Fish Shrinking as Ocean Temperatures Rise

One of the most economically important fish is shrinking in body weight, length and overall physical size as ocean temperatures rise, according to new research by LSU Boyd Professor R. Eugene Turner published today. The average body size of Menhaden — a small, silver fish — caught off the coasts from Maine to Texas — has shrunk by about 15 percent over the past 65 years.

Menhaden make up about one-half of the Atlantic and Gulf of Mexico fish harvest and had a dockside value of about $129 million in 2013. They are coastal species that spawn offshore and move to estuaries where juveniles grow to one- and two-year old fish. The air and sea surface temperature off the Atlantic coast and the Gulf of Mexico has steadily increased, especially in estuaries, where heat exchange occurs efficiently between air and sea. Adult menhaden return offshore where they are harvested with purse seine nets.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.