How badly did the recent record heat wave damage Washington’s shellfish beds?

Sara and Matthew Macias had just set the season’s trove of baby oysters at their farm on Hood Canal. The tide was at its lowest point of the month. Then the temperatures climbed from their typical 70s average to over 90 degrees one day and over 100 degrees the following two.

“The beach was exposed, so they were basically getting baked and fried,” said Sara Macias, co-owner of Olympic Oyster Co., a micro-farm in Lilliwaup adjacent to Mike’s Beach Resort, a waterfront lodge that her family has owned and operated for 70 years.

Olympic sells their farmed oysters to 20 restaurants in the Puget Sound region, from Olympia to Seattle. They employ two other farmers, but when the heat wave hit the Northwest, they were busy with their two children, ages 2 and 4, in a house without air conditioning.

“All of our energy was in keeping the kids safe,” said Macias. “By the time we got down to the beach, the tide had swung back to higher tides. We weren’t even able to see what exactly had transpired.”

She estimates they lost 50,000 oysters and 10,000 clams — about a quarter of their stock and $60,000 at market value — but cautioned that the precise toll is impossible to calculate at the moment and might never be known, as shellfish farming exists in a semi-controlled environment. Especially with the babies, she said, “You won’t really know until months later, when they’re not growing.”

When the tides receded again, they discovered a dearth of youngsters, their innards exposed to the sun and their light, delicate shells whisked away by water or wildlife.

The heat wave hit at perhaps the worst possible time for oyster farmers in the Pacific Northwest. In addition to coinciding with super-low tides, it happened during their off-season, when farmers like Macias are busy preparing for the lucrative cooler months, when oysters thrive.

At more than 300 farms, Washington state accounts for a quarter of U.S. shellfish production — valued at $108 million in market sales — according to the Pacific Shellfish Institute.

The Washington Department of Fish and Wildlife received at least six reports of shellfish die-off in Puget Sound waters after the record heat in late June, according to communications manager Ben Anderson. Some came from the public on recreational shellfish beaches and one from a grower.

“The suspicion, obviously, is it’s related to the heat wave,” Anderson said. Like Macias, he noted the impact won’t be known for some time but said the department is actively monitoring potential fallout.

Most agents are in the field right now gathering data at dozens of Puget Sound beaches for an annual population survey, he continued, which won’t wrap until the fall. Those results will offer insight as to how this season compares to previous years. If numbers are down, the heat wave will be referenced as a contributing factor, said Anderson.

LOW TIDES, HEAT A DEADLY COMBINATION

Unfortunately for Puget Sound farmers, simple geography worsened conditions for die-off, explained Bill Dewey, director of public affairs for Taylor Shellfish Market and a 40-year veteran of the shellfish industry. The upper and western Olympic Peninsula appears to have mostly been spared, as the tides there — such as at Willapa Bay in southwestern Washington — roll in three hours earlier.

So far, Taylor — which owns several farms and oyster bars — has not noticed major loss, but other farmers might not be so lucky.

Hama Hama, just a few miles south from the Macias family farm on the Hood Canal, on June 30 posted an image of an “impressive number” of open clam shells, as if they had been steamed right there on the rocky beach. Cockles also suffered, the company wrote on Instagram, but it’s “too soon to say how the oysters will fare.”

On Thursday, Hama Hama posted a happier photo of an oyster shell blanketed by spat, the beginnings of future mature oysters.

“It’s farming, and disasters happen — and thankfully not too often,” said Dewey, adding that heat mortality and summer mortality of Pacific oysters is “a frequent occurrence, and not well explained.”

He pointed to a recent Washington Sea Grant-funded study from University of Washington researchers, who discovered that plankton in the Salish Sea was producing high concentrations of yessotoxins — completely benign to humans but deadly to shellfish. Massive die-off in the state’s shellfish industry in 2018 and 2019 was previously a mystery.

Both Dewey and Macias acknowledged the role climate change plays in extreme weather moments like the June heat wave, and both emphasized the hopeful rarity of unusually high temperatures colliding with extremely low tides.

“The sun was beating down,” said Macias. “Had that had happened with higher tides, there would’ve been some loss … but it wouldn’t have been as serious.”

She worries about the long-game: It takes 12 to 18 months for an oyster to mature, so her business two years from now is affected by what happened last month.

Added Dewey, “This was really a perfect storm: a heat bomb and the biggest low tides of the year. The likelihood of those two things aligning again are pretty slim.”

Nonetheless, he said, “It’s early. Who knows? We may find out more as the tide progresses.”

REPORT SHELLFISH DIE-OFF TO WDFW

The Department of Fish & Wildlife has asked the public to report fish or shellfish die-offs related to low water levels, high temperatures or any environmental condition. The more information and numbers, the better.

“If you see what appears to be an unusual number of dead fish, or something like a single large sturgeon, we want to know about it,” said Kirt Huges of the agency’s fish management division in a release this week. “It’s unfortunate when we have to investigate any potential die-off, but with the public’s help we can get a more comprehensive picture of certain environmental impacts on these populations.”

Take heed when fishing as well, the agency said, as ongoing dry weather has depleted lakes and waterways. Avoid fishing at the hottest points in the day, and consider high alpine lakes this summer, where cooler temperatures translate to happier fish.

Notice die-off on a visit to a Washington beach or lake? Visit publicinput.com/X7060 to report it.

This story was originally published July 10, 2021 at 10:39 AM with the headline "How badly did the recent record heat wave damage Washington’s shellfish beds?."