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Maintenance of the North Atlantic Right Whale Catalog, Whale Scarring and Visual Health Databases, Anthropogenic Injury Case Studies, and Near Real-Time Matching for Biopsy Efforts, Entangled, Injured, Sick, or Dead Right Whales
... There were an estimated 458 animals in this population in 2015 (Pace et al. 2017) and an estimated 5.6 right whales died or were seriously injured each year from 2010−2014, 4.6 of those from entanglements (Hayes et al. 2017). Further, an assessment of entanglements documented through 2016 showed 84.7% of the cataloged right whales had scars from encounters with fishing gear (Knowlton et al. 2018). Fishing rope strength has been increasing, contributing to an increase in the severity (Knowlton et al. 2016) and lethality (van der Hoop et al. 2013, Robbins et al. 2015 of these entanglements. ...
... Although NMFS and the states of Massachusetts and Maine have made progress in addressing some of the fishery entanglement issues (Johnson et al. 2005), the continued entanglement-related mortality of right whales shows that more work is needed. Entanglement scarring data shows a steady increase in right whale entanglements over a 20 yr period from 57% through 1990 (Kraus 1990), to 71.9% through 2000 (Knowlton et al. 2003), to 75.6% through 2002 (Knowlton et al. 2005), to 82.9% through 2009 (Knowlton et al. 2012), and finally to 84.7% through 2016 (Knowlton et al. 2018). In addition, the observed number of right whales carrying gear (i.e. ...
North Atlantic right whales Eubalaena glacialis utilize the entire water column and are frequently entangled in ropes from fishing gear. Data from telemetry tags have shown that right whales can swim/feed at or near the seafloor. Because those data are limited, some uncertainty remains regarding the frequency of dives to the seafloor and thus the likelihood of right whale encounters with fishing ropes there. The North Atlantic right whale photo-identification catalog was used to determine the number of sightings of right whales with seafloor sediment on their bodies and the relative frequency and geographic location of those seafloor encounters. Between 1980 and 2016, there were 2053 detections of right whales with ‘mud’ on their bodies, which represents 2.9% of all sightings (n = 70593), or 58.2% of all cataloged whales (n = 730). Although muddy right whales were found throughout their range and in all months, 92.7% of all detections occurred in the Bay of Fundy in the summer where there was an average annual detection rate of 7.3%, with a maximum of 26% of sightings in 2010. Mud was found on whales of all age classes including calves of the year, and equally among males and females. These seafloor encounters suggest that any rope resting on, or floating above, the seafloor could pose an entanglement hazard. The use of sinking groundlines likely reduces the risk of entanglements for whales swimming near the seafloor, but may not eliminate the risk for whales making contact with the sediment.
North Atlantic right whales Eubalaena glacialis utilize the entire water column and are frequently entangled in ropes from fishing gear. Data from telemetry tags have shown that right whales can swim/feed at or near the seafloor. Because those data are limited, some uncertainty remains regarding the frequency of dives to the seafloor and thus the likelihood of right whale encounters with fishing ropes there. The North Atlantic right whale photo-identification catalog was used to determine the number of sightings of right whales with seafloor sediment on their bodies and the relative frequency and geographic location of those seafloor encounters. Between 1980 and 2016, there were 2053 detections of right whales with ‘mud’ on their bodies, which represents 2.9% of all sightings (n = 70593), or 58.2% of all cataloged whales (n = 730). Although muddy right whales were found throughout their range and in all months, 92.7% of all detections occurred in the Bay of Fundy in the summer where there was an average annual detection rate of 7.3%, with a maximum of 26% of sightings in 2010. Mud was found on whales of all age classes including calves of the year, and equally among males and females. These seafloor encounters suggest that any rope resting on, or floating above, the seafloor could pose an entanglement hazard. The use of sinking groundlines likely reduces the risk of entanglements for whales swimming near the seafloor, but may not eliminate the risk for whales making contact with the sediment.
North Atlantic right whales Eubalaena glacialis (hereafter right whales) have recently shifted their distribution away from some protected feeding habitats, which suggests large-scale changes in food supply have occurred. Quantifying the nature and extent of the apparent shift is key to exploring this hypothesis and planning or revising conservation strategies. This paper characterizes decadal right whale occurrence in the Bay of Fundy summer feeding habitat using data derived from 7522 h of survey effort collected over 30 yr (1987 to 2016) that yielded 11483 right whale sightings. Eight occurrence descriptors were derived to quantify temporal variation in right whale presence, encounter rates and time of arrival in the Bay. Time of arrival was modeled using linear and power function models fit to annual discovery curves. Principal component analysis showed 2 modes that explained 58 and 14% of the variation in occurrence, respectively. The first mode captured a significant decline in summertime right whale occurrence beginning in 2010. The second mode captured a decadal-scale cycle in seasonal timing of occurrence, which highlighted a sharp change from early to late occupancy at the turn of the millennium. Annual occurrence during the 2010-2016 period was anomalously low in both the Grand Manan Basin critical habitat and the Bay of Fundy Traffic Separation Scheme (shipping lanes), whereas encounters in the region NW of the critical habitat containing Owen Basin and The Wolves islands may be increasing due to a distributional shift within the Bay. We discuss the consequences of these changes for both population dynamics and future conservation of the species.
Animal movement plays a fundamental role in the ecology of migratory species, and understanding migration patterns is required for effective management. To evaluate intrinsic and environmental factors associated with probabilities of endangered North Atlantic right whales Eubalaena glacialis migrating to a wintering ground off the southeastern United States (SEUS), we applied a multistate temporary emigration capture-recapture model to 22 years of photo-identification data. Migration probabilities for juveniles were generally higher yet more variable than those for adults, and non-calving adult females were the least likely group to migrate. The highest migration probabilities for juveniles and adult males coincided with years of relatively high calving rates, following years of higher prey availability in a fall feeding ground. Right whale migration to the SEUS can be classified as condition-dependent partial migration, which includes skipped breeding partial migration for reproductive females, and is likely influenced by tradeoffs among ecological factors such as reproductive costs and foraging opportunities that vary across individuals and time. The high variability in migration reported in this study provides insight into the ecological drivers of migration but presents challenges to right whale monitoring and conservation strategies.
Aerial surveys can be used to estimate animal abundance, but animals unavailable for detection for portions of the survey can cause biased abundance estimates. Moreover, these biases may be variable owing to changes in behavior. We conducted focal follows to obtain surface and dive times of North Atlantic right whales Eubalaena glacialis in Cape Cod Bay (CCB) and measured the aircraft field of view; these metrics were combined to estimate availability and correct monthly abundance estimates from 1998 to 2017 generated via distance sampling methodology. We used a general least squares model to test for trends in abundance. Availability varied with month (0.27-0.85), likely linked to changes in the depth of copepod food resources. Detection probability varied across the years (0.43-0.87). Sightings per unit effort and counts of whales were significant, but downward-biased indicators of abundance and availability caused changes in bias over the season. Estimated abundance in CCB increased during the study period (4.9 whales yr ⁻¹ ), and estimated abundance in peak months increased at a faster rate (10% yr ⁻¹ for 1998-2017) than for the overall population (2.8% yr ⁻¹ for 1990-2010). Accurate abundance estimates are necessary to monitor long-term changes in abundance of right whales in CCB, to understand the importance of CCB relative to other areas, and improve management strategies to protect this endangered species from entanglements in fishing gear and ship-strikes. Failing to correct for seasonal variation in availability results in substantial and variable underestimation of abundance.
North Atlantic right whales (NARW), Eubalaena glacialis, were nearly exterminated by historical whaling. Their abundance slowly increased up until 2010, to a maximum of fewer than 500 whales, and since then they have been in decline. We assessed the extent to which the relatively slow increase demonstrated by NARW was intrinsic, and how much could be due to anthropogenic impacts. In order to do so, we first compared calf counts of three populations of Southern right whales (SRW), E. australis, with that of NARW, over the period 1992–2016. By this index, the annual rate of increase of NARW was approximately one-third of that of SRW. Next we constructed a population projection model for female NARW, using the highest annual survival estimates available from recent mark–resight analysis, and assuming a four-year calving interval. The model results indicated an intrinsic rate of increase of 4% per year, approximately twice that observed, and that adult female mortality is the main factor influencing this rate. Necropsy records demonstrate that anthropogenic mortality is the primary cause of known mortality of NARW. Anthropogenic mortality and morbidity has limited the recovery of NARW, and baseline conditions prior to their recent decline were already jeopardizing NARW recovery.
The North Atlantic right whale Eubalaena glacialis, one of the world's rarest mammals, experienced an alarming level of mortality in 2017. The estimated abundance as of 2016 was 451 animals. After 20 yr of relatively steady but slow growth, the population has declined since 2010. Mortality and serious injury from entanglement in commercial fishing gear have had a significant impact on recovery. Despite legal requirements to reduce fishery-related mortality, little or no real progress has been made over the last 2 decades. Here I took a relatively simple approach to estimate what the population trajectory since 1990 might have been under 4 different scenarios of reduced entanglement mortality. Under the best-case scenarios, the population at the end of the time-series would have been 25-30% higher than observed at present. If the population had not experienced nearly 3 decades of increasing entanglement, it could have been much more resilient to a disaster year like 2017.
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.
Body condition has been correlated with survival and reproductive success in bothterrestrial and marine mammals, including North Atlantic right whales Eubalaena glacialis. Weused photographs of individually identified right whales to assess visual changes in body conditionin reproductive females, adult males, juveniles, and entangled whales. Images from sightingsof individual whales were grouped sequentially by habitat region, and each group of images wasassigned a body condition score of good, fair, or poor based on the dorsal profile posterior to theblowholes. Temporally consecutive groups of images (n = 1496) of 340 individual whales werecompared to investigate the frequency, direction, and minimum timeframe between changes inbody condition. Changes in body condition scores of right whales were significantly influenced bygroup category. Lactating females and severely entangled right whales were more likely toexhibit declining body condition than other groups. Resting females were significantly more likelyto improve in condition than other groups but exhibited the longest timeframe for improving condition.Young juveniles were less likely to improve in condition compared to adult males, butremained in compromised condition less frequently than older juveniles and adult males. Theshortest timeframes between changing body condition scores were 11 d for declining conditionand 12 d for improving condition. This study demonstrates that photographic analysis can detectrapid body condition changes and identifies groups of right whales that are particularly vulnerableto declining condition and delayed recovery from energetically taxing events.
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.
The reproductive biology of the western North Atlantic right whale population was assessed using photoidentification techniques. From 1980 to 1992, 145 calves were born to 65 identified cows. There was no detectable trend in the number of calves produced per year. Mean age at first parturition was 7.57 years. The reproductively active female pool was static at approximately 51 animals from 1987 to 1992. Gross annual reproductive rate, population growth rate, and mortality rate were estimated to be 4.5, 2.5, and 2.0%, respectively. The population size was estimated to be 295 individuals in 1992. Mean calving interval, based on 86 records, was 3.67 years, significantly longer than the South African right whale population but not different from the Argentine population. There was an indication that calving intervals may be increasing over time, though the trend was not quite statistically significant (P = 0.083). Potential causes for the reduced growth rate of this population are unknown but include anthropogenic mortality, inbreeding depression resulting in reduced fecundity, competition for food from other species, climatic changes affecting food availability, and sublethal effects of toxic contaminants.
Baleen whales have among the lowest reproductive rates in the animal kingdom, coupled with high energetic demands on lactating mothers to support the rapid growth of their offspring. Because each offspring represents a large portion of a female's reproductive effort, strong selection pressure should be in place to minimize the potential for misplaced parental effort. However, we describe a case in which two North Atlantic right whale (Eubalaena glacialis) offspring were switched between mothers and remained with their "adopted" mothers throughout their first year of life (until they were weaned). The most reasonable explanation is that this swap was an accident caused by the females calving in close spatial and temporal proximity. The calves likely associated with the wrong mothers before any mother-offspring recognition system had developed, and an association then formed between these non-biological mother-offspring pairs. These data raise intriguing questions regarding how often this may occur in other wildlife populations, what mechanisms are used for mother- offspring recognition in whales, and how long it takes for this recognition to develop.
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.
Body condition is an indicator of health, and it plays a key role in many vital processes for mammalian species. While evidence of individual body condition can be obtained, these observations provide just brief glimpses into the health state of the animal. An analytical framework is needed for understanding how health of animals changes over space and time.Through knowledge of individual health we can better understand the status of populations. This is particularly important in endangered species, where the consequences of disruption of critical biological functions can push groups of animals rapidly toward extinction. Here we built a state-space model that provides estimates of movement, health, and survival. We assimilated 30+ years of photographic evidence of body condition and three additional visual health parameters in individual North Atlantic right whales, together with survey data, to infer the true health status as it changes over space and time. We also included the effect of reproductive status and entanglement status on health. At the population level, we estimated differential movement patterns in males and females. At the individual level, we estimated the likely animal locations each month. We estimated the relationship between observed and latent health status. Observations of body condition, skin condition, cyamid infestation on the blowholes, and rake marks all provided measures of the true underlying health. The resulting time series of individual health highlight both normal variations in health status and how anthropogenic stressors can affect the health and, ultimately, the survival of individuals. This modeling approach provides information for monitoring of health in right whales, as well as a framework for integrating observational data at the level of individuals up through the health status of the population. This framework can be broadly applied to a variety of systems - terrestrial and marine - where sporadic observations of individuals exist.
Northern right whales in the western North Atlantic number about 300 animals and have shown little sign of recovery in recent decades. Mortality and serious injury due to human activities, particularly commercial fishing and shipping, are thought to be significant factors limiting their recovery. From 1970-1999, 45 right whale deaths were reliably documented. Sixteen of these fatalities (35.5%) were due to ship collisions, and three (6.7%) were due to entanglement in fishing gear. The remainder were neonates (13; 28.9%) and 'unknown cause' mortalities (13; 28.9%). Criteria for defining serious injuries and mortalities from entanglement or ship strikes were developed and include any animal carrying fishing gear, cuts from entanglement or ship strike deeper than 8cm, swelling or necrosis, evidence of poor health from such interactions, and, in carcasses, evidence of haematoma, haemorrhaging or broken bones. A total of 56 animals fitting the defined criteria were documented from 1970-1999: 31 (55.4%) from entanglement and 25 (44.6%) from ship strikes. Nineteen were fatal (16 ship strikes, 3 entanglements), 10 were possibly fatal (2 ship strikes, 8 entanglements) and 27 were non-fatal (7 ship strikes, 20 entanglements). The breakdown of potentially serious injuries by age and sex reveals no difference in levels between sexes but shows a 3.3:1 higher level of interaction in juveniles and calves versus adults. The data show that ship strikes are more immediately lethal, but entanglements can result in long term deterioration of an animal and may be responsible for higher levels of mortality than previously thought. Considering that some animals become entangled, drown and never return to the surface, even these levels may be underestimated. Between 1986 and 1999, 84 animals were presumed dead based on a lack of resightings for six years. There were 32 confirmed deaths during this time period suggesting that at least as many unreported deaths occurred as carcasses were reported. Definitive actions need to be taken to reduce the level and severity of anthropogenic injuries and deaths. Actions could include continued disentanglement efforts, gear modifications, seasonal closures for fisheries, mandatory ship reporting, ships' routing measures and speed restrictions for commercial shipping.
Seventy mortalities of North Atlantic right whales Eubalaena glacialis (NARW) were documented between 2003 and 2018 from Florida, USA, to the Gulf of St. Lawrence, Canada. These included 29 adults, 14 juveniles, 10 calves, and 17 of unknown age class. Females represented 65.5% (19/29) of known-sex adults. Fourteen cases had photos only; 56 carcasses received external examinations, 44 of which were also necropsied. Cause of death was determined in 43 cases, of which 38 (88.4%) were due to anthropogenic trauma: 22 (57.9%) from entanglement, and 16 (42.1%) from vessel strike. Gross and histopathologic lesions associated with entanglement were often severe and included deep lacerations caused by constricting line wraps around the flippers, flukes, and head/mouth; baleen plate mutilation; chronic extensive bone lesions from impinging line, and traumatic scoliosis resulting in compromised mobility in a calf. Chronically entangled whales were often in poor body condition and had increased cyamid burden, reflecting compromised health. Vessel strike blunt force injuries included skull and vertebral fractures, blubber and muscle contusions, and large blood clots. Propeller-induced wounds often caused extensive damage to blubber, muscle, viscera, and bone. Overall prevalence of NARW entanglement mortalities increased from 21% (1970-2002) to 51% during this study period. This demonstrates that despite mitigation efforts, entanglements and vessel strikes continue to inflict profound physical trauma and suffering on individual NARWs. These cumulative mortalities are also unsustainable at the population level, so urgent and aggressive intervention is needed to end anthropogenic mortality in this critically endangered species.
Marine mammals are faced with increasing challenges from environmental fluctuation, climate change, and disturbances from human activities. Anthropogenic mortalities have been well documented, but it is difficult to assess the sub-lethal effects of disturbance on the fitness of marine wildlife, and to distinguish these impacts from natural variations in health and reproduction. Here, we used photographic data on body and skin condition, blowhole cyamids, and rake marks, to evaluate the health of North Atlantic right whales Eubalaena glacialis from 1980 to 2008. We applied a hierarchical Bayesian model to these data to estimate the underlying continuous health status of individuals, demographic groups, and the population to characterize health patterns and temporal trends. Visual health scores (scaled from 0 to 100) from 48560 sighting events were used to estimate the health of 622 identified right whales on a monthly basis. Health in most whales fluctuated between 70 and 90, and health scores of <60 were observed in whales in poor condition. Health varied by sex, age-class and reproductive state, with the greatest annual variability occurring in actively reproducing females. Calving females had significantly higher health scores than non-calving females, and a steep deterioration in population health coincided with a dramatic decline in calving from 1998 to 2000. Health in all demographic groups and the population declined over the 3 decades of observations. Given the inevitable data gaps that occur in most marine wildlife research, modeling advances such as the one presented here offer a promising approach to assess the complex interactions between biology, ecology, and sublethal anthropogenic disturbance on marine mammals.
Validation of steroid hormone immunoassays for blubber in the North Atlantic right whale (Eubalaena glacialis)
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Monitoring injured North Atlantic right whales
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North Atlantic Right Whale Consortium 2018 annual report card. Report to the North Atlantic Right Whale Consortium
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#3845-adult male) seen in June off the coast of France--he swam to Iceland
- Mogul
Mogul (#3845-adult male) seen in June off the coast of France--he swam to Iceland in
2018;