HSU Biologist: Gray Whale Strandings Not Uncommon

Humboldt State University biologists took tissue samples from this gray whale calf, found in Shelter Cove on May 22. (Philip Young)

Humboldt State University biologists took tissue samples from this gray whale calf, found in Shelter Cove on May 22. (Philip Young)

The gray whale washing ashore on Black Sands Beach in Shelter Cove on May 22 was not as rare an event as it might have seemed, particularly for this time of year.

“It’s a relatively common occurrence for [gray whale] calves to die on this part of their northern migration,” Dr. Dawn Goley, Humboldt State University’s coordinator for the Marine Mammal Stranding Network, said on Friday. “Killer whales and sharks can target them easily.”

She said other risk factors for calves include “malnutrition or because something might have happened to their mothers.” 

Goley said there are an typically between two and five gray whale strandings a year along the section of Northern California’s coast that runs from Southern Mendocino County to the Oregon border. In her 20 years at Humboldt State — Goley is a zoology professor — she said there have been roughly 40 reported strandings.

“We had a stranding three to four weeks ago off [the] Del Norte [County] coast,” Goley remarked.

The whale at Black Sands was a 21-foot-long female that Goley said was either around 3 months old or around 1 year and 3 months old. Either way, she said the calf was born during wintertime in the place where gray whales go to spend the winter — in their breeding and birthing grounds off the coast of Baja California.

At the time she died she was on her way to the waters off Southeast Alaska and possibly further north, to the Bering and Chukchi Seas in the Arctic Ocean.

“They typically feed in the Arctic in the summer. There’s lots of light and lots of nutrients,” Goley explained.

As for what killed this particular whale, Goley said it’s not entirely clear.

“There were definitely killer whale teeth marks in the flesh of the calf, so there’s evidence she was attacked. That may or may not have contributed to [her] death.”

If the mother was in poor condition by the time she got to Baja, Goley said it was possible “she didn’t have the reserves” to properly feed the calf. But she said the calf “didn’t look uncommonly emaciated. It didn’t look like she stranded because she was emaciated.”

As for reports that the whale was alive for a time on the beach, Goley said it was possible but offered another explanation. “She was right at tideline. So maybe she was being moved around by water.”

Goley said that two biologists from the HSU Marine Mammal Stranding Program examined the whale on Tuesday. She said they took tissue samples and conducted a visual examination. Tissue samples were taken for research and to advance understanding of marine mammals. She said tissue samples would compare blubber thickness with that of other stranded marine mammals.

The biologists did not do a full necropsy, she said, adding that no additional attempts would be made to determine a cause of death. “We won’t investigate further,” she said.

Goley said things would be different if gray whales were doing poorly and in danger of going extinct. “If there’s a stranding from a really tiny population, then it would be super-important to find a cause of death,” she said.

But gray whales were taken off the Endangered Species List approximately 20 years ago and today the population stands at an estimated 20,000.

“That’s healthy,” Goley remarked.

“When you have a population that’s robust it makes sense that the weaker and more vulnerable ones will strand [while] the stronger ones will survive. The larger the population, the more [strandings] you will see.”

Goley commented that it was best to let nature take its course when a stranding happens and not try to get stranded marine mammals back into the water, or dispose of the body.

Which is another way of saying that the whale on Black Sands will remain where it is until it isn’t there any longer.

“It’s a really good source of nutrients,” pointed out Alison Lui, coordinator of the HSU stranding program. “There are lots of scavengers [that will] rely on the carcass.”

As for the smell, that evidently won’t be a nuisance for Shelter Cove residents. Philip Young, the general manager of the Shelter Cove Resort Improvement District, said Friday that the whale is “at least a half-mile from the closest house. So I don’t see a problem with the odor.”

Young said he and others were doing some work not far from the whale on Thursday. “We couldn’t smell it,” he related.

Goley said she appreciated that HSU had been alerted to the stranding. She said she also appreciated the fact that managers at the King Range National Conservation Area worked closely with her team “during our response.”

“It’s really great to have partners in the Shelter Cove area and people that are as interested in marine mammals as we are up here. Together building community like this really helps us to understand what’s happening along our coast.”

The phone number for the HSU Marine Mammal Hotline is 707-826-3650 to report stranded marine mammals.