Climate Change Impacting Fish Spawning, While Not Enough Habitat Is Protected By Fisheries Managers

Photo: Nicola Twiley and Cynthia Graber, The Atlantic

We know that rising ocean temperatures are causing fish stocks to migrate to cooler waters, and now we have new evidence as to why.  A study by German scientists found that juvenile fish and fish that are ready to mate are especially sensitive to changes in water temperature, and as a result, up to 60 percent of all species may be forced to leave their traditional spawning areas as waters warm.  And a new study of fisheries habitat management found that the vast majority of U.S. waters have insufficient protections to ensure that fish stocks are healthy into the future despite climate change and other challenges.  Most marine protected areas don’t provide sufficient protection for fish stocks, and now fishing groups are counterproductively lobbying the government to eliminate all regulation of fishing in them.

Why This Matters:  Fish populations need functional habitat to survive and procreate.  Climate change is making finding this habitat more challenging for many species.  Marine protected areas — places where fish and their habitat are free from harmful gear and other types of development — are crucial.  If we want to eat wild-caught seafood in the future, then we need to conserve more essential habitat (30% by 2030 according to scientists) for them to have a chance.

Water Too Warm

The new study on warming ocean waters shows that many fish stocks are reaching their maximum tolerance for temperature increases. The study, published in the journal Science, found that “the temperature safety margins during the moments of spawning and embryo might be very precise, and over hundreds of thousands of years of evolution, marine and freshwater species have worked out just what is best for the next generation. Rapid global warming upsets this equilibrium.”  The lead author of the study said that because “fish have adapted their mating patterns to specific habitats over extremely long timeframes, and have tailored their mating cycles of specific ocean currents and food sources, it has to be assumed that being forced to abandon their normal spawning areas will mean major problems for them.”

The authors of a report published by the Center for American Progress (CAP) found that the current U.S. federal law that manages fisheries requires the National Marine Fisheries Service to identify “essential fish habitat” but then does not require fisheries management councils and the rules they develop to actually protect those areas that are crucial for healthy fish stocks.  The authors of the study looked at the “essential” habitat designated by agency scientists.  They then considered that the regional fishery management councils, which are tasked by the law with developing management regulations, are only required by the law “to minimize the adverse effects on this so-called essential habitat to the extent practicable.” They determined, as a result, that very few councils have found it practicable to do so.  It may seem counterintuitive, but the more that critical habitat is conserved, the more fish will spawn and remain plentiful.  The authors recommend that “improved EFH protections would provide the largest benefit and best chances of long-term economic prosperity to those council regions with the fewest protected habitats and the lowest coverage of fishing-restrictive area.”
To Go Deeper:  You can read the German study here, and the CAP Essential Fish Habitat report here.

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