Geographic and temporal patterns of non-lethal attacks on humpback whales by killer whales in the eastern South Pacific and the Antarctic Peninsula

Capella, Juan; Félix, Fernando; Flórez‐González, Lilián; Gibbons, Jorge; Haase, Ben; Guzmán, Héctor M.

doi:10.3354/esr00924

Cited by 8 publications

(7 citation statements)

References 52 publications

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“…The 12% rate observed in this study is similar to those reported for humpback whales on low-latitude breeding grounds and high-latitude breeding grounds where rates ranged from a minimum of 6% to a maximum of 26% (Mehta et al, 2007;Steiger et al, 2008;Capella et al, 2018).…”

Section: Killer Whale Scarringsupporting

confidence: 86%

“…Results of killer whale scarring studies in humpback and other baleen whales conducted by Mehta et al (2007) and Capella et al (2018) indicate that killer whale attacks occur mostly on calves, near breeding sites and during the first migration to feeding areas. Killer whale sightings off the coast of Oman are relatively rare (Minton et al, 2010;5OES and ESO, 2021) Northern Indian Ocean (e.g.…”

Section: Killer Whale Scarringmentioning

confidence: 99%

“…Killer whale tooth marks were defined as a set of three or more parallel, linear scars approximately equidistant from each other (sensu Mehta et al, 2007). To ensure consistency and minimise bias within our own dataset and to provide a comparable estimate, only good quality photographs portraying the entire ventral surface of the tail flukes were used to calculate prevalence of visible evidence of killer whale predation attempts (Naessig and Lanyon, 2004;Mehta et al, 2007;Steiger et al, 2008;Capella et al, 2018). Following Capella et al (2018), rake marks were categorised by the intensity of the visible scarring:…”

Section: Predation Attemptsmentioning

confidence: 99%

“…Visual health assessments using high resolution images of free-ranging cetaceans have proven to be an effective means to assess general health and body condition (Pettis et al 2004, Van Bressem et al, 2014a and occurrence and prevalence of barnacles (Kane et al, 2008). This methodology is also an effective means to examine the rate of anthropogenic scarring in cetacean populations, particularly those caused by vessel strikes (Moore et al, 2013;Hill et al, 2017, Bradford et al 2009, interaction with fishing gear (Robbins and Mattila, 2000;Neilson et al, 2009;Knowlton et al, 2012;Robbins, 2012;Basran et al, 2019), satellite tag insertion (Andrews et al 2019, Mizroch et al, 2010Robbins et al, 2013;Robbins et al, 2016), as well as predatory attempts by killer whales (Mehta, 2004;Naessig and Lanyon, 2004;Steiger et al, 2008;Capella et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman

Minton¹,

Bressem²,

Willson³

et al. 2022

JCRM

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The sub-population of humpback whales inhabiting the Arabian Sea is a small and genetically distinct population that remains in low latitudes year round. Designated as Endangered on the IUCN Red list of Threatened Species, the population faces a number of threats throughout its range, including entanglement in fishing gear, ship strikes, and habitat degradation. Research conducted primarily off the coast of Oman over the past 20 years has contributed to understanding the population’s distribution, abundance, and conservation status. However information on the population’s health and specific threats is limited. This study examines all available images of Arabian Sea humpback whales obtained between 2000 and 2018 for evidence of disease, predation, epizoites and human-induced scarring or injury to individuals. Tattoo-like skin disease was detected in 43.4% of 83 adult whales, with a roughly equal distribution between males and females. Prevalence of the disease was significantly higher in 2012-2018 (51.7%) than in 2000-2011 (24.1%). Killer whale tooth rakes were detected on the ventral surface of the tail flukes of 12% (95% CI 4.5-18%) of 77 individuals. Roughly two thirds (66.6%: 95% CI 52-80%) of the 42 individuals represented by good quality photos of the caudal peduncle region at the fluke insertion bore scarring patterns consistent with entanglement in fishing gear. Four individuals had injuries consistent with vessel strikes and at least two other individuals showed severe injuries and deformations likely caused by interactions with fishing gear. Documented entanglement events from Oman and Pakistan involved large-mesh nylon gillnets, known to be used extensively throughout the Arabian Sea. These findings indicate an urgent need to design effective management and mitigation of threats, and to continue monitoring Arabian Sea humpback whales, with an emphasis on methods that allow continued and expanded assessment of health, body condition, and anthropogenic interactions.

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Section: Killer Whale Scarringsupporting

confidence: 86%

Section: Killer Whale Scarringmentioning

confidence: 99%

Section: Predation Attemptsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman

Minton¹,

Bressem²,

Willson³

et al. 2022

JCRM

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“…The 15% scaring accumulation rate we found in humpback whales (the only species for which we examined this) was similar to that reported for Mexico, though in a smaller sample than we used (Mehta et al, 2007). The rake mark scaring rate we found in eastern North Pacific is similar to or toward the high end of what has been found in other parts of the world using similar methods (Cappella et al, 2018; Elwen et al, 2014; Félix & Haase, 2001; McCordic et al, 2014; Naessig & Lanyon, 2004; Testino et al, 2019), a conclusion that is in agreement with other interregional comparisons for this species (Mehta et al, 2007; Steiger et al, 2008). Our finding of a 42% scarring rate in gray whales in the eastern North Pacific is only slightly lower than the 44% scarring found in western gray whales off Sakhalin Island (Weller et al, 2018).…”

Section: Discussionsupporting

confidence: 89%

Killer whale predatory scarring on mysticetes: A comparison of rake marks among blue, humpback, and gray whales in the eastern North Pacific

Corsi

Calambokidis

Flynn

et al. 2021

Marine Mammal Science

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We investigated the predator–prey relationship between baleen whales and killer whales by observing predatory scarring (rake marks) on the tail flukes of three mysticete species from the eastern North Pacific Ocean: humpback, blue, and gray whales. We integrated both qualitative scores and new quantitative measures to compare predatory scarring left by killer whales on the three species. We found statistically significant interspecies differences in incidence, location, and accumulation rates of scarring. Gray whales showed a higher incidence of predatory scarring compared to the other two species. Humpback and gray whales bore most of their rake marks on the trailing edge of the tail fluke, while blue whales showed more evidence of predatory scarring on the leading edge of the fluke, potentially consistent with previously hypothesized theories of flee versus fight responses to killer whales for different mysticete species. Of whales with scarring, blue whales were twice as likely to suffer from fluke mutilation compared to humpback and gray whales. Humpback and gray whales were also significantly more likely to accumulate new rake marks over the years compared to blue whales. We examine how these differences provide insight into the prey‐specific hunting behavior of killer whales.

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Social Strategies of a Consummate Marine Predator: Mammal-Hunting Killer Whales

Srinivasan

2023

Fascinating Life Sciences

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Geographic and temporal patterns of non-lethal attacks on humpback whales by killer whales in the eastern South Pacific and the Antarctic Peninsula

Cited by 8 publications

References 52 publications

Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman

Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman

Killer whale predatory scarring on mysticetes: A comparison of rake marks among blue, humpback, and gray whales in the eastern North Pacific

Social Strategies of a Consummate Marine Predator: Mammal-Hunting Killer Whales

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