Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin
Killer whale (Orcinus orca) populations specialize in both prey and prey acquisition tactics around the world and may be a primary evolutionary driver of the habits of small cetaceans. Entanglement in fishing gear is the most significant anthropogenic threat to the survival of cetaceans worldwide. D...
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ftdoajarticles:oai:doaj.org/article:44eb64a380744072ba2c776cbe605582 2023-05-15T17:03:20+02:00 Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin Erin Ashe Rob Williams Alexandra Morton Philip S. Hammond 2021-04-01T00:00:00Z https://doi.org/10.3389/fmars.2021.606876 https://doaj.org/article/44eb64a380744072ba2c776cbe605582 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/fmars.2021.606876/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2021.606876 https://doaj.org/article/44eb64a380744072ba2c776cbe605582 Frontiers in Marine Science, Vol 8 (2021) bycatch predation data deficient cetacean Killer whale conservation Science Q General. Including nature conservation geographical distribution QH1-199.5 article 2021 ftdoajarticles https://doi.org/10.3389/fmars.2021.606876 2022-12-31T10:25:27Z Killer whale (Orcinus orca) populations specialize in both prey and prey acquisition tactics around the world and may be a primary evolutionary driver of the habits of small cetaceans. Entanglement in fishing gear is the most significant anthropogenic threat to the survival of cetaceans worldwide. Distinguishing between natural and human-caused sources of mortality and injury is a key task in marine mammal conservation and management. In British Columbia (BC), Canada, mammal-eating killer whales co-occur with Pacific white-sided dolphins (Lagenorhynchus obliquidens). Bycatch mortality rates are unknown here due to lack of systematic fisheries observer coverage. Drawing from more than three decades of first-hand observations of killer whale attacks on Pacific white-sided dolphins, we identify common themes with respect to predatory behavior of killer whales and anti-predatory responses of dolphins. With input from veterinary pathologists, we outline clues to distinguish killer whale rake marks from scars and wounds likely to be caused by fishery interactions. We examined photographs of 415 well-marked Pacific white-side dolphins for evidence of injuries and scars consistent with either killer whale attacks or fishery interactions. In this case study, healed scars from interactions with killer whale predators were ∼8× more common than scars from fishery interactions (3.9 vs. 0.5%), suggesting that predation is a much bigger threat to Pacific white-sided dolphins in the study area than anthropogenic impacts, or that dolphins are much less likely to survive a fishery interaction than a predation attempt. To advance our knowledge on poorly studied species, multiple lines of evidence will be needed. Article in Journal/Newspaper Killer Whale Orca Orcinus orca Killer whale Directory of Open Access Journals: DOAJ Articles Canada Pacific British Columbia ENVELOPE(-125.003,-125.003,54.000,54.000) Frontiers in Marine Science 8 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
bycatch predation data deficient cetacean Killer whale conservation Science Q General. Including nature conservation geographical distribution QH1-199.5 |
spellingShingle |
bycatch predation data deficient cetacean Killer whale conservation Science Q General. Including nature conservation geographical distribution QH1-199.5 Erin Ashe Rob Williams Alexandra Morton Philip S. Hammond Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin |
topic_facet |
bycatch predation data deficient cetacean Killer whale conservation Science Q General. Including nature conservation geographical distribution QH1-199.5 |
description |
Killer whale (Orcinus orca) populations specialize in both prey and prey acquisition tactics around the world and may be a primary evolutionary driver of the habits of small cetaceans. Entanglement in fishing gear is the most significant anthropogenic threat to the survival of cetaceans worldwide. Distinguishing between natural and human-caused sources of mortality and injury is a key task in marine mammal conservation and management. In British Columbia (BC), Canada, mammal-eating killer whales co-occur with Pacific white-sided dolphins (Lagenorhynchus obliquidens). Bycatch mortality rates are unknown here due to lack of systematic fisheries observer coverage. Drawing from more than three decades of first-hand observations of killer whale attacks on Pacific white-sided dolphins, we identify common themes with respect to predatory behavior of killer whales and anti-predatory responses of dolphins. With input from veterinary pathologists, we outline clues to distinguish killer whale rake marks from scars and wounds likely to be caused by fishery interactions. We examined photographs of 415 well-marked Pacific white-side dolphins for evidence of injuries and scars consistent with either killer whale attacks or fishery interactions. In this case study, healed scars from interactions with killer whale predators were ∼8× more common than scars from fishery interactions (3.9 vs. 0.5%), suggesting that predation is a much bigger threat to Pacific white-sided dolphins in the study area than anthropogenic impacts, or that dolphins are much less likely to survive a fishery interaction than a predation attempt. To advance our knowledge on poorly studied species, multiple lines of evidence will be needed. |
format |
Article in Journal/Newspaper |
author |
Erin Ashe Rob Williams Alexandra Morton Philip S. Hammond |
author_facet |
Erin Ashe Rob Williams Alexandra Morton Philip S. Hammond |
author_sort |
Erin Ashe |
title |
Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin |
title_short |
Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin |
title_full |
Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin |
title_fullStr |
Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin |
title_full_unstemmed |
Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin |
title_sort |
disentangling natural and anthropogenic forms of mortality and serious injury in a poorly studied pelagic dolphin |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/fmars.2021.606876 https://doaj.org/article/44eb64a380744072ba2c776cbe605582 |
long_lat |
ENVELOPE(-125.003,-125.003,54.000,54.000) |
geographic |
Canada Pacific British Columbia |
geographic_facet |
Canada Pacific British Columbia |
genre |
Killer Whale Orca Orcinus orca Killer whale |
genre_facet |
Killer Whale Orca Orcinus orca Killer whale |
op_source |
Frontiers in Marine Science, Vol 8 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/fmars.2021.606876/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2021.606876 https://doaj.org/article/44eb64a380744072ba2c776cbe605582 |
op_doi |
https://doi.org/10.3389/fmars.2021.606876 |
container_title |
Frontiers in Marine Science |
container_volume |
8 |
_version_ |
1766057175317217280 |