Warming oceans Archives - Saving Seafood

Ice all but disappeared from this Alaskan island. It changed everything.

April 28, 2025 — This tiny island in the middle of the Bering Sea had recently completed its longest winter stretch in recorded history with above-freezing temperatures — 343 consecutive hours, or 14 days — when Aaron Lestenkof drove out to look at Sea Lion Neck.

It was another warm February day. He saw no sea ice; scant snow on the ground.

Lestenkof is one of the sentinels on the island, a small team with the Aleut tribe who monitors changes to the environment across these 43 square miles of windswept hills and tundra. He is also one of 338 residents who still manage to live on St. Paul, something that has become significantly more complicated as the Bering Sea warms around them.

Over the past decade, steadily warming waters have thrown the North Pacific into turmoil, wiping out populations of fish, birds and crabs, and exposing coastlines to ever more battering from winter storms. The upheaval in the waters has brought so much change to this remote island, where residents still fill their freezers with reindeer and seals, that it has forced many to consider how long they can last.

The warm waters killed off about 4 million common murres — the largest die-off of any bird species ever recorded in the modern era — including almost 80 percent of those that nested on St. Paul. They wiped out about 10 billion snow crabs; caused the collapse of the main Alaskan fishery that relied on them; and prompted the closing, three years ago, of St. Paul’s largest source of tax revenue, a Trident Seafoods crab processing plant.

Read the full story at The Washington Post

Warmer Seas Grow Hardships For US Commercial Fishing Industry

August 21, 2023 — Climate change is forcing shifts in the American fishing industry as animals, fishermen and policymakers adjust to rising sea temperatures.

The National Oceanic and Atmospheric Association said in a release earlier this week that July was the fourth-consecutive month of record-setting ocean surface temperatures. The month was also the first time the average July temperature was greater than 1.8 degrees Fahrenheit above the long-term average.

“Globally, July 2023 set a record for the highest monthly sea surface temperature anomaly … of any month in NOAA’s climate record,” the agency’s release said.

Shifting ocean temperatures force changes big and small for U.S. fishery. Some species benefit from warmer ocean temperatures while others suffer. While the catch isn’t significantly changing, the livelihoods of the men and women employed by the fishing industry and those in their communities are changing rapidly.

Read the full story at the International Business Times

Warming oceans could set off cross-border fish fights

January 31, 2022 — Tensions between countries are likely to rise with the global temperature as valuable fish stocks fleeing warmer waters cross into different national boundaries, a new study suggests.

The climate crisis will push 45 per cent of the world’s shared fish stocks away from historic habitat ranges and migration routes by 2100, posing a challenge for international co-operation, said senior author William Cheung.

“Fish don’t recognize political boundaries,” said Cheung, associate professor with the University of British Columbia’s Institute for the Oceans and Fisheries.

Fishing allocations, who gets what and how much, are political constructs based on an existing range of conventions and treaties, but these agreements are going to have to adapt to new realities if global emission rates continue, Cheung said.

Overall, climate change is pushing transboundary stocks to fishing grounds closer to the Poles and in many cases, the shift is already happening, he said, adding shifts on the Pacific coast of Central America and West Africa will occur primarily along the equator.

Read the full story at the Toronto Star

Warmer, oxygen-poor waters threaten world’s ‘most heavily exploited’ fish

January 7, 2022 — In 2008, a team of researchers boarded an expedition vessel and set sail for the anchovy-rich waters off the coast of Peru. They were searching for a place to extract a sediment sample that would unearth secrets about the ocean from 130,000 years ago, a time when the planet was experiencing its last interglacial period. About 130 kilometers (80 miles) north of Lima, the researchers found an ideal spot; they bore into the seabed and drew out a 20-meter (66-foot) core sample.

Over the next 13 years, researcher Renato Salvatteci and a team of colleagues worked to date the core and measure fish debris. They were trying to figure out what fish were living along the Humboldt Current system off the coast of Peru during that interglacial period, when the ocean contained little oxygen and was about 2° Celsius (3.6° Fahrenheit) warmer than the average temperature experienced in the current Holocene epoch — conditions that almost match what scientists project for 2100 as climate change rapidly transforms our modern world.

Today, the Humboldt Current contributes to more than 15% of the global annual fish catch, mainly due to its abundance of Peruvian anchoveta (Engraulis ringens), a species in the anchovy family. It’s also what global conservation authority the IUCN calls “the most heavily exploited single-species fishery in world history.”

Every centimeter of the sediment held an astonishing amount of information — about 90 years’ worth, said Salvatteci, a fisheries engineer at Kiel University in Germany. What they found embedded in the ancient sediment wasn’t anchoveta, but the vertebrae of “considerably smaller” fish, such as mesopelagic and goby-like fish, that were able to cope with the low oxygen levels in the water. They published their findings in Science on Jan. 6.

Read the full story at Mongabay

New study: Chesapeake oyster decline not due to overfishing

November 14, 2018 — Warmer winters, rather than overharvesting, caused the steep decline of oysters and other commercially valuable shellfish in the Chesapeake Bay and elsewhere along the Atlantic coast, according to a controversial new study that’s getting pushback from some scientists.

The study, which appeared in Marine Fisheries Review, a quarterly journal of the National Oceanic and Atmospheric Administration, says that multi-year stretches of mild temperatures in normally weather months altered the food web in coastal waters. That impaired the growth and reproduction of oysters, quahogs, soft-shell clams and scallops, scientists said. It also led to increased predation on shellfish larvae and outbreaks of diseases.

“The temperatures got warm and that changed the whole environment, so [the oyster diseases] MSX and Dermo could flourish,” said Clyde MacKenzie, Jr., the study’s lead author and a longtime researcher at NOAA’s Northeast Fisheries Science Center at Sandy Hook, NJ. Mitchell Tarnowski, who runs the annual fall oyster survey for Maryland’s Department of Natural Resources, is the co-author.

The paper’s conclusions, especially its dismissal of overfishing as a factor in Chesapeake oyster declines, came under fire from scientists with the University of Maryland Center for Environmental Science and Chesapeake Bay Foundation. Its publication comes as the DNR prepares to release a first-ever stock assessment of the oyster population in the Upper Chesapeake, including an evaluation of whether current harvest levels are sustainable.

The scientific consensus has long been that overharvesting, disease and habitat loss over the decades devastated the Bay’s oyster population, with some estimates putting it in recent years at 1 percent or less of historic levels of abundance. From an annual commercial harvest of nearly 17 million bushels in 1880, landings have trended downward, hitting historic lows in 2003-04 of just 50,000 bushels. The harvest has rebounded some since then, though much of the gain has come via private oyster farming, especially in Virginia.

Read the full story at the Bay Journal

WHOI Led Research Team to Develop System to Predict Changes in Ocean Temps

October 30, 2017 — WOODS HOLE, Mass. — A research team led by the Woods Hole Oceanographic Institution has received a federal grant to develop a system to predict changes in ocean temperature.

The system will estimate seasonal and year-to-year temperature changes in the Northeast U.S. Shelf, which is seeing some of the highest ocean warming rates in the world and is home to a highly productive and commercially important marine ecosystem.

The Northeast Fisheries Science Center in Woods Hole and Stony Brook University are also part of the research team.

“Changes in ocean temperature hugely impacts the living organisms in coastal waters,” said Young-Oh Kwon, an associate scientist in WHOI’s Physical Oceanography Department and lead investigator of the new project.

Read the full story at CapeCod.com

Fish shrinking as ocean temperatures rise

October 4, 2017 — One of the most economically important fish is shrinking in body weight, length and overall physical size as ocean temperatures rise, according to new research by LSU Boyd Professor R. Eugene Turner published today. The average body size of Menhaden—a small, silver fish—caught off the coasts from Maine to Texas—has shrunk by about 15 percent over the past 65 years.

Menhaden make up about one-half of the Atlantic and Gulf of Mexico fish harvest and had a dockside value of about $129 million in 2013. They are coastal species that spawn offshore and move to estuaries where juveniles grow to one- and two-year old fish. The air and sea surface temperature off the Atlantic coast and the Gulf of Mexico has steadily increased, especially in estuaries, where heat exchange occurs efficiently between air and sea. Adult menhaden return offshore where they are harvested with purse seine nets.

Read the full story at Phys.org

In the Pacific – oceans and climate change have compromised livelihoods

September 20, 2017 — The Chiefs of Falealupo village, on the island of Savaii noticed a disturbing trend in the last ten years in their lagoon. The presence of crown of thorns have increased in alarming numbers. “It is impossible to fish here now. They have ruined the coral and now what was previously a productive reef, has been rendered useless by them,” Chief Aeau Mareko Lamositele.

According to them, their families used to be able to rely on fish from the lagoon in front of their village. “Now we have to venture further out, we have to fish for longer to get anything back,” Aeau said.

The people of Falealupo are dependent on the ocean for their daily sustanence and for their livelihoods. Through susbsistence fishing activities they are able to feed their families and sell any surplus for other family needs.

“It’s actually quite new, we haven’t ever experienced this, even into adulthood we were always able to fish here without any problems, and always return with plenty for the family,” Aeau said.

Crown of Thorns

The decline in fisheries and habitat health on the reefs of Falealupo have been attributed to a variety of factors, with one of them being an influx in the number of crown of thorns.

The crown of thorns has been a growing problem in Samoa. Scientists have found that rising sea temperatures increase the survival rate of the coral-eating crown-of-thorn starfish. Reports from the Australian Institute of Marine Science found that a 2-degree increase in temperature improved their likely survival rate by 240 per cent, or more than tripling it.

Read the full story at HuffPost

Climate change challenges the survival of fish across the world

September 18, 2017 — Climate change will force many amphibians, mammals and birds to move to cooler areas outside their normal ranges, provided they can find space and a clear trajectory among our urban developments and growing cities.

But what are the chances for fish to survive as climate change continues to warm waters around the world?

University of Washington researchers are tackling this question in the first analysis of how vulnerable the world’s freshwater and marine fishes are to climate change. Their paper, appearing online Sept. 11 in Nature Climate Change, used physiological data to predict how nearly 3,000 fish species living in oceans and rivers will respond to warming water temperatures in different regions.

“Climate change is happening. We need tools to try to identify areas that are going to be the most at risk and try to develop plans to conserve these areas,” said lead author Lise Comte, a postdoctoral researcher in the UW’s School of Aquatic and Fishery Sciences. “It’s important to look at the organisms themselves as we cannot just assume they will all be equally sensitive to these changes.”

The researchers compiled data from lab experiments involving nearly 500 fish species, conducted over the past 80 years by researchers around the world. These standardized experiments measure the highest temperatures fish are able to tolerate before they die. This analysis is the first time these disparate data from lab experiments have been combined and translated to predict how fish will respond in the wild.

Read the full story at Science Daily

Warm waters off West Coast has lingering effects for salmon

September 18, 2017 — SEATTLE — The mass of warm water known as “the blob” that heated up the North Pacific Ocean has dissipated, but scientists are still seeing the lingering effects of those unusually warm sea surface temperatures on Pacific Northwest salmon and steelhead.

Federal research surveys this summer caught among the lowest numbers of juvenile coho and Chinook salmon in 20 years, suggesting that many fish did not survive their first months at sea. Scientists warn that salmon fisheries may face hard times in the next few years.

Fisheries managers also worry about below average runs of steelhead returning to the Columbia River now. Returns of adult steelhead that went to sea as juveniles a year ago so far rank among the lowest in 50 years.

Scientists believe poor ocean conditions are likely to blame: Cold-water salmon and steelhead are confronting an ocean ecosystem that has been shaken up in recent years.

“The blob’s fairly well dissipated and gone. But all these indirect effects that it facilitated are still there,” Brian Burke, a research fisheries biologist with the Northwest Fisheries Science Center.

Read the full story from the Associated Press at the Seattle P-I