Marine biologists monitoring status of infected grey whale off coast of Vancouver Island

Marine biologists monitoring status of infected grey whale off coast of Vancouver Island
The infected site of a satellite-tagged grey whale dubbed 'Chocolate' is shown in this photo provided by fisheries officials.

A group of marine mammal biologists and veterinarians are tracking a grey whale infected after it was satellite-tagged off the coast of Vancouver Island last year.

Officials from the fisheries department of the U.S. National Oceanic and Atmospheric Administration, Fisheries and Oceans Canada and the Vancouver Aquarium provided the update Tuesdsay.

The scientists are “sharing information and expertise to promote the effective treatment” of the whale, which appears to have developed an infection after it was satellite-tagged back by NOAA Fisheries in September 2020.

“When last observed the animal was behaving normally and was generally healthy.”

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After that, the tag showed the whale making multiple trips from Washington to British Columbia in which it was behaving, feeding and swimming “normally.”

But 189 days after the tagging, researchers noticed in photos of the whale that a lesion had developed around the tagging site, and also spotted two lesions on the side of the whale’s body opposite the tag.

“The panel was concerned about lesions on the opposite side of the whale but could not determine if these lesions were related to the tagging site,” the NOAA said in a news release. “The panel agreed that the lesions did not pose an imminent danger to the animal’s health.”

NOAA reached out to Canadian counterparts at the DFO and the Vancouver Aquarium to collect more information via a boat and drone, leading to a plan to administer antibiotics to the whale.

On March 31 and April 1, four doses of antibiotics were delivered through a CO2-powered rifle, and researchers then collected breath samples to further analyze the whale’s condition.

On Tuesday, experts said they will continue to monitor the whale’s condition and expect that its body will continue to extrude the tag until it naturally falls out.

“We are hopeful that once this satellite tag is extruded, the tissue around the tagging site will heal. But we will continue to monitor the whale’s condition closely,” the NOAA said.

Grey whales are found in the north Pacific Ocean and are “seldom seen more than 10 kilometres from shore” and usually found in shallow waters less than 60 metres deep, according to the Department of Fisheries and Oceans.

Most of the grey whale population that breeds off the California coast in winter moves to feed as far north as Alaska, Russia and Canada in the spring, and passes through B.C. waters to get there, the DFO says.

But the Pacific Coast feeding group population of grey whales only travels as far north as the coastal waters off B.C. This group was listed as endangered in 2017 by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

The last population estimated was 243 whales, making the whales in this feeding group “vulnerable to stochastic events and threats including contamination from oil spills,” COSEWIC said. The NOAA has not designated the whales as such, counting them among the entire population of 20,000 Eastern North Pacific grey whales.

Jeff LawrenceJeff Lawrence

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