Climate change touches many aspects of our lives, including the food on our plates. Many of our foods are vulnerable as climate impacts worsen, from staple crops like maize to much-loved treats like coffee and chocolate.
Wild-caught seafood from our ocean is no exception. Marine fish and invertebrates are influenced by the conditions in their environment. Climate change is making the ocean warmer, more acidic and lower in oxygen. It’s also causing marine heatwaves, storms, sea ice loss and sea level rise. These changes disrupt where fish are found, what they eat, where they can survive and how productive their populations are, and they affect fisheries and coastal communities around the United States.
Below we share how five fish that we love to eat are affected by a changing climate. While some fish populations are less affected or more able to adapt, other fish rely on us to make good choices. We need to reduce emissions of greenhouse gases to head off the most severe impacts of climate change, but we also need to take additional steps to help fisheries adapt. Fortunately, there are actions that the people who manage fisheries can take now to support resilient fish stocks and prepare for climate change. The recent disappearance of more than a billion crabs in the Bering Sea and closure of the fishing season—where climate change is likely to be the major culprit—speaks to the urgent need for climate adaptation in fisheries.
October is National Seafood Month, and as we end this month celebrating the bounty of United States seafood, we should look ahead and ask, “How can we make sure we have sustainable seafood in the next generation?”
There are several species of shrimp caught in United States waters, from the Gulf of Mexico to the Gulf of Maine and along the West Coast. Northern shrimp, found in the northeast, are highly vulnerable to climate change, according to a climate vulnerability assessment done by the National Oceanic and Atmospheric Administration (NOAA). That assessment found that these shrimp were particularly sensitive to warming water temperatures and ocean acidification. In 2012, the collapse of the Atlantic population of northern shrimp was tied to a marine heat wave. Warm water temperatures were hard on the shrimp, but the warmer waters also brought a predator—longfin squid—into the areas where shrimp were located, which caused higher shrimp mortality.
In the Gulf of Mexico, white, brown and pink shrimp fisheries supply much of the shrimp that makes it way to grocery stores, fish markets and restaurants. By the end of the century, scientists have projected that pink shrimp could lose nearly 70% of their habitat in the Gulf as waters warm. But shrimp in the Gulf of Mexico are already being affected by massive climate-driven injections of freshwater when the Mississippi River floods. The freshwater influx forces some shrimp to move farther offshore to find saltier waters, can impact critical nursery habitat due to land loss and can also spur algal blooms that impact shrimp populations. Flooding of the Mississippi River in 2019 led to a catastrophic regional fishery disaster in Mississippi, Alabama and Louisiana that included shrimp fisheries.
It isn’t just the shrimp that face impacts from climate change. Fishing communities and the infrastructure they need for fishing—from boats to ramps and marinas—are also vulnerable from storms and sea level rise.
There are many tuna species that we eat, and as highly migratory fish, their management can be complicated. But if you’ve got a can of tuna sitting in your pantry, there’s a good chance it’s albacore (chunk white) tuna.
In the United States, there are three stocks of albacore: the North Pacific and South Pacific albacore stocks and a North Atlantic stock. The majority of albacore caught in the United States is North Pacific albacore tuna. These albacore spawn in warmer waters in the North Pacific and undergo an impressive migration that is shaped by ocean conditions each year. Likewise, the catch of albacore by fishermen off the West Coast catch is related to water temperatures. Since they are very mobile and eat a wide range of prey, North Pacific albacore may be more resilient to climate changes overall because they can move to avoid impacts and find food. Warming ocean temperatures are likely to cause North Pacific albacore to shift northward and could also change how long they spend in coastal waters off the West Coast. These changes have already started to have effects on the fishery and other fishing-related businesses, as the timing of migrations and locations of fish have shifted, which could also create conflicts as fish move across international boundaries.
Outside the United States, changes in the distribution of tuna could have serious impacts on many Pacific Island nations, where tuna fisheries form an important part of the economy and are critical to food security.
There are many different species of fish that we eat and call flounder, and generally flounders are flatfish that live on the seafloor. Along the Eastern Seaboard, summer flounder and winter flounder are two of the most popular flounders. Not surprisingly, summer flounder migrate into coastal bays in the summer months, while winter flounder can be found in shallow coastal waters in winter and spring. Scientists conducted a climate vulnerability assessment and found that summer flounder were moderately vulnerable to climate change. On the other hand, winter flounder had a very high vulnerability because their biology makes them sensitive to changes and they are expected to have high exposure to climate-driven environmental changes.
Both flounders have shifted their populations northward in the last few decades, and those shifts have been linked to warming. From the 1970s until now, the center of the summer flounder population has shifted roughly 70 miles northward and winter flounder about 20 miles. By the end of the century, the summer flounder population is predicted to shift another 85 miles northward, while winter flounder is predicted to shift almost 250 miles given a high emissions future. These shifts are already raising challenging questions about how the catch should be allocated among states and fleets, and who should oversee their management.
Technically “cod” refers to the three species of fish in the genus Gadus, belonging in the family Gadidae. Cod live in colder ocean waters, which can make them vulnerable as waters warm.
One species of cod, Pacific cod, can be found from the Bering Sea off Alaska to Southern California. In Alaska, Alaska Native people have stewarded and harvested Pacific cod since time immemorial, and Pacific cod continues to be a key cultural and food security resource today. Pacific cod also support economically important fisheries. Unfortunately, Pacific cod are sensitive to the temperature of their environment, and climate change is having serious impacts on these fish in the Gulf of Alaska. From 2014-2016, a large “blob” of warm water in the region disrupted the ecosystem—Pacific cod abundance declined by a whopping 70%, and the directed fishery for cod in the Gulf of Alaska closed in 2020. Warmer waters can limit the success of cod eggs hatching, slow the growth of cod as they mature and reduce the amount of food available. Marine heatwaves like the “blob” are expected to become more intense and more frequent with climate change, which is concerning because they can cause widespread disruptions to marine ecosystems.
Pacific salmon spawn in rivers, sometimes hundreds of miles upstream, and the young salmon make the journey back downstream to the ocean where they spend their lives before returning to their natal river to spawn. Along this journey, many Pacific salmon face a host of challenges to their survival, including dams, in-river and coastal habitat impacts, bycatch and pollution. On top of all this, the effects of climate change on the ocean, streams and on land can all impact the success of salmon populations. This matters because salmon play important roles in marine and freshwater ecosystems and contribute to the health of forests. Indigenous people throughout Alaska and the Pacific Northwest are deeply connected to the salmon they have stewarded since time immemorial, and salmon are central to many Indigenous cultures and food security throughout the region. Salmon support Tribal, subsistence, commercial and recreational fisheries; they are an important food source for many animals, including marine mammals; and they act as a source of nutrients to river and inland ecosystems when they travel upstream to spawn.
Many salmon populations are already facing multiple stressors leading to declines in population, and climate change is exacerbating these problems. Warming waters in both the ocean and in-river are having dramatic impacts on salmon populations. In Alaska, for example, Chinook and chum salmon on the Yukon and Kuskokwim Rivers have declined to the point that no subsistence or commercial fishing has been allowed for several years, creating a crisis of culture and food security. On the West Coast, scientists at NOAA Fisheries did an assessment of how 33 threatened salmon populations would be vulnerable to climate change along the West Coast. That assessment found that Chinook, coho and sockeye salmon populations were the most vulnerable, while others, like pink and chum salmon, were less vulnerable to climate change.
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