Feeding characteristics and prey profitability in five herring‐feeding killer whales <i>(Orcinus orca)</i> in northern Norway

Matika, Aimee F.; Jourdain, Eve; Cade, David E.; Karoliussen, Richard; Hammond, Philip S.

doi:10.1111/mms.12931

Cited by 3 publications

(1 citation statement)

References 39 publications

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“…Our findings (Figs 2 and 5 and 6) are also consistent with those of others showing that killer whales of all ecotypes primarily make short (<1 min), shallow (<10 m) dives-and comparatively fewer long (>1 min), deep (>10 m) dives [8][9][10]37,[46][47][48]. In our case, short duration dives occurred 10 times more frequently than long dives, and constituted about 90% of all the dives we recorded.…”

Section: Plos Onesupporting

confidence: 92%

Killer whale respiration rates

McRae,

Volpov,

Sidrow

et al. 2024

PLoS ONE

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Measuring breathing rates is a means by which oxygen intake and metabolic rates can be estimated to determine food requirements and energy expenditure of killer whales (Orcinus orca) and other cetaceans. This relatively simple measure also allows the energetic consequences of environmental stressors to cetaceans to be understood but requires knowing respiration rates while they are engaged in different behaviours such as resting, travelling and foraging. We calculated respiration rates for different behavioural states of southern and northern resident killer whales using video from UAV drones and concurrent biologging data from animal-borne tags. Behavioural states of dive tracks were predicted using hierarchical hidden Markov models (HHMM) parameterized with time-depth data and with labeled tracks of drone-identified behavioural states (from drone footage that overlapped with the time-depth data). Dive tracks were sequences of dives and surface intervals lasting ≥ 10 minutes cumulative duration. We calculated respiration rates and estimated oxygen consumption rates for the predicted behavioural states of the tracks. We found that juvenile killer whales breathed at a higher rate when travelling (1.6 breaths min-1) compared to resting (1.2) and foraging (1.5)—and that adult males breathed at a higher rate when travelling (1.8) compared to both foraging (1.7) and resting (1.3). The juveniles in our study were estimated to consume 2.5–18.3 L O2 min-1 compared with 14.3–59.8 L O2 min-1 for adult males across all behaviours based on estimates of mass-specific tidal volume and oxygen extraction. Our findings confirm that killer whales take single breaths between dives and indicate that energy expenditure derived from respirations requires using sex, age, and behavioural-specific respiration rates. These findings can be applied to bioenergetics models on a behavioural-specific basis, and contribute towards obtaining better predictions of dive behaviours, energy expenditure and the food requirements of apex predators.

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Section: Plos Onesupporting

confidence: 92%

Killer whale respiration rates

McRae,

Volpov,

Sidrow

et al. 2024

PLoS ONE

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High-resolution biologging of an Atlantic bluefin tuna captured and eaten by a supposed orca

Rudd,

Abel,

Baringo

et al. 2024

Sci Rep

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Biologging has been used on a range of wild animals to document spectacular feats of migration and behaviour. We describe the pursuit, capture, and ingestion of an adult Atlantic bluefin tuna (Thunnus thynnus) (175 cm, estimated weight: 81 kg), which was instrumented with a biologging tag, by a predator, most likely an orca (Orcinus orca). The predation event lasted over 19 min, with the tuna exhibiting elevated activity (max acceleration 3.12 g) and a rapid ascent from 126 m at 3.6 m. s − 1 followed by death and handling at the surface. Orca were separately recorded using video tags, capturing and handling tuna cooperatively in a manner consistent with the tuna data. We then present the longest orca accelerometry dataset from the ingested MiniPAT tag, with diel patterns of activity and 77 feeding events. These unique datasets provide insight into the energetic dynamics of two of the ocean's fastest predators.

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Males miss and females forgo: Auditory masking from vessel noise impairs foraging efficiency and success in killer whales

Tennessen,

Holt,

Wright

et al. 2024

Global Change Biology

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Understanding how the environment mediates an organism's ability to meet basic survival requirements is a fundamental goal of ecology. Vessel noise is a global threat to marine ecosystems and is increasing in intensity and spatiotemporal extent due to growth in shipping coupled with physical changes to ocean soundscapes from ocean warming and acidification. Odontocetes rely on biosonar to forage, yet determining the consequences of vessel noise on foraging has been limited by the challenges of observing underwater foraging outcomes and measuring noise levels received by individuals. To address these challenges, we leveraged a unique acoustic and movement dataset from 25 animal‐borne biologging tags temporarily attached to individuals from two populations of fish‐eating killer whales (Orcinus orca) in highly transited coastal waters to (1) test for the effects of vessel noise on foraging behaviors—searching (slow‐click echolocation), pursuit (buzzes), and capture and (2) investigate the mechanism of interference. For every 1 dB increase in maximum noise level, there was a 4% increase in the odds of searching for prey by both sexes, a 58% decrease in the odds of pursuit by females and a 12.5% decrease in the odds of prey capture by both sexes. Moreover, all but one deep (≥75 m) foraging attempt with noise ≥110 dB re 1 μPa (15–45 kHz band; n = 6 dives by n = 4 whales) resulted in failed prey capture. These responses are consistent with an auditory masking mechanism. Our findings demonstrate the effects of vessel noise across multiple phases of odontocete foraging, underscoring the importance of managing anthropogenic inputs into soundscapes to achieve conservation objectives for acoustically sensitive species. While the timescales for recovering depleted prey species may span decades, these findings suggest that complementary actions to reduce ocean noise in the short term offer a critical pathway for recovering odontocete foraging opportunities.

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Feeding characteristics and prey profitability in five herring‐feeding killer whales (Orcinus orca) in northern Norway

Cited by 3 publications

References 39 publications

Killer whale respiration rates

Killer whale respiration rates

High-resolution biologging of an Atlantic bluefin tuna captured and eaten by a supposed orca

Males miss and females forgo: Auditory masking from vessel noise impairs foraging efficiency and success in killer whales

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