Philip Hamilton

New England Aquarium

Only approximately 356 North Atlantic right whales (Eubalaena glacialis) remain. With extremely low levels of genetic diversity, limited options for mates, and variation in reproductive success across females, there is concern regarding the potential for genetic limitations of population growth from inbreeding depression. In this study, we quantifi...

Critically endangered North Atlantic right whales Eubalaena glacialis have recently shifted their summer distribution from the Bay of Fundy to the Gulf of St. Lawrence (GSL), Canada. Entanglement in fishing gear and vessel strikes remain the main lethal threats. Foraging on deep aggregations of Calanus prey in the Bay of Fundy involves stereotyped...

Body size is key to many life-history processes, including reproduction. Across species, climate change and other stressors have caused reductions in the body size to which animals can grow, called asymptotic size, with consequences for demography. A reduction in mean asymptotic length was documented for critically endangered North Atlantic right w...

The endangered North Atlantic right whale (Eubalaena glacialis) showed limited recovery from the cessation of industrial whaling until 2011, and has since been in decline. Research is therefore focused on identifying what factors are limiting recovery and what conservation actions will be most effective. A compromised reproductive rate is one of th...

Quantifying the cumulative effects of stressors on individuals and populations can inform the development of effective management and conservation strategies. We developed a Bayesian state–space model to assess the effects of multiple stressors on individual survival and reproduction. In the model, stressor effects on vital rates are mediated by ch...

The appropriate use and interpretation of passive acoustic data for monitoring the Critically Endangered North Atlantic right whale Eubalaena glacialis (hereafter right whale) rely on knowledge of their calling behavior and how it varies with respect to time, space, demographics, and observed behavior. To assess such relationships in a habitat of i...

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 eve...

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 in...

Photo identification is an important tool in the conservation management of endangered species, and recent developments in artificial intelligence are revolutionizing existing workflows to identify individual animals. In 2015, the National Oceanic and Atmospheric Administration hosted a Kaggle data science competition to automate the identification...

North Atlantic right whales (NARW) are critically endangered and have been declining in abundance since 2011. In the past decade, human-caused mortalities from vessel strikes and entanglements have been increasing, while birth rates in the population are at a 40 yr low. In addition to declining abundance, recent studies have shown that NARW length-...

While photo-identification is an effective tool to monitor individuals in wild populations, it has limitations. Specifically, it cannot be applied to very young animals before their identifying features have stabilized or to dead, decomposed animals. These shortfalls leave gaps in our understanding of survival, parentage, age structure, physical de...

North Atlantic right whales Eubalaena glacialis are most commonly observed along the eastern seaboard of North America; however, their distribution and occupancy patterns have become less predictable in the last decade. This study explores the individual right whales captured photographically from both dedicated and opportunistic sources from 2015...

Whaling has decimated North Atlantic right whales Eubalaena glacialis (NARW) since the 11th century and southern right whales E. australis (SRW) since the 19th century. Today, NARWs are Critically Endangered and decreasing, whereas SRWs are recovering. We review NARW health assessment literature, NARW Consortium databases, and efforts and limitatio...

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 l...

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 conservatio...

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 carcasse...

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 Unit...

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...

Baleen whales lack the strong and stable long-term bonds characteristic of odontocetes such as killer whales and sperm whales, and therefore, the social structure of baleen whales has received comparatively little attention. However, recent findings of long-term associations in both right whales and humpback whales have challenged the notion that b...

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...

Right whales are vulnerable to many sources of anthropogenic disturbance including ship strikes, entanglement with fishing gear, and anthropogenic noise. The effect of these factors on individual health is unclear. A statistical model using photographic evidence of health was recently built to infer the true or hidden health of individual right wha...

North Atlantic right whales Eubalaena glacialis are among the most endangered of the large whales. Although protected since 1935, their abundance has remained low. Right whales occupy the Atlantic Ocean from southern Greenland and the Gulf of St. Lawrence south to Florida. The highly industrialized mid-Atlantic region is part of the right whales' m...

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 variatio...

Although small populations are expected to lose genetic diversity through genetic drift and inbreeding, a number of mechanisms exist that could minimize this genetic decline. Examples include mate choice for unrelated mates and fertilization patterns biased toward genetically dissimilar gametes. Both processes have been widely documented, but the l...

The location of mating grounds used by Endangered North Atlantic right whales Eubalaena glacialis has eluded discovery despite centuries of whaling and decades of marine mammal surveys. If this species’ gestation duration is similar to the closely related southern right whale E. australis, then conception for the North Atlantic right whale occurs i...

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...

This appendix contains further details on the model and the construction of the Gibbs sampler. In addition, it details the priors for the ordinal health classes and for movement. (DOCX)

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...

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 rop...

A right whale (Eubalaena glacialis) from the western North Atlantic population, sighted in the Azores, was subsequently found to have moved back to the northwest Atlantic. The whale was sighted in the Azores on 5 January 2009 travelling in a west-south westerly direction at a constant speed. A photographic match was found to an adult female in the...

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 archi...

The North Atlantic right whale (Eubalaena glacialis) inhabits five areas along the east coast of North America at different times of the year. During 17 years of field observations, it has been found that only 59% of the newborn calves are brought to the Bay of Fundy nursery area. To examine whether this is because of population structuring, the mi...

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 misplac...

Like most mysticetes, North Atlantic right whale cows generally separate from their calves on their feeding grounds within a year. Right whale life history data from 1993 to 2005 were analyzed to determine the duration of cow/calf associations and where the pair separated. A change occurred with the 2001 cows; 71% of those available stayed with the...

Many long-term studies of wildlife populations rely on individual identification based on natural markings or genetic profiling, or both. However, only rarely are these 2 independent data sets systematically compared with each other to estimate the error rates inherent in these studies. Here, >25 years of photo-identification data on the endangered...

Author Posting. © Society for Marine Mammalogy, 2008. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Marine Mammal Science 25 (2009): 462-477, doi:10.1111/j.1748-7692.2008.00261.x. The general temporal and geographical p...

Parentage analyses of baleen whales are rare, and although mating systems have been hypothesized for some species, little data on realized male reproductive success are available and the patterns of male reproductive success have remained elusive for most species. Here we combine over 20 years of photo-identification data with high-resolution genet...

Marine mammal social interactions are poorly understood primarily because of the difficulty of observing these behaviors in the wild. Observations of copulations in North Atlantic right whale surface active groups (SAGs) have led to the hypothesis that the function of these groups is for conception. The occurrence and composition of SAGs sighted fr...

Unlike smaller marine mammals that lack the mass and power to break free from serious entanglements in fixed fishing gear, right whales can do so, but they are not always rope free. The remaining rope can gradually constrict one or more body parts and the resulting debilitation and ultimate death can take many months. Thus the practices that lead t...

A bstract North Atlantic right whales ( Eubalaena glacialis ) make a short, distinctive broadband sound that is produced internally called a Gunshot sound. This sound has been recorded in the Bay of Fundy, Canada from both single whales ( n = 9) and social surface active groups ( n =49). Those single whales producing Gunshot sounds whose sex could...

A bstract To assess large‐whale stocks following the cessation of land‐based South Georgia whaling in 1965, we report three independent sighting databases: a cruise in 1997, observations from Bird Island (NW of South Georgia) between 1979 and 1998, and mariner sightings between 1992 and 1997. All species were rare, with sightings of southern right...

A bstract Approximately one third of the North Atlantic right whale population has white ventral skin patches. Most white‐marked animals have both a belly and a chin patch, and the distribution of white pigment suggests that the patches represent a single ventral marking that varies in size and location. Population frequencies and cow‐calf inherita...

A North Atlantic right whale (Eubalaena glacialis) genomic library was developed and screened with a (GATA)8 probe to identify tetranucleotide microsatellite loci. Sixteen characterized loci were polymorphic in North Atlantic and/or South Atlantic (Eubalaena australis) right whales, 12 being polymorphic in E. glacialis, and 15 in E. australis. Four...

Conservation and management of many cetaceans is hindered by the difficulty of acquiring samples from free-swimming individuals to obtain essential data on health, diet, reproduction and physiological impacts of environmental and anthropogenic stressors. This is particularly true for large whales, which are logistically difficult to live-capture fo...

Author Posting. © IEEE, 2006. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in Proceedings Oceans 2006, Boston, MA, USA, 3 pp, doi:10.1109/OCEANS.2006.306792. Unlike smaller marine mammals that lack the mass and power to break free from serious entanglements in fixed...

North Atlantic right whales Eubalaena glacialis experienced decreased reproduction and body condition in the 1990s, causing concern about the overall health of this critically endangered population. Images from a detailed photo-identification catalog of right whales were analyzed for the presence of skin lesions. Lesions were categorized as white l...

The survival of North Atlantic right whales ( Eubalaena glacialis ) is seriously threatened by mortality caused by ships and entanglements in fishing gear. Demographic modeling indicates that the population is declining despite efforts to reduce anthropogenic mortalities, and in spite of recent increases in calving. The authors of this [Policy Foru...

North Atlantic right whales ( Eubalaena glacialis) commonly use sound to mediate social interactions between individuals. Surface active groups (SAGs) are the most commonly observed social interaction on the summer feeding grounds. These groups are typically composed of an adult female with two or more males engaged in social behavior at the surfac...

Few data exist on the marine distribution and host organisms of the parasitic sea lamprey, Petromyzon marinus. Some observers have speculated that cetaceans serve as hosts for these fish based on scars, but few lamprey – cetacean interactions have been described in detail in the literature. Here we discuss 35 previously unreported records of sea la...

Associations among North Atlantic right whales were investigated to better understand the ecology of this endangered species. Data on all sightings of photo-identified right whales from the western North Atlantic between 1935 and 2000 were inspected to determine whether or not whales were associated. Whales were considered associated if they were w...

The population of western North Atlantic right whales (Eubalaena glacialis) is distributed primarily between Florida, USA and NovaScotia, Canada, aggregating seasonally in five geographically distinct, high-use areas. To test the effectiveness of monitoring alldemographic classes (juvenile and adult males and females) of the population in these fiv...

North Atlantic right whale reproduction was assessed for the period 1980 through 1998. At the end of this period, we estimated there were between 299 and 437 right whales alive, including 70 mature females. Using maximum and minimum population estimates for the entire period, mean values for gross annual reproductive rate were 0.36 and 0.49 respect...

Few studies have examined systematic relationships of right whales (Eubalaena spp.) since the original species descriptions, even though they are one of the most endangered large whales. Little morphological evidence exists to support the current species designations for Eubalaena glacialis in the northern hemisphere and E. australis in the souther...

Although whales were signed in all months of the year except December, peak abundance occurred from February through April. Mothers with calves consistently appeared in April or later. Residency varied from 1-165 days. An unusual summer residency group, including 9 mother/calf pairs, present from July through October 1986, is discussed. -from Autho...