December 16, 2020 — The following was released by NOAA Fisheries:
Repeated marine heatwaves off the U.S. West Coast starting about 2013 fueled record harmful algal blooms that seeded a region off Northern California and Southern Oregon with toxic algae, a new study has found. That reservoir of harmful algae has, in turn, spread across the West Coast and forced the closure of valuable Dungeness crab and other shellfish seasons every year since 2015.
This year, for example, toxic algae have closed Dungeness crab harvest and some clamming in Washington through December.
“We now can see that marine heatwaves have the ability to seed new offshore hotspots, like ocean ‘crock pots’ where blooms can develop in subsequent years,” said Vera Trainer, a research scientist at NOAA Fisheries’ Northwest Fisheries Science Center in Seattle and lead author of the new research.
Early Warnings
The good news, she said, is that offshore surveys and studies have unraveled the way toxic algae spreads through coastal waters. These data can help fisheries managers anticipate and mitigate the impacts. Scientists share that detailed information through regional bulletins that serve as an early warning system for harmful algal blooms.
That way, managers can focus closures in the most affected areas, for example, while others remain open. Or they can open fisheries earlier before the toxins build up in shellfish. The alert system has reduced the need for coastwide closures with widespread economic impacts.
“The most valuable tool we have is knowledge of how these events develop, so we know where to expect impacts, and which areas remain safe,” she said.