The Rising Temperatures are Causing Fish to Shrink

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New research carried out by LSU Boyd Professor R. Eugene Turner has confirmed that one of the most economically important fish is shrinking significantly not just in its body weight, but in its length, and overall size too.

This is being caused by a rise in temperatures and is a huge concern.  One fish that’s being affected is called the Menhaden, and over the course of around 65 years, it has shrunk by about 15 percent.

Menhaden are extremely significant in the economy and make up around one half of all the Atlantic and Gulf of Mexico fish that are caught to be sold each year.  The dockside value for that is estimated to be around $129 million (2013 prices).  These fish are a significant source of food for various animals including, birds, whales, seals, and striped bass. Therefore the fact that they’re shrinking in size is going to affect the food consumption of other animals.

Gulf Menhaden have shrunk in body size by about 15 percent over the past 65 years, according to a new study by LSU Boyd Professor R. Eugene Turner.Photo Credit: Garold W. Sneegas via Fishes of Texas website.

Gulf Menhaden have shrunk in body size by about 15 percent over the past 65 years, according to a new study by LSU Boyd Professor R. Eugene Turner.Photo Credit: Garold W. Sneegas via Fishes of Texas website.

As part of his research, Turner calculated both the weight and length changes of these fish using data that had been gathered by the National Marine Fisheries Service from 1955 to 2010.  Results from the research showed a steady decline in the weight and size of these fish that were aged 3, 4, and five years old.  According to the data, a 4-year-old fish that was caught in 2010 weighed 11 percent less than the same aged fish in 1987.

In estuaries where these fish live, the surface temperature has increased steadily over the years, causing these fish to shrink.  “These changes are closely related to variations in the annual air temperature, which we used as a proxy for water temperature, for fish on both coasts,” said Turner.  “As the Earth’s atmosphere and oceans continue to warm, the future of menhaden, it seems, will be even smaller.”

Research Via; Louisiana State UniversityAdditional Link; Smaller size-at-age menhaden with coastal warming and fishing intensity, Geo: Geography and Environment. Featured image by Wade McDonald.

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