By DANA TIMS/YachatsNews.com
Scientists are tracking two significant but seemingly separate ocean events they say have the potential to play havoc with a number of fish, crab, squid and other sea-going creatures and the Oregon coast economies that rely on them.
The first is the latest incursion of a marine heatwave. It began in late April in the same general area as a 2014 heat wave – later known as “the blob” — that rang alarm bells up and down the West Coast.
This year’s heat wave has remained strong in offshore waters, according to scientists tracking it, and by late August had grown in size enough to place it in the top 10 marine heatwaves in terms of area since monitoring began in 1982.
At its most expansive, this heatwave was the second-largest ever recorded, said Andrew Leising, a research oceanographer who is helping lead efforts to track and predict marine heatwaves for the National Oceanic and Atmospheric Administration. It is also now one of the longest lasting heatwaves on record.
“We’re still fairly early in our research of these phenomenon and we don’t know all their effects,” Leising said. “But if a big heat wave comes to shore and stays there, it will definitely influence fish and other animals to shift north to look for colder water.”
The second event that is grabbing scientists’ attention is the newest version of low ocean oxygen levels that have been reported spring-to-summer in the Northwest for 20 years.
This year, however, the so-called “hypoxia season” is more extreme and longer lasting than anything previously reported, said Francis Chan, an Oregon State University marine ecologist. Chan is head of OSU’s Cooperative Institute for Marine Ecosystem and Resource Studies based in Newport.
“In looking at the historical record, it’s hard to fine any oxygen values as low as what we have measured this year,” he said. “For those of us looking at this as climate scientists, it’s really disheartening. The system is changing so fast that it is far outstripping what the models we work from have predicted.”
Warm water moves creatures elsewhere
By definition, heat waves occur when ocean temperatures are considerably warmer than usual for an extended period of time. A heat wave was declared in 2019, for instance, when temperatures at a depth of 40 meters registered about two degrees Celsius warmer than would otherwise be expected, Leising said.
Monitoring heatwaves is important because of the influence they can have on marine species, he said.
For example, a small species of squid, known as market squid, began showing up in larger numbers in Oregon’s coastal waters two years ago. Many assumed market squid were abandoning their usual areas around California’s Monterey Bay due to warming waters there and farther south toward Mexico.
But as mobile as squid can be, they ended up leaving behind a species of seal that relies heavily on market squid for food. Those Quadalupe fur seals’ breeding grounds are almost entirely on Quadalupe Island, Mexico.
“Squid definitely move with temperature,” Leising said. “And when they move up to Oregon, it has a big impact on fur seals. They can’t follow their food as well and it leaves them pretty vulnerable at a time they should be raising their pups.”
By continuing to track heat waves, he said, scientists can help provide commercial fishing interests with the same valuable information that traditional weather forecasts do for farmers.
Still, the data is so new that it is only now beginning to be used to help develop catch limits for ocean creatures that will likely be on the move much more in years ahead.
“Not many who fish use this resource right now,” Leising said. “But we do provide information of marine fishery councils, which can then be disseminated to anyone else needing that data.”
Crabbers first noticed oxygen levels
Chan’s work in monitoring ocean hypoxia events took a turn this year when commercial crabbers first began reporting die-offs of crabs on the ocean floor. He and other scientists quickly began an effort to install oxygen-measuring sensors attached to commercial crab pots.
“This information send data to a wheelhouse sensor that can help crabbers decide whether to put that pot back down or know they have to move because oxygen levels are so low,” Chan said. “In fact, crab fleet data was the only live data I was getting from the ocean itself.”
Looking ahead, Chan said he and other scientists are at something of a loss to predict exactly what is likely to come next in terms of the larger ocean circulation patterns that, increasingly, are being disrupted by climate change and other events.
“What we know for certain,” he said, “is that we are going to have to get used to surprises.”
- Dana Tims is an Oregon freelance writer who contributes regularly to YachatsNews.com. He can be reached at DanaTims24@gmail.com