Plan to dart tag orcas raises concerns

SEATTLE – Federal biologists plan next month to attach tiny satellite devices on Puget Sound’s endangered orcas off the West Coast to understand better where they go during winter. But some whale experts worry the tags – about the size of a 9-volt battery with two darts – could injure the orcas.

While dart tags have been used on other whale species, this is the first time they would be used on the southern resident killer whales that frequent the inland waters of Washington state and British Columbia.

Brad Hanson, a wildlife biologist with the National Oceanic and Atmospheric Administration Fisheries Service in Seattle, and his colleagues received federal approval last month to implant the transmitters on the dorsal fins of up to six orcas.

The orcas spend summer months in Puget Sound, but “that’s only half the story,” Hanson said, adding “we don’t know where they spend the bulk of their time.”

Tracking the animals in the winter would pinpoint their range of travel and help inform their critical habitat, he said. Visual sightings and ship surveys have shown the animals travel as far south as Monterey, Calif., and as far as the north coast of British Columbia during winter, but the information isn’t sufficient, Hanson said.

Ken Balcomb, senior scientist with the Center for Whale Research in Friday Harbor, Wash., said the dart tags are too invasive.

“I don’t believe the injury to the animals is warranted,” said Balcomb, who keeps a running census of the orcas. “It’s an injurious process. It sticks barbs in the whales that are serious attachment devices that do cause injury and can potentially become infected.”

Balcomb had applied for a federal permit in 2008 to tag the Puget Sound orcas because he believed at the time the devices were not harmful. He received federal approval in 2009, but he later declined to tag any orcas after witnessing injuries and wounds to other tagged whales.

“If you take the diameter of a golf ball, that’s the spread of tissue damage from each of two barbs. These will heal over time if they don’t get infected. Some of the barbs don’t come out,” Balcomb said.

The whale’s tissue will be impacted but will heal, Hanson said. “Within a few weeks, it basically heals back up, so you’re left with a couple of marks,” he added. They’re within the range of scars and marks that whales encounter naturally.

Hanson proposes tagging up to six orcas – adult males or nonreproducing females. He has been tagging 15 species of whales, such as humpbacks and blue whales, under a five-year federal permit. Puget Sound orcas were added more recently.