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Abstract and Figures
Human activities have placed populations of many endangered species at risk and mitigation efforts typically focus on reducing anthropogenic sources of mortality. However, failing to recognize the additional role of environmental factors in regulating birth and mortality rates can lead to erroneous demographic analyses and conclusions. The North Atlantic right whale population is currently the focus of conservation efforts aimed at reducing mortality rates associated with ship strikes and entanglement in fishing gear. Consistent monitoring of the population since 1980 has revealed evidence that climate-associated changes in prey availability have played an important role in the population's recovery. The considerable interdecadal differences observed in population growth coincide with remote Arctic and North Atlantic oceanographic processes that link to the Gulf of Maine ecosystem. Here, we build capture-recapture models to quantify the role of prey availability on right whale demographic transitional probabilities and use a corresponding demographic model to project population growth rates into the next century. Contrary to previous predictions, the right whale population is projected to recover in the future as long as prey availability and mortality rates remain within the ranges observed during 1980–2012. However, recent events indicate a northward range shift in right whale prey, potentially resulting in decreased prey availability and/or an expansion of right whale habitat into unprotected waters. An annual increase in the number of whale deaths comparable to that observed during the summer 2017 mass mortality event may cause a decline to extinction even under conditions of normal prey availability. This study highlights the importance of understanding the oceanographic context for observed population changes when evaluating the efficacy of conservation management plans for endangered marine species.
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... To be effective, such efforts need to be adapted to the rapidly changing marine environment (Meyer-Gutbrod and Greene, 2018;Roman et al., 2013;Salvadeo et al., 2013). Cook et al. (2019b) suggests that whale sanctuaries, such as the one in Skjálfandi Bay (which by default only forbids the activity of whaling in the designated area), are more effective in protecting whales when they adhere to ecosystem-based management principles: establishing a comprehensive set of objectives, assessment of ES trade-offs, accounting for social-ecological dynamics, and ensuring stakeholder consultation and participatory adaptive management (Long et al., 2015). ...
... It has been noted that while many species have an adaptive capacity to a certain extent, it is not known how fast any species will be able to adapt, and whether that adaptation will be able to keep pace with future changes (Ramp et al., 2015). With many species expanding their ranges into unprotected waters, some whales may not be able to disperse to areas with suitable environmental protection (Derville et al., 2019;Meyer-Gutbrod and Greene, 2018). Meyer-Gutbrod et al. (2021) found that a climate-driven regime shift occurred in the Gulf of Maine and Scotian Shelf regions of the Northwest Atlantic around 2010, negatively impacting the foraging environment, habitat use and demography of the right whale population. ...
... The effect of changes in lower trophic levels is an important topic in literature discussions on the future of whales in relation to climate change. The literature shows that whale populations whose habitat ranges have shifted over past decades have moved in tandem with changing prey, mostly phytoplankton and krill (Meyer-Gutbrod and Greene, 2018;Nicol et al., 2008;Record et al., 2019;Trathan et al., 2007;Tulloch et al., 2019;Víkingsson et al., 2014). Szesciorka et al. (2020) analysed migration timing of blue whales, environmental conditions, such as SST anomalies, chlorophyll concentration and abundance of prey (spring krill biomass from annual net tow surveys), during a 10 year period 2008-2017 in their summer feeding grounds in the waters off Southern California. ...
The paper presents a synthesis of some of the interdisciplinary work from the ARCPATH project that focuses on the effects of climate change on Arctic social-
ecological systems. It does so through the prism of whales and their recreational ecosystem services (ES). Whales present a group of species that are vulnerable
to climate change and, at the same time, are central to the economies, cultures, and identities of many Arctic coastal communities. One such community is the town of
Húsavík in Skj ́alfandi Bay, Iceland. The paper conducts an initial literature review to examine the effects of climate change on whales, globally, before using these
findings and site-specific data from climate change modelling, whale observations from whale watching boats and whale watching trip records to investigate possible
future impacts on whale watching in Skj ́alfandi Bay. The literature review identifies three categories of impacts on whales due to climate change, which concern
changing distributions and migration, prey availability, and sea-ice and ocean temperature. Linear regression models identify statistically significant relationships
between sea-surface temperatures (SST) and cetacean sightings for minke whales, blue whales and white-beaked-dolphins over the period 1995 to 2017. These
species appear to have changed their usual feeding areas, and the results imply that further increases in SST are likely to further affect whale distributions. Future
climate scenarios indicate that at least 2 ◦C of SST warming in Skj ́alfandi Bay up to 2050 might be inevitable regardless of the future emissions scenario, which
implies nearly certain change that would require adaptation. The reliance of the local tourism sector on whale watching makes Húsavík vulnerable to the effects of
climate change on whales. The results of this interdisciplinary inquiry emphasize the interconnectedness of different components of social-ecological systems and
calls for adaptation planning that would enhance the resilience of local community to climate change and conservation measures that could enhance the protection of
whales beyond the scope of the current whale sanctuary in Skj ́alfandi Bay.
... This increase in prey was driven by warming oceanic conditions in the Gulf of Maine (Meyer-Gutbrod et al., 2015). These prey resources declined when a distinct climatic shift flipped the oceanic conditions in subsequent years, followed by a decline in North Atlantic right whale fecundity rates (Meyer-Gutbrod et al., 2015;Meyer-Gutbrod & Greene, 2018). ...
... We show that the pregnancy rate of humpback whales was positively related with krill abundance from the previous year but, surprisingly, inversely related with krill abundance from 2 years prior. Previous studies of baleen whales and their reproductive rates show equivalent responses to variation in prey availability and oceanographic and sea ice conditions (Kershaw et al., 2021;Leaper et al., 2006;Meyer-Gutbrod et al., 2015;Meyer-Gutbrod & Greene, 2018). Specifically, a lagged negative relationship between krill availability and the breeding success of southern right whales was observed at South Georgia (Leaper et al., 2006). ...
The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since the 1970s. Rapid warming of the Western Antarctic Peninsula (WAP) over the past 50 years has resulted in decreased seasonal ice cover and a reduction of krill. The latter is being exacerbated by a commercial krill fishery in the region. Despite this, humpback whale populations have increased but may be at a threshold for growth based on these human-induced changes. Understanding how climate-mediated variation in prey availability influences humpback whale population dynamics is critical for focused management and conservation actions. Using an 8-year dataset (2013-2020), we show that inter-annual humpback whale pregnancy rates, as determined from skin-blubber biopsy samples (n = 616), are positively correlated with krill availability and fluctuations in ice cover in the previous year. Pregnancy rates showed significant inter-annual variability, between 29% and 86%. Our results indicate that krill availability is in fact limiting and affecting reproductive rates, in contrast to the krill surplus hypothesis. This suggests that this population of humpback whales may be at a threshold for population growth due to prey limitations. As a result, continued warming and increased fishing along the WAP, which continue to reduce krill stocks, will likely impact this humpback whale population and other krill predators in the region. Humpback whales are sentinel species of ecosystem health, and changes in pregnancy rates can provide quantifiable signals of the impact of environmental change at the population level. Our findings must be considered paramount in developing new and more restrictive conservation and management plans for the Antarctic marine ecosystem and minimizing the negative impacts of human activities in the region.
... Such critical habitat areas need to be properly identified, managed, and conserved in order to maintain viable populations . Environmental variability and change, however, can make conservation efforts more difficult, as it may shift the quality and distribution of these habitats [4,5]. Hence, understanding and predicting such dynamic changes is crucial to designing adaptive management measures. ...
... The Northwest Atlantic has been warming since 1980, and is projected to continue on this trend faster than other ocean basins  making it a natural laboratory to study the complex effects of climate change on marine predators and their prey. Recent shifts in right whale habitat in the region, for example, were linked to climate-related shifts in copepod distribution, and resulted in large additional whale mortality due to emerging new threats in their novel feeding habitat [5,. Such observations partly motivate the current study, as changes in leatherback scyphozoan prey distributions could potentially enhance threats to this endangered species. ...
Leatherback sea turtles (Dermochelys coriacea) migrate to temperate Canadian Atlantic waters to feed on gelatinous zooplankton (‘jellyfish’) every summer. However, the spatio-temporal connection between predator foraging and prey-field dynamics has not been studied at the large scales over which these migratory animals occur. We use 8903 tows of groundfish survey jellyfish bycatch data between 2006–2017 to reveal spatial jellyfish hot spots, and matched these data to satellite-telemetry leatherback data over time and space. We found highly significant overlap of jellyfish and leatherback distribution on the Scotian Shelf (r = 0.89), moderately strong correlations of jellyfish and leatherback spatial hot spots in the Gulf of St. Lawrence (r = 0.59), and strong correlations in the Bay of Fundy (r = 0.74), which supports much lower jellyfish density. Over time, jellyfish bycatch data revealed a slight northward range shift in the Gulf of St. Lawrence, consistent with gradual warming of these waters. Two-stage generalized linear modelling corroborated that sea surface temperature, year, and region were significant predictors of jellyfish biomass, suggesting a climate signal on jellyfish distribution, which may shift leatherback critical feeding habitat over time. These findings are useful in predicting dynamic habitat use for endangered leatherback turtles, and can help to anticipate large-scale changes in their distribution in response to climate-related changes in prey availability.
... Although northward habitat shifts have been observed for right whales (Simard et al., 2019), little is known about the energetic impact of prey alterations (Gavrilchuk et al., 2021) for future populations (Meyer-Gutbrod and Greene, 2018). Unlike more generalist predators such as sei whales (Balaenoptera borealis) that can exploit both calanoid copepods and small schooling fish (Burkhardt-Holm and N'Guyen, 2019), balaenids are not morphologically adapted to efficiently capture evasive fish prey. ...
The ecological impact of environmental changes at high latitudes (e.g., increasing temperature, and decreased sea ice cover) on low-trophic species, such as bowhead whales, are poorly understood. Key to understanding the vulnerability of zooplanktivorous predators to climatic shifts in prey is knowing whether they can make behavioural or distributional adjustments to maintain sufficient prey acquisition rates. However, little is known about how foraging behaviour and associated environmental conditions fluctuate over space and time. We collected long-term movement (average satellite transmission days were 397 (± 204 SD) in 2012 and 484 (± 245 SD) in 2013) and dive behaviour data for 25 bowhead whales (Balaena mysticetus) equipped with time-depth telemetry tags, and used hierarchical switching-state-space models to quantify their movements and behaviours (resident and transit). We examined trends in inferred two-dimensional foraging behaviours based on dive shape of Eastern Canada-West Greenland bowhead whales in relation to season and sea ice, as well as animal sex and age via size. We found no differences with regards to whale sex and size, but we did find evidence that subsurface foraging occurs year-round, with peak foraging occurring in fall (7.3 hrs d-1 ± 5.70 SD; October) and reduced feeding during spring (2.7 hrs d-1 ± 2.55 SD; May). Although sea ice cover is lowest during summer foraging, whales selected areas with 65% (± 36.1 SD) sea ice cover. During winter, bowheads occurred in areas with 90% (± 15.5 SD) ice cover, providing some open water for breathing. The depth of probable foraging varied across seasons with animals conducting epipelagic foraging dives (< 200 m) during spring and summer, and deeper mesopelagic dives (> 400 m) during fall and winter that approached the sea bottom, following the seasonal vertical migration of lipid-rich zooplankton. Our findings suggest that, compared to related species (e.g., right whales), bowheads forage at relatively low rates and over a large geographic area throughout the year. This suggests that bowhead whales have the potential to adjust their behaviours (e.g., increased time allocated to feeding) and shift their distributions (e.g., occupy higher latitude foraging grounds) to adapt to climate-change induced environmental conditions. However, the extent to which energetic consumption may vary seasonally is yet to be determined.
... Data in this thesis suggest that sampled Calanus finmarchicus are within 1‰ of the predicted values for each of the δ 13 C and δ 15 N for right whale prey (Eqns. 2 -3, below), thus indicating C. finmarchicus continues to be a nutrient source for North Atlantic right whales. This is in agreement with past research(Watkins & Schevill 1976, Meyer-Gutbrod & Greene 2018, Watkins & Schevill 1979 which concludes that C. finmarchicus is a key prey source for North Atlantic right whales.10.4 Review of hypothesesSIA has proven to be a useful tool for studying trophic dynamics and foraging ecology of marine mammals, especially whales. ...
Over the past two decades, the Gulf of Maine (GoM) has experienced an annual increase in sea surface temperature. Impacts to the marine ecosystem due to this thermal stress are not yet fully understood. One hypothesis suggests that the temperature increase has reduced productivity, thus affecting prey distribution. Tracking changes in prey choice is challenging; however, analytical methods such as stable isotope analysis (SIA) allow researchers to examine trophic dynamics in consumers over various time scales and assess ecological impact of possible oceanographic regime shifts. This thesis reports the results for the first two years of a five-year SIA study examining current trophic dynamics of GoM rorquals, including humpback (Megaptera novaeangliae) and fin (Balaenotera physalus) whales, using samples collected in situ via a crossbow-delivered biopsy dart. The results were compared to those from a previous GoM isotopic study completed prior to the warming period to assess any changes.
A multivariate analysis of the current data suggests fin whales (n = 2) have a lower
trophic level signature in comparison to humpbacks (n = 35), specifically due to differences in δ15N values. Recent δ13C values for humpbacks have shifted from historic values, becoming more negative in 2018 and becoming less negative in 2019, while δ15N values have remained statistically similar both years. Using isotopic fractionation constants, humpback isotopic values map well to contemporary samples of Atlantic herring (Clupea harengus), whose δ13C signals were more negative in 2018 than in 2019. This correlation supports the hypothesis that humpbacks continue to feed on herring, and that the variation in δ13C is a product of the change in the prey’s isotopic signature.
... Whales below the surface at depths that are 1-2 times the vessel's draft are also at risk, and even more vulnerable, due to the propeller suction effect (Silber et al., 2010). For whale populations, vessel strikes represent a form of additive mortality that is slow to be compensated for due to inherent low reproductive outputs Meyer-Gutbrod and Greene, 2018). A current example is the increase in vessel strikes of North Atlantic right whales (Eubalaena glacialis) , associated with the expansion of their summer foraging range into the Gulf of St. Lawrence (Davies and Brillant, 2019), which has positioned right whales directly within busy shipping lanes (Simard et al., 2019). ...
Collisions between vehicles and wildlife is a global conservation concern, and vessel strikes are a leading cause of serious injury and mortality for baleen whales. Yet vessel strikes have rarely been studied in the Arctic. Vessel traffic is increasing throughout the Arctic as sea ice is declining, leading to increased overlap between vessels and whales. We examined hypothetical vessel strike risk for the Bering-Chukchi-Beaufort (BCB) and Eastern Canada-West Greenland (ECWG) populations of bowhead whales during the open-water shipping season. We used satellite telemetry and aerial survey data to calculate monthly relative density of both populations, and satellite vessel tracking data to calculate monthly vessel density and speed. We estimated vessel strike risk by multiplying whale density by vessel density corrected by vessel speed. For the BCB population, the highest relative risk was near Utqiaġvik and Prudhoe Bay, Alaska, USA, and near Tuktoyaktuk, Northwest Territories, Canada. For the ECWG population, the highest risk was in the Gulf of Boothia, Cumberland Sound, and near Isabella Bay, Nunavut, Canada. Strike risk was highest in August and September, corresponding with monthly trends in vessel traffic. This study provides important information for focussed monitoring and to minimize/mitigate the threat of vessel strikes to bowhead whales. Although vessel strike risk is presently lower for these populations than for other temperate large cetacean populations, bowhead whale behaviour and projected increases in traffic elevates their risk in the Arctic. Measures to mitigate vessel strike risk to bowhead whales will likely benefit other Arctic marine mammals like beluga and narwhal.
... Additionally, anthropogenic disturbances such as fishery interactions (bycatch and entanglements), marine traffic (i.e. mortality by collision), pollution, and climate change still affect whales' survival (Meyer-Gutbrod & Greene, 2018). ...
Historical accounts of large whales in Peruvian waters existed before modern commercial whaling. Research on baleen and sperm (Physeter macrocephalus) whales was intense during whaling, thus producing essential knowledge on these species.
The populations of large whales have declined considerably with whaling pressure since 1925 in Peruvian waters. After the whaling moratorium in 1985, research on these species decreased, and a considerable gap in knowledge exists until nowadays. This review aims to conduct a historical analysis of the spatial distribution and abundance of baleen and sperm whales in the waters of Peru. During whaling, sperm whale distribution and abundance received most of the research effort as this species was the most important target of the whaling fleet. Also, blue (Balaenoptera musculus) and Bryde’s whale (B. edeni brydei) were considered abundant in Peru. Changes in their distribution and abundance were evaluated mainly based on captures or climatic events. Following the cessation of whaling, sightings of these species were restricted to occasional surveys, limiting the assessment of possible current changes in their distribution and abundance, as well as the updating of existing information. Humpback whales (Megaptera novaeangliae) were considered overexploited at the beginning of commercial whaling. After the moratorium, this species population started to grow, expanding its distribution along the northern coast. Currently, the humpback whale is the most studied species due to the onset of whale-watching activities in 2009. This allowed us to update and increase the knowledge about its distribution and abundance in northern Peru. The
findings of this study point at a need to considerably increase the research effort on large whales, particularly surveys to estimate population sizes of the species inhabiting the waters of Peru.
... The reduction in the number of breeding females has two contributing factors, a decline in the number breeding females post-2010, and a decline in the transition rate for non-breeding individuals to becoming breeding individuals. Female survival has been considered the key driving factor contributing to the recent decline (Corkeron et al., 2018); these results show that lack of pre-breeders starting to calve and so recruiting into the breeding cohort is also driving the decline, a point that has been missing from consideration of NARW conservation efforts, with current abundance estimates and population growth projections assuming maturity based upon an individual's age (Pace et al., 2017;Meyer-Gutbrod and Greene, 2018). By assuming maturity by age, individuals who delay first reproduction or never reproduce are grouped with breeding individuals which can bias projections by assuming a higher reproductive potential for the species. ...
Abundance and population trends of Critically Endangered North Atlantic right whales ( Eubalaena glacialis , NARW) have been estimated using mark-recapture analyses where an individual’s state is based upon set delineations of age, using historical estimates of age at first reproduction. Here we assigned individual females to states based upon their reproductive experience, rather than age. We developed a Bayesian mark-recapture-recovery model to investigate how survival, recapture, site-fidelity and dead-recovery probabilities vary for female NARW in different states, using data collected from 1977-2018. States were assigned as calves for individuals in their first year; pre-breeder for individuals greater than one year of age who had yet to produce a calf, or breeder if an individual had reproduced. A decline in abundance of female NARW was seen starting in 2014, with 185 females declining yearly to 142 by 2018. The largest decline was seen in breeding females, with 72 estimated to be alive at the beginning of 2018, while female pre-breeder abundance plateaued at around 70 between 2011- 2018. Females born from 2000 onwards had an average 4% (95% CI:0.03-0.06) chance of transitioning from pre-breeder to breeder, compared to 8% (95%CI:0.06-0.1) for females born prior. This reduction in transition rate from non-breeder to breeder for the current cohort resulted in breeding females declining to 51% of the female population by 2018. We show that a collapse in fecundity of breeding females, and the failure of pre-breeders to start breeding, is an important factor in understanding the current decline in abundance of the NARW.
... Many baleen whale, or mysticete, species were driven to near extinction because of commercial whaling by the mid-twentieth century . Since that time, the recovery of mysticete populations has been varied, ranging from the still critically endangered North Atlantic right whale (Eubalaena glacialis), to the slowly recovering blue whale (Balaenoptera musculus), to the rapidly recovering humpback whale (Megaptera novaeangliae, ). The different trajectories of these post-whaling mysticete population recoveries are linked to individual health parameters, such as body condition and reproductive productivity . ...
The large size of free-ranging mysticetes, such as humpback whales (Megaptera novaeangliae), make capture and release health assessments unfeasible for conservation research. However, individual energetic condition or reproductive health may be assessed from the gene expression of remotely biopsied tissue. To do this, researchers must reliably extract RNA and interpret gene expression measurements within the context of an individual's sex. Here, we outline an RNA extraction protocol from blubber tissue and describe a novel mammalian RNA sex determination method. Our method consists of a duplex reverse transcription-quantitative (real-time) polymerase chain reaction (RT-qPCR) with primer sets for a control gene (ACTB) and the X-chromosome inactivation gene (XIST). Products of each RT-qPCR had distinct melting temperature profiles based on the presence (female) or absence (male) of the XIST transcript. Using high-resolution melt analysis, reactions were sorted into one of two clusters (male/female) based on their melting profiles. We validated the XIST method by comparing results with a standard DNA-based method. With adequate quantities of RNA (minimum of approx. 9 ng µl⁻¹), the XIST sex determination method shows 100% agreement with traditional DNA sex determination. Using the XIST method, future cetacean health studies can interpret gene expression within the context of an individual's sex, all from a single extraction.
... Constant ocean dynamics reduce the governability of whale ES and imply that marine governance needs to be reflexive and adaptive (Koenigstein et al. 2016, Meyer-Gutbrod and Greene 2018, Richards et al. 2021. The stakeholder perspectives explored in the paper reveal the importance of considering local contexts in ES co-production and governance scale interplay, such as in Ecology and Society 27(2): 22 https://www.ecologyandsociety.org/vol27/iss2/art22/ the case of whale hunting and monitoring in Disko Bay, despite the embeddedness of whaling in the global governance system. ...
The social-ecological change in the Arctic is accelerated by the multifaceted effects of climate change and globalization. Among other things, this means changing human-ecosystem dynamics through altered availability, co-production, and governance of ecosystem services (ES). A group of species illustrative of this change are whales, migratory species that have played an important part in the culture and subsistence of Arctic communities for millennia. This study explores the changing human-nature interactions and whale ES governance by combining ES and interactive governance theories. A multi-method approach is applied to assess qualitatively the qualitative governability of whale ES in three Arctic coastal locations: Húsavík in Iceland, Andenes in Norway, and Disko Bay in Greenland. Based on a literature review, stakeholder mapping, observations, and analysis of 54 semi-structured stakeholder interviews, the study finds that whale ES governance involves multiple actors with differing preferences and values and that much of it happens outside of formal institutions, necessitating inclusive approaches to improve it. The study reveals some whale ES governance deficiencies and potentials, such as a mismatch between governance scales and a need for more formal governance practices based on scientific research and stakeholder inputs. Governance frameworks were present for provisioning whale ES related to whaling, but they were lacking for non-consumptive whale ES, such as whale watching. Addressing these issues can help to direct marine resource management toward sustainability by making it more inclusive, adaptive, and reflective of stakeholder needs and values. This goal could be advanced by applying the governance principles that view humans as an integral part of social-ecological systems, e.g., ecosystem stewardship and ecosystem-based management.
... Right whales are predicted to go extinct in less than 30 years (Meyer-Gutbrod and Greene, 2018). In addition to the issues caused by entanglements, shifts in right whale distributions, caused by climate change (e.g., changes in bottom water temperature, changes in prey abundance distribution, changes in temperature phenology, etc.), are causing management challenges. ...
Incorporating the effects of climate change in species management strategies is one of today's greatest conservation challenges. Mechanistic models can be used to address these challenges because they explain how climate change effects cascade through ecosystems and influence species distributions. We used structural equation models to test hypotheses about the cascading effects of climate change and basin-scale variables on the local abundance of North Atlantic right whales, a critically endangered species, in a historically important feeding habitat. We found that effects of the North Atlantic Oscillation, a basin-scale variable, on local right whale abundance occurred through a cascade of effects on other ecosystem variables, including chlorophyll a concentration, Calanus finmarchicus abundance, and zooplankton patchiness. These effects varied by month. We also found that the western Gulf of Maine spring thermal transition date (a proxy for climate change) is a major direct and indirect driver of variations in local right whale abundance. The indirect effect of earlier spring transition dates, through a pathway of prey abundance, suggested a decrease in local right whale abundance. However, right whale abundance increased because of the direct effect of regional spring transition date. The direct effect suggests that right whales may be using regional temperatures as a movement cue. The counteracting direct and indirect effects of spring transition date suggest that right whales could face a mismatch with their prey, which could ultimately result in another large-scale distribution shift. Our causal modeling approach demonstrates that the influence of climate change on local right whale abundance in the Gulf of Maine cascades through a network of variables. These cascading effects make predicting local right whale abundance challenging and suggest that successful endangered species conservation requires identifying the mechanisms underlying species distributions.
... In addition, the health of unimpacted NARW showed a significant decline in each F I G U R E 6 Summary of median health scores by decade for unimpacted whales prior to first entanglement detection and for entangled whales according to injury severity with health scores measured during each whale's entanglement health window. Values in each show the upper and lower whiskers (the most extreme point no more than 1.5 times the box range), the upper and lower hinge (approximately the first and third quantiles), and the median (Appendix S5) decade suggesting this model is detecting food limitation, which has been described in other studies (Meyer-Gutbrod & Greene, 2018;Rolland et al., 2016;Stewart et al., 2021), or other factors that could affect health. If food limitations or other factors were not occurring, we would have expected the unimpacted category to remain unchanged. ...
North Atlantic right whales frequently become entangled in fishing gear, which can negatively affect their reproductive output and probability of survival. We estimated individual whale health from a hierarchical Bayesian model fit to photographic indices of health. We reviewed 696 whales sighted from 1980 to 2011 and assigned 1196 entanglement events to 573 individuals in six categories of increasing injury severity and estimated monthly median health scores (0–100 scale) for the duration of their life within the study period. We then quantified the relationship between entanglement injury events and their severity with survival, reproduction, and population health. Severe entanglements resulted in worse health for all whales—males and females with severe injuries were eight times more likely to die than males with minor injuries. Females with severe injuries that survived had the lowest birth rates. Though the relationship between entanglement and fecundity was complex, we found that as the health of reproductively active females declined, their calving intervals increased. Unimpacted whale health scores declined significantly over three decades, 1980s, 1990s, and 2000s, suggesting food limitations may be contributing to population‐wide health declines. Decadal health scores of entangled whales showed a more notable reduction in health suggesting a clear and perhaps synergistic effect.
... From 2012 to 2020, right whales averaged only 10.1 calves per year, with no calves born in 2018 (Pettis et al., 2021). Under these conditions, the right whale population can only grow if there are no deaths from ship strikes or from entanglements in fishing ropes (Corkeron et al., 2018;Meyer-Gutbrod and Greene, 2018). Sublethal entanglements make it harder for right whales to grow, potentially contributing to lower reproductive success (Stewart et al., 2021). ...
The article by Meyer-Gutbrod and colleagues in this issue demonstrates that the endangered North Atlantic right whale’s preferred prey has declined as the Northwest Atlantic has warmed. Right whales are now spending more time foraging in historically colder habitats, but they are producing fewer calves. The low calf production could reflect a delay between the decline in the potential productivity of their traditional habitats and its increase in their new habitats. This delay would result in a “climate deficit” in their fitness. Right whales must also learn to forage successfully in their new habitats, creating an additional loss of fitness termed an “adaptation deficit.” Humans will also face unavoidable climate deficits, but we have more options for minimizing adaptation deficits.
... The latter work demonstrated that potential extinctions of marine mammals that were most at risk from global warming could induce a disproportionate loss of functional diversity in marine ecosystems. There are welldocumented shifts in the spatiotemporal distribution of cetaceans (e.g., Friday et al. 2013, Ramp et al. 2015, Meyer-Gutbrod and Greene 2018, pinnipeds (Szpak et al. 2018, e.g., Hückstädt et al. 2020, and polar bears (Ursus maritimus; e.g., Laidre et al. 2020) due to climate changeinduced ecosystem shifts. In addition, several other studies have documented the impact of localized anthropogenic activities on marine mammals, such as underwater noise, pollution, ship strikes, and over-harvesting of prey species (Davidson et al. 2012, Jepson et al. 2016, Azzellino et al. 2017, Scales et al. 2017, Abrahms et al. 2019). ...
Many cetacean species are at risk from anthropogenic disturbances including climate change, pollution, and habitat degradation. Identifying cetacean hotspots for conservation management is therefore required. Aotearoa–New Zealand waters are used by 53% of the world’s cetacean species and are a global cetacean diversity hotspot. Using geographic predictions of cetacean taxa, we aimed to identify important areas within New Zealand waters using two methods: estimates of cetacean richness and a spatial prioritization analysis. For both methods, we investigated how varying levels of uncertainty in predictions of the taxa’ occurrence layers would affect our interpretation of cetacean hotspots. Despite some marked spatial differences in distribution of important areas for cetacean diversity, both methods, across all uncertainty scenarios, highlighted six distinct deep offshore regions as important habitat. Generally, inshore areas had lower richness estimates than offshore areas, but these remain important for conservation for species with limited ranges (e.g., the endemic Māui and Hector’s dolphins), and in some places had similar richness values to offshore hotspots. Furthermore, inshore hotspots had lower uncertainty in predicted taxa distribution and richness estimates. The use of two different uncertainty estimates allows the integration of distributional information from differing sources (different modeling methods with varying numbers of cetacean records) to be integrated in a robust and conservative way. Identification of cetacean hotspots with varying levels of uncertainty provides a robust and efficient step toward prioritizing areas for conservation management in a participatory process.
... In contrast, right whale usage of traditional habitats located in eastern Canadian shelf waters was reduced over the last decade (Davis et al. 2017, Record et al. 2019. Historically, right whale occupancy of feeding habitats has varied with Calanus abundance (Baumgartner & Mate 2003, Patrician & Kenney 2010, Davies et al. 2015, and climate-driven changes in prey availability are a central hypothesis for explaining decadal-scale changes in foraging patterns (Greene et al. 2013, Meyer-Gutbrod et al. 2015, Greene 2016, Grieve et al. 2017, Meyer-Gutbrod & Greene 2018. However, the specific mechanisms by which environmental conditions influenced Calanus spp. ...
Starting ~2010, declines in Calanus finmarchicus and Calanus hyperboreus, the biomass dominant copepods on the northwest Atlantic shelf, coincide with notable ocean warming and a northward shift in endangered North Atlantic right whale (Eubalena glacialis) foraging habitat from the Bay of Fundy/Western Scotian Shelf to the southern Gulf of St. Lawrence (sGSL). Abundance changes in right whales’ prey, lipid-rich Calanus late stages, are known to relate to shifts in Calanus demography and changes in Calanus transport. Our objective was to investigate how these mechanistic drivers shaped potential whale preyscapes during the relatively cooler, high-abundance 2000′s vs the warmer, lower abundance 2010′s. Here, bio-physical Calanus model “Cool Year” and “Warm Year” simulations are used to quantify relative effects of the physical environment vs population level. Analysis is focused on the western sGSL, where right whales have recently been observed foraging in high numbers. Simulations indicate that Calanus variability is most strongly influenced by changes in advection from upstream areas, linked to river runoff and winds on the coastal Gaspé Current in late spring and summer. In the simulated Cool Year (2008), high runoff is associated with a strong Gaspé Current hugging the coastline and advection of Calanus into the western sGSL. Conversely, in the simulated Warm Year (2012), lower runoff led to a separation of the Gaspé Current from the coast, transporting Calanus eastward along the Laurentian Channel, away from Shediac Valley. Variation in population size drives changes in late stage Calanus delivery to the western sGSL in late summer and fall. Complementary analyses on the Western Scotian Shelf indicate that the source of Calanus to Roseway Basin can shift between the coastal Nova Scotia Current and Scotian Shelf slope water, but large declines in upstream population drive lower Warm Year abundance. Our findings inform marine managers about how Calanus high abundance areas may continue to change in the future.
... Whereas strategy 1 corresponds to the vital rates of 1995 in , where the authors note that the mortality has increased, especially in mother whales. Studies cited by Fujiwara and Caswell in , as well as more recent studies, attribute the increased mortality of mothers to: collisions with ships; entanglement with fishing gear; and, changes in prey availability caused by climate-associated fluctuations in prey availability [6,24,25]. The vital rates for strategy 1 lead to ρ 1 := r(A 1 ) = 0.9762. ...
An adaptive switching feedback control scheme is proposed for classes of discrete-time, positive difference equations, or systems of equations. In overview, the objective is to choose a control strategy which ensures persistence of the state, consequently avoiding zero which corresponds to absence or extinction. A robust feedback control solution is proposed as the effects of different management actions are assumed to be uncertain. Our motivating application is to the conservation of dynamic resources, such as populations, which are naturally positive quantities and where discrete and distinct courses of management actions, or control strategies, are available. The theory is illustrated with examples from population ecology.
... Additionally, long-term assessment of faecal hormones in right whales have yielded extensive data on the endocrine patterns expected for various reproductive states in this species (Rolland et al., 2005, Hunt et al., 2006. Because NARWs face increased anthropogenic and environmental pressures (fishing gear entanglements, vessel interactions, human-generated underwater noise, climate change and shifting prey distributions) and non-sustainable reproductive rates (Meyer-Gutbrod and Greene, 2017, Corkeron et al., 2018, Sharp et al., 2019, the availability of efficient and diverse tool sets to monitor stress and reproduction is critical to guiding management and recovery efforts (Harcourt et al., 2019). ...
As studies quantifying steroid hormones in marine mammal blubber progress, methodological refinements may improve the utility and consistency of blubber hormone measurements. This study advances blubber extraction methodologies by testing a simplified extraction protocol that reduces time and complexity compared to a protocol widely used in cetacean blubber studies. Using blubber samples archived from remote biopsy (n = 21 live whales) and necropsy collection (n = 7 dead whales) of North Atlantic right whales (NARW; Eubalaena glacialis) of known life history states, we performed analytical and biological validations to assess the feasibility of measuring reproductive (testosterone, progesterone) and glucocorticoid (cortisol) hormones in blubber via enzyme immunoassay following the simplified extraction. Analytical validations (parallelism, accuracy, extraction efficiency, repeatability) showed the simplified extraction produced similar results to the extended protocol, offering a more efficient and consistent technique. In live, apparently healthy whales, blubber testosterone concentrations (mean ± SE) were significantly higher in males (2.02 ± 0.36 ng/g) compared to females (0.81 ± 0.15 ng/g). Blubber progesterone was highest in a confirmed pregnant female (60.3 ng/g), which was 12-fold greater than the mean concentration of non-pregnant females (4.56 ± 0.88 ng/g). Blubber cortisol concentrations in whales that died from anthropogenic causes averaged 5.31 ± 2.28 ng/g, whereas most live, healthy whales had cortisol values below 1 ng/g. Among living whales, a whale actively entangled in fishing gear had the highest blubber cortisol measurement (3.51 ng/g), exhibiting levels similar to whales that died from acute entanglement (2.88 ± 0.42 ng/g). Overall, the highest blubber cortisol concentration (18.0 ng/g) was measured in a dead whale with a severe chronic entanglement, approximately 30-fold greater than mean blubber cortisol of apparently healthy whales (0.58 ± 0.11 ng/g). The methodological approach presented here provides a reference for researchers interested in an alternative, streamlined technique for hormone extraction of cetacean blubber and contributes to the diverse tool set for stress and reproductive assessments of endangered NARWs.
... Other studies on baleen whale reproductive rates have also shown responses to prey availability and oceanic conditions; specifically with changes in sea-ice conditions affecting temporal access to preferred feeding grounds (Moore & Huntington, 2008;Perryman et al., 2002), changes in the availability of their preferred copepod prey (Meyer-Gutbrod & Greene, 2018;Meyer-Gutbrod et al., 2015) and large-scale climate anomalies (Cartwright et al., 2019). Here, similar to previous reports in other cetacean populations (Kellar et al., 2017;Wasser et al., 2017), it appears that one of the drivers of the relationship between variation in environmental conditions and calving success could be the effects on foetal loss/calf survival, rather than on pregnancy rates alone. ...
Climate change has resulted in physical and biological changes in the world's oceans. How the effects of these changes are buffered by top predator populations, and therefore how much plasticity lies at the highest trophic levels, are largely unknown. Here endocrine profiling, longitudinal observations of known individuals over 15 years between 2004 and 2018, and environmental data are combined to examine how the reproductive success of a top marine predator is being affected by ecosystem change. The Gulf of St. Lawrence, Canada, is a major summer feeding ground for humpback whales (Megaptera novaeangliae) in the North Atlantic. Blubber biopsy samples (n = 185) of female humpback whales were used to investigate variation in pregnancy rates through the quantification of progesterone. Annual pregnancy rates showed considerable variability, with no overall change detected over the study. However, a total of 457 photo‐identified adult female sightings records with/without calves were collated, and showed that annual calving rates declined significantly. The probability of observing cow–calf pairs was related to favourable environmental conditions in the previous year; measured by herring spawning stock biomass, Calanus spp. abundance, overall copepod abundance and phytoplankton bloom magnitude. Approximately 39% of identified pregnancies were unsuccessful over the 15 years, and the average annual pregnancy rate was higher than the average annual calving rate at ~37% and ~23% respectively. Together, these data suggest that the declines in reproductive success could be, at least in part, the result of females being unable to accumulate the energy reserves necessary to maintain pregnancy and/or meet the energetic demands of lactation in years of poorer prey availability rather than solely an inability to become pregnant. The decline in calving rates over a period of major environmental variability may suggest that this population has limited resilience to such ecosystem change.
... Decline in food availability and poor body condition is known to cause reduced calving rates, and reproductive stress further challenging population recovery efforts (Christiansen et al., 2020;Meyer-Gutbrod et al., 2015;Rolland et al., 2016;Williams et al., 2013). Without improvement, the NARW population is predicted to reach extinction in less than 30 years (Meyer-Gutbrod and Greene, 2018). ...
An 8X15k oligonucleotide microarray was developed consisting of 2334 Eubalaena glacialis probes and 2166 Tursiops truncatus probes and used to measure the effects, at transcriptomic level, of cadmium exposure in right whale kidney fibroblast cells. Cells were exposed to three concentrations (1 μM, 0.1 μM, and 0.01 μM) of cadmium chloride (CdCl2) for three exposure times (1, 4, and 24 h). Cells exposed to 1 μM CdCl2 for 4 h and 24 h showed upregulated genes involved in protection from metal toxicity and oxidative stress, protein renaturation, apoptosis inhibition, as well as several regulators of cellular processes. Downregulated genes represented a suite of functions including cell proliferation, transcription regulation, actin polymerization, and stress fiber synthesis. The collection of differentially expressed genes in this study support proposed mechanisms of cadmium-induced apoptosis such as ubiquitin proteasome system disruption, Ca²⁺ homeostasis interference, mitochondrial membrane potential collapse, reactive oxygen species (ROS) production, and cell cycle arrest. The results also have confirmed the right whale microarray as a reproducible tool in measuring differentiated gene expression that could be a valuable asset for transcriptome analysis of other baleen whales and potential health assessment protocols.
... Our simulations showed that blue whales are in all likelihood well adapted to cope with fluctuations of 5%, but that they may incur considerable energy loss at higher density fluctuations. A link between food availability and calving rate has been documented in several species including blue whales (e.g., Ward et al., 2009;Seyboth et al., 2016;Meyer-Gutbrod and Greene, 2018). In blue whales from Antarctica, a simulated reduction of 50% in mean swarm density during an entire feeding season of 120 days resulted in an estimated 80% decrease in calving rate (Wiedenmann et al., 2011). ...
Blue whale survival and fitness are highly contingent on successful food intake during an intense feeding season. Factors affecting time spent at the surface or at depth in a prey patch are likely to alter foraging effort, net energy gain, and fitness. We specifically examined the energetic consequences of a demonstrated reduction in dive duration caused by vessel proximity, and of krill density reductions potentially resulting from krill exploitation or climate change. We estimated net energy gain over a simulated 10-h foraging bout under baseline conditions, and three scenarios, reflecting krill density reductions, vessel interactions of different amplitudes, and their combined effects. Generally, the magnitude of the effects increased with that of krill density reductions and duration of vessel proximity. They were also smaller when peak densities were more accessible, i.e., nearer to the surface. Effect size from a reduction in krill density on net energy gain were deemed small to moderate at 5% krill reduction, moderate to large at 10% reduction, and large at 25 and 50% reductions. Vessels reduced cumulated net energy gain by as much as 25% when in proximity for 3 of a 10-h daylight foraging period, and by up to 47–85% when continuously present for 10 h. The impacts of vessel proximity on net energy gain increased with their duration. They were more important when whales were precluded from reaching the most beneficial peak densities, and when these densities were located at deeper depths. When krill densities were decreased by 5% or more, disturbing foraging blue whales for 3 h could reduce their net energy gain by ≥30%. For this endangered western North Atlantic blue whale population, a decrease in net energy gain through an altered krill preyscape or repeated vessel interactions is of particular concern, as this species relies on a relatively short feeding season to accumulate energy reserves and to fuel reproduction. This study highlights the importance of distance limits during whale-watching operations to ensure efficient feeding, as well as the vulnerability of this specialist to fluctuations in krill densities.
... Continued warming of Arctic waters may result in the large, lipid-rich Arctic species being replaced with smaller temperate/subarctic species that thrive in warmer conditions and are comparatively lower in energy content (Beaugrand et al. 2002, Beaugrand 2009). Such ecosystem changes will likely alter the stability of current food web structures (McMeans et al. 2013) and impact the foraging success of zooplanktivorous marine predators, such as bowhead whales Balaena mysticetus (Meyer-Gutbrod & Greene 2018). ...
Climate change may affect the foraging success of bowhead whales Balaena mysti -cetusby altering the diversity and abundance of zooplankton species available as food. However,assessing climate-induced impacts first requires documenting feeding conditions under currentenvironmental conditions. We collected seasonal movement and dive-behaviour data from 25Eastern Canada−West Greenland bowheads instrumented with time-depth telemetry tags andused state-space models to examine whale movements and dive behaviours. Zooplankton sampleswere also collected in Cumberland Sound (CS) to determine species composition and biomass. Wefound that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement wasthe dominant behaviour in CS, suggesting that the tagged whales allocated considerable time tofeeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic cope-pods such as Calanus glacialisand C. hyperboreusduring summer. Dive behaviour changed sea-sonally in CS. Most notably, probable feeding dives were substantially shallower during springand summer compared to fall and winter. These seasonal changes in dive depths likely reflectchanges in the vertical distribution of calanoid copepods, which are known to suspend develop-ment and overwinter at depth during fall and winter when availability of their phytoplankton preyis presumed to be lower. Overall, CS appears to be an important year-round foraging habitat forbowheads, but is particularly important during the late summer and fall. Whether CS will remaina reliable feeding area for bowhead whales under climate change is not yet known.
... The current leading causes of mortality for right whales are entanglement in fishing gear and ship strikes (Johnson, Kraus, Kenney, & Mayo, 2007;Knowlton & Brown, 2007;Kraus et al., 2016). The long-term survival of the species is now considered uncertain, both because of these direct impacts of human activity (Corkeron et al., 2018;Kraus et al., 2016;Pennisi, 2017) and longer term threats from changing distribution of food resources as a result of climate change (Meyer-Gutbrod & Greene, 2018). ...
The North Atlantic right whale (Eubalaena glacialis) is one of the world's most highly endangered baleen whales, with approximately 400-450 individuals remaining. Massachusetts Bay (MB) and Cape Cod Bay (CCB) together comprise one of seven areas in the Gulf of Maine where right whales seasonally congregate. Here, we report on acoustically detected presence of right whales in MB over a nearly 6 year period, July 2007-April 2013, a time of both rapid ocean warming throughout the Gulf of Maine and apparent changes in right whale migratory dynamics. We applied an automated detection algorithm to assess hourly presence of right whale "up-calls" in recordings from a 19-channel acoustic array covering approximately 4,000 km2 in MB. Over the survey, up-calls were detected in 95% of 8 day periods. In each year, as expected, we observed a "peak season" of elevated up-call detections in late winter and early spring corresponding to the season when right whales congregate to feed in CCB. However, we also saw an increase in right whale occurrence during time periods thought to be part of the "off-season." With the exception of 2009-2010, when acoustic presence was unusually low, the mean percent of hours in which up-calls were detected increased every year, both during the peak season (from 38% in 2008 to 70% in 2012), and during the summer-fall season (from 2% in 2007 to 13% in 2012). Over the entire study, the peak season start date varied between 17 January and 26 February. Changes in right whale phenology in MB likely reflect broadscale changes in habitat use in other areas within the species range. This study demonstrates the value of continuous long-term survey datasets to detect and quantify shifts in cetacean habitat use as environmental conditions change and the long-term continued survival of right whales remains uncertain.
... Accidental collisions with ships that cause fatalities or serious injury are commonplace and are considered a serious threat for a number of coastal whales. For example, over half of the known mortalities in populations of North Atlantic right whales Eubalaena glacialis in recent decades have been from ship strike, endangering the survival of the species (Meyer-Gutbrod & Greene 2018). However, the issue of ship strike is not limited to cetaceans, which are particularly vul nerable because they must surface to breathe. ...
... However, the resulting plans can constrain opportunities for the fishing industry if the management action is conservative and overly lacking in flexibility for adjustments in space and time (Maxwell et al., 2015;Dunn et al., 2016). In addition, anomalous years can result in protected species shifting out of their normal habitats, where protections may be in place, and into unprotected waters, leading to crises such as mass entanglements of North Atlantic right whale (Eubalaena glacialis) in fishing gear during 2017 (Meyer-Gutbrod and Greene, 2018). ...
Worldwide fisheries management has been undergoing a paradigm shift from a single-species approach to ecosystem approaches. In the United States, NOAA has adopted a policy statement and Road Map to guide the development and implementation of ecosystem-based fisheries management (EBFM). NOAA’s EBFM policy supports addressing the ecosystem interconnections to help maintain resilient and productive ecosystems, even as they respond to climate, habitat, ecological, and social and economic changes. Managing natural marine resources while taking into account their interactions with their environment and our human interactions with our resources and environment requires the support of ecosystem science, modeling, and analysis. Implementing EBFM will require using existing mandates and approaches that fit regional management structures and cultures. The primary mandate for managing marine fisheries in the United States is the Magnuson-Stevens Fishery Conservation and Management Act. Many tenets of the Act align well with the EBFM policy, however, incorporating ecosystem analysis and models into fisheries management processes has faced procedural challenges in many jurisdictions. In this paper, we review example cases where scientists have had success in using ecosystem analysis and modeling to inform management priorities, and identify practices that help bring new ecosystem science information into existing policy processes. A key to these successes is regular communication and collaborative discourse among modelers, stakeholders, and resource managers to tailor models and ensure they addressed the management needs as directly as possible.
... ship strikes and entanglement in fisheries gear. Climate change is predicted to continue moving prey northward due to climatic forcing and decadal ecosystem shifts (Meyer-Gutbrod & Greene, 2018 For example, if a new haulout of pinnipeds emerges on ice or along shore, oil and gas operations are required to remain a sufficient distance away such that the haulout is not disturbed by noise or traffic (US Department of the Interior, 2015). ...
Important marine mammal areas (IMMAs) are discrete portions of habitat, important to marine mammal species, that have the potential to be delineated and managed for conservation. Although IMMAs are not a blueprint for marine protected areas or other conservation designations, they are useful for providing a foundation for marine spatial planning and systematic conservation planning that can then lead to protected areas or special spatial regulations. To be most useful for supporting management and conservation, however, the information coming out of IMMAs needs to reflect current conditions. An ‘early warning system’ is proposed with a generic set of indicators to flag when marine mammal species in IMMAs require management interventions due to changing distributions or decreasing populations. Rather than signifying that quantitative thresholds have been reached, these indicators comprise alerting information derived from visual or acoustic census, satellite imagery analysis, whale‐watching logs, or increases in mortality reported by stranding networks that can trigger additional targeted research. Although it is possible that in some regions data will be sufficient to provide quantifiable indicators, the system is meant to rely on existing data sources, and be adaptable to the circumstances of each region. Regional expert groups can utilize early warning system information and feed it into IMMA‐related spatial planning in two ways: by nominating additional areas of interest, and by providing a scientific rationale for revising IMMA boundaries, to be considered at the next decadal IMMA regional expert workshop. IMMA‐driven consolidation of information that is as current as possible will prove valuable for enhancing regional cooperation to conserve marine mammals, and will be useful as countries implement new protected areas to conserve marine mammals and other marine biodiversity.
Northward range shifts are increasingly being identified in mobile animals that are responding to climate change. Range shifts are consequential to animal ecology, ecosystem function, and conservation goals, yet for many species these cannot be characterised without means of synoptically measuring their distribution. The distribution of critically endangered North Atlantic right whale (Eubalaena glacialis; NARW) north of 45°N has been largely unknown due to a lack of systematic monitoring. The objectives of this study were to characterize the spatial and temporal variation in NARW acoustic occurrence in the northern portion of their foraging range. In addition, we sought to identify relevant NARW migratory corridors and explore potential previously unidentified high-use habitats beyond the highly surveyed Gulf of St. Lawrence (GSL). To achieve this, passive acoustic monitoring data were collected and analyzed from 67 moorings and 13 gliders deployed (across 38 recording stations) throughout the Atlantic Canadian continental shelf, between 42°N and 58°N during 2015 through 2017. The results support that while a portion of the population has moved northward into the GSL, this shift was constrained to temperate latitudinal ranges < 52°N during the study period. NARWs were not detected in the Labrador Sea and Newfoundland Shelf, despite their preferred prey occurring in those areas. NARWs were present on the Scotian Shelf (45°N) nearly year-round, but only from May through December in the Cabot Strait (50°N). These results indicate that the northern range of the population is probably influenced by energetic requirements to minimize the distance between suitable foraging habitat and low latitude calving grounds, rather than an absence of suitable foraging conditions in high latitude waters, or other environmental or physiological factors. This work provides critical information to conserve the species and mitigate human-induced risks.
Context Shipping impacts are a major environmental concern that can affect the behaviour and health of marine mammals and fishes. The potential impacts of shipping within marine parks is rarely considered during the planning process. Aims We assessed the areal disturbance footprint of shipping around Australia, its overlap with marine parks, and known locations of megafauna, so as to identify areas of concern that warrant further investigation. Methods Automatic Identification System (AIS) shipping data from 2018 to 2021 were interpreted through a kernel-density distribution and compared with satellite data from ∼200 individuals of megafauna amalgamated from 2003 to 2018, and the locations of marine parks. Key results Over 18% of marine parks had shipping exposure in excess of 365 vessels per year. Around all of Australia, 39% of satellite-tag reports from whale shark and 36.7% of pygmy blue and humpback whale satellite-tag reports were in moderate shipping-exposure areas (>90 ships per year). Shipping exposure significantly increased from 2018 despite the pandemic, including within marine parks. Conclusions These results highlight the wide-scale footprint of commercial shipping on marine ecosystems that may be increasing in intensity over time. Implications Consideration should be made for assessing and potentially limiting shipping impacts along migration routes and within marine parks.
Changes in the physical oceanography of the Northwest Atlantic stemming from both natural and anthropogenic climate change impact the foraging ecology and distribution of endangered North Atlantic right whales. In this study, right whale sightings from 1990 to 2018 were analyzed to examine decadal patterns in monthly habitat use in 12 high‐use areas. Depth‐integrated abundances of late‐stage Calanus finmarchicus and Calanus hyperboreus were also analyzed for decadal variations in the right whale foraging habitats. There were significant differences in the occurrence, seasonal timing, and persistence of foraging habitats across these three decades. In the decades of the 1990s and the 2010s, prey was less abundant than in the 2000s, corresponding to reduced use of the Southeast US calving grounds in the winter, increased use of Cape Cod Bay in winter and spring, and reduced use of Roseway Basin in the fall. In the 2010s, right whale sightings increased in Southern New England and the Gulf of St. Lawrence in the spring and summer, respectively. Summertime declines in the 2010s in late‐stage copepod abundances in the Gulf of Maine and surrounding regions, as well as in the Gulf of St. Lawrence, indicate that recent increased use of the Gulf of St. Lawrence is driven by a decline in prey in traditional foraging habitats rather than by an increase in prey in the new foraging habitat. This analysis of decadal‐scale differences in right whale sightings and prey abundance is critical for redefining right whale distribution patterns for the most recent (post‐2010) decade.
North Atlantic right whale (NARW) distribution shifts have led to increased presence in the US mid‐Atlantic, which includes the New York Bight (NYB), an area with substantial vessel traffic. NARW vessel strikes are mitigated by a seasonal management area (SMA) that is active November–April. Within the SMA, vessels ≥ 19.8 m must travel at ≤10 knots. However, until recently, surveys of the NYB were not conducted after the NARW distribution shifted. Thus, it was unclear whether the SMA captured NARW presence in the NYB. Outside the SMA, voluntary speed restrictions are implemented over a limited area when NARW calls are acoustically detected; therefore, it was important to quantify NARW vocal activity. Acoustic recordings (2016–2020) were analyzed to determine NARW presence, vocal states, and diel pattern of vocal activity. NARWs were detected outside SMA boundaries, and medium/high vocal states (21–69 calls over 3–6 h) occurred while the SMA was inactive. Therefore, the SMA spatiotemporal boundaries should be revised. Vocal activity was highest at night (22:00–1:00), and NARWs were acoustically detected when they were not detected by aerial surveys, illustrating acoustic detections are a viable method for triggering mitigation measures when NARWs are vocalizing but are not visually observed.
Climate change is affecting species distributions in space and time. In the Gulf of Maine, one of the fastest-warming marine regions on Earth, rapid warming has caused prey-related changes in the distribution of the critically endangered North Atlantic right whale (Eubalaena glacialis). Concurrently, right whales have returned to historically important areas such as southern New England shelf waters, an area known to have been a whaling ground. We compared aerial survey data from two time periods (2013–2015; 2017–2019) to assess trends in right whale abundance in the region during winter and spring. Using distance sampling techniques, we chose a hazard rate key function to model right whale detections and used seasonal encounter rates to estimate abundance. The mean log of abundance increased by 1.40 annually between 2013 and 2019 (p = 0.004), and the mean number of individuals detected per year increased by 2.23 annually between 2013 and 2019 (R2 = 0.69, p = 0.001). These results demonstrate the current importance of this habitat and suggest that management options must continually evolve as right whales repatriate historical habitats and potentially expand to new habitats as they adapt to climate change.
Oceanic fronts constitute boundaries between hydrologically distinct water masses and comprise one of the most productive regions of the world’s ocean. Fronts associated with density gradients (active fronts) profoundly structure planktonic communities in adjacent waters, but less is known about the impacts of density-compensated (passive) fronts. Two such fronts are found in the European Arctic, the Arctic Front (AF) and the Polar Front (PF), that both separate warmer and saltier, Atlantic water from the colder, but fresher Arctic water. As scrutinized research on the influence of passive fronts on zooplankton at large spatial and temporal scales had been lacking, we tackled the question of their role in maintaining distinct communities, employing globally unique, 12-year-long gelatinous zooplankton (GZ) and hydrological time series from the European Arctic. The GZ, owing to their fast reproductive cycles and passive dispersal, reflect particularly well the local environment. We therefore compared GZ communities between zones separated by the two fronts, disentangled their drivers, and analyzed community shifts occurring whenever front relocation occurred. We have identified fifteen GZ taxa, distributed among three distinct communities, specific for front-maintained zones, and selected the following taxa as indicators of each zone: W—west of the AF, within the Greenland Sea Gyre, Beroe spp.; C—central, in between the AF and the PF, Aglantha digitale; and E—east of the PF, in the West Spitsbergen Shelf Mertensia ovum. Taxonomic composition of these communities, and their specific abundance, persisted throughout time. We also showed that relocation of either front between the sampling years was subsequently followed by the restructuring of the GZ community. Our results indicate that passive oceanic fronts maintain distinct GZ communities, with probable limited exchange across a front, and provide a new perspective for the Arctic ecosystem evolution under progressing Atlantification.
The critically endangered North Atlantic right whale population (Eubalaena glacialis) has experienced multiple periods of decreased reproduction within its observable history, which have played a role in the overall decline of the species. In addition to this synchronized variation in reproduction across the population, there exists considerable individual variation in fecundity. To determine the impacts of family history and habitat use behavior on these individual variations in fecundity, photo identification data collected during four decades of visual monitoring were used to create a calving index for sexually mature females that could be used to evaluate matrilineal influence on fecundity. Reproductive life histories were analyzed to assess fecundity variation within matrilines over time. Individual variations in fecundity were also assessed with respect to a recent climate-driven habitat distribution shift by a loyal cohort of right whales that use the Gulf of St. Lawrence during the summer and autumn seasons. Lifetime fecundity in the oldest known living reproductive female, or matriarch, in a matriline was positively associated with the fecundity of her female progeny. Sexually mature females that have used the Gulf of St. Lawrence since 2015 were significantly more likely to give birth over this time period compared to individuals who did not use that habitat. Individuals of both sexes were significantly more likely to use the Gulf of St. Lawrence if their mothers did as well; however, this association declined as offspring aged. These results provide insight on the environmental, behavioral, and genetic factors that contribute to individual variation in fecundity. Low calving rates and increased dangers posed by habitat use shifts in the past decade have played a major role in the species' decline, and these new insights into the mechanistic drivers of right whale reproduction and habitat use show that lineage guides progeny behavior and reproductive success. As anthropogenic climate change continues to disrupt right whale seasonal distributions through changing ocean circulation patterns, understanding the demographic consequences of novel habitat use patterns will be essential to updating protective policies.
Climate change is a relevant threat on a global scale, leading to impacts on ecosystems and ocean biodiversity. A considerable fraction of marine life depends on sound. Marine mammals, in particular, exploit sound in all aspects of their life, including feeding and mating. This work explores the impact of climate change in sound propagation by computing the three‐dimensional global field of underwater sound speed. The computation was performed based on present conditions (2006–2016) and a “business‐as‐usual” future climate scenario (Representative Concentration Pathway 8.5), identifying two “acoustic hotspots” where larger sound speed variations are expected. Our results indicate that the identified acoustic hotspots will present substantial climate‐change‐induced sound speed variations toward the end of the century, potentially affecting the vital activities of species in the areas. Evidence is provided of the impact of such variation on underwater sound transmission. As an example of a species impacted by underwater transmission, we considered one marine mammal endangered species, the North Atlantic right whale (Eubalaena glacialis), in the northwestern Atlantic Ocean. To the best of our knowledge, this is the first global‐scale data set of climate‐induced sound speed changes expected under a future scenario. This study provides a starting point for policies oriented research to promote the conservation of marine ecosystems and, in particular, endangered marine mammals.
If you could somehow ask a North Atlantic right whale what she thinks the future holds, what would she say? Right whales must, in some way, think about the future in order to make survival decisions. As an ocean science community, our eyes are trained increasingly on the future as well. The twin global environmental crises of climate change and biodiversity loss have elevated the science of real-world prediction to one of urgent interest. At timescales ranging from hours to decades, society is asking ocean science for actionable predictions, projections, and forecasts, with the hope of mitigating and adapting to the changing ocean. Meeting this challenge requires more than the ability to predict ocean dynamics.
Ocean warming linked to anthropogenic climate change is impacting the ecology of marine species around the world. In 2010, the Gulf of Maine and Scotian Shelf regions of the Northwest Atlantic underwent an unprecedented regime shift. Forced by climate-driven changes in the Gulf Stream, warm slope waters entered the region and created a less favorable foraging environment for the endangered North Atlantic right whale population. By mid-decade, right whales had shifted their late spring/summer foraging grounds from the Gulf of Maine and the western Scotian Shelf to the Gulf of St. Lawrence. The population also began exhibiting unusually high mortality in 2017. Here, we report that climate-driven changes in ocean circulation have altered the foraging environment and habitat use of right whales, reducing the population’s calving rate and exposing it to greater mortality risks from ship strikes and fishing gear entanglement. The case of the North Atlantic right whale provides a cautionary tale for the management of protected species in a changing ocean.
This study addresses the problem of determining optimal design of passive acoustic monitoring (PAM) systems for detecting and localizing whale calls in real-time in variable-noise environments. The performance of various PAM system is assessed using the detection theory and simulation modeling applied to the context of North Atlantic right whale (NARW) upcalls in feeding grounds and noisy shipping corridor of the Gulf of St. Lawrence. Realistic simulations are performed using an estimated NARW upcall source level (SL), the actual shipping traffic, measured local fleet ship SLs, and transmission loss (TL) from a regional 2.5-D propagation model accounting for the bathymetric and environmental structures. The comparisons consider single-hydrophone and hydrophone-array PAM systems, mounted on buoys, gliders, or cabled to shore and three families of NARW upcall detectors. The targeted performance is a low false-alarm rate of 1 per day and a detection probability > 0.5. The time-frequency-based detector offers the best trade-off between detection performance and robustness against NARW upcall variability. The effective detection ranges are ∼ 15 times lower with single-hydrophone systems compared to hydrophone-arrays, whose beamforming enhances the signal in the upcall direction while damping interfering discrete noise from nearby transiting ships in other directions. Detecting and localizing NARWs in the large target areas (>10000-km² scale) is possible with a few well-located arrays of 10–20 hydrophones, which appears as the optimal cost/performance trade-off.
The nutraceutical market for EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) is promoting fishing for Euphasia superba (Antarctic krill) in the Southern Ocean and Calanus finmarchicus in Norwegian waters. This industry argues that these species are underexploited, but they are essential in their ecosystems, and climate change is altering their geographical distribution. In this perspective, we advocate the cessation of fishing for these species to produce nutraceuticals with EPA and DHA. We argue that this is possible because, contrary to what this industry promotes, the benefits of these fatty acids only seem significant to specific population groups, and not for the general population. Next, we explain that this is desirable because there is evidence that these fisheries may interact with the impact of climate change. Greener sources of EPA and DHA are already available on the market, and their reasonable use would ease pressure on the Arctic and Antarctic ecosystems.
Shipping is responsible for transporting 90% of the world's trade. This book provides a comprehensive review of the impact shipping has on the environment. Topics covered include pollutant discharges such as atmospheric emissions, oil, chemical waste, sewage and biocides; as well as non-pollutant impacts including invasive species, wildlife collisions, noise, physical damage, and the environmental effects associated with shipwrecks and shipbreaking. The history of relevant international legislation is also covered. With chapters written by eminent international authors, this book provides a global perspective on the environmental impact of ships, making it a useful reference for advanced students and researchers of environmental science, as well as practitioners of maritime law and policy, and marine business.
Conservation physiology tools can be difficult to employ in the wild. Here we discuss developments in conservation physiology research of large whales, a taxonomic group that is famously difficult to study with traditional tools. We focus on the North Atlantic right whale ( Eubalaena glacialis ) and southern right whale ( Eubalaena australis ), two closely related species that present similar logistical challenges for research, yet differ in population status and conservation pressures. Research has advanced via a suite of creative approaches including photo-identification, visual health assessment, remote methods of assessing body condition, and endocrine research on non-plasma sample types such as faeces, respiratory vapour, and baleen. These efforts have illuminated conservation-relevant physiological questions for both species, such as discrimination of acute from chronic stress, identification of likely causes of mortality, and monitoring causes and consequences of changes in body condition and reproduction.
The Atlantification of the European Arctic has been an increasingly discussed topic in polar science over the past two decades. The alteration of local marine ecosystems towards a more temperate state and the appearance/range expansion of subarctic-boreal species at higher latitudes is a complex phenomenon induced mainly by the changing properties of Atlantic water (AW) transported from the south. Areas under the direct influence of AW experience biological Atlantification of their communities on all trophic levels, resulting in the growing complexity of arctic food webs. Here, besides summarising the main documented messages of biological Atlantification, we take a critical view on the threat posed on Arctic marine communities. We take into account the formation of the Arctic marine fauna, as well as the nature of (re)colonisation of Arctic sites by boreal organisms when evaluating the extent of the issue. We take a look at the history of Arctic colonisations by boreal organisms in an attempt to identify ‘neonative taxa returning home’. We also highlight the role of floating plastic debris as an ‘instrument from the toolbox of the Anthropocene’ aiding the distribution of marine taxa.
Climate-induced changes in calanoid copepod ( Calanus spp.) availability in traditional feeding areas might explain why a large proportion of the North Atlantic right whale Eubalaena glacialis population has fed in the Gulf of St. Lawrence (Canada) in recent years. However, little is known about the distribution of copepods in the gulf, and whether their abundance is sufficient to energetically sustain right whales. We used a mechanistic modelling approach to predict areas within the gulf that have foraging potential for adult female right whales, based on the annual energetic needs of resting, pregnant and lactating females, and their theoretical prey density requirements. We identified suitable foraging areas for right whales by coupling a foraging bioenergetics model with a 12 yr data set (2006-2017) describing the abundance and 3-dimensional distribution of late-stage Calanus spp. in the gulf. Prey densities in the southern gulf (from Shediac Valley to the Magdalen Islands) supported all 3 reproductive states in most (≥6) years. However, foraging habitat became progressively sparse in the southern gulf over time, with noticeably less suitable habitat available after 2014. Few other potentially suitable foraging areas were identified elsewhere in the gulf. Overall, the availability of foraging habitat in the gulf varied considerably between years, and was higher for resting females than for pregnant and lactating females. Our findings are consistent with the recent low calving rates, and indicate that prey biomass in the Gulf of St. Lawrence may be insufficient in most years to support successful reproduction of North Atlantic right whales.
The endangered St. Lawrence Estuary (SLE) beluga population is declining and has shown no sign of recovery over the past decades despite several protective measures. Changes in the availability of food resources and exposure to organohalogen contaminants have been suggested as potential factors limiting the recovery of this population. Studies on SLE belugas have suggested that contaminant exposure may perturb energy metabolism, however, whether this translates into changes in energy reserves (lipid composition) and body condition is unknown. The objective of this study was to investigate the relationships between body condition and concentrations of organohalogens (polychlorinated biphenyls, organochlorine pesticides, and flame retardants) and a range of lipid metabolites (fatty acids, acylcarnitines, lysophosphatidylcholines, phosphatidylcholines, and sphingomyelins) in blubber samples collected from 51 SLE beluga carcasses recovered between 1998 and 2016 for which the cause of mortality was documented. Blubber Σ 9 fatty acid concentrations in SLE belugas significantly decreased between 1998 and 2016, suggesting a decline in energy reserves over the past two decades. Concentrations of several phosphatidylcholine analogues were greater in blubber of beluga males and/or females that were in poor body condition compared to those in good body condition. Moreover, concentrations of phosphatidylcholine acyl-alkyl C32:2 were greater in females that died from primary starvation (poor body condition). Greater concentrations of Σ 12 emerging flame retardants were also found in blubber of SLE beluga females that were in poorer body condition. This study suggests that the use of membrane lipids including phosphatidylcholine concentrations may be a good indicator of body condition and energy reserve status in blubber of marine mammals.
Oceanic top predators, the marine ecosystems that support them and dependent socio-economic systems have been the subject of studies by researchers under the Climate Impacts on Oceanic Top Predators (CLIOTOP) regional programme since 2005. Research conducted under the programme has focused on how climate change is affecting the pelagic ocean, with a range of impacts detected or predicted for open ocean biology, and provision of ecosystem services such as food. Research has also focused on exploring the socio-economic consequences of oceanic change, and in some cases, evaluating the adaptation options that can reduce the vulnerability to climate change. In this special issue, 18 papers arising from the 4th CLIOTOP symposium, held in Keelung, Taiwan Republic of China in October 2018, report on a wide range of predator responses to historical climate variability, and changes in marine systems associated with climate change and commercial fishing. They describe new frameworks and approaches for understanding the population and spatial dynamics, trophodynamics, and future distributions of a range of species as well as identifying individual drivers of change and future risks to populations. Several contributions further our understanding of the trophic linkages between prey and predators and the pathways through which the environment can influence predators. Research conducted through collaborations facilitated by CLIOTOP align with several of the goals set out under the 2030 Agenda for Sustainable Development and a number of the challenges identified as needing to be addressed in order to achieve the societal outcomes of the UN Decade of Ocean Science for Sustainable Development 2021-2030. Setting future research directions that maximise the potential of the network of scientists contributing to the CLIOTOP programme will assist in progressing the science required for achieving a sustainable future.
North Atlantic right whales (Eubalaena glacialis) feed and migrate in areas of the inshore and offshore trap fishery for American lobster (Homarus americanus) in the Northeast U.S. In addition to a recent increase in lethal and sub-lethal interactions with Canadian snow crab gear, entanglement in both Canadian and U.S. lobster trap gear threatens the continued existence of this endangered species. The U.S. National Marine Fisheries Service is considering a number of measures to prevent right whale entanglement bycatch that could impact lobster fishing effort. The U.S. lobster fishery in Maine expends approximately 7.5 times as much effort as the Canadian fishery in Lobster Fishing Area 34, where Canadian fishers catch about 3.7 times more lobster per trap than their counterparts in Maine. From 2007 to 2013 in Maine, lobster landings doubled as the number of traps fell 10.5% and landings per trap increased by about 125%. The state of Massachusetts has achieved record high landings since trap/pot seasonal closures have been implemented to protect right whales, especially within the Statistical Reporting Areas most affected by the closures. Therefore, a negative economic impact should not be assumed with effort reduction. In fact, reducing effort may serve to increase fishing profits while supporting the protection of endangered North Atlantic right whales and the long-term sustainability of the lobster fishery.
North Atlantic right whales (NARW) are one of the most endangered marine animals with a global population of ~400 individuals left. Recent climate-driven shifts in distribution have significantly increased their mortality risk from human activities. After twelve NARWs died in the Gulf of St. Lawrence in 2017 from fishing gear entanglement and ship strikes, Canada adopted measures designed to decrease overlap between these whales and relevant threats. Real-time monitoring of whale distribution combined with dynamic management of shipping corridors and fishing areas proved to be effective in reducing regional mortality to zero in 2018. Yet, this complex system was expensive to implement and caused tension with affected sectors. Following stakeholder consultations, Canada modified the system of static and dynamic measures for the 2019 season. These measures were less effective and eight observed right whale deaths triggered additional emergency responses. This paper reviews scientific and legal tools that were used to implement spatial management of NARW and marine activities between 2017 and 2019. It identifies key legislation that directs the government to protect NARW, such as the Species at Risk Act (SARA), as well as the regulatory tools under the Fisheries Act and Canada Shipping Act and discusses weaknesses in the implementation of these legal frameworks that contributed to compromised outcomes. The paper concludes with recommendations designed to promote recovery and protect endangered species that may undergo similar changes in distributions and threats under ongoing climate and environmental change. The need to strengthen the role of Canada's Species at Risk Act in future conservation efforts is highlighted, specifically the need to address the effects of climate change in recovery planning and the importance of expanding critical habitat protections.
North Atlantic right whales (Eubalaena glacialis) once occurred seasonally in Irish waters but in recent decades their presence has declined. This study reviews the existing literature to develop an understanding of the past distribution of North Atlantic right whales, their abundance, temporal occurrence, interspecies associations and apparent use of Irish waters. Ancillary information supporting these core aims was investigated to provide a context for the historical misidentification of North Atlantic right whales and the development of Irish whaling to evaluate the presence of this species in Irish waters. Records of the species within the Irish Exclusive Economic Zone (EEZ), between 1300—1987 were validated based on the available data to three confidence levels: definite, probable and possible right whales. Seventeen records comprising at least 42 individual whales exist (including probable Basque whaling effort from the fourteenth century to the sixteenth century). Of the records available, 52% were considered ‘definitely’ right whales with eight comprising 22 individuals from two early twentieth century and two mid-seventeenth century commercial whaling stations operating in the northwest of Ireland. Six ‘probable’ right whale records involving 15 individuals were identified, including two sightings from the late twentieth century while two ‘possible’ records of five individuals were also noted. The previous importance of Ireland's north western coastline as a potential early summer feeding area in the Northeast Atlantic for migrating right whales, along with the apparent extirpation of the species in the region are also discussed.
This paper contributes to documenting a change in the distribution of North Atlantic right whales Eubalaena glacialis (NARWs) that occurred in the 2010s, when the whales largely abandoned their traditional summering grounds in the Gulf of Maine/Bay of Fundy/Scotian shelf. Data from a year-round passive acoustic monitoring (PAM) network in the Gulf of St. Lawrence were exploited to build the time series of NARW incursions into this inland sea of the Northwest Atlantic, from June 2010 to November 2018. NARWs visited the southern Gulf of St. Lawrence every year from June to January, until ice freeze-up. The earliest detections were made at the end of April and the latest in mid-January. Call occurrence peaked between August and the end of October. NARW contact calls were not detected at the most upstream station at Les Escoumins, in the Lower St. Lawrence estuary, or at the northeastern connection of Belle Isle Strait with the Atlantic, which was monitored from November 2010 to November 2011. The mean daily occurrence of NARWs in the feeding grounds off Gaspé quadrupled after 2015 compared to 2011-2014. Long-term continuous PAM data provided invaluable information to document this marine mammal distribution shift.
How and why collapses occur according to the science of complex systems. Includes a section on the networked structure of complex systems and a chapter featuring “Amelia the Amoeba,” Ugo Bardi’s unicellular assistant, whose descendants in a Petri dish experience all kinds of collapses.
Determining reproductive rates of marine mammal populations can give insight into their persistence and resilience in changing environments. As our marine environments continue to degrade along developed coastal fringes and as mankind’s influences extend across even our widest oceans, there is a concern that the reproductive functioning of marine mammals may be affected adversely. Since many marine mammal species and populations are still in the recovery phase post-commercial harvest, and yet others are endangered or threatened by ongoing pressures, further environmental changes may represent direct or indirect threats to their reproductive potential. In this chapter, we review the current methods employed to investigate various aspects of reproductive science in fully-marine mammals, including direct observation of reproductive behavior and output, endocrinology to determine reproductive state, and assisted reproductive technologies to enhance reproductive outcomes. In particular, we focus on the most recent developments and innovations to reproductively sample marine mammals. Two case studies are presented to illustrate the challenges thrown up to researchers studying free-ranging marine mammals, and to highlight diversity in research approach. The North Atlantic right whale is on the brink of extinction through historic overharvest and present-day entanglement and ship strike. Environmental disruption to their migration routes and declining population health has resulted in reduced reproductive rates. In contrast, the main current threats to the reproductive success and survival of the vulnerable dugong are extreme weather events that affect availability of its seagrass diet. Climate disruption with increasingly severe coastal storms and flooding threaten the health of coastal seagrass beds, and consequently reproductive success and survival of this species. It is anticipated that climate change may have diverse and often serious effects on marine mammal reproduction in populations around the globe.
North Atlantic right whales (Eubalaena glacialis Müller 1776) present an interesting problem for abundance and trend estimation in marine wildlife conservation. They are long lived, individually identifiable, highly mobile, and one of the rarest of cetaceans. Individuals are annually resighted at different rates, primarily due to varying stay durations among several principal habitats within a large geographic range. To date, characterizations of abundance have been produced that use simple accounting procedures with differing assumptions about mortality. To better characterize changing abundance of North Atlantic right whales between 1990 and 2015, we adapted a state–space formulation with Jolly-Seber assumptions about population entry (birth and immigration) to individual resighting histories and fit it using empirical Bayes methodology. This hierarchical model included accommodation for the effect of the substantial individual capture heterogeneity. Estimates from this approach were only slightly higher than published accounting procedures, except for the most recent years (when recapture rates had declined substantially). North Atlantic right whales' abundance increased at about 2.8% per annum from median point estimates of 270 individuals in 1990 to 483 in 2010, and then declined to 2015, when the final estimate was 458 individuals (95% credible intervals 444–471). The probability that the population's trajectory post-2010 was a decline was estimated at 99.99%. Of special concern was the finding that reduced survival rates of adult females relative to adult males have produced diverging abundance trends between sexes. Despite constraints in recent years, both biological (whales' distribution changing) and logistical (fewer resources available to collect individual photo-identifications), it is still possible to detect this relatively recent, small change in the population's trajectory. This is thanks to the massive dataset of individual North Atlantic right whale identifications accrued over the past three decades. Photo-identification data provide biological information that allows more informed inference on the status of this species.
Individuals store energy to balance deficits in natural cycles; however, unnatural events can also lead to unbalanced energy budgets. Entanglement in fishing gear is one example of an unnatural but relatively common circumstance that imposes energetic demands of a similar order of magnitude and duration of life-history events such as migration and pregnancy in large whales. We present two complementary bioenergetic approaches to estimate the energy associated with entanglement in North Atlantic right whales, and compare these estimates to the natural energetic life history of individual whales. Differences in measured blubber thicknesses and estimated blubber volumes between normal and entangled, emaciated whales indicate between 7.4 × 1010 J and 1.2 × 1011 J of energy are consumed during the course to death of a lethal entanglement. Increased thrust power requirements to overcome drag forces suggest that when entangled, whales require 3.95 × 109 to 4.08 × 1010 J more energy to swim. Individuals who died from their entanglements performed significantly more work (energy expenditure × time) than those that survived; entanglement duration is therefore critical in determining whales’ survival. Significant sublethal energetic impacts also occur, especially in reproductive females. Drag from fishing gear contributes up to 8% of the 4-year female reproductive energy budget, delaying time of energetic equilibrium (to restore energy lost by a particular entanglement) for reproduction by months to years. In certain populations, chronic entanglement in fishing gear can be viewed as a costly unnatural life-history stage, rather than a rare or short-term incident.
Climate change became real for many Americans in 2012 when a record heat wave affected much of the United States, and Superstorm Sandy pounded the Northeast. At the same time, a less visible heat wave was occurring over a large portion of the Northwest Atlantic Ocean. Like the heat wave on land, the ocean heat wave affected coastal ecosystems and economies. Marine species responded to warmer temperatures by shifting their geographic distribution and seasonal cycles. Warm-water species moved northward, and some species undertook local migrations earlier in the season, both of which affected fisheries targeting those species. Extreme events are expected to become more common as climate change progresses (Tebaldi et al., 2006; Hansen et al., 2012). The 2012 Northwest Atlantic heat wave provides valuable insights into ways scientific information streams and fishery management frameworks may need to adapt to be effective as ocean temperatures warm and become more variable.
Opportunistic reports were used to measure levels of human-caused serious injury and
mortality to baleen whale stocks along the United States east coast and Atlantic Canadian
Provinces for 2009 through 2013. Whale injury and mortality events were evaluated using
criteria for injury severity and for assigning injuries and mortalities to natural or human causes.
The average annual human- caused serious injury and mortality rate during the period was 4.55
for North Atlantic right whales, 9.0 for Gulf of Maine humpback whales, 3.55 for Western North
Atlantic fin whales, 0.4 for Nova Scotian sei whales, 7.7 for Canadian East Coast minke whales,
0.2 for Northern Gulf of Mexico Bryde’s whales, and 0 for Western North Atlantic blue whales.
The number of serious injuries and mortalities not reported is unknown, and actual levels may be
Entanglement in fixed fishing gear is a conservation concern for whales worldwide, including in the United States where deaths of North Atlantic right and humpback whales have exceeded management limits for decades. We examined fishing gear removed from live and dead entangled whales along the US East Coast and the Canadian Maritimes from 1994-2010 to investigate rope polymer type, breaking strength, and diameter in relation to whale species, age, and injury severity. For the 132 retrieved ropes from 70 cases, average tested breaking strength was 2616 lbs (SD 1863; range 180-8910 lbs), which is 26% lower than strength at manufacture (mean 3530 SD 2224; range 650-12000 lbs). Median rope diameter was 3/8 inch. Right and humpback whales were found in ropes with significantly stronger breaking strengths at manufacture than minke whales (4338 3850 and 2353 mean lbs, respectively). Adult right whales were found in stronger ropes (mean 7664 lbs) than juvenile right whales (mean 3446 lbs) and all humpback whale age classes (mean 3906 lbs). For right whales, injuries have become more severe over the past three decades, possibly due to changes in rope manufacturing in the mid 1990's that resulted in stronger ropes at the same diameter. Our results suggest that broad adoption of ropes with breaking strengths of 1700 lbs or less could reduce the number of life-threatening entanglements for large whales by at least 72%, and still be strong enough to withstand the routine forces involved in many fishing operations. A reduction of this magnitude would achieve nearly all of the mitigation legally required for US stocks of North Atlantic right and humpback whales. Reduced breaking strength ropes should be developed and tested to determine the feasibility of its use in a variety of fisheries. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
Management plans for North Atlantic right whales Eubalaena glacialis focus on preventing mortality from ship strikes and fishing gear entanglement. However, recovery may also be limited because individuals are under nutritional stress. We quantified the food requirements of North Atlantic right whales by age, sex and reproductive state and compared their predicted needs with field estimates of prey consumption to assess whether any demographic group of right whales might be nutritionally stressed. Energy requirements were estimated using a bioener - getics model that accounted for uncertainty in energy inputs and outputs. Consumption was estimated with prey samples taken near feeding whales in Cape Cod Bay (n = 28 net collections) and the Bay of Fundy (n = 19 optical plankton recordings). We found that calves required the least energy (~1767 MJ d-1) and that lactating females required the most (~4120 MJ d -1). Juveniles required considerably more energy than adult males and non-reproductive females. Our estimates of energy requirements for juveniles (~1906 MJ d-1), adult males (~1793 MJ d-1), and nonreproductive females (~2104 MJ d-1) compared favorably with estimates of actual consumption in Cape Cod Bay and the Bay of Fundy (i.e. they differed by ≤15%), suggesting that our model was reliable. However, lactating females appear to have obtained considerably less than their predicted energy requirements in both habitats. These findings suggest that lactating females may be experiencing an energy deficit, which may affect reproductive rates and slow population recovery. Nutritional stress may thus be limiting the recovery of North Atlantic right whales.
Despite an elevated mortality rate from lethal interactions with humans, the North Atlantic right whale population has continued to grow during the first decade of the new millennium. This unexpected population growth is the result of a 128% increase in female-specific reproduction relative to the 1990s. Here, we demonstrate that the recent increase in annual right whale calf production is linked to a dramatic increase in the abundance of its major prey, the copepod species Calanus finmarchicus, in the Gulf of Maine. The resurgence of C. finmarchicus was associated with a regime shift remotely forced by climatic changes in the Arctic. We conclude that decadal-scale variability in right whale reproduction may be largely driven by fluctuations in prey availability linked to climate-associated ecosystem regime shifts.
Entanglement in non-mobile fishing gear has been identified as one of the leading
causes of mortality in North Atlantic right whales Eubalaena glacialis. To investigate this issue
further, all available photographs of right whales taken from 1980 to 2009 were examined for
evidence of entanglement with gear used in fisheries based on presence of rope or netting on the
whale or scars inferred to have been caused by an encounter with rope. Photographs of 626
individual whales were assessed and 1032 unique entanglement events were documented. Of the
626 animals, 519 (82.9%) had been entangled at least once and 306 of the 519 (59.0%) had been
entangled more than once. Males and females were entangled at similar rates. Juveniles were
entangled at a higher rate than adults. On average, 25.9% of adequately photographed animals
acquired new wounds or scars from fishing gear annually with no significant trend over time
detected. However, the annual percentage of animals observed with rope on the body increased
significantly during the study period, suggesting that it is becoming more difficult for whales to
free themselves completely from fishing gear. Such high annual rates of entanglement remain a
serious conservation concern for right whales because entanglements can have both lethal and
sub-lethal effects. Federally required changes to fixed-gear fisheries in US waters have not
reduced serious injuries and mortality to legally required levels. Here we show how documenting
various annual rates of entanglement can monitor progress and impacts that fishing gear regulations
may have on right whale recovery.
ABSTRACT: To reduce right whale Eubalaena glacialis deaths caused by ship collisions along the
US East Coast, a rule was implemented on 8 December 2008 requiring all vessels ≥65 feet (19.8 m)
to travel 10 knots (18.5 km h−1) or less in 10 seasonal management areas (SMAs). To evaluate the
effectiveness of this rule, we plotted the locations of all right whale and humpback whale
Megaptera novaeangliae carcasses attributed to ship-strikes since December 1990 in US waters to
determine their proximity to SMAs. In the 18 yr pre-rule period, 13 of 15 (87%) right whales and
12 of 26 (46%) humpback whales killed by ships were found inside later SMA boundaries or
within 45 nmi (83 km) of their perimeters during later active dates. In the first 5 yr after the rule
became effective, no ship-struck right whales were found inside or within 45 nmi of any active
SMA. This was nearly twice as long as the longest pre-rule period without discovery of a ship-struck
carcass in those areas during effective time periods. Based on the 18 yr pre-rule period, bootstrap
resampling analyses revealed that the probability of finding no ship-struck whales in or near
SMAs during the first 5 yr post-rule period would be a statistically significant reduction in such
deaths (p = 0.031). The results suggest the rule has been effective at reducing right whale deaths.
We suggest enlarging SMAs to include additional parts of the right whale migratory corridor.
Although there are a number of techniques for determining age in dead baleen whales, few exist for live, free-swimming animals. Photo-identification records of 374 cataloged individuals through 1996 were used to assess the age of first parturition, the age structure and the longevity of the North Atlantic fight whale Eubalaena glacialis. Nearly the entire population is identified and the majority of the whales have extensive sighting histories dating from 1980, with some earlier sightings dating as far back as 1935. The observed mean age at first parturition for females with complete sighting histories (n = 13) is 8.7 yr and the age at which whales are considered adults, based on the mean age of first observed parturition for all known-age females (n = 20), is 9 yr. Juveniles and calves constitute 26 to 31% of the population, considerably less than in other baleen whale species. One whale is at least 65 yr old, and reproductive histories of others span up to 29 yr. Although the 65 plus yr old whale is possibly reproductively senescent, her apparent lack of calving may be due to anthropogenic factors or to undocumented calvings.
Balancing human uses of the marine environment with the recovery of protected species requires accurate information on when and where species of interest are likely to be present. Here, we describe a system that can produce useful estimates of right whale Eubalaena glacialis presence and abundance on their feeding grounds in the Gulf of Maine. The foundation of our system is a coupled physical-biological model of the copepod Calan us finmarchicus, the preferred prey of right whales. From the modeled prey densities, we can estimate when whales will appear in the Great South Channel feeding ground. Based on our experience with the system, we consider how the relationship between right whales and copepods changes across spatial scales. The scale-dependent relationship between whales and copepods provides insight into how to improve future estimates of the distribution of right whales and other pelagic predators.
Although trends in reproduction, mortality, and entanglement events have been analyzed for the endangered North Atlantic right whale (Eubalaena glacialis) population, no method has been available to assess individual right whale health. Here, we describe a technique for assessing health based on evaluation of selected physical parameters from archived photographs of right whales. A scoring system was developed to assess body and skin condition, blowhole cyamids, and rake marks in over 200 000 photographs. Comparison of body condition scores of females during calving and noncalving years found that females were significantly thinner in calving years and in the year after calving compared with the year before calving, showing that changes in body condition known to occur during the reproductive cycle can be successfully evaluated from photographs. Comparison of scores for all parameters between living whales and whales with more than a 5-year gap in sighting history ("presumed dead") found that presumed dead whales received health assessment scores indicating compromised health with body condition emerging as a key visual indicator. This health assessment method provides a new tool to monitor health trends in right whales at individual and population levels and may provide a model for assessments of other well-photographed cetaceans.
Management plans to reduce human-caused deaths of North Atlantic right whales Eubalaena glacialis depend, in part, on knowing when and where right whales are likely to be found. Local environmental conditions that influence movements of feeding right whales, such as ultra- dense copepod patches, are unpredictable and ephemeral. We examined the utility of using the regional-scale mean copepod concentration as an indicator of the abundance of right whales in 2 crit- ical habitats off the northeastern coast of the United States: Cape Cod Bay and Great South Channel. Right whales are usually found in Cape Cod Bay during the late winter and early spring, and in the Great South Channel during the late spring and early summer. We found a significant positive relationship between mean concentration of the copepod Calanus finmarchicus in the western Gulf of Maine and the frequency of right whale sightings in the Great South Channel. In Cape Cod Bay we found a significant positive relationship between the mean concentration of other copepods (largely Pseudocalanus spp. and Centropages spp.) and the frequency of right whale sightings. This information could be used to further our understanding of the environmental factors that drive seasonal movement and aggregation of right whales in the Gulf of Maine, and it offers a tool to resource managers and modelers who seek to predict the movements of right whales based upon the concentration of copepods.
The demographic responses of long-lived endangered species to climate variability can be complex. Nonlinearities in physical and biological processes can obscure relationships between changes in climate and corresponding demo- graphic responses. Efforts to conserve such species will require an understanding of the multi-tiered mechanisms link- ing climate variability to ecosystem processes and population dynamics. Here, we describe the physical-biological coupling of oceanographic processes linking climate variability to the reproduction of North Atlantic right whales. These findings suggest that future climate change, through its regional effects in the Northwest Atlantic, may emerge as a significant factor influencing recovery of this highly endangered species.
With the end of commercial whaling, it was thought that populations of the highly endangered North Atlantic right whale (Eubalaena glacialis) would gradually recover. However, recent modeling studies have shown that the population's growth rate increased gradually during the 1980s, but began declining in the early 1990s, when female mortality rates increased substantially. Demographic projections predict that, assuming birth and mortality rates remain comparable to those observed in the early 1990s, the population will become extinct in less than 200 years. Further extrapolations suggest that reducing mortality rates by a few female deaths per year through conservation efforts would be sufficient to support a slow recovery of the population. However, the effects of climate variability and change on calving rates may make the North Atlantic right whale even more vulnerable than previous projections have suggested. Failure to incorporate the effects of climate in demographic projections may lead us to underestimate the conservation efforts required to ensure recovery of this whale population.
During recent decades, historically unprecedented changes have
been observed in the Arctic as climate warming has increased precipitation, river
discharge, and glacial as well as sea ice melting. Additionally, shifts in the Arctic’s
atmospheric pressure field have altered surface winds, ocean circulation, and
freshwater storage in the Beaufort Gyre. These processes have resulted in variable
patterns of freshwater export from the Arctic Ocean, including the emergence of
great salinity anomalies propagating throughout the North Atlantic. Here, we link
these variable patterns of freshwater export from the Arctic Ocean to the regime
shifts observed in Northwest Atlantic shelf ecosystems. Specifically, we hypothesize
that the corresponding salinity anomalies, both negative and positive, alter the timing
and extent of water-column stratification, thereby impacting the production and
seasonal cycles of phytoplankton, zooplankton, and higher-trophic-level consumers.
Should this hypothesis hold up to critical evaluation, it has the potential to
fundamentally alter our current understanding of the processes forcing the dynamics
of Northwest Atlantic shelf ecosystems.
Many criteria for statistical parameter estimation, such as maximum likelihood, are formulated as a nonlinear optimization problem. Automatic Differentiation Model Builder (ADMB) is a programming framework based on automatic differentiation, aimed at highly nonlinear models with a large number of parameters. The benefits of using AD are computational efficiency and high numerical accuracy, both crucial in many practical problems. We describe the basic components and the underlying philosophy of ADMB, with an emphasis on functionality found in no other statistical software. One example of such a feature is the generic implementation of Laplace approximation of high-dimensional integrals for use in latent variable models. We also review the literature in which ADMB has been used, and discuss future development of ADMB as an open source project. Overall, the main advantages of ADMB are flexibility, speed, precision, stability and built-in methods to quantify uncertainty.
Summary • There is a clear need to increase our ability to predict the consequences of environmental change. The seven main approaches that are currently used are: extrapolation, experiments, phenomenological models, game-theory population models, expert opinion, outcome-driven modelling and scenarios. Each approach has different strengths and weaknesses. In practice, several approaches are often combined. • Adaptive management aimed at testing hypotheses is excellent in principle and widely advocated. In reality, however, it is almost never carried out because the changes in management usually have to be severe in order to bring about detectable changes in a reasonable time, and the political risks of such management are usually considered too high. • Game-theory population models are used to determine population-level phenomena based upon the decisions individuals make in response to resource depletion, interference, territoriality or rank. This allows predictions to be made regarding responses to novel conditions. The main drawback is that for some models considerable information is required. • Much of conservation practice is not based upon evidence. Evidence-based conservation is the practice of accumulating, reviewing and disseminating evidence with the aim of formulating appropriate management strategies. Evidence-based medicine revolutionized medical practice and similar opportunities exist to improve conservation practice. • Synthesis and applications. The conventional approach of making assumptions and deriving models to make predictions about the consequences of environmental change is often unsatisfactory for complex problems, with considerable uncertainty. Tackling such problems is likely to require greater exploration of techniques such as expert opinion, output-driven modelling and scenarios. Journal of Applied Ecology (2006) 43, 599–616doi: 10.1111/j.1365-2664.2006.01182.x
Survival probability is of interest primarily as a component of population dynamics. Only when survival estimates are included in a demographic model are their population implications apparent. Survival describes the transition between living and dead. Biologically important as this transition is, it is only one of many transitions in the life cycle. Others include transitions between immature and mature, unmated and mated, breeding and non¿breeding, larva and adult, small and large, and location x and location y. The demographic consequences of these transitions can be captured by matrix population models, and such models provide a natural link connecting multi-stage mark-recapture methods and population dynamics. This paper explores some of those connections, with examples taken from an ongoing analysis of the endangered North Atlantic right whale (Eubalaena glacialis). Formulating problems in terms of a matrix population model provides an easy way to compute the likelihood of capture histories. It extends the list of demographic parameters for which maximum likelihood estimates can be obtained to include population growth rate, the sensitivity and elasticity of population growth rate, the net reproductive rate, generation time, measures of transient dynamics. In the future, multi-stage mark-recapture methods, linked to matrix population models, will become an increasingly important part of demography.
Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends in sea ice, freshwater export, and surface ocean salinity continue. It is more difficult to predict ecological responses to abrupt climate change in the more distant future as tipping points in the Earth's climate system are exceeded.
A recent study by Brook et al. empirically tested the performance of population viability analysis (PVA) using data from 21 populations across a wide range of species. The study concluded that PVAs are good at predicting the future dynamics of populations. We suggest that this conclusion is a result of a bias in the studies that Brook et al. included in their analyses. We present arguments that PVAs can only be accurate at predicting extinction probabilities if data are extensive and reliable, and if the distribution of vital rates between individuals and years can be assumed stationary in the future, or if any changes can be accurately predicted. In particular, we note that although catastrophes are likely to have precipitated many extinctions, estimates of the probability of catastrophes are unreliable.