Saving Seafood

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

Study: Marine heat waves will decimate fish at twice the rate climatologists previously predicted

June 9, 2020 — Over the last decade, two massive marine heatwaves, better known as “blobs” swept the North Pacific Ocean, raising surface temperatures more than 5 degrees Fahrenheit causing blooms of toxic algae and major die-offs in the ecosystem. A new study from the University of British Columbia reports that as these heatwaves continue, they may have far more devastating implications to fisheries than previously predicted.

Climate scientists have known for years that global warming would have devastating long-term impacts on marine species. Already, fast-melting Bering Sea ice is threatening spotted seals and other marine mammals. Warming Gulf of Alaska waters wiped out cod eggs in 2019, causing a crash in cod stocks. Record warm waters in the Yukon River last summer killed thousands of migrating salmon with heat stress.

While climate change is steadily warming oceans all over the world, marine heatwaves, like the two North Pacific “Blobs,” are causing more dramatic swings in surface temperatures. In 2014 and again in 2019, ocean temperatures in Alaska rose as much as 5 degrees Fahrenheit.

Read the full story at Alaska Public Media

In hot water? Study says warming may reduce sea life by 17%

June 12, 2019 — The world’s oceans will likely lose about one-sixth of their fish and other marine life by the end of the century if climate change continues on its current path, a new study says.

Every 1.8 degrees Fahrenheit that the world’s oceans warm, the total mass of sea animals is projected to drop by 5%, according to a comprehensive computer-based study by an international team of marine biologists. And that does not include effects of fishing.

If the world’s greenhouse gas emissions stay at the present rate, that means a 17% loss of biomass — the total weight of all the marine animal life — by the year 2100, according to Tuesday’s study in the Proceedings of the National Academy of Sciences. But if the world reduces carbon pollution, losses can be limited to only about 5%, the study said.

“We will see a large decrease in the biomass of the oceans,” if the world doesn’t slow climate change, said study co-author William Cheung, a marine ecologist at the University of British Columbia. “There are already changes that have been observed.”

While warmer water is the biggest factor, climate change also produces oceans that are more acidic and have less oxygen, which also harms sea life, Cheung said.

Read the full story at the New Bedford Standard-Times

Climate Change May Shrink the World’s Fish

A new study suggests warming sea temperatures could result in smaller fish sizes.

August 22, 2017 — Warming temperatures and loss of oxygen in the sea will shrink hundreds of fish species—from tunas and groupers to salmon, thresher sharks, haddock and cod—even more than previously thought, a new study concludes.

Because warmer seas speed up their metabolisms, fish, squid and other water-breathing creatures will need to draw more oxygen from the ocean. At the same time, warming seas are already reducing the availability of oxygen in many parts of the sea.

A pair of University of British Columbia scientists argue that since the bodies of fish grow faster than their gills, these animals eventually will reach a point where they can’t get enough oxygen to sustain normal growth.

“What we found was that the body size of fish decreases by 20 to 30 percent for every 1 degree Celsius increase in water temperature,” says author William Cheung, director of science for the university’s Nippon Foundation—Nereus Program.

These changes, the scientists say, will have a profound impact on many marine food webs, upending predator-prey relationships in ways that are hard to predict.

“Lab experiments have shown that it’s always the large species that will become stressed first,” says lead author Daniel Pauly, a professor at the university’s Institute for the Ocean and Fisheries, and principal investigator for the Sea Around Us. “Small species have an advantage, respiration-wise.”

Still, while many scientists applaud the discovery, not all agree that Pauly’s and Cheung’s work supports their dramatic findings. The study was published today in the journal Global Change Biology.

Read the full story at National Geographic

Warmer Global Ocean Pushes Fish to Extremes

August 15, 2016 — The opening lyrics in Bob Dylan’s classic tune “The Times They Are A-Changin’” told us to acknowledge that the waters around us were quickly rising. And while Dylan was surely referring to the sociopolitical climate of the day, those words still ring true in the physical sense as well. Climate change and global warming — or whatever phrase you use for our planet’s current ecological ailments — have generated much debate for the last several decades. These topics just seem to make some people, well, hot and bothered. Some choose to reject the notion that we’re seeing fairly, if not very, rapid changes in climate, but unfortunately, the data say otherwise. And this phenomenon we’re witnessing is directly linked to, if not driven by, what’s going on in the earth’s oceans.

In reality, the world’s oceans comprise a single large, connected entity called the global ocean. This expansive mass of water churns with currents, both visible and hidden, that not only exert control over marine ecosystems but also create profound effects on terrestrial ones.

The Long Term

Most anglers have heard plenty of talk over the last year or so about the record-breaking water temperatures in the Pacific, brought on by the last El Niño. Indeed, last year’s event ranked as the most significant ever recorded. No matter how severe the episode, however, El Niño events typically linger only a year or so. And although these ephemeral conditions seem to garner a lot of press, bigger problems have been unfolding for some time. Many environmental scientists agree that ocean temperatures are rising on a long-term, global level.

Read the full story at Sport Fishing Magazine