If Food Could Talk by Theodore Dumas

Author:Theodore Dumas
Language: eng
Format: epub
Publisher: Koehler Books
Published: 2020-08-28T16:00:00+00:00

Fish that can’t adapt are more likely to perish

Marine species referred to as “generalists” may be least affected since they are not particular in the food types they eat and can adapt to various habitats. “Specialists,” those animals that have limited mobility and food sources, will suffer the most. From a NOAA study of eighty-two saltwater animals on the Northeast US continental shelf, it has been estimated that about 17 percent are temporarily benefitting. Examples include anchovies, black sea bass, bluefish, and Spanish mackerel. Twenty-eight percent are at minimal risk, including the dusky shark, porbeagle, sand tiger, and spiny dogfish. Forty-three percent are already showing negative impacts, such as the Atlantic cod, Atlantic halibut, Atlantic salmon, Atlantic sea scallop, blue mussel, eastern oyster, and winter flounder.

Scallops and salmon are amongst the most susceptible fish to increasing global temperatures. To go off track for a moment, as part of metabolism in our bodies, CO2 is produced, and we exhale it so it doesn’t accumulate. If it does, blood acidity increases due to the formation of carbonic acid. Returning to the topic at hand, the same is true of CO2 in the air and acidity in our oceans. More CO2 in the air equals more carbonic acid in the ocean. Increased ocean acidification hinders shell development and movement in scallops, making them more vulnerable to predators. Other shellfish, like clams and oysters, will also be impacted by ocean acidification. If unchecked, it is fairly safe to assume that climate change will cause most types of shellfish and corals to perish before the turn of the century. A 50 percent loss in scallop yield is expected by 2050.

Salmon spend part of their lives in smaller bodies of water that warm up more than the open ocean, and so salmon are more temperature sensitive than many other fish species. As rivers become warmer, the water can hold less oxygen, which the salmon need to breathe. The warmer water also makes them more susceptible to parasites and disease. At least three species of salmon of the Great Northwest are now considered endangered as a direct result of increasing water temperature of rivers and estuaries in Washington State: the spring Chinook salmon, the summer steelhead trout, and the bull trout. Salmon and trout belong to the same fish family, Salmonidae, but spend different amounts of time in fresh versus salt water. Ocean acidification is negatively impacting the food supply for salmon, which includes krill and pteropods, also known as sea butterflies. Also, as sea levels rise, more salt water is pushed inland, altering the river and estuary hydrology balance and further exacerbating the salmon survival problem (similar to the effects of Potomac River overflow into the Washington DC tidal basin increasing salinity at the roots of cherry trees).

The sockeye salmon of Alaska’s Bristol Bay may have it the worst. Unlike other salmon species, these poor fish have a “blob” of warm seawater in the North Pacific Ocean on one side and land on the other. The blob is a shifting mass of warm water, up to seven degrees warmer than normal.

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