Ocean heat waves along the Pacific coast trigger a squid bloom, scientists say

0

Ocean heatwaves triggered by climate change have fueled a dramatic surge in the squid market along the Washington and Oregon coasts over the past two decades, new research shows.

From central California to northern Washington, the squid market has increased fivefold over the past 22 years, according to a report published by the American Fisheries Society last month. But the biggest surges were seen in Washington and Oregon, where models showed that each state saw a 39-fold and 25-fold increase in squid population densities, respectively, during the period studied.

It’s not yet clear if the trend is temporary or how it will affect coastal communities and the rest of the ecosystem. But the environmental and economic implications are significant, scientists say, and the answers could help them better understand the mechanics of climate change and more accurately predict the impact of warming ocean temperatures on aquatic life.

Marine heatwaves — also known as “blobs” — can upset an ecosystem’s intricate balance and have done so several times along the Pacific coast in recent years.

“This study allowed us to see for the first time how the squid would respond to extreme warming events like the ocean heatwave,” said Mary Hunsicker, one of the lead authors of the study and a researcher at the Northwest Fisheries Science Center of the National Oceanic and Atmospheric Administration. “We know that with climate change and warming temperatures coupled with increasing variability in climate patterns, we will see more of these extreme events.”

The study, led by researchers from NOAA, Oregon State University and the University of California at Santa Cruz, used data collected by the National Marine Fisheries Service between 1998 and 2019 and created a model to account for changes in population density and distribution of squid along the Pacific coast.

They found that the increase in squid population density was noticeable in warmer, saltier waters, but more pronounced in areas of unusually high temperatures.

The main reason for this “squid bloom,” as one researcher put it, is a warming ocean.

“It appears that these increases are strongly associated with marine heat waves, and that the expansion is happening across the entire northern California-Washington border, but most rapidly in these northern strata,” said Brandon Chasco, a scientist at NOAA’s Northwest Fisheries Science Center and another Author of the report.

Erratic or unpredictable changes in surface temperature are hardly new in this part of the Pacific Ocean.

The Southern El Niño Oscillation is a climate pattern that triggers a cycle of warming and cooling—El Niño, or La Niña—in the eastern Pacific every two to seven years. Each cycle has a significant impact on sea temperatures, currents, inshore fisheries and the weather.

However, marine heat waves are a more contemporary phenomenon.

Since 2014, several marine heat waves have occurred along the Washington coast. These “blobs,” as they’re called, are pools of water that can be 1 to 2 degrees Fahrenheit warmer at the edges and up to 5 degrees warmer in the center.

A 2016 to learn Then University of Washington graduate student Hillary Scannell found that ocean heatwaves have been increasing in frequency since the 1970s.

The first Pacific Coast blob in 2013 spanned an area of ​​the Pacific Ocean larger than the continental US for 17 months, with a surface temperature 2.7 degrees Fahrenheit above normal. Research at the time predicted that these blobs would naturally reappear every one to five years.

Then, in late 2019, another popped up on the west coast.

Marine heatwaves can upset the intricate balance of an aquatic ecosystem and have devastating effects on wildlife.

According to a report published in January 2020, the 2014 marine heatwave was most likely the cause of a massive die-off of more than 62,000 common guillemots — a fish-eating seabird in the North Pacific.

the report It was estimated that the total death toll was closer to 1 million birds, as only a small proportion normally washes ashore after dying in the sea.

California squid, or Doryteuthis opalescens, breed quickly and don’t live long. Adults can grow up to 12 inches in length and they have an abundance of predators and prey.

This makes them very responsive to environmental changes and an important part of the food chain.

The market squid lives up to 1 year and its range extends across the eastern Pacific coastal waters from Mexico to Alaska.

It feeds on smaller fish, crabs, shrimp and other juvenile squid. It is also a vital food source for many fish, sharks, marine mammals and birds – namely the harbor seal, California sea lion, chinook salmon, blue shark, shelduck – and of course humans.

As climate change continues to exacerbate extreme weather events, species like the market squid are entering areas where they have never been seen before.

A greater presence of market squid in Washington could disrupt the existing ecosystem.

“The question is, how will that be balanced?” said Caitlin Akselrud, a California fisheries expert and graduate student in the University of Washington’s School of Aquatic and Fishery Sciences. “Personally, I don’t know the answer to that question.”

Akselrud’s research focuses on developing models to predict squid abundance in the market.

By volume, market squid make up the largest fishery in California. As they became more common farther north along the Pacific coast over the past 20 years, Oregon fisheries rushed to capitalize on them.

According to the Pacific Fisheries Information Network, Oregon squid harvests grew from zero in 2015 to 1,260 tons in 2016 and to a record 4,667 tons in 2020. Revenue for this fishery increased to nearly $1.1 million in 2016 $6 million in 2020.

Oregon squid harvests rose from almost nothing half a decade ago to more than 10 million pounds last year. In 2021, the state passed its first regulations on catching market squid.

However, the Washington fishery has been slower to bite.

According to Lorna Wargo of the Washington Department of Fish and Wildlife, hardly anyone in Washington is commercially involved with the squid market. The handful of Washington vessels that fish for squid go to Oregon or California where there is infrastructure that allows squid processing.

“A fishery just hasn’t developed, although there is evidence that squid abundance has increased,” Wargo said.

Scientists hope that more research into sea temperature and salinity as biodiversity functions could help develop an “early warning system” that could be used by coastal fishing communities to predict changes in market squid populations.

“We don’t have a precise understanding of this yet, but we definitely expect that these shifts will have an impact on fishing communities and other animals in the ocean,” Hunsicker said. “What we’re really trying to do is learn more about the mechanisms driving these changes.”

Share.

Comments are closed.