Saving Seafood

Study of US tuna fisheries explores nexus of climate change, sustainable seafood

April 14, 2021 — A new study published in Elementa by researchers at the University of California, Santa Cruz and NOAA examines traditional aspects of seafood sustainability alongside greenhouse gas emissions to better understand the ‘carbon footprint’ of U.S. tuna fisheries.

Fisheries in the United States are among the best managed in the world, thanks to ongoing efforts to  selectively, end overfishing, and rebuild fish stocks. But  could bring dramatic changes in the marine environment that threaten  productivity and sustainability. That’s one reason why researchers set out to broaden the conversation about sustainability in seafood by comparing the carbon emissions of different  fishing practices.

The paper also puts those emissions in context relative to other sources of protein, like tofu, chicken, pork, or beef. In particular, the study examined how the carbon footprint of tuna was affected by how far from shore fishing fleets operated, or what type of fishing gear they used.

“This can be an opportunity to look at fisheries from different angles, all of which may be important,” said Brandi McKuin, the study’s lead author and a postdoctoral researcher in  at UC Santa Cruz.

Read the full story at PHYS.org

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

Study finds declines in size of Alaska salmon

September 15, 2020 — A recent study that dove into more than 60 years of records from the Alaska Department Fish and Game found that salmon returning to Alaska’s rivers are on average smaller than they were in the past.

The study, headed up by biologists from the University of California Santa Cruz and the University of Alaska, Fairbanks, attributes declines in salmon size to “shifting age structures associated with climate and competition at sea.”

Read the full story at Seafood Source

ISSF Awards Grand Prize in Seafood Sustainability Contest

March 10, 2020 — The following was released by the International Seafood Sustainability Foundation:

Doctoral student Melissa Cronin of the University of California, Santa Cruz, is the Grand Prize winner in ISSF’s International Seafood Sustainability Foundation (ISSF) Seafood Sustainability Contest. She receives a $45,000 prize from ISSF for her contest entry, “Incentivizing Collaborative Release to Reduce Elasmobranch Bycatch Mortality,” which proposes handling-and-release methods that purse-seine vessel skippers and crew can use to reduce the mortality of manta rays and devil rays incidentally caught during tuna fishing.

Her winning proposal calls for cooperative workshops with purse-seine skippers and observers, offering financial rewards for the design, testing, and onboard implementation of feasible, scalable techniques for safely removing rays from vessel decks.

It also includes training observers in tagging rays to track their post-release survival. Rays, in addition to sharks, are the species groups most vulnerable in the purse-seine fishery. In the Indian Ocean, for example, rays comprise the majority of bycatch in tuna fishers’ free-school sets: bycatch overall on such sets represents 0.9% of the total catch, and 34% of that is rays.

Ms. Cronin is a Ph.D. candidate in the Conservation Action Lab at UC Santa Cruz studying Ecology and Evolutionary Biology. Learn more about her research experiences and winning idea in her ISSF blog post and video.

In addition to the $40,000 Grand Prize, the award includes a trip, with an estimated $5,000 value, to a tuna event. ISSF will arrange for Ms. Cronin to present her proposal at a Regional Fisheries Management Organization (RFMO) event this year.

Read the full release here

Alaska pollock fish sticks, surimi processing generates “significant” greenhouse gas emissions

January 24, 2020 — The processing of Alaskan pollock into products such as fish sticks, surimi and fish fillets generates “significant greenhouse gas emissions,” researchers at the University of California, Santa Cruz have found.

According to a study released by the university, the processing of the products post-catch results in almost twice as many emissions as the fishing itself. Typically, climate impact analysis of fishing ends once the catch is brought on-board.

Read the full story at Seafood Source