Movements and Spatial Use of False Killer Whales in Hawaii: Satellite Tagging Studies in 2009

Baird, Robin W.; Schorr, Gregory S.; Webster, Daniel L.; McSweeney, Daniel J.; Hanson, M. Bradley; Andrews, Russel D.

doi:10.21236/ada539300

Cited by 4 publications

(4 citation statements)

References 10 publications

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“…The false killer whale #025, photographed on 29 March 1999, is also known as HIPc186 by the Cascadia Research Collective. This individual was reported to have a bent dorsal fin when it was tagged in December 2009 (Baird & Gorgone, 2005;Baird et al, 2011), demonstrating a survivorship of approximately 10 years. The long duration between sightings of individuals from all three species with bent dorsal fins suggests that odontocetes can survive this injury, but the observed incidence of this condition represents the minimum number of cases as there could be others that were fatal and therefore not reported.…”

Section: Discussionmentioning

confidence: 99%

Incidence of Odontocetes with Dorsal Fin Collapse in Maui Nui, Hawaii

Stack¹,

Currie²,

McCordic³

et al. 2019

Aquatint's Mammon's

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We examined the incidence of bent or collapsed dorsal fins of eight species of odontocetes observed in the nearshore waters of Maui Nui, Hawaii. Between 1995 and 2017, 1,312 distinctive individual odontocetes were photographically documented. Our photo-identification catalogs include 583 spinner dolphins (Stenella longirostris longirostris), 164 bottlenose dolphins (Tursiops truncatus), 132 short-finned pilot whales (Globicephala macrorhynchus), 253 pantropical spotted dolphins (Stenella attenuata), 82 false killer whales (Pseudorca crassidens), 70 melonheaded whales (Peponocephala electra), 15 pygmy killer whales (Feresa attenuata), and 13 rough-toothed dolphins (Steno bredanensis). Of these, two false killer whales (2.44% of catalog), two spinner dolphins (0.34% of catalog), and three pantropical spotted dolphins (1.19% of catalog) displayed major dorsal fin disfigurements. Both spinner dolphins and two of the spotted dolphins had multiple resights spanning several years, with one spotted dolphin having a 16-year span between resights. The two false killer whales with bent dorsal fins did not have any resights and were only sighted once throughout the study period. We also present the first progression of dorsal fin collapse after a significant injury to the leading edge of a spinner dolphin. Results from this research expand our knowledge on injuries to marine mammals and the survivorship of wild dolphins with dorsal fin injuries and contribute to the management of odontocetes in Hawaii, where interactions with fishing gear are a significant conservation issue.

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Section: Discussionmentioning

confidence: 99%

Incidence of Odontocetes with Dorsal Fin Collapse in Maui Nui, Hawaii

Stack¹,

Currie²,

McCordic³

et al. 2019

Aquatint's Mammon's

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“…Preying on exceedingly large species, such as grey whale calves accompanied by defensive mothers, comes with the risk of injury to the predator, and requires expending considerable time and energy to handle and subdue calves [22,65]. The rewards of net energy gained by killing a grey whale calf must offset the associated risks of the hunt [70]. This may explain why we consistently observed large groups of transient killer whales forming in Monterey Bay during the spring-with most hunts on grey whale calves involving 15 or more whales, suggesting that the probability of successfully killing a grey whale calf increases with killer whale group size.…”

Section: Plos Onementioning

confidence: 99%

Foraging behaviour and ecology of transient killer whales within a deep submarine canyon system

McInnes,

Lester,

Dill

et al. 2024

PLoS ONE

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Transient killer whales have been documented hunting marine mammals across a variety of habitats. However, relatively little has been reported about their predatory behaviours near deep submarine canyons and oceanic environments. We used a long-term database of sightings and encounters with these predators in and around the Monterey Submarine Canyon, California to describe foraging behaviour, diet, seasonal occurrence, and habitat use patterns. Transient killer whales belonging to the outer coast subpopulation were observed within the study area 261 times from 2006–2021. Occurrences, behaviours, and group sizes all varied seasonally, with more encounters occurring in the spring as grey whales migrated northward from their breeding and calving lagoons in Mexico (March-May). Groups of killer whales foraged exclusively in open water, with individuals within the groups following the contours of the submarine canyon as they searched for prey. Focal follows revealed that killer whales spent 51% of their time searching for prey (26% of their time along the shelf-break and upper slope of the canyon, and 25% in open water). The remainder of their time was spent pursuing prey (10%), feeding (23%), travelling (9%), socializing (6%), and resting (1%). Prey species during 87 observed predation events included California sea lions, grey whale calves, northern elephant seals, minke whales, common dolphins, Pacific white-sided dolphins, Dall’s porpoise, harbour porpoise, harbour seals, and sea birds. The calculated kill rates (based on 270 hours of observing 50 predation events) were 0.26 California sea lions per killer whale over 24 hours, 0.11 grey whale calves, and 0.15 for all remaining prey species combined. These behavioural observations provide insights into predator-prey interactions among apex predators over submarine canyons and deep pelagic environments.

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“…Three distinct populations of false killer whales are found in the Hawaiian Archipelago, with one currently listed as endangered under the U.S. Endangered Species Act (Baird, 2009;Oleson et al, 2010;Bradford et al, 2020). These delphinids are known to interact with fisheries throughout the archipelago leading to whale mortality or injury (Baird, 2009;Oleson et al, 2010) at sometimes unsustainable rates.…”

Section: Introductionmentioning

confidence: 99%

“…Endangered Species Act (Baird, 2009;Oleson et al, 2010;Bradford et al, 2020). These delphinids are known to interact with fisheries throughout the archipelago leading to whale mortality or injury (Baird, 2009;Oleson et al, 2010) at sometimes unsustainable rates. Thus, these populations have been a focus of extensive survey efforts to collect visual data for abundance estimation citepBradford2020.…”

Section: Introductionmentioning

confidence: 99%

Vocal behavior of false killer whale (Pseudorca crassidens) acoustic subgroups

2023

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Understanding the vocal behavior of cetaceans is an important component of many passive acoustic applications. This study quantifies the vocal behavior of acoustic subgroups of false killer whales (Pseudorca crassidens) from the Hawaiian Archipelago. The acoustic subgroups (N = 523) exhibit diverse vocal behavior that varies between encounters. Overall, 29% of acoustic subgroups only echolocate, 16% only whistle, and 55% emit both types of vocalizations. These results contribute important information for developing automated passive acoustic cetacean tracking, localization, and classification techniques, and thus, support future cetacean monitoring and assessment efforts.

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Movements and Spatial Use of False Killer Whales in Hawaii: Satellite Tagging Studies in 2009

Cited by 4 publications

References 10 publications

Incidence of Odontocetes with Dorsal Fin Collapse in Maui Nui, Hawaii

Incidence of Odontocetes with Dorsal Fin Collapse in Maui Nui, Hawaii

Foraging behaviour and ecology of transient killer whales within a deep submarine canyon system

Vocal behavior of false killer whale (Pseudorca crassidens) acoustic subgroups

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