Saving Seafood

California Harbor Porpoises Rebound After Coastal Gillnetting Stopped

January 14, 2021 — The following was released by NOAA Fisheries:

Harbor porpoises have rebounded in a big way off California. Their populations have recovered dramatically since the end of state set-gillnet fisheries that years ago entangled and killed them in the nearshore waters they frequent. These coastal set-gillnet fisheries are distinct from federally-managed offshore drift-gillnet fisheries. They have been prohibited in inshore state waters for more than a decade. The new research indicates that the coastal set gillnets had taken a greater toll on harbor porpoise than previously realized.

The return of harbor porpoises reflects the first documented example of the species rebounding. It’s a bright spot for marine wildlife, the scientists write in a new assessment published in Marine Mammal Science.

“This is very good evidence that if we can eliminate the deaths in fishing nets, marine mammal populations can come back in a big way,” said Karin Forney, a research biologist with NOAA Fisheries’ Southwest Fisheries Science Center who is based in Monterey Bay.

The State of California managed set-gillnet fisheries for white seabass and halibut in coastal waters off central California beginning in the 1930s. Before the 1980s, there was little solid information about the impacts of coastal set-gillnets on protected species such as marine mammals and seabirds. Harbor porpoises were vulnerable to this coastal fishery because they frequent shallow inshore waters where the nets were historically set.

The scientists estimated, based on a combination of data, that as many as 300 harbor porpoises per year may have been killed in California’s coastal set-gillnet fisheries during the 1980s. One 1994 study (PDF, 4 pages) confirmed the deaths of more than 50 harbor porpoises in Monterey Bay alone, with the authors speculating that the true number was far higher.

Read the full release here

Pacific Leatherback Turtles off the West Coast Disappearing, New Survey Shows

December 16, 2020 — The following was released by NOAA Fisheries:

Enormous Pacific leatherback turtles are so ancient they lived with the dinosaurs. Now a new survey shows that leatherbacks that forage off the U.S. West Coast are trending towards extinction in as little as a few decades.

These endangered turtles are the largest living turtles, weighing up to 1,500 pounds. They are fully protected in U.S. waters, likely the safest waters they traverse in their cross-Pacific migrations. After feeding on jellyfish and growing in U.S. waters, adult turtles migrate back west across the Pacific Ocean to beaches in Indonesia and Solomon Islands. That’s where they reproduce and females lay their eggs.

Biologists fear illegal, unregulated, or insufficiently regulated fishing on the high seas may catch and kill many leatherbacks on their year-long treks across the ocean. They also suffer from poaching and loss of habitat in their nesting areas.

“Probably the safest place for Pacific leatherbacks is in the West Coast Exclusive Economic Zone,” said research biologist Scott Benson of NOAA Fisheries’ Southwest Fisheries Science Center. The Exclusive Economic Zone is the area where U.S. laws apply to 200 miles offshore. “It’s what happens in all of the other waters they are swimming through that really worries us.”

Benson is lead author of the new study of western Pacific leatherbacks, one of two populations of leatherback turtles in the Pacific, published last month in Global Ecology and Conservation.

Read the full release here

Salmon study sheds light on why fall-run fish are bigger than their spring-run cousins

October 30, 2020 — For the Yurok people, who have lived at the mouth of the Klamath River for generations, the spring run of Chinook salmon (Oncorhynchus tshawytscha) is a welcome—and nutritious—relief from winter. But as the fish have dwindled to just a fraction of their original numbers, Indigenous groups there are pushing to have them protected by the Endangered Species Act. New research, which suggests genes play only a small role in distinguishing the spring salmon from their fall-run cousins, may call into question the need for such a designation.

The rivers of the Pacific Northwest used to teem with two waves of Chinook: those that arrived in March or April, and those that came 6 months later, swimming from the sea to their upriver breeding grounds. Although technically the same species, the spring-run and fall-run fish have some “iconic differences,” says Eric Anderson, a molecular geneticist at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center. Spring salmon are smaller, fattier, and less sexually mature than fall fish. They also swim further upriver to breed.

To tease out the genetic basis of those differences, Anderson and colleagues teamed up with Yurok fishers living at the mouth of the Klamath River in northern California. Together, they examined 500 fish as they started their upstream journeys in all four seasons. The researchers measured the size of each fish, assessed its fattiness and reproductive status, and took samples of its DNA. The researchers gathered similar data from other rivers.

Past studies have shown that a small region of the salmon chromosome 28 contains two genes, GREB1L and ROCK1, that vary between spring and fall salmon. Anderson and his colleagues did further genomic studies, sequencing the whole genomes of 160 fish in the hopes of linking the two genes to the spring and fall traits. The data set is “impressive” and the work unique says Sheela Phansalkar Turbek, an evolutionary biologist at the University of Colorado, Boulder, who was not involved with the work.

Read the full story at Science Magazine

Small Genetic Difference Determines Chinook Salmon Migration Timing, New Study Shows

October 30, 2020 — The following was released by NOAA Fisheries:

The annual migration of Chinook salmon up West Coast rivers from the ocean has enriched ecosystems, inspired cultures, and shaped landscapes. Yet the timing of their migration is controlled by one small section of their genome, according to research published this week in Science.

This is the first time scientists have linked a single gene region to such an influential difference in a vertebrate species. For salmon, it determines whether they return upriver from the ocean in spring or fall. This has crucial implications for other species that rely on them for food. First author Neil Thompson of the University of California Santa Cruz and NOAA Fisheries’ Southwest Fisheries Science Center said that this small genetic difference can have a major effect on a complex pattern of migration and reproduction.

Fish migrating upriver in spring may access habitat such as higher elevation tributaries. These habitats become less accessible to Chinook salmon migrating later in the year when stream flows decline. The result is that fall-run Chinook salmon remain lower in the watershed without continuing up into the tributaries.

However, the construction of dams in the West blocked spring-run Chinook salmon from much of their original spawning habitat. This contributed to the listing of several spring-migrating fish under the Endangered Species Act. Fall-run Chinook salmon on the West Coast are generally more abundant.

The scientists identified the gene region influencing migration with whole-genome sequencing. Then, they scientists examined the genetic pattern in more than 500 Chinook salmon caught by the Yurok Tribe in the Klamath River estuary. They analyzed the effects of variation in this genetic region on migration timing and other physiological traits.

Read the full release here

PFMC: Call for data and information – Essential Fish Habitat Review for Coastal Pelagic Species

October 30, 2020 — The following was released by the Pacific Fishery Management Council:

The Pacific Fishery Management Council, National Marine Fisheries Service, and the NOAA Southwest Fisheries Science Center have initiated a review of essential fish habitat provisions in the Coastal Pelagic Species Fishery Management Plan.  This call for data and information is intended to support the review.  Information and data sources can include published scientific literature, unpublished scientific reports, information from interested parties, and previously unavailable or inaccessible data.  Information relevant to the CPS EFH review should be submitted no later than Monday November 30th, 2020.

Please see the “Call for data and information” announcement on the Council’s website for further details..

West Coast Waters Shift Toward Productive Conditions, But Lingering Heat May “Tilt” Marine Ecosystem

March 6, 2020 — The following was released by NOAA Fisheries:

Burgeoning populations of anchovy and a healthy crop of California sea lion pups reflected improved productivity off parts of the West Coast in 2019. However, lingering offshore heat worked against recovery of salmon stocks and reduced fishing success, a new analysis reports.

The California Current Ecosystem Status Report explains that ocean conditions off the West Coast remain unusually variable. This has been the case since the arrival of a major marine heatwave in 2014 known as “The Blob.” NOAA Fisheries’ two West Coast laboratories, the Northwest Fisheries Science Center and Southwest Fisheries Science Center, issue the report each year to the Pacific Fishery Management Council.

“There is not a real clear picture here,” said Chris Harvey, co-editor of the report developed by the two laboratories’ Integrated Ecosystem Assessment approach. The approach integrates physical, biological, economic, and importantly social conditions of the California Current marine ecosystem into the decision-making process. “On the one hand, we have a lot of anchovy out there. On the other hand, we also have a lot of warm water. That is not usually a sign of improved productivity.”

Read the full release here

Why Do Whales Migrate? They Return to the Tropics to Shed their Skin, Scientists Say

February 24, 2020 — The following was released by NOAA Fisheries:

Whales undertake some of the longest migrations on earth, often swimming many thousands of miles, over many months, to breed in the tropics. The question is why—is it to find food, or to give birth?

In a research paper in Marine Mammal Science, scientists propose that whales that forage in polar waters migrate to low latitudes to maintain healthy skin.

“I think people have not given skin molt due consideration when it comes to whales, but it is an important physiological need that could be met by migrating to warmer waters,” said Robert Pitman, lead author of the new paper and marine ecologist with Oregon State University’s Marine Mammal Institute. He was formerly with NOAA Fisheries’ Southwest Fisheries Science Center in La Jolla, California.

More than a century ago, whalers recognized that most whales that forage in high latitudes migrate to the tropics for calving. Scientists have never agreed on why. Because of their size, large whales should be able to successfully give birth in frigid polar waters. Due to reduced feeding opportunities in the tropics, most whales fast during their months-long migrations.

So why go to the trouble?

Read the full release here

Marine Heatwave in the Pacific Shrinks from “Blob” in Size, Retreats Farther Offshore

November 11, 2019 — The following was released by NOAA Fisheries:

The vast marine heatwave that spread warm temperatures across the northeast Pacific Ocean late in the summer and fall of 2019 has declined in size and pulled back from the West Coast, possibly reducing its immediate impacts on coastal ecosystems.

It has declined to about half the size and intensity it displayed in August. However scientists caution that the heatwave designated MHW NEP19a remains two to three times the size of Alaska and still retains enormous amounts of heat in the upper layers of ocean. It remains one of the top four or five largest heatwaves on record in the North Pacific in the last 40 years.

“What we are seeing now is a smaller heatwave that is farther offshore, but there is still a very large span of the Pacific Ocean that is much warmer than usual,” said Andrew Leising, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center (SWFSC) in La Jolla, California. Leising has developed criteria to detect and gauge the size and magnitude of marine heatwaves. “The question is, where does it go from here? That’s what we’re watching now.”

The edge of the heatwave is now about 1,500 kilometers (about 930 miles) from the West Coast, but still envelops much of the Gulf of Alaska. It no longer so closely resembles the enormous earlier marine heatwave known as “the Blob” that affected much of the West Coast through 2014 and 2015, causing reverberations through the food web.

Low salmon returns to many West Coast rivers in the last few years have been linked to the Blob, which reduced the availability of food when the salmon first entered the ocean as juveniles.

Read the full release here

A vast heat wave is endangering sea life in the Pacific Ocean. Is this the wave of the future?

October 17, 2019 — A vast region of unusually warm water has formed in the northeastern Pacific Ocean, and scientists are worried that it could devastate sea life in the area and fuel the formation of harmful algal blooms.

The broad swath of warm water, now known as the Northeast Pacific Marine Heat Wave of 2019, was first detected in early June. Now data from weather satellites and buoys show that it measures six to seven times the size of Alaska, which spans more than 600,000 square miles.

Given its size and location, the marine heat wave rivals a similar one that arose in 2014 and persisted for two years. That heat wave, known simply as “the blob,” occupied roughly the same region of the Pacific and became known for triggering widespread die-offs of marine animals including sea birds and California sea lions.

“The moms were going out to get food, but when they couldn’t find anything, they swam off and the babies were just left dying,” Andrew Leising, an oceanographer at the National Oceanographic and Atmospheric Administration’s Southwest Fisheries Science Center in La Jolla, California, said of the sea lions and their inability to find enough squid and fish to feed on.

Read the full story at NBC News

Is ‘The Blob’ back? New marine heat wave threatens Pacific

September 18, 2019 — In the fall of 2014, marine ecologist Jennifer Fisher was stunned when jellyfish and tiny crustaceans typically found in warmer waters filled her nets off the coast of Oregon. The odd catch was just one sign of the arrival of a vast patch of warm water that came to be known as “The Blob”—a massive marine heat wave that lasted 3 years and dramatically disrupted ecosystems and fisheries along North America’s Pacific coast.

Now, with oceanographers warning that a new Blob could be forming in the Pacific Ocean, Fisher is again preparing for strange encounters when she heads out on a research cruise later this month. “This is a very similar situation,” says Fisher, who works at Oregon State University’s Hatfield Marine Science Center in Newport.

This time, however, Fisher and other scientists say they won’t be taken by surprise. They are preparing to more quickly share data on heat wave impacts with each other and with managers who may have to impose new catch limits to protect valuable fisheries. When The Blob arrived 5 years ago, “we didn’t realize the impact” it would have, recalls Toby Garfield, a physical oceanographer with the National Oceanic and Atmospheric Administration’s (NOAA’s) Southwest Fisheries Science Center in San Diego, California. “We’re going to stay ahead of this one.”

Read the full story at Science Magazine