. This paper compares different policy tools for ocean closure management around a unique shark aggregation site in Israel's nearshore coastal waters. We provide a set of recommendations based on an optimal management approach that allows humans to enjoy marine recreational activities such as fishing, while maintaining safe conditions for these apex predators which are vital to the local marine ecosystem. To learn more about recreational fishers' derived benefits, we use a benefit transfer method. Our main conclusion is that dynamic time-area closures offer sustainable and effective management strategies. Since these closures are based on near real-time data, they might successfully preserve specific species in limited areas (i.e., small areas).
... However, the efficacy of an MPA for conserving highly mobile species is often uncertain. Animal-tracking data recorded by biologging and biotelemetry offer opportunities for evaluating the efficacy of existing MPAs (124,125), determining effective MPA sizes (126), and optimizing MPA design (127). Fine-scale GPS tracking of seabirds combined with anonymized fishery data allowed estimates of the distance over which bird behavior is influenced by fishing vessels (128). ...
Addressing important questions in animal ecology, physiology, and environmental science often requires in situ information from wild animals. This difficulty is being overcome by biologging and biotelemetry, or the use of miniaturized animal-borne sensors. Although early studies recorded only simple parameters of animal movement, advanced devices and analytical methods can now provide rich information on individual and group behavior, internal states, and the surrounding environment of free-ranging animals, especially those in marine systems. We summarize the history of technologies used to track marine animals. We then identify seven major research categories of marine biologging and biotelemetry and explain significant achievements, as well as future opportunities. Big data approaches via international collaborations will be key to tackling global environmental issues (e.g., climate change impacts), and curiosity about the secret lives of marine animals will also remain a major driver of biologging and biotelemetry studies.
... Thus, assessing the space use of multiple species concurrently can help to demonstrate enhanced efficacy of marine spatial protection, particularly as MPAs are rarely established with a single species in mind (Casselberry et al., 2020;Hays et al., 2020). Once a tagged fish moves outside of the range of a receiver however, there is a significant degree of uncertainty; even notoriously site faithful grey reef sharks for example, can appear to undertake different scales of 'longrange' movements (134 km derived from acoustic telemetry [Heupel, Simpfendorfer, & Fitzpatrick, 2010] and 926 km derived from satellite tracking [White et al., 2017]). This is beginning to be remedied, in part, through cross-boundary tracking initiatives such as the FACT (Florida Atlantic Coast Telemetry) Network, the Integrated Tracking of Aquatic Animals in the Gulf of Mexico (iTAG), OTN and IMOS, but remains an issue for non-networked, isolated or remote protected areas. ...
Acoustic telemetry (AT) has become ubiquitous in aquatic monitoring and fish biology, conservation and management. Since the early use of active ultrasonic tracking that required researchers to follow at a distance their species of interest, the field has diversified considerably with exciting advances in both hydrophone and transmitter technology. Once a highly specialised methodology however, AT is fast becoming a generalist tool for those wishing study or conserve fishes, leading to diversifying application by non-specialists. With this transition in mind, we evaluate exactly what AT has become useful for, discussing how the technological and analytical advances around AT can address important questions within fish biology. In doing so, we highlight the key ecological and applied research areas where AT continues to reveal crucial new insight, and in particular, when combined with complimentary research approaches. We aim to provide a comprehensive breakdown of the state of the art for the field of AT, discussing the ongoing challenges, where its strengths lie, and how future developments may revolutionise fisheries management, behavioural ecology and species protection. Through selected papers we illustrate specific applications across the broad spectrum of fish biology. By bringing together the recent and future developments in this field under categories designed to broadly capture many aspects of fish biology, we hope to offer a useful guide for the non-specialist practitioner as they attempt to navigate the dizzying array of considerations and ongoing developments within this diverse toolkit.
... Satellite tags are advantageous for measuring the efficacy of large, remote protected areas as data can be recorded independently of geopolitical zones, and in areas beyond national jurisdiction (White et al., 2017;MacKeracher et al., 2019;Sequeira et al., 2018). Emphasis in recent years has been placed on amalgamating sources of tracking data in order to optimize tagging outcomes and produce results on a global scale (see Sequeira et al., 2018;Harcourt et al., 2019, andHays et al., 2019). ...
Satellite telemetry as a tool in marine ecological research continues to adapt and grow and has become increasingly popular in recent years to study shark species on a global scale. A review of satellite tag application to shark research was published in 2010, provided insight to the advancements in satellite shark tagging, as well as highlighting areas for improvement. In the years since, satellite technology has continued to advance, creating smaller, longer lasting, and more innovative tags, capable of expanding the field. Here we review satellite shark tagging studies to identify early successes and areas for rethinking moving forward. Triple the amount of shark satellite tagging studies have been conducted during the decade from 2010 to 2020 than ever before, tracking double the number of species previously tagged. Satellite telemetry has offered increased capacity to unravel ecological questions including predator and prey interactions, migration patterns, habitat use, in addition to monitoring species for global assessments. However, <17% of the total reviewed studies directly produced results with management or conservation outcomes. Telemetry studies with defined goals and objectives produced the most relevant findings for shark conservation, most often in tandem with secondary metrics such as fishing overlap or management regimes. To leverage the power of telemetry for the benefit of shark species, it remains imperative to continue improvements to tag function and maximize the outputs of tagging efforts including increasing data sharing capacity and standardization across the field, as well as spatial and species coverage. Ultimately, this review offers a status report of shark satellite tagging and the ways in which the field can continue to progress.
... The spawning of Indian mackerel, Sardine, Threadfin bream, Cephalopods, Tunas, Seerfish, Sciaenids, and other commercial fishes occurs during February to June season (Sekharan 1955;Devaraj 1977;Silas 1985;Mohanraj et al. 2003;Bhendarkar et al. 2013;2018) and have a significant role in the reproduction and enhancement of the fisheries stock. Protecting key spawning or nursery areas of vulnerable species can also be highly effective for stock enhancement (White et al. 2017). Since fishing and other human activity are restricted, this allows depleted populations to recover while protecting key species and vulnerable habitats. ...
The COVID-19 pandemic-induced lockdown has indisputably affected the aquaculture industry across the globe. India imposed a nationwide lockdown to contain the outbreak of COVID-19 that disrupted normalcy and economic activities. The fisheries sector was also highly affected. Hence, a study was conducted from July – December 2020 to understand the stakeholders’ perception of the impact of COVID-19 lockdown, wherein 517 stakeholders participated (online) in the first stage. The policy reforms suggested by the stakeholders were referred to the fisheries experts in the second stage for prioritization towards implementation. Data analysis depicted that a majority (81%) of the stakeholders were aware of COVID-19 lockdown impacts on their businesses. Due to this unprecedented lockdown, labour availability was hampered, transport facilities were fully halted and access to inputs like seed, feed, and advisory were largely affected. Importantly, all stakeholders unanimously adduced to the uncertainty over the future of the fisheries sector. Moreover, fishery experts feel that enabling policies for the promotion of awareness, appropriate training, and transparency in the implementation of schemes, credit facilities, and price regulation can have a massive positive impact. Further, the study also recommends utilizing the potential of e-resources (ICTs and IoT) to digitize the business networking of fishery sector stakeholders.
... Rhodolith beds can also serve as stepping stones for many species. Therefore, the creation of no-take marine protected areas can be used for the preservation of rhodolith beds and as one of the best measures for the maintenance of reef biodiversity and ecosystem services, such as artisanal fisheries [111,112]. However, effective conservation actions must be integrated with other sectors of the blue economy and society, such as the mining industry, universities, and coastal communities, through the development of marine spatial planning (MSP). ...
Marine carbonate sediments have economic value because of their high concentration of calcium minerals and important trace elements. However, increasing mining interest in these stocks is threatening unique ecosystems, such as rhodolith beds, which provide many ecosystem goods and services. We review the potential of the unexplored Brazilian deposits and the rising conflicts with other blue economic sectors and biodiversity hotspots. The tropical Southwestern Atlantic Ocean, particularly the Brazilian Exclusive Economic Zone, has the largest deposit of marine limestone worldwide, which is very attractive to the global industry, with reserves measured at more than 1355,157,240 tons of CaCO3 and it is especially useful as a supply for agriculture and animal nutrition. This large mining potential raises concerns regarding licenses and potential impacts, especially considering the biological and socio-economic importance of extensive rhodolith beds, which may conflict with mining. Additionally, future dredging activities will take place in vulnerable ecosystems without adequate marine spatial planning (MSP). Currently, there is no long-term scientific information on the available carbonate stocks, stock recoverability, risks to connectivity with other ecosystems (e.g., coral reefs), and the reduced provision of ecosystem services which may affect activities such as artisanal fisheries. In this context, encouraging carbonate mining without science-based information and MSP accelerates the unsustainable exploitation of this important ecosystem. This activity will contribute to the degradation of tropical marine biodiversity and threaten the food security of traditional and vulnerable human communities, which is in opposition to the Sustainable Development Goals and reaching the 2030 United Nations Agenda.
... This is most likely considerably too small to achieve elasmobranch conservation goals, especially considering that only 2.8% of the world's oceans are fully protected 25 . Although criticisms exist regarding their effectiveness 38,39 , potential positive effects of large FPAs on elasmobranch species have recently been highlighted 4,40,41 . Most existing FPAs, however, are small, and therefore potentially unable to deliver full conservation benefits for large or mobile elasmobranchs. ...
Elasmobranchs are heavily impacted by fishing. Catch statistics are grossly underestimated due to missing data from various fishery sectors such as smallscale fisheries. Marine Protected Areas are proposed as a tool to protect elasmobranchs and counter their ongoing depletion. We assess elasmobranchs caught in 1,256 fishing operations with fixed nets carried out in partially protected areas within Marine Protected Areas and unprotected areas
beyond Marine Protected Areas borders at 11 locations in 6 Mediterranean
countries. Twenty-four elasmobranch species were recorded, more than onethird belonging to the IUCN threatened categories (Vulnerable, Endangered, or Critically Endangered). Catches per unit of effort of threatened and data deficient species were higher (with more immature individuals being caught) in partially protected areas than in unprotected areas. Our study suggests that despite partially protected areas having the potential to deliver ecological benefits for threatened elasmobranchs, poor small-scale fisheries management inside Marine Protected Areas could hinder them from achieving this important conservation objective.
... www.nature.com/scientificreports/ inadequate size and lack of connectivity with habitats outside of parks 49 as even large protected areas offer only partial refuge for highly mobile predators 50 .Thus, our results reinforce the message that area protection should be accompanied by addressing conditions that enable their success-within and beyond park boundaries 51 . ...
In the face of an accelerating extinction crisis, scientists must draw insights from successful conservation interventions to uncover promising strategies for reversing broader declines. Here, we synthesize cases of recovery from a list of 362 species of large carnivores, ecologically important species that function as terminal consumers in many ecological contexts. Large carnivores represent critical conservation targets that have experienced historical declines as a result of direct exploitation and habitat loss. We examine taxonomic and geographic variation in current extinction risk and recovery indices, identify conservation actions associated with positive outcomes, and reveal anthropogenic threats linked to ongoing declines. We find that fewer than 10% of global large carnivore populations are increasing, and only 12 species (3.3%) have experienced genuine improvement in extinction risk, mostly limited to recoveries among marine mammals. Recovery is associated with species legislation enacted at national and international levels, and with management of direct exploitation. Conversely, ongoing declines are robustly linked to threats that include habitat modification and human conflict. Applying lessons from cases of large carnivore recovery will be crucial for restoring intact ecosystems and maintaining the services they provide to humans.
... tiger sharks). Large MPAs appear to be critical for the effective conservation of reef-associated sharks, especially given that some reef-associated shark species can travel long distances (White et al., 2017;MacNeil et al., 2020). Therefore, despite the protection of NNP Corales del Rosario and San Bernardo from industrial fisheries, the size of the MPAs combined with permitted artisanal fishing (present during this study) is not likely to be adequate for reef shark conservation. ...
Artisanal fisheries are socially and economically important along the Caribbean coast of Colombia. These fisheries remain poorly characterized, making it difficult to estimate their potential impact, especially on non‐targeted catch such as elasmobranchs.
A rapid assessment framework was used to investigate the exploitation, use, and relative abundance of elasmobranchs and predatory teleosts in a region along the Caribbean coast of Colombia. In‐person structured interview surveys ( n = 188) were conducted during the autumn of 2016 at eight fishing towns around Cartagena and the islands of the Natural National Park (NNP) Corales del Rosario and San Bernardo. Baited remote underwater video systems (BRUVS) ( n = 200) deployed at four reefs were used to assess the relative abundance of elasmobranchs and other predatory teleosts.
Fishers reported capturing eight shark and five ray taxa. Although 99% of fishers indicated that they did not target sharks, 83% reported keeping the catches to sell, eat, or both. Similarly, 81% of fishers did not target rays, but 90% reported retaining catches. Most fishers (84%) perceived a decline of sharks in the coastal waters since they started fishing, compared with 41% reporting batoid declines. BRUVS data support the perceptions of elasmobranch declines. Elasmobranch abundances were very low and no difference was detected between protected and unprotected reefs. Results were similar for teleost taxa, but there were higher abundances inside one marine protected area (MPA) that had high enforcement.
Taken together, the data suggest considerable degradation of not only elasmobranch populations but also predatory fish populations of coral reef habitats in a region of the Colombian Caribbean. Furthermore, artisanal fishers continue to exploit coral reef resources inside MPAs unless there is strong enforcement. Enforcement can be difficult with limited resources, and therefore community‐based conservation methods may be more effective. Engagement with the local fishing community may help to reduce existing tensions and improve compliance.
For highly mobile marine species such as pelagic elasmobranchs, the development of effective spatial management requires a comprehensive understanding of movement ecology. Research incorporating movement data across seasons and life stages, including reproductive states, is valuable for informing spatial management, yet is absent for most species. In the Northwest (NW) Atlantic Ocean (hereafter referred to as NW Atlantic), the porbeagle shark Lamna nasus is a pelagic species that is overfished, has a live retention ban (Canada) or landings regulations (United States), and is also commonly captured incidentally as bycatch. Research on the spatiotemporal dynamics of NW Atlantic porbeagle habitat use is limited, with all previous research utilizing pop-off satellite archival tags that are prone to large uncertainty in location estimates. This study used higher-accuracy fin-mount satellite tags to identify patterns in habitat use across life stages and seasons for porbeagle sharks tagged off the northeastern coast of the United States. During the summer and fall, the 95% kernel density estimate (referred to as “activity space”) of tagged porbeagles occurred almost exclusively on the continental shelf in the Gulf of Maine and Georges Bank. Activity space expanded and shifted southwards to include offshore environments during the winter and spring for juveniles, mature non-gravid females, and mature females of unknown reproductive states, while the activity space of mature males and gravid females remained in shelf waters year-round. This finding differs from the previous assumption that southward migrations are linked to reproduction for NW Atlantic porbeagles. Tagged porbeagles were also found to have a relatively small 50% kernel density estimate (referred to as “high occupancy area”) located around Cape Cod, Massachusetts that was well-conserved across life stages and seasons. This relatively static, small high occupancy area has implications for the population’s conservation given the high amount of fishing activity (rod-and-reel, trawl, gillnet) occurring within this region. Given the overlap between porbeagle high occupancy area and fishing activity, as well as the relatively high recapture rate of tagged sharks (10.5%), the coastal waters around Cape Cod, Massachusetts should be considered for spatial management of the NW Atlantic porbeagle.
We present national implementation progress on international and regional legal obligations up to 2020 and discuss recent developments in shark conservation management in the region. This study provides insights into the complexity of implemented measures and actions related to shark conservation and fisheries management, governed by various legal instruments. Measures were primarily identified through regional fisheries management organisations (RFMO) reports, reports of Focal Point meetings under the Barcelona Convention, and national reports under the Convention on Biological Diversity (CBD) and the Convention on Migratory Species (CMS). A total of 208 implemented measures across different categories were found. The most common types of measures focused on monitoring, the regulation of human activities, and assessments of impacts on sharks. EU countries generally implemented more measures compared to non-EU countries, even after accounting for contributions by non-governmental organisations (NGOs). Spain was leading in terms of number of actions related to shark governance. However, when considering standardization based on Gross Domestic Product (GDP), Egypt, Morocco, and Algeria had the highest values, putting results into perspective, as countries widely share legal commitments, but do not have the same development status, capacities, and resources. Higher implementation efforts were associated with higher Human Development Index and higher government indicators. Governments were found to lead 63 % of measures, particularly related to legal obligations, while NGOs and researchers also made significant contributions, as identified through survey questionnaires. The responses also highlighted that overfishing, illegal fishing, an increasing marketing of shark meat, and mislabelling remain issues at national level.
Marine Protected Areas (MPAs) have been considered one of the most effective conservation management
strategies worldwide. Despite its relevance, anthropogenic disturbances continue to cast doubt on its importance.
Here we explored the effects of the protection of no-take zones on the fish community in a recent Brazilian Hope
Spot. Threatened and fishery-target species distributions and ecological descriptors were assessed by underwater
visual censuses and submersible rotating videos from 2020 to 2022. There were significant differences between
areas (Protected, Rasa is., and Far) where fish median richness was higher in both sampling techniques and
higher median densities through submersible rotating videos within MPA limits compared to non-protected
areas. Besides that, Cagarras Islands Natural Monument sheltered about 84.7% (n = 17) of the total threat
ened species recorded in the study area, according to the International Union for Conservation of Nature clas
sification. Our results integrated with stakeholders’ knowledge may provide a powerful message to decision-
makers about the importance of protected areas for marine conservation. In this context, it is fundamental to
consider Hope Spots as an opportunity to change unsustainable human practices and enhance the conservation of
the marine life worldwide.
Understanding residency patterns and space use of a species is key to the implementation of effective conservation and management practices. The characterization of movement patterns of species within an ecosystem can provide insight into why animals use particular habitats, such as for feeding or reproduction, and how movements are influenced by various biotic and abiotic factors. Furthermore, by describing the fine scale movements of a species within an ecosystem, patterns of habitat use, movement corridors, and focal areas can be identified, at both the population and individual level. These types of studies have historically been limited in polar ecosystems compared to lower latitude ecosystems, due to the logistical challenges of working in polar regions. In this study, we used a large acoustic telemetry array consisting of 83 receivers to study patterns of movement and residency of Arctic Skates (Amblyraja hyperborea) in Scott Inlet, Canada, a location of particular interest for the Canadian Government due to the impacts of climate change affecting the Arctic as well as its significance to the development of the community fishery for Greenland Halibut. (Reinhardtius hippoglossoides). Over the six years of this long-term acoustic telemetry study, we found that arctic skates exhibit variability in the residential behavior between males and females with females being detected at more consistent rates throughout the annual cycle while males exhibit increased detection rates between the months of April and November. Arctic Skates generally remained within or in
x
the vicinity of Scott Inlet, exhibiting limited large scale movements away from the area, and showed strong site fidelity towards a secondary channel that runs perpendicular to the main Scott Inlet channel. This secondary channel also represented a key core activity area of the inlet for a majority of the skates. Due to the limited movement range and small activity space exhibited by the Arctic Skates, this population, and the species more broadly, may be at an increased risk for localized anthropogenic disturbances.
Context
Data on chondrichthyan (sharks, rays, and chimaeras) populations is largely lacking for many countries and territories in the Indo-Pacific.
Aims
This study aims to provide a desktop review and information synthesis of the biodiversity, threats, and conservation of chondrichthyans in the Samoan archipelago (Samoa and American Samoa), focusing on their interactions with fisheries and exploring their social, cultural, and economic values.
Methods
This study uses various literature sources, citizen science, and in-country engagement to assemble a review of current available information on chondrichthyans.
Key results
A total of 67 chondrichthyans were documented to be present or potentially present in Samoa and American Samoa, consisting of 23 ray species and 44 shark species. Thirty-six of these species were listed in Threatened categories on the International Union for the Conservation of Nature Red List of Threatened Species. A biological productivity analysis conducted for species with sufficient information indicated that the silvertip shark (Carcharhinus albimarginatus), silky shark (Carcharhinus falciformis), bull shark (Carcharhinus leucas), oceanic whitetip (Carcharhinus longimanus), and whitetip reef shark (Triaenodon obesus) had the highest relative productivities.
Conclusions
Both Samoa and American Samoa have relatively diverse shark and ray communities with management plans in place to protect chondrichthyans. These include participation in Western and Central Pacific Fisheries Commission initiatives, spatial protections, and community-based management programs.
Implications
Current management approaches have the potential to provide significant protection to sharks and rays, however, their effectiveness may be hindered by a lack of proper enforcement, or compliance at the national and community levels.
In Ghana, students have rarely been engaged in shark conservation programs. The study aimed to provide the perceptions and mis- conceptions about sharks among students in Ghana. From the Western region of Ghana, two senior high schools were visited from March to June 2023, and 111 questionnaires were administered to them with the assistance of a resident teacher. Most of these students believe that i) sharks do not eat humankind as food, ii) fishing activities do not affect shark behavior, iii) the decline in fish does not affect the shark population, and iv) fishermen in Ghana face a lot of shark attacks. On perceptions, most of the students perceived that i) shark fishing should not be stopped, ii) shark ecotourism will yield more money than shark fishing, and iii) MPAs will conserve shark population in Ghana. From the study, it was evident that knowledge and attitudes showed a strong positive correlation (r = 0.61). Therefore, incorporating shark related topics into the curricula of schools, taking students on educational tours to the fishing communities, and engaging them in outreach programs will enlighten their knowledge of sharks and foster their awareness of shark conservation and shark ecotourism in Ghana.
1- Elasmobranchs, encompassing an array of sharks and rays, confront a threat of extinction on a global scale. The Sea of Marmara (SoM) stands out as a critical refuge for these endangered species.
2- This study harnesses data derived from comprehensive trawl surveys, representing the first area-based evaluation of the elasmobranchs inhabiting the SoM. Sampling protocols were carried out at 10 separate stations along the 980-km coastline of the SoM, each bounded by different ecological characteristics and anthropogenic influences.
3- A total of eight shark species and six ray species were caught in the towed area of the entire the SoM. Notably, Scyliorhinus canicula and near-threatened Raja clavata constitute more than 50% of the total abundance. Additionally, rare, and critically endangered species, including the Oxynotus centrina, Squatina squatina, Dipturus batis, and Myliobatis aquila, were documented, expanding our knowledge of their presence in the region.
4- Spatial distribution heterogeneity was pronounced within species.
5- Size distributions were species-specific, and the presence of both juvenile and adult individuals suggested successful reproduction and growth.
6- Records expand the known size range in the SoM for six shark and three ray species. It also provides first-size information based on the total length of the S. stellaris and D. batis.
7- Additionally, the urgent need for field-based conservation efforts is highlighted, citing a previously unidentified important sensitive areas located in the southern part of the SoM.
随着全球变暖的加剧和人类在海洋领域活动的增多,珊瑚礁生态系统的生态状况越来越严峻。珊瑚礁白化,鱼类数量减少,濒危海洋物种数量增多等问题愈发突出。这些生态问题对全球生态稳定和人类社会的可持续发展造成了难以忽视的影响。因此,珊瑚礁生态系统的生态保护策略研究逐渐成为一个重要的研究领域。为了实现更为合理和高效的珊瑚礁生态系统修复,基于计算机图模型构建技术的资源分配方法成为珊瑚礁生态系统保护策略的重要研究方面。资源分配是指通过模拟计算实现在合理的位置新增合理规模的人工礁等人工自然资源的过程。计算机图模型构建的主要目的是,实现传统方法难以做到的全球范围生态系统建模和模拟工作。然而,目前的生态系统资源分配策略方法面临几个主要的挑战:1.在大数据背景下,种群间的依赖关系确定困难且相关数据采集难度大,因此相关领域建模效率较低;2.种群竞争压力和负载压力难以量化,导致难以对生态修复策略提供量化计算支持;3.资源分配过程难以量化,对新增资源的资源量和地理位置难以准确计算。本研究针对以上几个问题,在计算机图模型构建技术的基础之上提出了竞争图构建方法,实现了种群竞争压力和负载压力量化以及资源分配,达到了优化生态系统修复工作流程,提高生态系统修复效率,并减少生态系统修复人员的工作量的效果。资源分配算法的主要目标是,在尽可能少的增加人工礁等人工生态资源的情况下,尽可能降低生态系统中所有种群的平均竞争压力和平均负载压力。本研究以珊瑚礁生态系统内部种群为研究对象,基于计算机图模型构建技术,研究了珊瑚礁生态系统的多对象资源分配问题,主要完成了以下工作:(1)针对全球珊瑚礁生态系统的大规模种群间依赖关系确定困难,大规模种群量化建模低效的问题,本研究提出了基于地理学第一定律的竞争图模型构建方法,并提出了模型构建算法。本研究实现了大规模种群的快速建模并确定了种群间的依赖关系,为进一步实现大规模种群竞争和负载压力量化以及精准的资源分配优化过程奠定了坚实基础;(2)针对大规模种群的竞争和负载压力量化困难问题,本研究提出了竞争图上的竞争值和负载值定义并分别提出了不同的查询方法。本研究基于图局部敏感哈希方法实现了大规模种群的竞争压力量化,并实现了负载压力量化。实验结果表明了查询方法在大数据背景下的可行性和高效性,为实现量化的多对象资源分配策略提供了支持;(3)针对可量化的资源分配策略制定困难问题,本研究基于竞争压力和负载压力量化提出了多对象资源分配方法,实现了在尽可能少的增加人工生态资源的情况下,实现尽可能好的生态系统修复效果的目标。同时,本研究方法可以计算出较为精确的新增资源位置,以及新增资源的规模。实验结果说明了多对象资源分配算法的鲁棒性和高效性;
Acoustic telemetry (AT) has become ubiquitous in aquatic monitoring and fish biology, conservation and management. Since the early use of active ultrasonic tracking that required researchers to follow at a distance their species of interest, the field has diversified considerably with exciting advances in both hydrophone and transmitter technology. Once a highly specialised methodology however, AT is fast becoming a generalist tool for those wishing to study or conserve fishes, leading to diversifying application by non‐specialists. With this transition in mind, we evaluate exactly what AT has become useful for, discussing how the technological and analytical advances around AT can address important questions within fish biology. In doing so, we highlight the key ecological and applied research areas where AT continues to reveal crucial new insights, and in particular, when combined with complimentary research approaches. We provide a comprehensive breakdown of the state of the art for applications of AT, discussing the ongoing challenges, where its strengths lie, and how future developments may revolutionise fisheries management, behavioural ecology and species protection. Through selected papers we illustrate specific applications across the broad spectrum of fish biology. By bringing together the recent and future developments in this field under categories designed to broadly capture many aspects of fish biology, we hope to offer a useful guide for the non‐specialist practitioner as they attempt to navigate the dizzying array of considerations and ongoing developments within this diverse toolkit.
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Understanding how environmental drivers influence shark and ray spatial and temporal patterns can provide crucial knowledge for their evidence-based protection and long-term monitoring. However, information on which drivers of variation are most important for elasmobranch communities on soft sediments is limited. Using baited remote underwater stereo-video systems (stereo-BRUVs), we investigated how seasonal and environmental variables affected the elasmobranchs of the iSimangaliso Wetland Park marine protected area (MPA) in South Africa (SA). In total, 11 species were identified from 48 sites between 12 m and 33 m water depth in a sandy habitat. While species richness was similar across seasons, the total abundance of elasmobranchs recorded was higher in winter than summer. The species assemblage composition varied significantly between seasons, with the Human’s whaler shark Carcharhinus humani prevalent in summer and the Critically Endangered whitespotted wedgefish Rhynchobatus djiddensis more abundant during winter. Most species were sighted throughout the entire depth range, but rays were more common in shallower waters (< 25 m depth), while C. humani and R. djiddensis were more common in the deeper depth zone of this study. This research provides baseline information about this previously unexplored sandy habitat for elasmobranchs in a site of regional and global significance. Records of species of conservation concern in the sampling area highlight the importance of protecting sand environments within an MPA.
Common marine spatial planning challenges include lack of data on the marine environment, high mobility of both animals and humans, and plan implementation challenges including lack enforcement and compliance with regulations along with monitoring deficiencies. These can be potentially addressed using geospatial technologies (GTs) such as remote sensing, GPS and GIS. This research presents geospatial tools that are available for the process of developing, implementing, and monitoring marine spatial plans. Tools include satellites and water-based platforms carrying various sensors and receivers for environmental ocean data, vessel tracking and animal telemetry via multispectral, acoustic, radar, and other means. Planners and ocean managers might not always be aware of technological solutions available for the development and implementation of marine spatial plans. Here, urgent planning needs, summarized from various publications, are linked to GTs solutions published in relevant literature between the years 2015–2020. The GTs were used for data collection, dynamic human activities’ management, environmental monitoring and enforcement, all as required by marine spatial plans. This paper concludes with insights into GT solutions that can enhance the process of evidence-based management and spatial planning in marine environments.
Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here we investigated the evolutionary history of the endangered grey reef shark ( Carcharhinus amblyrhynchos ) across its range by sequencing thousands of RAD-seq loci in 173 individuals in the Indo-Pacific (IP) . We first bring evidence of the occurrence of a range expansion (RE) originating close to the Indo-Australian Archipelago (IAA) where two stepping-stone waves (east and westward) colonized almost the entire IP. Coalescent modeling additionally highlighted a homogenous connectivity ( Nm ~10 per generation) throughout the range, and an isolation by distance model suggested the absence of barriers to dispersal despite the affinity of C. amblyrhynchos to coral reefs. This coincides with long-distance swims previously recorded, suggesting that the strong genetic structure at the IP scale (FST ~ 0.56 between its ends) is the consequence of its broad current distribution and organization in a large number of demes. Our results strongly suggest that management plans for the grey reef shark should be designed on a range-wide rather than a local scale due to its continuous genetic structure. We further contrasted these results with those obtained previously for the sympatric but strictly lagoon-associated Carcharhinus melanopterus , known for its restricted dispersal ability. C. melanopterus exhibits similar RE dynamic, but is characterized by stronger genetic structure and a non-homogeneous connectivity largely dependent on local coral reefs availability. This sheds new light on shark evolution, emphasizing the roles of IAA as source of biodiversity and of life history traits in shaping the extent of genetic structure and diversity.
Ecosystem services are important to people and nature. Our world survives on these ecosystem services, and it is extremely important in watersheds. Businesses can incorporate ecosystem services into their properties.
The rapid expansion of human activities threatens ocean-wide biodiversity. Numerous marine animal populations have declined, yet it remains unclear whether these trends are symptomatic of a chronic accumulation of global marine extinction risk. We present the first systematic analysis of threat for a globally distributed lineage of 1,041 chondrichthyan fishes-sharks, rays, and chimaeras. We estimate that one-quarter are threatened according to IUCN Red List criteria due to overfishing (targeted and incidental). Large-bodied, shallow-water species are at greatest risk and five out of the seven most threatened families are rays. Overall chondrichthyan extinction risk is substantially higher than for most other vertebrates, and only one-third of species are considered safe. Population depletion has occurred throughout the world's ice-free waters, but is particularly prevalent in the Indo-Pacific Biodiversity Triangle and Mediterranean Sea. Improved management of fisheries and trade is urgently needed to avoid extinctions and promote population recovery.
Significance
Shark populations are declining worldwide because of overexploitation by fisheries with unknown consequences for ecosystems. Although the harvest of oceanic sharks remains largely unregulated, knowing precisely where they interact with fishing vessels will better aid their conservation. We satellite track six species of shark and two entire longline fishing vessel fleets across the North Atlantic over multiple years. Sharks actively select and aggregate in space-use “hotspots” characterized by thermal fronts and high productivity. However, longline fishing vessels also target these habitats and efficiently track shark movements seasonally, leading to an 80% spatial overlap. Areas of highest overlap between sharks and fishing vessels show persistence between years, suggesting current hotspots are at risk, and arguing for introduction of international catch limits.
Understanding the efficacy of marine protected areas (MPAs) for wide-ranging predators is essential to designing effective management and conservation approaches. The use of acoustic monitoring and network analysis can improve our understanding of the spatial ecology and functional connectivity of reef-associated species, providing a useful approach for reef-based conservation planning. This study compared and contrasted the movement and connectivity of sharks with different degrees of reef association. We examined the residency, dispersal, degree of reef connectivity, and MPA use of grey reef (Carcharhinus amblyrhynchos), silvertip (C. albimarginatus), and bull (C. leucas) sharks monitored in the central Great Barrier Reef (GBR). An array of 56 acoustic receivers was used to monitor shark movements on 17 semi-isolated reefs. Carcharhinus amblyrhynchos and C. albimarginatus were detected most days at or near their tagging reef. However, while C. amblyrhynchos spent 80% of monitoring days in the array, C. albimarginatus was only detected 50% of the time. Despite both species moving similar distances (,50 km), a large portion of the population of C. albimarginatus (71%) was detected on multiple reefs and moved more frequently between reefs and management zones than C. amblyrhynchos. Carcharhinus leucas was detected less than 20% of the time within the tagging array, and 42% of the population undertook long-range migrations to other arrays in the GBR. Networks derived for C. leucas were larger and more complex than those for C. amblyrhynchos and C. albimarginatus. Our findings suggest that protecting specific reefs based on prior knowledge (e.g., healthier reefs with high fish biomass) and increasing the level of protection to include nearby, closely spaced reef habitats (,20 km) may perform better for species like C. albimarginatus than having either a single or a network of isolated MPAs. This design would also provide protection for larger male C. amblyrhynchos, which tend to disperse more and use larger areas than females. For wide-ranging sharks like C. leucas, a combination of spatial planning and other alternative measures is critical. Our findings demonstrate that acoustic monitoring can serve as a useful platform for designing more effective MPA networks for reef predators displaying a range of movement patterns.
Mature science reveals opportunities for policy progress.
Most spatial marine management techniques (e.g., marine protected areas) draw stationary boundaries around often mobile marine features, animals, or resource users. While these approaches can work for relatively stationary marine resources, to be most effective marine management must be as fluid in space and time as the resources and users we aim to manage. Instead, a shift towards dynamic ocean management is suggested, defined as management that rapidly changes in space and time in response to changes in the ocean and its users through the integration of near real-time biological, oceanographic, social and/or economic data. Dynamic management can refine the temporal and spatial scale of managed areas, thereby better balancing ecological and economic objectives. Temperature dependent habitat of a hypothetical mobile marine species was simulated to show the efficiency of dynamic management, finding that 82.0 to 34.2 percent less area needed to be managed using a dynamic approach. Dynamic management further complements existing management by increasing the speed at which decisions are implemented using predefined protocols. With advances in data collection and sharing, particularly in remote sensing, animal tracking, and mobile technology, managers are poised to apply dynamic management across numerous marine sectors. Existing examples demonstrate that dynamic management can successfully allow managers to respond rapidly to changes on-the-water, however to implement dynamic ocean management widely, several gaps must be filled. These include enhancing legal instruments, incorporating ecological and socioeconomic considerations simultaneously, developing 'out-of-the-box' platforms to serve dynamic management data to users, and developing applications broadly across additional marine resource sectors.
Most spatial marine management techniques (e.g., marine protected areas) draw stationary boundaries around often mobile marine features, animals, or resource users. While these approaches can work for relatively stationary marine resources, to be most effective marine management must be as fluid in space and time as the resources and users we aim to manage. Instead, a shift towards dynamic ocean management is suggested, defined as management that rapidly changes in space and time in response to changes in the ocean and its users through the integration of near real-time biological, oceanographic, social and/or economic data. Dynamic management can refine the temporal and spatial scale of managed areas, thereby better balancing ecological and economic objectives. Temperature dependent habitat of a hypothetical mobile marine species was simulated to show the efficiency of dynamic management, finding that 82.0 to 34.2 percent less area needed to be managed using a dynamic approach. Dynamic management further complements existing management by increasing the speed at which decisions are implemented using predefined protocols. With advances in data collection and sharing, particularly in remote sensing, animal tracking, and mobile technology, managers are poised to apply dynamic management across numerous marine sectors. Existing examples demonstrate that dynamic management can successfully allow managers to respond rapidly to changes on-the-water, however to implement dynamic ocean management widely, several gaps must be filled. These include enhancing legal instruments, incorporating ecological and socioeconomic considerations simultaneously, developing 'out-of-the-box' platforms to serve dynamic management data to users, and developing applications broadly across additional marine resource sectors.
Marine defaunation, or human-caused animal loss in the oceans, emerged forcefully only hundreds of years ago, whereas terrestrial defaunation has been occurring far longer. Though humans have caused few global marine extinctions, we have profoundly affected marine wildlife, altering the functioning and provisioning of services in every ocean. Current ocean trends, coupled with terrestrial defaunation lessons, suggest that marine defaunation rates will rapidly intensify as human use of the oceans industrializes. Though protected areas are a powerful tool to harness ocean productivity, especially when designed with future climate in mind, additional management strategies will be required. Overall, habitat degradation is likely to intensify as a major driver of marine wildlife loss. Proactive intervention can avert a marine defaunation disaster of the magnitude observed on land.
Copyright © 2015, American Association for the Advancement of Science.
The degree of reef isolation is thought to limit the frequency of long-range dispersals in reef-associated sharks. Therefore, understanding how the behaviour and spatial ecology of a species differ across reef habitats is essential for developing sound conservation approaches. The present study examined the residency, movement and activity space of grey reef sharks (Carcharhinus amblyrhynchos) in the central Great Barrier Reef (GBR). An array of 56 acoustic receivers covering 17 semi-isolated coral reefs across 150 km was used to monitor shark movements. Forty C. amblyrhynchos were tagged with acoustic transmitters and monitored from 251-821 d. Most sharks were detected on a single reef; however, some individuals (4 females; 10 males) moved to up to five reefs. Residency index ranged from 0.02-1.0, with a mean ± SD of 0.78 ± 0.26. Mixed effect models showed that weekly and monthly residency was mainly influenced by shark size, with little or no effect of environmental parameters. Although C. amblyrhynchos were present year-round, juvenile sharks had lower residency to their tagging reef than adults. In addition, mature females were detected less between November and mid-February, which coincides with reported parturition in the central GBR. Long-term monitoring data revealed that C. amblyrhynchos exhibited high residency to their tagging reef, and therefore even in systems with semi-isolated reefs such as the GBR this species may benefit from spatial management approaches at the reef level. However, behavioural differences between sexes and life-stages of C. amblyrhynchos reported in this study suggest marine reserves may provide lower protection relative to remote and isolated coral reefs.
Spiny dogfish (Squalus acanthias) are assumed to be a highly migratory species, making habitual north-south migrations throughout their northwestern Atlantic United States (U.S.) range. Also assumed to be a benthic species, spiny dogfish stock structure is estimated through Northeast Fisheries Science Center (NEFSC) bottom-trawl surveys. Recent anomalies in population trends, including a recent four-fold increase in estimated spawning stock biomass, suggest alternative movement patterns could exist for this shark species. To obtain a better understanding of the horizontal and vertical movement dynamics of this species, Microwave Telemetry pop-up satellite archival X-Tags were attached to forty adult spiny dogfish at the northern (Gulf of Maine) and southern (North Carolina) extents of their core U.S. geographic range. Reconstructed geolocation tracks ranging in lengths from two to 12 months suggest that the seasonal migration patterns appear to be local in nature to each respective northern and southern deployment site, differing from previously published migration paradigms. Differences in distance and direction traveled between seasonal geolocations possibly indicate separate migratory patterns between groups. Kernel utilization distribution models also suggest strong separate core home ranges. Significant differences in seasonal temperature and depths between the two regions further substantiate the possibility of separate regional movement patterns between the two groups. Vertical utilization also suggests distinct diel patterns and that this species may not utilize the benthos as previously thought, potentially decreasing availability to benthic gear.
In 2012 we conducted an integrated ecological assessment of the marine environment of the Pitcairn Islands, which are four of the most remote islands in the world. The islands and atolls (Ducie, Henderson, Oeno, and Pitcairn) are situated in the central South Pacific, halfway between New Zealand and South America. We surveyed algae, corals, mobile invertebrates, and fishes at 97 sites between 5 and 30 m depth, and found 51 new records for algae, 23 for corals, and 15 for fishes. The structure of the ecological communities was correlated with age, isolation, and geomorphology of the four islands. Coral and algal assemblages were significantly different among islands with Ducie having the highest coral cover (56%) and Pitcairn dominated by erect macroalgae (42%). Fish biomass was dominated by top predators at Ducie (62% of total fish biomass) and at Henderson (35%). Herbivorous fishes dominated at Pitcairn, while Oeno showed a balanced fish trophic structure. We found high levels of regional endemism in the fish assemblages across the islands (45%), with the highest level observed at Ducie (56% by number). We conducted the first surveys of the deep habitats around the Pitcairn Islands using drop-cameras at 21 sites from depths of 78 to 1,585 m. We observed 57 fish species from the drop-cams, including rare species such as the false catshark (Pseudotriakis microdon) and several new undescribed species. In addition, we made observations of typically shallow reef sharks and other reef fishes at depths down to 300 m. Our findings highlight the uniqueness and high biodiversity value of the Pitcairn Islands as one of the least impacted in the Pacific, and suggest the need for immediate protection.
Covering more than half the planet, the deep ocean sequesters atmospheric CO2 and recycles major nutrients; is predicted to hold millions of yet-to-be-described species; and stores mind-boggling quantities of untapped energy resources, precious metals, and minerals (1). It is an immense, remote biome, critical to the health of the planet and human well-being. The deep ocean (defined here as below a typical continental shelf break, >200 m) faces mounting challenges as technological advances—including robotics, imaging, and structural engineering—greatly improve access. We recommend a move from a frontier mentality of exploitation and single-sector management to a precautionary system that balances use of living marine resources, energy, and minerals from the deep ocean with maintenance of a productive and healthy marine environment, while improving knowledge and collaboration.
Humpback whales (Megaptera novaeangliae) are managed by the International Whaling Commission as 7 primary populations that breed in the tropics and migrate to 6 feeding areas around the Antarctic. There is little information on individual movements within breeding areas or migratory connections to feeding grounds. We sought to better understand humpback whale habitat use and movements at breeding areas off West Africa, and during the annual migration to Antarctic feeding areas. We also assessed potential overlap between whale habitat and anthropogenic activities. We used Argos satellite-monitored radio tags to collect data on 13 animals off Gabon, a primary humpback whale breeding area. We quantified habitat use for 3 cohorts of whales and used a state-space model to determine transitions in the movement behavior of individuals. We developed a spatial metric of overlap between whale habitat and models of cumulative human activities, including oil platforms, toxicants, and shipping. We detected strong heterogeneity in movement behavior over time that is consistent with previous genetic evidence of multiple populations in the region. Breeding areas for humpback whales in the eastern Atlantic were extensive and extended north of Gabon late in the breeding season. We also observed, for the first time, direct migration between West Africa and sub-Antarctic feeding areas. Potential overlap of whale habitat with human activities was the highest in exclusive economic zones close to shore, particularly in areas used by both individual whales and the hydrocarbon industry. Whales potentially overlapped with different activities during each stage of their migration, which makes it difficult to implement mitigation measures over their entire range. Our results and existing population-level data may inform delimitation of populations and actions to mitigate potential threats to whales as part of local, regional, and international management of highly migratory marine species.
Population connectivity and spatial distribution are fundamentally related to ecology, evolution and behaviour. Here, we combined powerful genetic analysis with simulations of particle dispersal in a high-resolution ocean circulation model to investigate the distribution of green turtles foraging at the remote Palmyra Atoll National Wildlife Refuge, central Pacific. We analysed mitochondrial sequences from turtles (n = 349) collected there over 5 years (2008-2012). Genetic analysis assigned natal origins almost exclusively (approx. 97%) to the West Central and South Central Pacific combined Regional Management Units. Further, our modelling results indicated that turtles could potentially drift from rookeries to Palmyra Atoll via surface currents along a near-Equatorial swathe traversing the Pacific. Comparing findings from genetics and modelling highlighted the complex impacts of ocean currents and behaviour on natal origins. Although the Palmyra feeding ground was highly differentiated genetically from others in the Indo-Pacific, there was no significant differentiation among years, sexes or stage-classes at the Refuge. Understanding the distribution of this foraging population advances knowledge of green turtles and contributes to effective conservation planning for this threatened species.
Our study quantified the nutrients and energy introduced into the nesting beach at Melbourne Beach, Florida, from distant foraging grounds by loggerhead sea turtles, Caretta caretta. The fate of eggs deposited into 97 nests was determined by monitoring nests throughout incubation. The organic matter, energy, lipid, nitrogen, and phosphorus content of fresh eggs, eggs at successive stages of development, hatchlings, and hatching remains were determined. From these analyses, we estimated the flow of energy and nutrients introduced into the 14 305 nests (~1.6 x 106 eggs) deposited in a 21-km stretch of Melbourne Beach in 1996. We quantified the amount of energy and nutrients incorporated into each of four pathways: ingested by nest predators; consumed by detritivores, decomposers, and plants; lost as metabolic heat or gases during embryological development and hatching; or returned to the ocean as hatchlings. Each nest introduced a mean of 688 g of organic matter, 18 724 kJ of energy, 151 g of lipids, 72 g of nitrogen, and 6.5 g of phosphorus into the beach. Twenty-five percent of the organic matter, 27% of the energy, 34% of the lipids, 29% of the nitrogen, and 39% of the phosphorus introduced into the nests returned to the ocean as hatchlings. Quantities of energy and nutrients transported by the turtles are comparable to quantities moved by other important biological transporters. Human activities have substantially altered the quantity of energy and nutrients transported, and the distribution of those nutrients on the beach. By introducing nutrients into beach ecosystems, sea turtles may help maintain stable dune systems that are critical to their reproductive success.
The benefits of implementing no-take Marine Protected Areas (MPAs) for the conservation of highly mi-gratory species are not easy to assess. They depend on several factors, such as the fish mobility, fisher behaviour and the area covered by the MPA with respect to the distribution area of the species to protect. In this study, we explore the simultaneous effects of MPAs and fishing scenarios on skipjack tuna population dynamics, using the spatially-explicit APECOSM-E model. The model represents the size-structured population dynamics of skipjack tuna in the Indian Ocean and their dependence on climatic variability and exploitation by fisheries. Numerical experiments were run from the beginning of industrial fisheries in the early 1980s to the year 2030, considering different scenarios for the future development of fisheries. These scenarios combined different trends in fishing effort and technological development, either assuming a continuous increase following historical trends or a stabilization of these factors at present values. The simulations were designed to explore the effects of two MPAs of different size and location: the recently estab-lished Chagos MPA, and a hypothetical MPA covering a large part of the Western Indian Ocean, where most of the skipjack catches are presently made. We modelled the redistribution of fishing effort around the MPAs assuming that the fishers had partial knowledge of the spatial distribution of the skipjack population. The effects of the two MPAs on the population dynamics, catch and fishing mortality are shown. Our results revealed a very minor effect of the Chagos MPA on the skipjack tuna population, while the Western Indian Ocean MPA had an important impact on the fishing mortality and succeeded in stabilizing the spawning population. The simulations also showed that the effect of an MPA depends on the evolution of fisheries and it is therefore important to explore different fishery scenarios to assess the future benefits of an MPA.
Marine species conservation died prematurely early in the new millennium before it had a chance to grow and flourish. The revolution happened; the world turned and moved on to managing higher-order ecological processes and services. The revolutionary conservation and research agenda of the new millennium has at least four interrelated themes: super-sized marine protected areas (MPAs; Wood et al., 2008; Pala, 2013), the ecosystem approach to fisheries management (ICES, 2005), ecosystem services and the economic valuation of nature and the poverty alleviation paradigm (Millennium Ecosystem Assessment, 2005; Sachs et al., 2009; Roe, 2013), plus the outlying game-changer of climate change (Hoegh-Guldberg and Bruno, 2010). These themes all involve higher-level aggregate attributes and values of biodiversity. Here, I pick one issue, MPAs, as a synecdoche – the part that may reflect the whole – of how conserving aggregate ecological attributes may dilute effective conservation. Traditionally, marine conservation has followed the terrestrial template of population-and species-specific interventions by local government, in many cases prompted by the efforts of non-governmental organizations. Those species closest to extinction have been painstakingly nursed back to viability one newborn at a time in zoo-based captive breeding programmes, before being reintroduced into the wild, often into newly restored or protected habitats (Redford et al., 2011). Governments also employ species protection legislation to minimize threats through enforced spatial protection of critical habitat, usually by protected areas and parks. On land, conservation has become increasingly strategic, especially with the advent of the mega-environmental non-governmental organizations (eNGOs, such as World Wildlife Fund, The Nature Conservancy, and Conservation International). An increasingly global-scale strategic approach to terrestrial conservation has been facilitated by in-house teams of conservation biologists who designed the most effective conservation outcomes, nationally and internationally. This creative environment led to one of the most iconoclastic papers in conservation biology – 'Biodiversity hotspots for conservation priorities' (Myers et al., 2000) – in which, the authors revealed the 25 terrestrial hotspots of exceptional
Large marine vertebrates are particularly susceptible to anthropogenic threats because they tend to be long-lived, late to mature and wide-ranging. Loggerhead sea turtles (Caretta caretta) are characterised by such life history traits and are listed as ‘Endangered’ by The World Conservation Union. Although juvenile movements and at-sea behaviour of adult females are relatively well studied, little is known about the movements of males and their subsequent exposure to threats. Shark Bay, Western Australia, is home to the largest breeding population of loggerhead turtles in Australia. We assessed the large-scale movements of nine adult male loggerhead turtles, with the goal of aiding conservation and management policies. During 7 months outside the breeding season, all nine turtles stayed within the Shark Bay World Heritage Area, with most showing fidelity to small coastal foraging areas. Several turtles, however, showed relatively large movements between core foraging areas. None of the four turtles that continued transmitting through the breeding season exhibited obvious movements towards nesting beaches, suggesting that mating may occur on foraging grounds or that males are not mating every year. Quantifying male loggerhead movements assists conservation planning by identifying biologically relevant spatial scales at which research and management strategies should be designed.
This study examines life history patterns and correlations between traits related to body size, reproduction, age, and growth in sharks, using data from 230 populations representing 164 species, 19 families, and 7 orders. The analysis focused on interspecific life history variability, but intraspecific and intrapopulation variation were also considered. Interspecifically, body size correlated positively with litter size and offspring size, and a tradeoff between litter size and offspring size was found after factoring out the effects of body size. Offspring size correlated negatively with growth completion rate (K), but the correlation became positive after correcting for the effects of body size. Parental size for males and females was negatively correlated with K. Parental size and size at maturity exhibited a strong positive correlation, with sexual maturity occurring at about 75% of maximum size in both sexes. Males were 10% smaller than females and reached their maximum length 34% faster than females on average. Females tend to mature later and live longer than males, but age at maturity is reached at about 50% of maximum age in both sexes. Maximum size and empirical longevity were not significantly correlated in females, but were positively correlated in males. Size and age at maturity also exhibited a moderate positive correlation in males, especially after excluding data for Squalus acanthias. Principal component and cluster analyses were used to reflect similarities among life history traits of 40 populations from 34 species, and at least three separate life history strategies were identified.
Large predators are often highly mobile and can traverse and use multiple habitats. We know surprisingly little about how predator mobility determines important processes of ecosystem connectivity. Here we used a variety of data sources drawn from Palmyra Atoll, a remote tropical marine ecosystem where large predators remain in high abundance, to investigate how these animals foster connectivity. Our results indicate that three of Palmyra's most abundant large predators (e.g., two reef sharks and one snapper) use resources from different habitats creating important linkages across ecosystems. Observations of cross-system foraging such as this have important implications for the understanding of ecosystem functioning, the management of large-predator populations, and the design of conservation measures intended to protect whole ecosystems. In the face of widespread declines of large, mobile predators, it is important that resource managers, policy makers, and ecologists work to understand how these predators create connectivity and to determine the impact that their depletions may be having on the integrity of these linkages.
Over 50% of the total bigeye tuna (BET) landed in the Western Central Pacific Ocean is caught incidentally in the purse seine fishery and sold for canning at prices less than US10/kg. The combined fishing mortality by all gears will soon reduce the BET biomass in the Pacific Ocean to less than that capable of producing maximum sustainable yield. Closure of the high-seas enclaves in 2009 was hailed as a conservation measure, but was not scientifically evaluated before implementation and appears to have had no beneficial effect on the BET stock. A spatially explicit age-structured ecosystem model, SEAPODYM, is used to simulate alternative area-based fishery management policies to conserve bigeye tuna in the Western Central Pacific Ocean. Closing the high-seas enclaves to purse seine fishing has negligible effect on the BET biomass. Fishery management policies that control mortality on both juveniles and adults, through prohibition of fish aggregation devices in the purse seine fishery and restrictions on longline fishing in spawning areas, are the most efficient conservation policies. Large-scale benefits from bigeye conservation measures will become apparent only in the 2030s, assuming timely implementation and minimal effects of climate change.
Remotely sensed tracking data collected on animal movement is vastly un-derutilized due to a lack of statistical tools for appropriate analysis. Features of such data that make analysis particularly challenging include the presence of estimation errors that are non-Gaussian and vary in time, observations that occur irregularly in time, and com-plexity in the underlying behavioral processes. We develop a state–space framework that simultaneously deals with these features and demonstrate our method by analyzing three seal pathway data sets. We show how known information regarding error distributions can be used to improve inference of the underlying process(es) and demonstrate that our frame-work provides a powerful and flexible method for fitting different behavioral models to tracking data.
The decline of large‐bodied predatory species in the oceans is a concern both from a sustainability perspective and because such species can have important ecological roles. Sharks are particularly vulnerable to fishing as their life histories are characterized by late age at maturity, large body size, and low fecundity.
Substantial shark population declines have been documented for a number of coastal and pelagic systems, with high population abundance limited to a few remote locations. The relative abundance and composition of reef shark populations are assessed from 1975 to 2006 at a remote, largely uninhabited, group of atolls in the central Indian Ocean; the Chagos Archipelago.
Number of sharks observed per scientific dive declined from a mean of 4.2 in the 1970s to 0.4 in 2006, representing a decline of over 90%. Silvertip sharks displayed an increase in abundance from 1996, whereas blacktip and whitetip reef sharks were rarely encountered in 2006.
Poaching in the archipelago, is the most likely cause of these declines, highlighted by a number of illegal vessels containing large numbers of sharks arrested since 1996. The data highlight that shark populations, even in remote, otherwise pristine, marine areas, are vulnerable to distant fishing fleets, and a range of strategies will need to be used in concert for their conservation. Copyright © 2010 John Wiley & Sons, Ltd.
Electronic tracking tags are major tools of ecological research and management, but programming sophisticated tags can be challenging. We discovered that a common programming scheme can negatively affect the quality of tracks collected by Argos tags. Here we describe the problem and how it occurred. We then simulated a series of tracks with different data collection schemes to investigate how spatial precision and temporal frequency affect the overall quality of tracking data. Tracks were simulated using a two-state composite correlated random walk (CCRW). Tracks were simulated with two spatial scales, using parameters estimated from northern elephant seal (large scale) and California sea lion (small scale) tracking data. Onto each simulated track, observations of varying precision, frequency, and censoring were imposed. We then fit the CCRW in a state-space model (SSM) to the simulated observations in order to assess how data quality and frequency affected recovery of known behavioral state and location. We show that when movement scales are small, regular observations were critical to recover behavior and location. In addition, tracks with frequent regular locations (increasing N) overcame low spatial accuracy (e.g., Argos) to detect small-scale movement patterns, suggesting frequently collected Argos locations may be as good as infrequently collected GPS in some circumstances. From these results and our experience tracking animals generally, we produce a set of guidelines for those manufacturing, programming, and deploying electronic tracking tags to maximize the utility of the data they produce.
Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (~14 km away) and one grey reef shark completed a round trip of ~250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.
We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked - the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as 'Vulnerable' to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.
Animal movements, residence times, and subsequently foraging strategies, should vary with habitat quality. We used acoustic and satellite telemetry, as well as stable isotopes, to look at movement patterns, macro-scale habitat use, and trophic ecology of blacktip reef sharks, Carcharhinus melanopterus, between two lagoons (eastern and western) at Palmyra Atoll, a US National Wildlife Refuge in the central Pacific. Sharks in the Palmyra lagoons have relatively small home ranges and appear to obtain most of their energy from the lagoon ecosystem. Sharks showed low levels of migration between lagoons over periods of several years, and individuals in the larger western lagoon tended to have longer residence times than those in the smaller eastern lagoon. Furthermore, for sharks in the western lagoon, there was no relationship between total length (TL) and δ15N, 13C relative isotope concentrations, or a Body Condition index (BC). For sharks in the eastern lagoon, TL was positively related to δ15N and negatively related to δ13C and BC. These results suggest that there are low levels of mixing of sharks between lagoons, and these are leading to differences in trophic ecology and potentially foraging success. Although the causative factors behind these differences are unknown, shark home range location can potentially lead to variation in trophic ecology, even over small spatial scales.
Leatherback turtles (Dermochelys coriacea) are currently critically endangered and could be on the verge of extinction within the Pacific Ocean. In 2004–7, satellite transmitters were attached to 46 female turtles nesting at Playa Grande, Costa Rica, to further investigate their distribution and movements in the eastern Pacific to improve conservation measures. State-space models (SSM) provide a valuable tool for modelling movement data by simultaneously accounting for measurement error and variability in the movement dynamics. Track simulations and a measure of the uncertainty for each position estimate allowed model performance with large amounts of missing satellite data to be assessed, as this is common for marine animals. A switching SSM was applied to the tracks of the turtles, which also provided an estimate of the behavioural mode at each location. This enabled the internesting period to be objectively defined based on a shift between these two modes. This switch occurred later than the last observed nesting event, indicating turtles did not immediately move offshore and the length of time and area that turtles utilise during internesting could previously have been underestimated. The movement parameters, mean turning angle and autocorrelation in speed and direction, for each mode were similar to those in the Atlantic Ocean, but the foraging phase was more prolonged and widely dispersed suggesting that food patches are less predictable in the Pacific. This may explain the long period between nesting seasons.
Until recently, large apex consumers were ubiquitous across the globe and had been for millions of years. The loss of these
animals may be humankind’s most pervasive influence on nature. Although such losses are widely viewed as an ethical and aesthetic
problem, recent research reveals extensive cascading effects of their disappearance in marine, terrestrial, and freshwater
ecosystems worldwide. This empirical work supports long-standing theory about the role of top-down forcing in ecosystems but
also highlights the unanticipated impacts of trophic cascades on processes as diverse as the dynamics of disease, wildfire,
carbon sequestration, invasive species, and biogeochemical cycles. These findings emphasize the urgent need for interdisciplinary
research to forecast the effects of trophic downgrading on process, function, and resilience in global ecosystems.
Pelagic marine predators face unprecedented challenges and uncertain futures. Overexploitation and climate variability impact the abundance and distribution of top predators in ocean ecosystems. Improved understanding of ecological patterns, evolutionary constraints and ecosystem function is critical for preventing extinctions, loss of biodiversity and disruption of ecosystem services. Recent advances in electronic tagging techniques have provided the capacity to observe the movements and long-distance migrations of animals in relation to ocean processes across a range of ecological scales. Tagging of Pacific Predators, a field programme of the Census of Marine Life, deployed 4,306 tags on 23 species in the North Pacific Ocean, resulting in a tracking data set of unprecedented scale and species diversity that covers 265,386 tracking days from 2000 to 2009. Here we report migration pathways, link ocean features to multispecies hotspots and illustrate niche partitioning within and among congener guilds. Our results indicate that the California Current large marine ecosystem and the North Pacific transition zone attract and retain a diverse assemblage of marine vertebrates. Within the California Current large marine ecosystem, several predator guilds seasonally undertake north-south migrations that may be driven by oceanic processes, species-specific thermal tolerances and shifts in prey distributions. We identify critical habitats across multinational boundaries and show that top predators exploit their environment in predictable ways, providing the foundation for spatial management of large marine ecosystems.
On 1st April 2010, the British Government announced designation of the British Indian Ocean Territory--or Chagos Archipelago--as the world's largest marine protected area (MPA). This near pristine ocean ecosystem now represents 16% of the worlds fully protected coral reef, 60% of the world's no-take protected areas and an uncontaminated reference site for ecological studies. In addition these gains for biodiversity conservation, the Chagos/BIOT MPA also offers subsidiary opportunities to act as a fisheries management tool for the western Indian Ocean, considering its size and location. While the benefits of MPAs for coral-reef dwelling species are established, there is uncertainty about their effects on pelagic migratory species. This paper reviews the increasing body of evidence to demonstrate that positive, measurable reserve effects exist for pelagic populations and that migratory species can benefit from no-take marine reserves.
No-take marine reserves are widely recognized as an effective conservation tool for protecting marine resources. Despite considerable empirical evidence that abundance and biomass of fished species increase within marine reserve boundaries, the potential for reserves to provide fisheries and conservation benefits to adjacent waters remains heavily debated. This paper uses statistical and population models to evaluate published empirical data on adult spillover from marine reserves and shows that spillover is a common phenomenon for species that respond positively to reserve protection, but at relatively small scales, detectable on average up to 800 m from reserve boundaries. At these small scales, local fisheries around reserves were likely unsustainable in 12 of 14 cases without the reserve, and spillover partially or fully offsets losses in catch due to reserve closure in the other two cases. For reserves to play a role in sustaining and replenishing larger-scale fished stocks, networks of reserves may be necessary, but as few exist this is difficult to evaluate. The results suggest reserves can simultaneously meet conservation objectives and benefit local fisheries adjacent to their boundaries.
Despite an Indo-Pacific wide distribution, the movement patterns of grey reef sharks (Carcharhinus amblyrhynchos) and fidelity to individual reef platforms has gone largely unstudied. Their wide distribution implies that some individuals have dispersed throughout tropical waters of the Indo-Pacific, but data on large-scale movements do not exist. We present data from nine C. amblyrhynchos monitored within the Great Barrier Reef and Coral Sea off the coast of Australia. Shark presence and movements were monitored via an array of acoustic receivers for a period of six months in 2008. During the course of this monitoring few individuals showed fidelity to an individual reef suggesting that current protective areas have limited utility for this species. One individual undertook a large-scale movement (134 km) between the Coral Sea and Great Barrier Reef, providing the first evidence of direct linkage of C. amblyrhynchos populations between these two regions. Results indicate limited reef fidelity and evidence of large-scale movements within northern Australian waters.
Marine protected areas (MPAs) that exclude fishing have been shown repeatedly to enhance the abundance, size, and diversity of species. These benefits, however, mean little to most marine species, because individual protected areas typically are small. To meet the larger-scale conservation challenges facing ocean ecosystems, several nations are expanding the benefits of individual protected areas by building networks of protected areas. Doing so successfully requires a detailed understanding of the ecological and physical characteristics of ocean ecosystems and the responses of humans to spatial closures. There has been enormous scientific interest in these topics, and frameworks for the design of MPA networks for meeting conservation and fishery management goals are emerging. Persistent in the literature is the perception of an inherent tradeoff between achieving conservation and fishery goals. Through a synthetic analysis across these conservation and bioeconomic studies, we construct guidelines for MPA network design that reduce or eliminate this tradeoff. We present size, spacing, location, and configuration guidelines for designing networks that simultaneously can enhance biological conservation and reduce fishery costs or even increase fishery yields and profits. Indeed, in some settings, a well-designed MPA network is critical to the optimal harvest strategy. When reserves benefit fisheries, the optimal area in reserves is moderately large (mode ≈30%). Assessing network design principals is limited currently by the absence of empirical data from large-scale networks. Emerging networks will soon rectify this constraint.
ARGOS satellite telemetry is one of the most widely used methods to track the movements of free-ranging marine and terrestrial animals and is fundamental to studies of foraging ecology, migratory behavior and habitat-use. ARGOS location estimates do not include complete error estimations, and for many marine organisms, the most commonly acquired locations (Location Class 0, A, B, or Z) are provided with no declared error estimate.
We compared the accuracy of ARGOS Locations to those obtained using Fastloc GPS from the same electronic tags on five species of pinnipeds: 9 California sea lions (Zalophus californianus), 4 Galapagos sea lions (Zalophus wollebaeki), 6 Cape fur seals (Arctocephalus pusillus pusillus), 3 Australian fur seals (A. p. doriferus) and 5 northern elephant seals (Mirounga angustirostris). These species encompass a range of marine habitats (highly pelagic vs coastal), diving behaviors (mean dive durations 2-21 min) and range of latitudes (equator to temperate). A total of 7,318 ARGOS positions and 27,046 GPS positions were collected. Of these, 1,105 ARGOS positions were obtained within five minutes of a GPS position and were used for comparison. The 68(th) percentile ARGOS location errors as measured in this study were LC-3 0.49 km, LC-2 1.01 km, LC-1 1.20 km, LC-0 4.18 km, LC-A 6.19 km, LC-B 10.28 km.
The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies. The error was non-normally distributed with each LC highly right-skewed. Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals. Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data.
The ocean remains the least observed part of our planet. This deficiency was made obvious by two recent developments in ocean governance: the emerging global movement to create massive marine protected areas (MPAs) ( 1 ) and a new commitment by the United Nations (UN) to develop a legally binding treaty to better manage high-seas biodiversity ( 2 ). Both policy goals cause us to confront whether it is meaningful to legislate change in ocean areas that we have little capacity to observe transparently. Correspondingly, there has been a surge in interest in the potential of publicly accessible data from automatic ship identification systems (AIS) to fill gaps in ocean observation. We demonstrate how AIS data can be used to empower and propel forward a new era of spatially ambitious marine governance and research. The value of AIS, however, is inextricably linked to the strength of policies by which it is backed.
Fishing pressure has increased the extinction risk of many elasmobranch (shark and ray) species. Although many countries have established no-take marine reserves, a paucity of monitoring data means it is still unclear if reserves are effectively protecting these species. We examined data collected by a small group of divers over the past 21 years at one of the world's oldest marine protected areas (MPAs), Cocos Island National Park, Costa Rica. We used mixed effects models to determine trends in relative abundance, or probability of occurrence, of 12 monitored elasmobranch species while accounting for variation among observers and from abiotic factors. Eight of 12 species declined significantly over the past 2 decades. We documented decreases in relative abundance for 6 species, including the iconic scalloped hammerhead shark (Sphyrna lewini) (-45%), whitetip reef shark (Triaenodon obesus) (-77%), mobula ray (Mobula spp.) (-78%), and manta ray (Manta birostris) (-89%) rays, and decreases in the probability of occurrence for 2 other species. Several of these species have small home ranges and should be better protected by an MPA, which underscores the notion that declines of marine megafauna will continue unabated in MPAs unless there is adequate enforcement effort to control fishing. In addition, probability of occurrence at Cocos Island of tiger (Galeocerdo cuvier), Galapagos (Carcharhinus galapagensis), blacktip (Carcharhinus limbatus), and whale (Rhincodon typus) sharks increased significantly. The effectiveness of MPAs cannot be evaluated by examining single species because population responses can vary depending on life history traits and vulnerability to fishing pressure.
© 2015 Society for Conservation Biology.
1. Double-tagging experiments are invaluable for determining the accuracy and precision of location data provided by different telemetry technologies used with free-ranging animals.
2. We developed a state-space modelling framework for estimating the precision of telemetry location data based on double-tagging experiments. The model is simultaneously fitted to multiple data types with different temporal resolutions while including errors in all data.
3. We used the model to estimate the precision of a specific geolocation method based on light and sea surface temperature applied to a large marine telemetry dataset. Data were available from double-tagging experiments on 111 animals representing seven marine species including 4 sharks, 2 birds and 1 pinniped. Study animals carried electronic tags that provided geolocation estimates as well as more precise satellite-based location data (Argos and Global Positioning System).
4. Estimates of the precision of geolocations were similar to previous findings. The overall estimated SD of geolocation errors for each species ranged from 0·5 to 3·9° for longitude and 0·8 to 3·6° for latitude.
5. While these results are specific to this particular type of location estimation method, the state-space framework presented here is a robust approach to estimating the precision of various types of telemetry location data from double-tagging experiments. The model simultaneously allows for appropriate inferences about true animal locations and movement.
Over the past 6 years, the United States, Australia, and the United Kingdom have created huge marine reserves that have banned fishing in more than 1.9 million square kilometers of ocean. Unlike an older generation of preserves that mostly focused on small patches of coral or coastal fish stocks, these vast new sanctuaries are designed to protect high-seas ecosystems that include fish and other animals that routinely wander over huge territories. The trend delights conservation scientists who are worried about overexploitation of the world's oceans. But researchers are struggling to design and fund studies that will enable them to monitor changes over vast areas and determine whether the reserves are actually helping to rebuild marine populations.
As shark populations collapse and public concern rises, some national governments have established shark sanctuaries. These countries, such as Marshall Islands, Maldives, and Venezuela, have been touted to be “safeguarding” ([ 1 ][1]) and “protecting” ([ 2 ][2]) sharks. The Marshall Islands
Over a 4-year period, free-ranging sharks were studied by ultrasonic telemetry and direct underwater observation. Twenty-six intermittent multi-day trackings were conducted, of from 2-6 (x = 3.5) days of contact, and with overall durations of 2-23 days. Three transmitter attachment methods were used and evaluated: 1) dorsal-fin mount, 2) body-cavity insertion and 3) self-ingestion in bait. Observed activity spaces of the telemetered sharks ranged in area from 0.19 km2 to 53 km2 (x = 4.2 km) and in length from 300 m to 16 km (x = 3.6 km). Movement patterns suggested that: 1) sharks tagged near the ocean reefs were generally nomadic, moving relatively long distances along the reefs and 2) sharks tagged on lagoon reefs or pinnacles had a more home-ranging pattern with different day and night areas, often returning day-after-day to the tagging site. The overall daytime mean rate of movement was 1.7 km/h, while the nighttime rate was significantly higher at 3.3 km/h. Observed daytime grouping patterns were of the following three intergrading types: 1) polarized schools-seen close to bottom over level areas, 2) loose aggregations-usually near ocean-reef dropoffs and 3) lone individuals-usually over shallower reefs and lagoon pinnacles.
Ecology Letters (2010) 13: 1055–1071
Abstract
Whereas many land predators disappeared before their ecological roles were studied, the decline of marine apex predators is still unfolding. Large sharks in particular have experienced rapid declines over the last decades. In this study, we review the documented changes in exploited elasmobranch communities in coastal, demersal, and pelagic habitats, and synthesize the effects of sharks on their prey and wider communities. We show that the high natural diversity and abundance of sharks is vulnerable to even light fishing pressure. The decline of large predatory sharks reduces natural mortality in a range of prey, contributing to changes in abundance, distribution, and behaviour of small elasmobranchs, marine mammals, and sea turtles that have few other predators. Through direct predation and behavioural modifications, top‐down effects of sharks have led to cascading changes in some coastal ecosystems. In demersal and pelagic communities, there is increasing evidence of mesopredator release, but cascading effects are more hypothetical. Here, fishing pressure on mesopredators may mask or even reverse some ecosystem effects. In conclusion, large sharks can exert strong top‐down forces with the potential to shape marine communities over large spatial and temporal scales. Yet more empirical evidence is needed to test the generality of these effects throughout the ocean.
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