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We used satellite-linked radio telemetry to document the geographic and vertical movements and thermal habitats of whale sharks in the Sea of Cortez and as they migrated into the north Pacific Ocean. Of 17 sharks tagged between 1994 and 1996, six dispersed widely in the Sea of Cortez during 12–39 days of tracking. Four others left the Sea of Cortez...
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Context 1
... other ten sharks either moved out of BLA ( Figure 3) or out of the Sea of Cortez (Figure 4) and were tracked for 17-1144 days. Four of those sharks (#2, #3, #8, #12) moved into the northern Sea of Cortez until contact was lost, whereastwo (#5, #11) traveled south soon after being tagged (Figure 3). ...
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... other ten sharks either moved out of BLA ( Figure 3) or out of the Sea of Cortez (Figure 4) and were tracked for 17-1144 days. Four of those sharks (#2, #3, #8, #12) moved into the northern Sea of Cortez until contact was lost, whereastwo (#5, #11) traveled south soon after being tagged (Figure 3). At least four sharks (#10, #13, #14, #15) eventually migrated away from the Sea of Cortez and two of them (#10, #15) traveled substantial distances westward. ...
Citations
... Despite their impressive size, they are rarely sighted and face numerous threats, including bycatch, vessel collisions, and changes in oceanographic conditions (Norman et There are approximately 20 recognized global hotspots for whale shark activity, many of which are seasonal feeding aggregations occurring in easily accessible surface waters (Norman et al., 2017;Reynolds et al., 2022). Noteworthy locations with such constellation include Ningaloo Reef in Australia (Taylor 1996), Belize (Young 2008), Seychelles (Rowat and Gore 2007), Madagascar (Jonahson and Harding 2007), Maldives (Kundur 2012), Mozambique (Speed et al. 2008), Mexico (Eckert and Stewart 2001), Qatar (Robinson et al. 2017), Ma a Island (Rohner et al. 2013), and St Helena (Perry 2017). These aggregations offer valuable opportunities to study the environmental factors affecting phytoplankton and zooplankton, examine how prey availability impacts whale sharks, and support the tourism industry by drawing visitors eager to observe these magni cent creatures in their natural habitat. ...
The whale shark ( Rhincodon typus , Smith 1828) is among the largest fish that tends to swim at the surface in aggregation. Several locations in are known habitats for whale sharks. However, there is still a need to understand the environmental factors that influence their occurrences and sighting. This paper investigated the environmental factors essential to whale sharks' s in Kilindoni bay, Mafia. Data were collected through observations supplemented with secondary historical data sets from 2012 to 2019, including whale shark sightings and environmental variables. These datasets were obtained from the Marine Megafauna Foundation (MMF) and the Tanzania Fisheries Research Institute (TAFIRI). The Generalized Linear Model (GLM) was used to analyse 510 whale shark sighting records from October to February (2012–2019). The variables involved were sea surface temperature, zooplankton abundance, moon illumination, and weather conditions. Results revealed that weather conditions (χ2 = 10.626, df = 4, p = 0.031), zooplankton abundance (χ2 = 206.580, df = 2, p = 0.001), and moon illumination (χ2 = 7.464, df = 1, p = 0.006) are significant factors influencing the sighting of whale sharks. Sea Surface Temperature (χ2 = 0.951, df = 1, p = 0.329) was not a significant factor in the sighting of whale sharks. Generally, weather conditions, moon illumination, and zooplankton abundance were vital factors for the Mafia's distribution of whale sharks. The study recommends sustained, regular monitoring of environmental variables linked to whale sharks, reinforcing the implementation of a code of conduct for whale shark sighting, and advocating for an integrated management approach inclusive of all local stakeholders.
... The first use of satellite telemetry involved tracking a basking shark with a towed Argos transmitting tag for 17 days (Priede 1984). Subsequent studies in the early-to-mid-1990s estimated the positions of tagged individuals (e.g., whale sharks, blue sharks, and blue marlin) using towed and early fin tags, with some success (Eckert & Stewart 2001;B.A. Block, unpublished data). In the mid-1990s, pop-up satellite archival tags were developed, expanding tag deployments to a range of pelagic fishes (e.g., Block et al. 1998). ...
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.
... A speeddistance-angle filter was applied prior to fitting the SSM, on the basis of values in Vaudo et al. (2017). We set v max to 1.4 m s -1 , equivalent to 5 km h -1 , on the basis of previously reported rates of movement in whale sharks (Eckert and Stewart 2001;Motta et al. 2010;Gleiss et al. 2011;Guzman et al. 2022). ...
Context Satellite telemetry has revolutionised the study of animal movement, particularly for mobile marine animals, whose movements and habitat make consistent, long-term observation difficult. Aims Summarise the movements of Rio Lady, a mature female whale shark (Rhincodon typus), to characterise these movements, and to predict expected behaviour throughout the Gulf of Mexico (GOM). Methods Rio Lady was tracked using satellite telemetry for over 1600 days, generating over 1400 locations and travelling over 40,000 km. State–space and move persistence modelling enabled characterisation of behaviour, and machine learning (ML) enabled the development of habitat-suitability models to predict habitat utilisation, on the basis of location transmissions and their environmental covariates. Key results Rio Lady exhibited annually consistent patterns of movements among three regions within the GOM. Final ML models produced seasonally dynamic predictions of habitat use throughout the GOM. Conclusions The application of these methods to long-term location data exemplifies how long-term movement patterns and core areas can be discovered and predicted for marine animals. Implications Despite our limited dataset, our integrative approach advances methods to summarise and predict behaviour of mobile species and improve understanding of their ecology.
... Depth was estimated based on the criteria described above (see 2.3), providing an informative view of how they occupy vertical space. While all four sharks spent a vast majority of their time in the upper half of the habitat and less than 4% of the aggregate observations occupying the bottom 50% of the water's depth, consistent with reports from the wild (Eckert and Stewart, 2001;Rowat and Gore, 2007;Womersley et al., 2021;Andrzejaczek et al., 2022), we were interested to see if the sharks in this study differed from each other in this respect. An omnibus chi-square test of the four depth categories noted for each shark suggested extreme deviations from expected frequencies, indicating at least one shark differs from the rest in its proclivity for certain depths ( Figure 4A; c 2 (9, 31080) = 2362, p = 0). ...
... Other notable similarities to wild sharks were depth preferences. While artificial habitat constraints complicate direct comparison, our data suggest that aquarium whale sharks prefer the surface over deeper depths, congruent with work from the wild (Eckert and Stewart, 2001;Rowat and Gore, 2007;Andrzejaczek et al., 2022). The study by Andrzejaczek et al. (2022) compellingly shows that whale sharks spend a statistical majority of their time in the top 250 meters of the water column, though it is important to note that they also had the widest range (0-1896 m), engaging in deep dives (as shown elsewhere (Brunnschweiler et al., 2009;Tyminski et al., 2015)) and have recently been observed bottomfeeding . ...
Rhincodon typus, or the whale shark, is the largest extant fish in the world and is classified as endangered on the IUCN’s Red List. Due to their enormous size and conservation status, whale sharks are rarely housed in aquaria. Here we present a behavioral analysis culminating from a large effort by 89 observers from 2008–2012 to study four R. typus (ID codes: AL, TA, TR, YU) longitudinally in an aquarium setting. We found that relatively simple behavioral metrics such as swim speed, depth occupation, swimming direction, and lead-follow interactions demonstrated R. typus individual variation and responses to habitat changes. All sharks displayed increased swim speeds 30-minutes before regimented feed times, when there was scent of food being fed to other animals in the habitat. Consistently in the habitat, one male shark (YU) was recorded swimming more at depth, faster, almost exclusively clockwise, and engaged in fewer close proximity interactions with others than expected by chance. In contrast, a larger female shark (AL) was observed swimming the slowest, at the surface more than others, led other sharks more than she followed, and had strong lead-follow interactions with another shark of the opposite sex (TA). TA and TR did not differ from each other in depth profiles or speed, but did differ in their proclivity to lead or follow. Depth preferences and lead-follow interactions suggest some partitioning of the habitat and the possibility of social hierarchy in this species. These results represent the first longitudinal behavioral analysis of aquarium R. typus, offering meaningful similarities and contrasts to field observations.
... The ETP is home to several highly migratory chondrichthyan species that are also iconic for marine tourism in the ETP (Eckert & Stewart, 2001;Ketchum et al., 2014;Lara-Lizardi et al., 2020). While the capacity of migratory species to move across gradients of environmental cues may confer adaptability and potentially enable them to adjust to new conditions, highly migratory species have complex migration patterns and depend on the availability of suitable habitat in many locations. ...
Climate change is an environmental emergency threatening species and ecosystems globally. Oceans have absorbed about 90% of anthropogenic heat and 20%–30% of the carbon emissions, resulting in ocean warming, acidification, deoxygenation, changes in ocean stratification and nutrient availability, and more severe extreme events. Given predictions of further changes, there is a critical need to understand how marine species will be affected. Here, we used an integrated risk assessment framework to evaluate the vulnerability of 132 chondrichthyans in the Eastern Tropical Pacific (ETP) to the impacts of climate change. Taking a precautionary view, we found that almost a quarter (23%) of the ETP chondrichthyan species evaluated were highly vulnerable to climate change, and much of the rest (76%) were moderately vulnerable. Most of the highly vulnerable species are batoids (77%), and a large proportion (90%) are coastal or pelagic species that use coastal habitats as nurseries. Six species of batoids were highly vulnerable in all three components of the assessment (exposure, sensitivity and adaptive capacity). This assessment indicates that coastal species, particularly those relying on inshore nursery areas are the most vulnerable to climate change. Ocean warming, in combination with acidification and potential deoxygenation, will likely have widespread effects on ETP chondrichthyan species, but coastal species may also contend with changes in freshwater inputs, salinity, and sea level rise. This climate-related vulnerability is compounded by other anthropogenic factors, such as overfishing and habitat degradation already occurring in the region. Mitigating the impacts of climate change on ETP chondrichthyans involves a range of approaches that include addressing habitat degradation, sustainability of exploitation, and species-specific actions may be required for species at higher risk. The assessment also highlighted the need to further understand climate change's impacts on key ETP habitats and processes and identified knowledge gaps on ETP chondrichthyan species.
... Therefore, this study aimed to analyze the presence of PAHs and OCPs in whale shark skin biopsies in the sighting area of Bahía de Los Ángeles (BLA), in the Gulf of California, Mexico; which is influenced by tourist, fishing, agricultural and fuel transportation activities. A mean travel rate of up to 23.6 km/day has been reported in whale sharks tagged in BLA (Eckert and Stewart 2001), but R. typus juveniles can remain in BLA from several days to a month or more (Ramírez-Macías et al. 2012); therefore, subacute exposure to these contaminants could occur in the study area (ATSDR 2015). ...
... Cagnazzi et al. (2019) also did not found statistically significant relationships between OCP levels and size in species such as the great hammerhead shark (Sphyrna mokarran) and C. limbatus. It is important to note that only male and juvenile organisms were sampled, due to the segregation by sex and size of whale sharks in BLA (Eckert and Stewart 2001), so it was not possible to evaluate differences in the content of contaminants with respect to sex; on the other hand, even if R. typus is a highly migratory species, they are also considered philopatric organisms, demonstrating fidelity to BLA as a foraging area (Nelson and Eckert 2007;Rowat and Brooks 2012;Ramírez-Macías et al. 2012). ...
The whale shark (Rhincodon typus) is a filter-feeding organism that can be considered a sentinel species, and Bahía de los Ángeles (BLA) in the Gulf of California is an important sighting site for these elasmobranchs. This filter-feeding organism can be considered a pollutant sampler from the marine environment. Persistent organic pollutants are toxic compounds with high mobility and environmental persistence, bioaccumulation and trophic transfer. Among these are polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). The present work aimed to determine concentrations of PAHs and OCPs in whale shark skin biopsies, collected in 2021 at BLA. Mean detected levels of PAHs and OCPs were 279.4 ng/g dw (dry weight) and 1478.1 ng/g dw, respectively. Analysis of similarities between the ordered sizes (4.2–7.6 m) and the concentrations of PAHs and OCPs indicated no significant differences. Individual PAHs detected indicate pyrogenic and petrogenic sources; the presence of pesticides at levels higher than those of hydrocarbons may be related to agricultural activity in the areas surrounding the Baja California peninsula. This study is the first report of PAH levels in R. typus for the Gulf of California and Mexico.
... Whilst capable of vast oceanic migrations (Eckert & Stewart, 2001;Guzman et al., 2018), these sharks commonly form seasonal aggregations in coastal waters (Colman, 1997;Heyman et al., 2001;Rowat et al., 2011). The population structure of these aggregations varies between location, but many aggregations appear to be dominated by a single sex and size class (Ketchum et al., 2012;Riley et al., 2010;Rowat et al., 2007). ...
Despite being the world's largest fish, many questions remain regarding the ecology and behaviour of the whale shark (Rhincodon typus). We present the first direct evidence of whale sharks engaging in bottom‐feeding behaviour and provide potential explanations for this foraging strategy. We suggest that whale sharks actively feed on benthic prey, either predominantly in deepwater environments or where the abundance of such prey exceeds that of planktonic food sources. We also highlight the potential for ecotourism and citizen science projects to contribute to our understanding of marine megafauna behavioural ecology.
... ARGOS transmissions were filtered by deleting all transmissions in land (dry), quality "Z" and movements representing speeds over 100 km/day (6.4 km faster than the maximum speed reported by Eckert and Stewart, 2001). Two comparable analyses were performed: one using complete filtered transmission data (CD) of the animals and one with partially trimmed or removed trajectories (see l Figures S1) for suspicious of earlier detachment or freely floating tags (sensu Hearn et al., 2013). ...
... In comparison, tracking data from 27 adult female R. typus tagged near Darwin Island in the Galaṕagos archipelago revealed that individuals remained in the tagging area for short periods of time before moving into the open equatorial Pacific (Hearn et al., 2016). Similarly, immature individuals tagged in the Gulf of California largely remained in the Gulf, while adults moved out into the Pacific (Eckert and Stewart, 2001;Ramıŕez-Macıás et al., 2017). Taken together, these studies indicate the importance of the coastal waters of the tropical eastern Pacific and the offshore areas of the Cocos and Galapagos islands as foraging and migratory habitats for R. typus (Acuña-Marrero et al., 2014). ...
... Based on our observations, most modeled locations from tagged individuals occurred within high-impact vessel traffic areas, that is, a high density of vessels moving at high speed. Previous studies have found that individual R. typus spend approximately half of their time in surface waters (< 10 m depth) (Eckert and Stewart, 2001;Rowat and Gore, 2007;Womersley et al., 2021), and interactions with ships can result in behavioral modification, disturbance, displacement, injury, and even mortality (Pirotta et al., 2019;Womersley et al., 2021). Given the spatial overlap between marine vessels and R. typus habitat use, injury and mortality from ship collisions could be a significant factor in observed population declines (Womersley et al., 2022). ...
Whale sharks (Rhincodon typus) are found circumglobally in tropical, subtropical, and warm temperate waters, and their known seasonal aggregations and migratory movements are influenced by factors such as ocean currents, thermobiological systems, and patterns of productivity. Several locations in the eastern tropical Pacific Ocean are known habitats for R. typus; Although it has long been known that whale sharks aggregate along the Panama coast, little is known in relation to their movement patterns, behavior, and habitat use. In this study, we investigated the movements and behaviors of R. typus tagged in Panama in relation to oceanographic variables and examined the overlap of foraging habitat and migratory routes with marine protected areas (MPAs), industrial fishing areas, and marine traffic. Satellite tracks from 30 R. typus tagged in the coastal waters of Panama were examined, including nine tags suspicious of earlier detachment. A hidden Markov model was then used to identify different behavioral states (foraging and migrating) and their relationships with environmental variables (sea surface temperature, primary productivity, chlorophyll-a concentrations, and eddy location/speed) Tracks were also superimposed on maps of MPAs, industrial fishing areas, and regional marine vessel traffic to identify the degree of overlap. Rhincodon typus foraged mainly within the Panamanian exclusive economic zone but also moved north and south along the coast and out to the open ocean. Significant differences in environmental conditions were found between sites in which foraging and migrating behaviors were recorded. Higher productivity and chlorophyl concentration were associated with foraging behavior, while higher eddy speeds were observed when sharks migrated. Rhincodon typus used MPAs; however, there was a high degree of overlap between their habitat and areas of industrial fishing and marine vessel traffic. Our results highlight the use of the coastal waters of Panama, oceanic seamounts, and ridges, MPAs and industrial fishing areas by R. typus for foraging and migration. Additionally, our findings highlight the importance of satellite tracking studies for understanding the behavior and habitat use of highly mobile migratory species, such as R. typus.
... Kondisi ini menunjukkan bahwa hiu paus di perairan Kwatisore hidup menempati wilayah landasan total di atas 200 m. Ukuran panjang total hiu paus (total length) yang hidup di perairan Kwatisore menunjukkan ukuranukuran yang digolongkan sebagai ukuran remaja dan didominasi oleh jenis kelamin jantan, yang lebih menyukai perairan dangkal (Wolfson, 1983;Silas, 1963;Kaikini et al., 1959;Eckert & Stewart, 2001;Borrell et al., 2011). Syah et al. (2018 mengemukakan faktor oseanografi yang paling berpengaruh terhadap distribusi kemunculan hiu paus di perairan Probolinggo adalah kedalaman perairan dengan nilai persen kontribusi adalah 71,0% dengan kedalaman perairan 9-14 m. ...
Hiu paus (Rhincodon typus) adalah ikan terbesar di dunia yang sangat berpotensi dalam bidang wisata, namun potensi ancamannya juga tinggi jika tidak dikelola dengan baik. Perairan Kwatisore merupakan salah satu habitat hiu paus di Indonesia yang terlihat sering muncul. Hal tersebut menjadi fenomena yang unik karena hiu paus muncul setiap hari dan sepanjang tahun, sehingga berpeluang untuk pengembangan wisata. Penelitian ini bertujuan untuk mengkaji karakteristik pola makan hiu paus dan agregasinya, terutama total jumlah kemunculan dan jumlah individu di perairan Kwatisore. Pengambilan data dalam penelitian ini berupa data primer dan dilakukan dari bulan Juli sampai September 2020. Metode pengambilan data dilakukan sekali setiap bulan (time series) melalui koleksi untuk mengkaji pola makan antar individu hiu paus dengan pengamatan secara langsung ketika hiu paus naik ke permukaan perairan dan berada di dalam bagan yang berjumlah 5 unit alat tangkap bagan. Hasil penelitian menunjukkan bahwa terjadi 275 kemunculan hiu paus, yang terdiri dari 18 individu. Jumlah kemunculan dan jumlah individu hiu paus sangat tergantung pada hasil tangkapan ikan teri oleh setiap unit alat tangkap bagan. Kemunculan hiu paus berada dalam petuanan hak ulayat laut Kampung Akudiomi. Kemunculan hiu paus dominan terjadi pada pagi hari dan persentase kemunculan 100% berjenis kelamin jantan dengan ukuran panjang total berkisar antara 3 hingga 7,5 m.
... In general, the distribution and abundance of the whale shark are influenced by several oceanographic processes such as upwelling, coastal currents, and fronts, which increase the productivity of the surrounding environment (Taylor 1996;Eckert and Stewart 2001;Duffy 2002;Norman 2002;Ryan et al. 2017). In places where whale sharks appear around the world, it is often associated with warm water temperatures and other environmental parameters that can increase the productivity of the marine environment, which supports the creation of localized concentrations of food. ...
... This is very suitable for the presence of whale sharks. Several studies have shown that whale sharks are generally found in the Sea Surface Temperature range between 18-32 °C (Eckert and Stewart 2001;Rowat and Engelhardt 2007;Sleeman et al. 2007;Sequeira et al. 2012). Therefore, the relationship between whale shark abundance and predictors of Sea Surface Temperature has a clear correlation (Wilson et al. 2001;Sequeira et al. 2012;Hacohen-Domené et al. 2015). ...
Manuhutu JF, Wiadnya DGR, Sambah AB, Herawati EY. 2021. The presence of whale sharks based on oceanographic variations in Cenderawasih Bay National Park, Papua, Indonesia. Biodiversitas 22: 4948-4955. Oceanographic factors have an important role in the study of estimating the distribution of fish resource habitats. Sea Surface Temperature (SST), Sea Surface Chlorophyll (SSC), Current Speed, Sea Surface Height (SSH), and bathymetry are important parameters that have been used in estimating the habitat of certain species. Through analyzing these environmental factors, research on the appearance and distribution of whale shark habitats in the Cenderawasih Bay National Park in Papua, Indonesia, utilized field observation data and satellite imagery. This study applied data on the presence of whale sharks and oceanographic parameter data from satellite recordings during 2019 – 2020. Analysis of the relationship and habitat modeling between the monthly presence of whale sharks and environmental parameters was carried out through the Generalized Additive Model (GAM) statistical approach and spatial analysis through the Geographic Information System approach. In the GAM analysis, data on the presence of whale sharks was used as a response variable. In contrast, the predictor variables consisted of SST, SSC, current speed, SSH, and bathymetric data. The results showed that the highest frequency of whale shark presence occurred in the transitional monsoon, with an average presence of 31.77 ± 4.00 %. The study also showed that all predictors showed a highly significant relationship (P < 0.001) to the number of whale sharks present. SST values range from 30.3 – 31.3 °C, SSC of 0.39 – 0.86 mg/L, the current speed of 0.46 – 0.65 m/s, SSH showed 0.63 to 1.00 cm, and bathymetry between 40 – 50 m . In the GAM model, the SST and SSC parameters were the two most important parameters that affect the presence of whale sharks, followed by SSHD, depth (bathymetry), and current parameters.
