In 2001, we began long-term monitoring using scan sampling methodology to study the relative abundance and distribution of humpback whales (Megaptera novaeangliae) on their Hawaiian breeding grounds. Samples were collected annually (2001–2019) from a shore site overlooking Kawaihae Bay, Hawaiʻi Island. Each sample included the number of whales, pod composition, and position. Whale numbers increased

Conservation efforts of the beluga whale (Delphinapterus leucas) of the St. Lawrence estuary include a mortality surveillance program which has the objective of documenting the causes of mortality. The evaluation of the animal's body condition is a key component in the diagnostic process. There is currently no consensual method to measure or calculate body condition indices in beluga whales. Morphological

El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM) indirectly affect tooth growth of marine mammals, through changes in prey abundance, availability, and composition. This is reflected as variation in the dentine deposition, which determines the formation of annual layers, called growth layer groups (GLGs). The aim of this work was to study potential effects of ENSO and SAM on South

The glycopatterns of the glycans secreted by the mucosa of stomach and duodenal ampulla of the striped dolphin, Stenella coeruleoalba were studied by histochemical (Periodic acid-Schiff, Alcian Blue pH 2.5, High Iron Diamine) and lectin-binding (SBA, DBA, PNA, WGA, MAA-II, SNA, ConA, UEA-I, AAA, LTA) techniques. The stomach can be divided into four compartments: main stomach, two connecting chambers

Population genomic data sets have enhanced power to detect cryptic and complex population structure and generate valuable information for the conservation and management of wildlife species. Globally, killer whales (Orcinus orca) are considered to have a complex population structure due to their ability to specialize in a variety of ecological niches. In the Australasian region, they are found year

Photographic identification is an essential research and management tool for marine mammal scientists. However, manual identification of individuals is time-consuming. To shorten processing times, we developed finFindR, an open-source application that uses a series of neural networks to autonomously locate dorsal fins in unedited field images, quantify an individual's unique fin characteristics, and

The short-term response of humpback whales to boat approach and remote biopsy sampling was investigated in a breeding ground according to age-class, sex, female reproductive status, social context, sampling system, habitat, and repeated sampling with more than 20 years of data. In a total of 2,248 observed behavioral responses to biopsy sampling, 58.7% showed no response, 40.7% were considered to be

The Antarctic Peninsula (AP) is rapidly warming and empirical data on abundance trends of marine organisms are required to understand the impact of these physical changes, and interacting anthropogenic impacts, on the ecosystem. Recent estimates inferred increasing abundance of Type A killer whales at the top of this food chain, and here we provide new data on the abundance of Type B1 and B2 killer

Satellite imagery has been used to improve scientific research worldwide. In this study, the southern right whale (Eubalaena australis) was chosen to test the use of medium, high, and very high resolution (VHR) satellite images, on the Brazilian breeding ground. These images were used to identify the whales and were compared to aerial survey data collected in the same area. The VHR satellite images

Age estimating wild dolphins using noninvasive methods will improve our understanding of their ontogeny. Speckles appear on the ventral through to the lateral areas of Indo-Pacific bottlenose dolphins (Tursiops aduncus) as they age. Age-related changes in the speckle density and shape were examined using type classification. Speckles first appeared on the ventral area of the genital area at approximately

Bony labyrinth morphology varies across marine mammals and contains key information regarding hearing sensitivity and ecology. The hearing ranges of globicephaline (Delphinidae: Globicephalinae) or melon-headed dolphins, known as “Blackfish,” have been extensively studied using acoustic technologies, but clade-wide morphological analysis of the bony labyrinth is lacking. In this study, we investigate

Shark predation risk impacts many facets of dolphin life, including habitat use and foraging strategies. Because direct predation is rarely observed, researchers instead examine dolphins in situ for past injuries that can be attributed to sharks. We analyzed existing photo-ID catalogs of common bottlenose (Tursiops truncatus) and Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas

Reactions of southern right whales (SRWs) related to whale-watching boats have been reported in Patagonia, but there are no quantitative data showing how these whales react to boats not preforming whale-watching trips. The objective of this study was to investigate the reaction of SRWs to transiting vessels. Data were collected off the coast of Puerto Madryn city, and were analyzed by means of cumulative

Sea otters, Enhydra lutris, were once abundant along the nearshore areas of the North Pacific. The international maritime fur trade that ended in 1911 left 13 small remnant populations with low genetic diversity. Subsequent translocations into previously occupied habitat resulted in several reintroduced populations along the coast of North America. We sampled sea otters between 2008 and 2011 throughout

Understanding spatiotemporally varying animal distributions can inform ecological understanding of species' behavior (e.g., foraging and predator/prey interactions) and support development of management and conservation measures. Data from an array of echolocation-click detectors (C-PODs) were analyzed using Bayesian spatiotemporal modeling to investigate spatial and temporal variation in occurrence

The Mexican Caribbean and Belize are home to one of the largest populations of Caribbean manatees (Trichechus manatus manatus). However, the transboundary Hondo River estuary is less examined compared to the surrounding protected areas. This paper provides a quantitative description of the spatial and temporal variability in abiotic factors and manatee distribution throughout the Hondo River estuary

Sperm whales are present along the Caribbean islands in family groups of mature females, juveniles, and newborns. Their abundance and demographic rates remain poorly known. Using photo-identification data, we estimated the abundance and annual survival of sperm whales in Guadeloupe from January to April 2001–2013. A total of 1,492 photographs of tail flukes were scored (ranging from 1 to 5) in terms

Availability of preferred salmonid prey and a sufficiently quiet acoustic environment in which to forage are critical to the survival of resident killer whales (Orcinus orca) in the northeastern Pacific. Although piscivorous killer whales rely on echolocation to locate and track prey, the relationship between echolocation, movement, and prey capture during foraging by wild individuals is poorly understood

Since the 1980s, cetacean morbillivirus (CeMV) has caused mass mortality events worldwide. However, no epizootics had been recorded in the South Atlantic, until an unusual mortality event (UME) linked to Guiana dolphin cetacean morbillivirus (GD-CeMV) began in Ilha Grande Bay, southeastern Brazil, in November 2017. In a five-month period, the UME spread to neighboring Sepetiba Bay and accounted for

Marine mammals rely on blubber mainly for energy storage, buoyancy, and streamlining. Mysticetes are born with a relatively thin fat layer that grows rapidly during nursing. However, little information on blubber deposition patterns is available for baleen whale calves. We measured blubber thickness at nine body locations in 350 southern right whale (Eubalaena australis) newborn to 4–6‐month‐old calves

Species or subspecies that are difficult to distinguish based on morphological characters are common in all major marine groups and habitats (Churchill & Uhen, 2019; Knowlton, 1993). Ringed seals form a particularly interesting group in this respect, consisting of both widespread marine populations as well as small local populations inhabiting fresh or brackish water environments. The unique evolutionary

The maintenance of a tightly regulated heart lipidome is a general hallmark of mammal health. However, in the case of cetaceans, heart tissue lipid composition remains obscure. This work represents a first in‐depth state‐of‐the‐art characterization of the lipid content of small cetacean hearts, namely those of Delphinus delphis, Phocoena phocoena, and Stenella coeruleoalba. Phospholipid classes identified

Indo‐Pacific humpback dolphins (Sousa chinensis) use whistles to communicate with their conspecifics. Little is known about the acoustic repertoire of Indo‐Pacific humpback dolphins in waters southwest of Hainan Island, a newly recorded population in 2014. In this study, whistles of Hainan humpback dolphin population were collected by using autonomous acoustic recorders. The fundamental frequencies

Domoic acid (DA) and saxitoxin (STX)‐producing algae are present in Alaskan seas, presenting exposure risks to marine mammals that may be increasing due to climate change. To investigate potential increases in exposure risks to four pagophilic ice seal species (Erignathus barbatus, bearded seals; Pusa hispida, ringed seals; Phoca largha, spotted seals; and Histriophoca fasciata, ribbon seals), this

Data collected opportunistically aboard marine wildlife tourism vessels are an inexpensive source of spatial information on the target species. Although these data are often challenging to analyze, they can be used to monitor spatiotemporal changes in species distribution and behavior. Disruptions from whale‐watching vessels to behaviors such as foraging can be particularly harmful to cetaceans, but

When a social species inhabits disparate environments with different requirements, it presents an ideal study framework for investigating plasticity in social structure. Common dolphins (Delphinus delphis) are wide‐ranging offshore delphinids that generally form societies with fission‐fusion dynamics within large schools and exhibit weak social bonds. In Port Phillip, southeastern Australia, common

Tracking marine mammals with electronic devices enables researchers to better understand animal movements and at‐sea behavior. For pinnipeds, instruments are typically glued to the animal's hair, either directly to the pelage or via a fabric patch. These instruments are retrieved by cutting the pelage or cutting through the patch. The impact of these modifications to the pelage is presumed to be minimal

Observational studies describe rough‐toothed dolphins (Steno bredanensis) actively foraging during the day on epipelagic species. Using data from depth‐transmitting satellite tags deployed on nine individuals off Kauaʻi, we investigated diving behavior and the effects of lunar phase and solar light levels on vertical movements. Overall, tagged rough‐toothed dolphins primarily used near‐surface waters

UNESCO World Natural Heritage sites are established to ensure the long‐term conservation of natural areas. Nemuro Strait in northern Japan is adjacent to the Shiretoko World Natural Heritage Site, and attracts various trophic levels of marine species, including marine mammals. Although the coexistence of humans and marine mammals is an important issue in this area, the temporal habitat use of cetaceans

Recovery rates for baleen whales that were decimated by exploitation vary between species and populations. Age determination is critical for the understanding of recovery trends and population structure, but determining age in free‐ranging individuals remains challenging. Recent research has suggested that the methylation level of some genes in skin samples may provide age determinations with accuracy

We estimated density and abundance of the threatened southwest Alaska distinct population segment of northern sea otters (Enhydra lutris kenyoni) in two management units. We conducted aerial surveys in Bristol Bay and South Alaska Peninsula management units in 2016, and modeled sea otter density and abundance with Bayesian hierarchical distance sampling models and spatial environmental covariates (depth

Male–male contest behavior can contribute to spatial distributions of male pinnipeds during breeding seasons. To maximize breeding opportunities, the most competitive males would be expected to be surrounded by the highest numbers of reproductive‐age females. As information regarding fine‐scale spatial ecology of Weddell seals is lacking, we performed an exploratory study using kernel density analyses

Passive acoustics has been used extensively to study bottlenose dolphins; yet very few studies have examined the spatial, temporal, and environmental influences on vocalization types (echolocation, burst pulse sounds, and whistles), and few are long-term and provide high temporal resolution over multiple years. We used data from 2013 to 2018 to establish baseline acoustic patterns for bottlenose dolphins

South Asian river dolphins (Platanista gangetica) are among the most endangered of the world's cetaceans. The two subspecies in the family Platanistidae, Indus, and Ganges river dolphins (P. g. minor and P. g. gangetica), are both threatened by dams and barrages, declining river flows, fisheries bycatch, and pollution. We examine differences in external and skull morphology between dolphins in each

Accurate estimates of drag on marine animals are required to investigate the locomotive cost, propulsive efficiency, and the impacts of entanglement if the animal is carrying fishing gear. In this study, we performed computational fluid dynamics analysis of a 10 m (length over all) right whale to obtain baseline measurements of drag on the animal. Swimming speeds covering known right whale speed range

The impact of remotely piloted aircraft systems (RPAS) on marine mammals remains poorly documented despite their increasing use. In the high‐Arctic Archipelago of Svalbard, where marine mammals face increasing pressure from climate change and expanding tourism, the use of RPAS remains largely unregulated. In this study we assessed the impacts of RPAS across a range of species to provide science‐based

Studies of the social behavior of Cuvier's beaked whales (Ziphius cavirostris) are challenging because of their deep-water habitat usually far from shore and the limited time they spend at the surface. The sociality of these deepest diving mammals is of interest, however, especially for our understanding of how social systems evolve in extreme habitats. High levels of scarring suggest that males compete

Presented here is the first comprehensive and updated compilation of history, distribution, and findings of Stejneger's beaked whales (Mesoplodon stejnegeri) in Alaska. Stejneger's beaked whales are a poorly understood, elusive, deep-diving cetacean species found in the North Pacific Ocean. Since Stejneger's beaked whale strandings data in Alaska through 1994 were last published, 35 additional strandings

Santa Catarina State, in southern Brazil, is an important breeding ground for the southern right whale and it is possible to record mother-calf pairs and unaccompanied adults that migrate to this coast to either give birth, mate, or socialize. From the geographical position of the sightings, spatial segregation was evaluated between mother-calf pairs and unaccompanied whales. Using GAM, we analyzed

Male humpback whales produce complex sounds known as songs during their breeding season. Previous studies have shown diel patterns of song in their breeding areas, but there had been no similar studies in the breeding area around Okinawa, Japan. To study diel patterns of song and the behavior of humpback whales in Okinawa, we conducted 24 hr recording with a fixed hydrophone in 2007, and vessel-based

The fully aquatic lifestyle of dugongs means that direct observation of social tusk use is not usually possible. This study used body scarring as an indicator of tusk function by males. Tusk rake scars on 298 live wild dugongs, of both sexes and all sizes, were categorized and counted in over 1,000 photographs, and examined in relation to maturity and reproductive activity over seasons. All dugongs

Blow or respiratory vapor collection is a noninvasive technique for monitoring the physiology of cetaceans and although this technique shows promise, a major challenge of blow collection is difficulty quantifying samples due to variable amounts of seawater contamination. Here, we aimed to (1) determine whether blow samples could be collected from free-swimming belugas, (2) assess whether urea could

The marine otter (Lontra felina) has a patchy distribution associated with rocky coastlines along the Pacific coast of South America. In Peru marine otters are found from La Libertad (8°04′S) to Tacna (18°09′S), however, few studies have assessed its population and conservation status. To assess marine otters' current distribution along the Peru coastline, we conducted visual surveys and collected

Populations of the South American sea lion (SASL, Otaria byronia) have been intensely exploited for leather and oil in different parts of its distribution range throughout the 19th and 20th centuries, generating large changes in abundance. In Patagonia, the SASL population was reduced by more than 90% of its original abundance, and it began to recover after sealing ended. The aim of this work was to

Organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) have been detected in a variety of marine mammal species at levels associated with adverse health effects. Little is known about OC levels and impacts on health in pinnipeds with different life histories. We determined the health and levels of 18 OC pesticides and 16 PCB congeners in blubber samples from 20 Steller sea lions and 39

Little is known about exposure to diseases or the health of ice‐associated seals of the Bering Sea, which include ribbon (Histriophoca fasciata), spotted (Phoca largha), and bearded seals (Erignathus barbatus). To assess exposure to several pathogens, ribbon and spotted seals were sampled from the pack ice of the Bering Sea, and bearded seals were sampled in Kotzebue Sound, Alaska. Serum was tested

Atlantic white-sided dolphins (Lagenorhynchus acutus) are highly social odontocetes with a poorly understood tendency to mass strand. With limited capacity to study social ecology in the open ocean, mass strandings provide an opportunity to improve our understanding of group structure. Our study of 32 mass stranding events that occurred on Cape Cod, Massachusetts, between 1999 and 2009 identifies aspects

Little information exists on the current status of Southern Hemisphere sei whales (Balaenoptera borealis). We assessed their distribution and abundance along the west coast of the Falkland Islands (southwest Atlantic) during February and March 2018, using line transect and nonsystematic surveys. Abundance estimates were generated for a single survey stratum using design- and model-based approaches

A bioenergetic model is developed from empirically derived equations of morphometric, ventilatory and thermoregulatory variables to compare estimated field metabolic rates (FMR) of gray whale calves to estimates of unregulated body heat losses and consequent required thermogenesis at birth, natal lagoon departure, and weaning. Estimates of FMR are based on rates of oxygen consumption. Body surface

Bryde's‐like whales are a complex of medium‐sized baleen whales that occur in tropical waters of all three major ocean basins. Currently, a single species of Bryde's whale, Balaenoptera edeni Anderson, 1879, is recognized, with two subspecies, Eden's whale, B. edeni edeni and Bryde's whale, B. edeni brydei (Olsen, 1913), although some authors have recognized these as separate species. Recently, a new

Entanglement of whales in fishing gear occurs globally and where populations are recovering from past exploitation, entanglement frequency is likely to increase. The Western Australian population of humpback whales (Megaptera novaeangliae) is growing rapidly, yet from 1990 to 2010 the number of whales reported entangled in gear from the pot-based western rock lobster fishery was relatively stable at

To date, few consistent relationships between survival in rehabilitation programs and diagnostic measures recorded upon admission have been identified for harbor seal pups. Veterinary records for 718 unweaned Pacific harbor seal pups (Phoca vitulina richardii) admitted to a rehabilitation center were examined to identify clinical factors associated with preweaning survival and develop a triage tool

The northwest Atlantic subspecies of gray seal (Halicheorus grypus grypus) has been increasing for more than a half century and has reestablished breeding colonies in Canadian and US waters. In 2016, visual, oblique, and vertical large‐format digital photographic surveys were conducted at all known breeding colonies in the northwest Atlantic. Total pup production in the northwest Atlantic was estimated

Elephant seals, Mirounga spp., are highly dimorphic, having different energetic requirements according to age and sex, and foraging in various ecological and oceanographic contexts. Resource partitioning has been shown for the sub‐Antarctic populations of southern elephant seals, M. leonina, where colonies are surrounded by narrow shelves that deepen abruptly. In contrast, seals from Península Valdés

We examined bone mineral density (BMD) in the pectoral flipper of the common bottlenose dolphin, Tursiops truncatus. These data addressed the need to define a comprehensive target site for osteodensitometric assessment and to provide a descriptive bone density data set for this species. We analyzed 388 radii from 279 bottlenose dolphins using dual energy X‐ray absorptiometry (DXA), the accepted standard

Mortality is a demographic metric crucial for understanding the dynamics of endangered populations such as Cook Inlet beluga whales (CIBWs, Delphinapterus leucas), but patterns of mortality are currently not well understood for CIBWs, making decisions about recovery actions challenging. We combined long‐term photo‐ID data from approximately 420 individual belugas identified during the period 2005–2017

Recoveries of gray seal (Halichoerus grypus) populations across their eastern Atlantic distribution have led to a steady increase in seal‐fishery interactions. Fishers have estimated depredation of salmonids (Salmo spp.) and monkfish (Lophius spp.) as high as 40% and 59% respectively in Ireland. However, empirical evidence for the consumption of these species has been extremely limited due to diagnostic

Blood values of wild cetacean population are a valuable tool to drive proper management of threatened species. Reference intervals of 26 serum analytes were determined from 107 apparently healthy Amazon river dolphins (Inia geoffrensis) wild‐caught in the Mamirauá Sustainable Development Reserve (3°3′S, 64°51′W), central Amazon, Brazil. No differences were detected between males and females or between

We used sighting reports, including decades of citizen‐reported Hawaiian monk seal (Neomonachus schauinslandi) sightings, to describe female breeding biology and reproductive success in the main Hawaiian Islands. We first used this data set to describe the timing of events in the female reproductive cycle. We then conducted an expert review of patterns in sighting histories to detect unobserved pupping

Harbor porpoises, Phocoena phocoena, off California, comprise four recognized population stocks: Morro Bay (MOR), Monterey Bay (MRY), San Francisco‐Russian River (SFRR), and Northern California‐Southern Oregon (NCSO). The three southernmost stocks experienced substantial bycatch in gill net fisheries during the 1970s and 1980s. While the SFRR stock received full protection from gill nets in 1989, the