Orca satellite tagging halted after dart found in dead whale

April 16, 2016

L95, a 20-year-old male from the southern resident population, was found dead in Esperanza Inlet in Nootka Sound on March 30.

A controversial satellite tagging program for orcas has been temporarily suspended by U.S. researchers after one of the affected whales turned up dead in B.C. waters with fragments of a dart still in its fin.

L95, a 20-year-old male from the endangered southern resident population, was found in Esperanza Inlet in Nootka Sound on March 30.

Several weeks earlier, the orca had been tagged with a satellite tracking dart while swimming off the Olympic Peninsula in Washington state by the U.S. National Oceanic and Atmospheric Administration (NOAA).

While the necropsy by Fisheries and Oceans Canada found no clear cause of death, concerns were raised when parts of the dart from the satellite tag were found at the base of the dorsal fin. The dart is designed to detach once the tag is implanted.

“That’s really concerning for us, because those tags are designed to fully detach and leave nothing behind, said NOAA spokesman Michael Milstein.

As a result, the NOAA suspended the program as soon as it got the necropsy results, he said.

“We decided to do a complete reassessment of the tags and the deployment before we do any further tagging.”

Some killer whale experts are calling for a complete and permanent end to the darting program.

Calls to end dart tagging

“We don’t know yet if this dart-tagging had anything to do with L95’s death, but it certainly didn’t help,” said Michael Harris, executive director of the Pacific Whale Watching Association, in a statement on Thursday.

Likewise, Kenneth Balcomb, senior scientist of the Center for Whale Research, raised concerns about the tagging program, noting two other satellite-tagged orcas have gone missing or have died subsequent to tagging.

“Maybe these are also coincidental losses. However, it is not coincidental that at least seven other satellite-tagged whales are still carrying hardware embedded in their tissues from the attachment fixtures, and some of the wounds have festered with restructuring tissue around the attached hardware,” said Balcomb in a recent blog post.

“In my opinion, the tag attachment methodology was overly barbaric and defective from the get-go, and the entire tagging program should be rethought and evaluated for efficacy.”

The researcher says the whales are one of the most highly studied animal populations in the world and other non-invasive methods should be used to study them.

Darting defended by researchers

The NOAA biologists who implanted the tags, however, are defending the program, saying it provides important data on the whales’ movements and they plan to restart the program once they solve the problems with the darts.

In particular, the program provides valuable information on the animals’ movements and food sources in the winter, when they are difficult to study using other methods such as acoustic tracking and drone photography.

“We are on the verge of designating critical winter habitat for these whales, which would give that habitat additional protection, but in order to do that we have to understand which areas are most important, and that’s what these tags are for.

“But at the same time we want to ensure the tagging is as safe and unobtrusive as possible, because we certainly don’t want to risk any harm to the whales.”

Tags not used in Canada

Lance Barrett-Lennard, the head of the Vancouver Aquarium’s cetacean research program, said he has used the tags years ago while doing research in Alaska and agrees the tagging program provides valuable data.

“We need that winter data, and telemetry is the most efficient way to get it,” he said.

Although the darts do wound the animal, he said, the wounds generally heal and there is no confirmed case of an orca dying or suffering a serious injury from the tags.

Even so, his own experience left him with concerns about the invasive nature of the darts, and he said they are not used by Canadian researchers.

“These tags they do cause some injury. It is a question of trade-offs. Is the information worth it or not? The feeling here in B.C. was we should probably wait until there are more benign ways to track animals,” he said.

He points out that Fisheries and Oceans Canada has a good acoustic monitoring program on the West Coast for tracking the animals.

Tagging by numbers

Over the past five years, eight orcas in the endangered southern resident population have been tagged by the program, along with about 15 from the transient Biggs population, which range from Alaska to California.

L95 was tagged off the Olympic Peninsula in Washington state, according to NOAA researcher Brad Hanson, who runs the tagging program.

The darts are fired into the whales at close range from an air-pressure device. The full dart is about 15 centimetres long, while the satellite tag that remains on the animal is about the size of a nine-volt battery. The darts are made from titanium, similar to surgical implants used for humans, because of the metal’s bio-compatiblilty.

On average, the tag remains on the animal for about 30 days, but some remain for up to three months. In total, the tags have been used on about 500 marine animals from 19 different species.

Source: cba.ca

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