'The blob' contributes to major abalone die-off, forces fisheries closure, postponement

A red abalone (right) attached to a rock in the Pacific Ocean. Two red sea urchins are to its left. (Photo: Scott Groth/Oregon Department of Fish and Wildlife)

A creature that lives among the rocks of the sea is starving to death.

Several factors contributed to the recent die-off of red abalone, but a significant component was “the blob,” a warm mass of water that formed in the Pacific coastal waters a few years ago that helped to kill off a main food source for the abalone.

Those factors have meant that the long-living, oval-like “glorified marine garden snail” is facing “unprecedented environmental conditions,” according to scientists.

Most of the abalone are in California, but they live as far north as Coos Bay, Oregon. So when things got dire in California -- and that state decided late last year to close its abalone fishery for this year -- Oregon decided to postpone its own abalone fishing season until the situation could be reviewed.

The mollusks are popular with divers. In northern California, recreational fishing for them generates tens of millions of dollars of economic activity. Commercial fishing for the shellfish is prohibited in both states.

Laura Rogers-Bennett, senior scientist for the California Department of Fish and Wildlife, said that during the department’s biggest abalone survey ever last year, scientists found the seafloor littered with abalone corpses -- 30 to 38 percent of all of them had died.

The die-off shocked Sonke Mastrup, CDFW’s environmental program manager for invertebrate fisheries. He said he’s been involved in the abalone fishery since the 1970s and has never seen anything like this.

“People don’t comprehend, unless you were there watching it, about how quickly this changed from a really robust, healthy fishery to a disaster in less than three years,” he said.

No Help for Kelp

The disaster emanated from what scientists called a “perfect storm” of events.

First, the ocean ecosystem was disrupted by a massive die-off of a large species of sea star due to a wasting syndrome. That eliminated a predator of the purple sea urchin, which underwent a population explosion, allowing it to out-compete the abalone for the same food source – kelp.

Throw in an El Niño event and, lastly, the most significant factor, the blob that warmed the waters off the coasts of Washington, Oregon and California in 2014 and 2015, and the stage was set for calamity.

“That warm water had a very negative impact on our kelp forests,” said Rogers-Bennett.

Which is bad for abalone, since their primary food source is bull kelp, a type of algae, which Rogers-Bennett said can grow to be 50 feet high.

“That bull kelp died during this warm water event, and we lost close to 95 percent of our kelp forest in those years,” she said. “We’ve had single-year El Niños typically in the past and we never saw a big broad-scale change that persisted. But what’s different this go-around is the warm water persisted in this warm water blob.”

There are bull kelp forests in Oregon, too. Most of it grows on two large reefs off the state’s southern coast. Scott Groth, the south coast shellfish biologist for the Oregon Department of Fish and Wildlife, said there’s “very clearly” been a reduction in kelp in Oregon as well.

The reef off the coast of Port Orford, the state’s largest, is “down to the bare bones, kelp-wise,” he said.

Groth noted that most of Oregon’s abalone live closer to the beach than farther offshore where the reefs are, and the inshore kelp has looked OK. The lack of kelp farther offshore has had a big impact on the state’s sea urchin fishery, he said. And like in California, there has been an explosion of purple sea urchins.

Oregon’s abalone fishery is far smaller than California’s. While California issues about 25,000 abalone permits a year, Oregon only issues about 300. But when California closed its fishery, abalone enthusiasts set their gaze northward.

“California’s closure could lead to a large fishing shift to Oregon, which would cause a spike in harvest under the current rules,” Groth said in a news release issued late last year announcing Oregon’s postponement. “Yet we suspect that Oregon’s abalone population has declined from historic levels.”

He said there are plans to do an abalone survey in Oregon this summer. The first-ever survey in the state was done in 2015.

Getting People Back to Abalone Fishing

In 2005 the California Fish and Game Commission adopted the Abalone Recovery and Management Plan. Within it there were triggers that prescribed when the abalone fishery should close.

Anything below a density of .3 abalone-per-square meter would trigger a closure. During the recent crisis, scientists measured the density as .15 abalone-per-square meter.

“It was an off-the-chart difference,” Mastrup said.

At the very least scientists will need to measure .3 abalone-per-square meter for the fishery to be reopened, he said.

When the commission voted to close California’s fishery for 2018, it directed the CDFW to come up with a new plan. Mastrup said the 2005 plan required full recovery of the fishery before it could be opened back up. But he said the new plan will lay out a way to open up the fishery in steps. The tradeoff, however, will be a slower recovery of the fishery.

Public hearings on the draft of the new plan will be held in June. Mastrup said he hopes the commission adopts the final version by December.

In Oregon, a public hearing on the future of its abalone fishery will be March 16. The public can send comments for the record directly to the ODFW commission or to Groth at Scott.D.Groth@state.or.us.

close video ad
Unmutetoggle ad audio on off