||| FROM THE CANADIAN PRESS |||
VICTORIA — A long-running study of more than 50 dead killer whales in the Pacific Ocean concludes human activity poses deadly threats to the orcas. Killer-whale deaths from Alaska to B.C., south to California and west to Hawaii linked to human activity were found in every age class from calves to adults, said the study published Wednesday in the open access journal Plus One.
The findings indicate that understanding and being aware of each threat is vital for the management and conservation of orca populations, said Stephen Raverty, a B.C. scientist and the report’s lead author.
Some of the direct causes of orca deaths were attributed to blunt force trauma from collisions with ships or cuts from the propellers of vessels, while indirect causes were related to ingested fish hooks, various human-caused pollutants and malnutrition, Raverty said.
“In one case in Alaska, a young animal swallowed a hook that perforated the back of the throat and resulted in bacteria entering the body and the animal died of a blood-borne bacteria infection,” he said.
Raverty, who’s a veterinary pathologist at the B.C. Agriculture Ministry and a marine mammal researcher, said the study also provides a baseline understanding of orca health necessary for future research.
“There have been a variety of indirect things that have been demonstrated to impact killer-whale health and what we’re saying is this is more direct evidence of human activities that impact the overall well-being of these animals,” he said.
The study involved necropsies on the remains of 53 killer whales found from the North Pacific to Hawaii from 2004-13. It also examined the data from 35 other orca deaths from 2001-17, said Raverty.
The study was able to confirm the cause of death in 22 of the 53 orcas, and “death related to human interaction was found in every age class.”
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