Jared R. Towers

Fisheries and Oceans Canada | DFO

Depredation of demersal longlines by killer and sperm whales is a widespread behaviour that impacts fisheries and whale populations. To better understand how depredating whales behave in response to fishing activity, we deployed satellite-linked location and dive-profile tags on a sperm and killer whale that were depredating Patagonian toothfish fr...

In British Columbia, Bigg’s (transient) killer whales have been opportunistically photo-identified for several decades. This report uses a 61-year archive of photo-identification data from 1958-2018 to provide information on the abundance and distribution of Bigg’s killer whales known from BC. In total, 766 unique individuals were identified in a t...

Relationships between seabirds and cetaceans can vary from symbiotic to predatory. At high latitude seas in the Southern Hemisphere, giant petrels (Macronectes spp.) and male sperm whales (Physeter macrocephalus) are often solitary, but commercial longlining for Patagonian toothfish (Dissostichus eleginoides) provides consistent feeding opportuniti...

Climatic changes have had significant impacts on marine ecosystems, including apex predators such as cetaceans. A more complete understanding of the potential impacts of climate change on cetaceans is necessary to ensure their conservation. Here we present a review of the literature on the impacts of climate change on cetacean distribution, habitat...

This article presents details on the 24th confirmed and reported live sighting of Shepherd's beaked whale and the only documentation of it to date east of Tristan da Cunha and west of Australia.

Endangered Southern Resident killer whales (Orcinus orca) are fish-eaters that preferentially prey on adult Chinook salmon (Oncorhynchus tshawytscha). Despite being salmon specialists, individuals from all three killer whale pods (J, K, L) have been observed harassing and killing porpoises (family Phocoenidae) without consuming them. Retrospectivel...

Researchers can investigate many aspects of animal ecology through noninvasive photo–identification. Photo–identification is becoming more efficient as matching individuals between photos is increasingly automated. However, the convolutional neural network models that have facilitated this change need many training images to generalize well. As a r...

Age-related changes in the patterns of local relatedness (kinship dynamics) can be a significant selective force shaping the evolution of life history and social behaviour. In humans and some species of toothed whales, average female relatedness increases with age, which can select for a prolonged post-reproductive lifespan in older females due to...

Genome sequences can reveal the extent of inbreeding in small populations. Here, we present the first genomic characterization of type D killer whales, a distinctive eco/morphotype with a circumpolar, subantarctic distribution. Effective population size is the lowest estimated from any killer whale genome and indicates a severe population bottlenec...

An unusual influx of Shorttailed Shearwaters Ardenna tenuirostris occurred in British Columbia marine waters in 2021 with concentrations of thousands of birds in the Blackfish Sound region of eastern Queen Charlotte Strait and hundreds, possibly thousands, in the northern Salish Sea. Birds began to arrive in mid-August, built to a peak in mid-Septe...

Bowhead whales occur in the Arctic year-round. Their movements are largely correlated with seasonal expansions and reductions of sea ice, but a few recent extralimital sightings have occurred in the eastern and western North Atlantic and one was also documented in the western North Pacific over 50 years ago. Here we present details of a juvenile bo...

Biometric identification techniques such as photo-identification require an array of unique natural markings to identify individuals. From 1975 to present, Bigg’s killer whales have been photo-identified along the west coast of North America, resulting in one of the largest and longest-running cetacean photo-identification datasets. However, data m...

Identifying mortality sources and mitigation solutions is crucial in species management and conservation. In killer whales (Orcinus orca), mortality events may pose a serious concern for the conservation of small discrete populations, especially if they involve entire groups. This study investigated 19 incidents involving 116 killer whales from a m...

The extended female postreproductive life span found in humans and some toothed whales remains an evolutionary puzzle. Theory predicts demographic patterns resulting in increased female relatedness with age (kinship dynamics) can select for a prolonged postreproductive life span due to the combined costs of intergenerational reproductive conflict a...

The extended female post-reproductive lifespan found in humans and some toothed whales remains an evolutionary puzzle. Theory predicts demographic patterns resulting in increased female relatedness with age (kinship dynamics) can select for a prolonged post-reproductive lifespan due to the combined costs of inter-generational reproductive conflict...

TThree forms of killer whales (Orcinus orca) occur around the subantarctic islands of the southern Indian Ocean (42-53°S; 34-74°E). The form encountered in both inshore and offshore waters, described as generalist in its feeding preferences (seals, whales, penguins and fish as prey) and known to depredate toothfish from longliners has been opportun...

Killer whales are known to live strand in many regions around the world. Some populations regularly and repeatedly do so in pursuit of prey, but this behaviour is otherwise relatively rare. Off the west coast of North America, historical records of live stranded killer whales indicate that most individuals perished, were euthanized, or captured for...

Censuses of the northern resident killer whale population using photo-identification have been conducted annually since 1973. These studies are based on photographic recapture of permanent natural markings on every individual within the population. In this report, we summarize northern resident killer whale population trends over the time series of...

From June to August 2012, we conducted over 500 h of visual surveys from Cormorant Island, British Columbia, to determine behaviour and habitat use patterns of nearby cetaceans. Seven species were documented, but Minke Whales (Balaenoptera acutorostrata) were by far the most common and were observed lunge feeding at the surface on 15 occasions. In...

Two populations of killer whales aggregate around Vancouver Island to feed primarily on Chinook salmon. Aerial photogrammetry of endangered southern residents has documented some adults growing to smaller lengths in recent decades, suggesting that early growth may have been constrained by low Chinook availability in the 1990s. We investigated wheth...

In 1955, 17 killer whales (Orcinus orca) stranded on a beach in Paraparaumu, New Zealand. From the grainy, black and white photographs (Fig. 1), it was clear that they were not typical killer whales: they were small, with narrow, pointy dorsal fins, a bulbous head, and the prominent white eyepatch normally found on killer whales was reduced to a ti...

The minke whale (Balaenoptera acutorostrata) is a small species of baleen whale with a cosmopolitan distribution. Despite extensive study on the vocalizations of other balaenopterids, the acoustic repertoire of minke whales is not well known. Individuals of the North Pacific subspecies (B. acutorostrata scammoni) produce unique vocalizations (‘boin...

The innovation and diffusion of novel foraging strategies within a population can increase the capacity of individuals to respond to shifts in prey abundance and distribution. Since 2011, some humpback whales (Megaptera novaeangliae) off northeastern Vancouver Island (NEVI), Canada, have been documented using a new feeding strategy called “trap‐fee...

Yukusam is the name given to a male sperm whale who was first documented off northeastern Vancouver Island in February 2018. He spent several weeks in this area before traveling south to the inland waters of the Salish Sea in late March 2018. Sperm whale clicks have been used as a proxy to determine overall size by using the time difference of arri...

From 11 February to 31 March 2018, a lone male sperm whale visited coastal waters from the northeast to southern ends of Vancouver Island. This whale, named "Yukusam" after the Namgis First Nation word for Hanson Island, near where the whale was first observed and recorded, is the first sperm whale recorded acoustically in the area since 1984 and i...

The minke whale (Balaenoptera acutorostrata) is the smallest species of baleen whale and has a cosmopolitan distribution. Despite extensive study on the vocalizations of other balaenopterids, the acoustic repertoire of minke whales is not well known. Individuals of the North Pacific subspecies of common minke whale (B. a. scammoni) are known to pro...

During February and March, 2018, a lone sperm whale known as Yukusam was recorded first by Orcalab in Johnstone Strait and subsequently on multiple hydrophones within the Salish Sea [1]. We learn and denoise these multichannel clicks trains with AutoEncoders Convolutional Neural Net (CNN). Then, we build a map of the echolocations to elucidate vari...

Fin Whale distribution and habitat use in northern waters of British Columbia (BC) were investigated using a multi-scale study approach based on data collected by Fisheries and Oceans Canada’s Marine Mammal Research Section. Ship-based survey data were used to model Fin Whale distribution as a function of habitat features in Hecate Strait and Queen...

Background: Common bottlenose dolphins (Tursiops truncatus) are distributed globally in tropical and warm-temperate waters with coastal and offshore ecotypes known. In the eastern North Pacific Ocean, common bottlenose dolphins are typically found in offshore waters as far as 41° N and in coastal waters as far as 38° N. Despite considerable survey...

Infanticide can be an extreme result of sexual conflict that drives selection in species in which it occurs. It is a rarely observed behaviour but some evidence for its occurrence in cetaceans exists in three species of dolphin. Here we describe observations of an adult male killer whale (Orcinus orca) and his postreproductive mother killing a neon...

Historically, Fin Whales (Balaenoptera physalus) were relatively common off the west coast of North America but very few records of their occurrence in waters between Vancouver Island and continental North America exist. To confirm their presence in these waters we collected photographs documenting at least 13 unique individuals during 43 encounter...

Laterally bent dorsal fins are rarely observed in free-ranging populations of cetaceans, contrary to captivity, where most killer whale Orcinus orca adult males have laterally collapsed fins. This topic has been poorly explored, and data/information on its occurrence and possible causes are limited. The present study: (i) undertakes a review of the...

The ability of individuals to adapt to environmental change can be determined by physiology, as well as by behavioural flexibility. The innovation and spread of novel foraging strategies within a population can increase individuals’ capacities to respond to shifts in prey abundance, distribution, or behaviour. Since 2011, humpback whales off northe...

Two populations of fish-eating Killer Whales, Northern Resident and Southern Resident, inhabit waters off Canada’s west coast. The populations were listed under the Species at Risk Act (SARA) as Threatened and Endangered, respectively, in 2003. As required by the SARA, efforts have since been underway to identify critical habitat for these populati...

Field studies of the life history and ecology of killer whale populations off Canada’s west coast have been conducted annually since 1973. These studies are based on the identification of individual whales from photographs of permanent, natural markings. In this report, we summarize abundance trends in the northern resident killer whale population...

Marine planning must take into consideration the reality that we need to ac- count for many of the things in the marine environment that are of immense value to coastal communities and for which we currently pay nothing. British Columbia’s northern Vancouver Island communities derive great economic bene t from the marine ecosystems surrounding them...

Patagonian toothfish longliners operating around South Georgia regularly experience high levels of depredation by killer and sperm whales. Between May 7 and June 15 I spent 40 days aboard the fishing vessel, San Aspiring, conducting research into this issue. In addition to undertaking effort to photo-identify every killer and sperm whale encountere...

In 2013 the BC sea otter population had a minimum of 6,754 sea otters: 5,612 sea otters were counted in the Vancouver Island region and 1,142 sea otters in the central mainland coast region. The population has continued to grow and expand its range since the last survey, demonstrating population growth patterns that are typical among recovering sea...

During the summer and autumn of 2013, Blue-footed Boobies (Sula nebouxii) irrupted north of their usual range in greater numbers than ever previously documented. A sub-adult photographed off northeastern Vancouver Island, B.C. on 201 3 September 24 is the first confirmed record of this species in Canada.

In the eastern North Pacific Ocean, common minke whales (Balaenoptera acutorostrata) are widespread but encountered relatively infrequently. It is generally believed that they make annual migrations between higher latitudes in the summer and lower latitudes in the winter; however, in some temperate coastal regions where common minke whales have bee...

The route taken by northward migrating gray whales during spring between Vancouver Island and southeastern Alaska, a distance of about 575 km, has long been uncertain. It is generally believed that the whales closely follow the western, outer coastline of Haida Gwaii (formerly the Queen Charlotte Islands), an archipelago lying between Vancouver Isl...

Mammal-eating transient killer whales off Canada’s Pacific coast are listed as Threatened under the Species-at-Risk Act. A Recovery Strategy for transient killer whales was prepared by DFO in 2007, but insufficient information was available to identify critical habitat in that document. Here we present an assessment of the habitat use and requireme...

Killer whales are easily recognizable by the appearance of their naturally occurring markings in both photographs and during field observations. This report presents updated identification images and demographic data for Bigg's (transient) killer whales known from numerous encounters between 1974 and 2012 in the coastal waters of British Columbia,...

The conversion from analogue to digital formats in scientific photography has created a need for new photo management and analysis tools for some large datasets. In order to maintain continuity with metadata working standards used for long time series of photo-identification data on film, we managed and analyzed a multi-year dataset of over 75,000...

Field studies of the life history and ecology of killer whale populations off Canadaʼs Pacific coast have been conducted annually since 1973. These studies are based on the identification of individual whales from photographs of permanent, natural markings. In this report, we summarize abundance trends in the northern resident killer whale populati...

Studies have shown that killer whale (Orcinus orca) communities in high latitudes regularly comprise assemblages of sympatric ‘ecotypes’—forms that differ in morphology, behavior, and prey preferences. Although they can appear superficially similar, recent genetic evidence suggests that breeding is assortative among ecotypes within individual commu...