The plight of the enigmatic southern resident killer whales: Have we done all we can to recover these icons of the Salish Sea?

Southern Resident killer whales recognize no boundaries but frequent the coastal waters of southern British Columbia (Canada) and northern Washington State (USA). Having acknowledged their conservation plight, the two respective national governments have afforded this distinct and much-valued population the status of ‘Endangered’ under their respective endangered species laws. Divergent natural resource management regimes, endangered species legislation, and marine use profiles in the two nations have at times limited a concerted conservation push for these killer whales. However, much has been learned over the past 20 years about the three primary threats to their recovery - diminished prey (primarily Chinook salmon), underwater noise, and high levels of industrial contaminants. This research has, in turn, led to a number of steps in the two jurisdictions to recover the SRKW and improve their habitat. This panel will review past successes and failures in the quest for killer whale recovery, and contribute to a forward-looking agenda that addresses a notable and timely opportunity: ‘What more can we do to recover SRKW?’. The panel will encourage attendees to reflect on constraints and opportunities on the path to recovery. The session will provide a safe place for ‘outside the box’ ideas where boldness and innovation are encouraged to address the challenges facing the species in this transboundary region

Extensive core microbiome in drone-captured whale blow supports a framework for health monitoring

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in mSystems 2 (2017): e00119-17, doi:10.1128/mSystems.00119-17.The pulmonary system is a common site for bacterial infections in cetaceans, but very little is known about their respiratory microbiome. We used a small, unmanned hexacopter to collect exhaled breath condensate (blow) from two geographically distinct populations of apparently healthy humpback whales (Megaptera novaeangliae), sampled in the Massachusetts coastal waters off Cape Cod (n = 17) and coastal waters around Vancouver Island (n = 9). Bacterial and archaeal small-subunit rRNA genes were amplified and sequenced from blow samples, including many of sparse volume, as well as seawater and other controls, to characterize the associated microbial community. The blow microbiomes were distinct from the seawater microbiomes and included 25 phylogenetically diverse bacteria common to all sampled whales. This core assemblage comprised on average 36% of the microbiome, making it one of the more consistent animal microbiomes studied to date. The closest phylogenetic relatives of 20 of these core microbes were previously detected in marine mammals, suggesting that this core microbiome assemblage is specialized for marine mammals and may indicate a healthy, noninfected pulmonary system. Pathogen screening was conducted on the microbiomes at the genus level, which showed that all blow and few seawater microbiomes contained relatives of bacterial pathogens; no known cetacean respiratory pathogens were detected in the blow. Overall, the discovery of a shared large core microbiome in humpback whales is an important advancement for health and disease monitoring of this species and of other large whales.Funding for sample analysis was provided through a grant to A.A., M.J.M., and J.W.D. from the Ocean Life Institute of the Woods Hole Oceanographic Institution. Attachments for collection surfaces on the hexacopter were constructed with funding support from NOAA’s UAS Program

Ecotypic variation and predatory behavior among killer whales (Orcinus orca) off the eastern Aleutian Islands, Alaska

From 2001 to 2004 in the eastern Aleutian Islands, Alaska, killer whales (Orcinus orca) were encountered 250 times during 421 days of surveys that covered a total of 22,491 miles. Three killer whale groups (resident, transient, and offshore) were identified acoustically and genetically. Resident killer whales were found 12 times more frequently than transient killer whales, and offshore killer whales were encountered only once. A minimum of 901 photographically identified resident whales used the region during our study. A total of 165 mammal-eating transient killer whales were identified, and the majority (70%) were encountered during spring (May and June). The diet of transient killer whales in spring was primarily gray whales (Eschrichtius robustus), and in summer primarily northern fur seals (Callorhinus ursinus). Steller sea lions (Eumetopias jubatus) did not appear to be a preferred prey or major prey item during spring and summer. The majority of killer whales in the eastern Aleutian Islands are the resident ecotype, which does not consume marine mammals

Physical constraints of cultural evolution of dialects in killer whales

Data collection was supported by a variety of organizations, including the Russian Fund for the Fundamental Research (Grant No. 15-04-05540), the Rufford Small Grants Fund, Whale and Dolphin Conservation, the Fundação para a Ciência e a Tecnologia (Grant No. SFRH/BD/30303/2006), Russell Trust Award of the University of St. Andrews, the Office of Naval Research, the Icelandic Research Fund (i. Rannsóknasjóður), the National Geographic Society Science and Exploration Europe (Grant No. GEFNE65-12), Vancouver Aquarium Marine Science Centre, the Canadian Ministry of Fisheries and Oceans, and the North Gulf Oceanic Society.Odontocete sounds are produced by two pairs of phonic lips situated in soft nares below the blowhole; the right pair is larger and is more likely to produce clicks, while the left pair is more likely to produce whistles. This has important implications for the cultural evolution of delphinid sounds: the greater the physical constraints, the greater the probability of random convergence. In this paper the authors examine the call structure of eight killer whale populations to identify structural constraints and to determine if they are consistent among all populations. Constraints were especially pronounced in two-voiced calls. In the calls of all eight populations, the lower component of two-voiced (biphonic) calls was typically centered below 4 kHz, while the upper component was typically above that value. The lower component of two-voiced calls had a narrower frequency range than single-voiced calls in all populations. This may be because some single-voiced calls are homologous to the lower component, while others are homologous to the higher component of two-voiced calls. Physical constraints on the call structure reduce the possible variation and increase the probability of random convergence, producing similar calls in different populations.PostprintPeer reviewe

Killer whales and marine mammal trends in the North Pacific : a re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis

This paper is not subject to U.S. copyright. The definitive version was published in Marine Mammal Science 23 (2007): 766–802, doi:10.1111/j.1748-7692.2006.00093.x.Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50–100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem

Echolocation in wild killer whales (Orcinus orca)

Echolocation by odontocete whales has been demonstrated in captive settings many times, yet little is known about its use and function in the wild. In this thesis, I describe echolocation sounds in pods of killer whales (Orcinus orca) off the coasts of British Columbia and Alaska. I examine the relationships between echolocation and water clarity, ambient noise, and behavioural activity. I compare echolocation by two populations with different feeding habits and foraging patterns. The study provides new insight into the functional role of odontocete echolocation, and into the relative contributions of vision and passive listening to spatial perception and prey detection. Underwater recordings were made during 111 encounters with killer whales. Known members of the resident (fish-eating) population were photographically identified 85 times, and transients (mammal eaters) 23 times. Click sounds characteristic of echolocation were identified in the recordings aurally, and by spectrographic and waveform analysis. Most clicks occurred in series (trains), but isolated clicks were occasionally detected. Echolocation behaviour differed strikingly between residents and transients. An echolocation index (EI) was defined as the average percentage of time that an individual produced click trains. The mean EI for residents was 4.24%, 27 times greater than for transients. The duration of resident click trains averaged 6.83 s, compared to 0.86 s for transients. Resident click trains were comprised of evenly spaced clicks, whereas transient trains had uneven click spacing. Transient individuals used isolated clicks once every five minutes, four times as often as residents. For resident killer whales, EI values were significantly higher during foraging and travelling than during other behavioural activities. In residents, EI declined with group size. This was also true of transients, for the recordings in which click trains were detected. Transient EI levels were significantly higher when close to shore than when offshore. No relationship between EI and ambient noise level was found for either residents or transients. Residents increased the amplitude of their clicks in response to increasing ambient noise levels. No relationship was found between water clarity and EI for either type of killer whale. I suggest that the differences in echolocation behaviour between residents and transients are accounted for by their different prey. Fish have little or no aural sensitivity in the frequency range of killer whale clicks. Marine mammals are able to detect clicks, and may use them to evade killer whale attacks. The use of isolated clicks and short, irregular, quiet click trains makes transient echolocation less detectable by marine mammals than the echolocation used by residents. Passive listening is probably the principal technique that transients use to locate prey, whereas residents use echolocation in combination with passive listening when foraging. Vision is not a major factor in locating prey, but may be used by either whale type during pursuits. Finally, I suggest that both residents and transients obtain much of their positional and orientational information using passive listening alone.Science, Faculty ofZoology, Department ofGraduat

Culture and competition in killer whales (abstract only)

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Population structure and mating patterns of Killer Whales (Orcinus orca) as revealed by DNA analysis

This thesis reports a genetic investigation of population segregation, social organization, and mating patterns in killer whales (Orcinus orca) of the northeastern Pacific Ocean. Previous studies identified two sympatric, non-associating populations, fish-eating residents and mammal-eating transients, and described many aspects of their demography, ecology, and social behaviour. Less is known about a third offshore population. Here, I focused on two aspects of killer whale social organization that are unusual among wellstudied mammals: maintenance of complete segregation between residents and transients in sympatry, and lack of dispersal in individual residents of either sex. I began by developing and testing lightweight pressure-propelled biopsy darts. They were an efficient way of acquiring skin samples from free-ranging whales and caused only minor behavioural responses in sampled animals. Using these darts and sampling stranded carcasses, colleagues and I collected biopsies from 269 individually-identified killer whales in British Columbia and Alaska. I used DNA from the biopsies to sequence the mitochondrial D-loop of 111 matrilines, and genotyped all individuals at 11 polymorphic microsatellite loci. I found that residents and transients are strongly differentiated genetically and that there is little or no gene flow between them. Both are divided into three genetically-differentiated regional subpopulations. Each resident subpopulation is more closely related to other resident subpopulations than to any transient subpopulation and vice versa, implying that the differences between residents and transients stem from a single divergence. The offshore population is not closely related to either of the other populations. The propensity of killer whales to live in fixed groups of a few hundred individuals apparently allows sympatric or parapatric populations to diverge genetically and could eventually result in speciation. I examined mating patterns in residents by conducting paternity tests and analysing fixation indices based on microsatellite genotypes. I found that residents rarely mate within their pods. Further, in the most thoroughly-sampled resident subpopulation, most matings were between rather than within acoustic clans (groups of pods with similar acoustic repertoires). Because pods within clans proved to be closely related, inter-clan mating appears to be an inbreeding avoidance mechanism. Most matings were between individuals from the same subpopulation. This pattern of population segregation coupled with inbreeding avoidance closely resembles marriage patterns in many human societies.Science, Faculty ofZoology, Department ofGraduat

Call Usage Learning by a Beluga (Delphinapterus leucas) in a Categorical Matching Task

The ability to modify the structure and context of vocalizations through learning plays a key role in the social interactions of many species.  The investigation of categorical matching, an aspect of contextual vocal learning, is the first step toward determining how contextual learning plays a role in the use, comprehension, and categorization of sounds in the wild.  To this end, we conducted a study at the Vancouver Aquarium to test the ability of a juvenile female beluga, Qila, to respond to playbacks of two types of in-air beluga calls with vocalizations that matched the category of call played (a scream, which is a vocalization type shaped over time with reinforcement and not part of this species'natural repertoire, and a pulse-train, a natural call category).  We first tested Qila with random sequences of the same version of the two vocalizations with which she had been trained.  Her overall success in matching all playback stimuli was above chance but not statistically so (66%).  She had more difficulty matching screams (54% success) than pulse trains (80% success).  We next played random sequences of six novel pulse-trains and seven novel screams, which Qila had not been trained with.  She responded correctly to the set of novel stimuli of both call types in 64% of the trials, a success rate that did not differ statistically from chance.  Again, she had more difficulty matching screams (55% success), relative to pulse trains (74% success).  These results indicate that Qila successfully matched only pulse trains, the class that is part of this species’ natural repertoire.  Her poor performance on matching screams might be partly explained by a difficulty to perceive categorically a signal that lacks a function in the natural repertoire of belugas.Keywords: categorical matching, contextual learning, vocal learning, categorization, beluga