Saving Seafood

Fish stocks are on the line: Climate change impacts global fishing yields

March 16, 2026 — As the saying goes, there are plenty more fish in the sea—but climate change is rapidly challenging that notion, with fish stocks around the world under threat. New modeling from Monash University predicts how climate change will alter fishing yields in many regions, threatening food security, livelihoods and the future of marine life as a sustainable food source.

Existing prediction models have looked at how fish species respond to warming temperatures in the absence of evolutionary change. However, the research published in Science now looks at how fish will evolve in response to future climates.

Fisheries provide billions of people with animal protein, for which the demand is predicted to increase. But as oceans warm and weather patterns shift, fish are evolving, breeding less or disappearing from waters entirely.

Read the full article at phys.org

Warming Waters Threaten Seafood Supply

March 13, 2026 — In the world’s waters, fish are making a quiet, biological retreat. The once simple rules of the ocean—grow larger than potential predators—are being rewritten as temperatures reach record highs. Desperate to survive, fish are hitting the fast-forward button on life in a biological shift that will soon impact what ends up on dinner tables globally.

Fish are getting smaller and dying at higher rates as they adapt to warming waters, researchers warn in a report released Thursday in the journal Science. This evolutionary change will reduce global fish yields by one-fifth under current warming predictions, and up to 30 percent in high-emissions scenarios.

This will trigger potentially irreversible evolutionary processes, shaking up entire ecosystems and food webs, with consequences for the billions of people who rely on seafood for protein—a demand expected to increase.

“What I found frightening about this work was that it was difficult to identify winners and losers—there are simply no real winners here,” said Craig White, the study’s co-author and an evolutionary physiologist at Monash University in Australia. “The combination of warming and evolution was always bad for fisheries.”

Read the full article at Inside Climate News

Protecting Largest, Most Prolific Fish May Boost Productivity of Fisheries, New Research Finds

August 17, 2021 — The following was released by NOAA Fisheries:

Management of many of the largest fisheries in the world assumes incorrectly that many small fish reproduce as well as fewer large ones with similar total masses, a new analysis has found. That can lead to overharvesting the largest, most prolific fish that can contribute the most to the population.

Better protection of larger, mature females could improve the productivity of major fisheries. This is crucial at a time when fisheries are increasingly important in providing food resources around the world. The results were published in Proceedings of the National Academy of Sciences this week.

“It is a fundamental question in fisheries management—how much reproduction can you count on?” said Dustin Marshall of Monash University in Australia, lead author of the research. “When you are expecting smaller females to produce the same number of eggs per body mass as larger, older females, you’re not going to have an accurate picture.”

Building on Earlier Research

The new research applies previous findings that questioned longtime assumptions of fisheries management. Traditional thinking held that reproduction is a function of biomass. That means that fish representing a certain mass would produce similar numbers of offspring regardless of their age or maturity. However, syntheses of previous research by some of the same authors demonstrated that larger, older, and more mature fish produce more offspring. Also, previous work suggests that offspring of these older, larger mothers may survive at higher rates.

Management measures, such as establishing Marine Protected Areas that provide refuge for fish to grow larger, can help boost the yields of fisheries and replenish depressed species. They can in effect provide a reservoir of more mature fish with greater reproductive capacity.

“We need to ask, ‘How can we make the most of these fish that reproduce more efficiently—both to sustain the species and to support sustainable fisheries?” said E.J. Dick, a fisheries research biologist at NOAA Fisheries’ Southwest Fisheries Science Center and senior author of the paper.

By contrast, when fishing removes the more prolific larger fish, the traditional assumptions tend to overestimate the production of eggs and the population’s capacity to replenish itself. That can lead to overharvesting which for many of the largest fisheries could remove around twice as many fish as intended, the scientists found.

“In this paper, we connect the dots between early findings that large, old Pacific rockfish produced more eggs per body mass than smaller ones did, and Professor Marshall’s more recent work showing that many other species do, too,” said Marc Mangel, professor emeritus of mathematical biology at UC Santa Cruz and a coauthor. “Without recognizing this, fisheries scientists and managers may overestimate the number of spawning fish needed to produce a certain level of recruitment, and set mortality levels from fishing too high.”

Recognizing Greater Capacity

In their new analysis, the scientists examined whether the largest fisheries in the world take the findings into account. In many cases, they found, fisheries do not.

“This systematic error could help to explain why some stocks have collapsed despite active management,” the scientists wrote. They recommended that managers recalibrate future species stock assessments to recognize the greater reproductive capacity of larger fish. This could reduce overharvesting and may even boost the yields of fisheries.

“Such reductions could have negative repercussions in the short-term, for both food security and the economy, but will yield positive benefits in the long-term,” the scientists wrote. They said that better recognizing the capacity of larger fish could help boost the catches of Atlantic cod fisheries in the longer term, for example.

“Our work suggests that modern management could respond to this challenge by better leveraging the reproductive potential of larger, older fish in exploited stocks more so than is presently the case, using relatively simple policy innovations,” they said.

The research was conducted by scientists from:

  • Monash University
  • Queensland University of Technology
  • University of California Santa Cruz
  • Leibniz Institute of Freshwater Ecology and Inland Fisheries
  • NOAA Fisheries

Read the full release here

Mother of cod: We’re fishing exactly the wrong fish, scientists warn

May 11, 2018 — The bigger a female fish grows, the more eggs she lays — disproportionately so.

That’s the conclusion driven home in a report published Thursday in the journal Science. Biologists at Monash University in Australia and the Smithsonian Tropical Research Institute in Panama gathered egg data from 342 fish species across the world’s oceans.

At the extreme end, the vermilion snapper, Rhomboplites aurorubens, had a 400-fold difference in eggs between the littlest and biggest mama fish. A small female snapper lays around 4,000 eggs. A whopper of a vermilion snapper can deposit eggs by the million, study authors Diego Barneche and Dustin Marshall, colleagues at Monash University, told The Washington Post.

This research won’t come as a surprise to any field biologists who work with fish. Mark Wuenschel, who works at the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center and was not a part of this study, said the size effect was so well known it has an acronym among researchers: BOFFFF, for Big Old Fat Fecund Female Fish. But this work is valuable because a BOFFFF’s importance is often tough to assess, Wuenschel said — because these fish are fished out of the population.

Read the full story at the Washington Post