Bluefin tuna are going hungry in a sea full of fish because their foraging habits are most efficient with larger, not necessarily more abundant prey, according to a study led by by Walter Golet, assistant research professor in the School of Marine Sciences and the Gulf of Maine Research Institute.
The abundance of herring doesn’t help the tuna during foraging because the herring population growth has translated to smaller body sizes, meaning tuna have to eat more fish to pack on the right amount of traveling fat, according to the article. Tuna in the Gulf of Maine have relocated their hunting grounds to offshore banks and locales on the northwest Atlantic shelf, where herring are bigger, the article states.
Management strategies for small pelagic fish, including sardines, herrings and anchovies, have the potential to alter food web dynamics and energy flow through changes in the size and abundance of these species. Changes in these fish stocks impact marine mammals and bluefin tuna whose physiology is geared toward high energetic returns while foraging.
Source: Walter J. Golet, et. Al, The paradox of the pelagics: why bluefin tuna can go hungry in a sea of plenty, Marine Ecology Progress Series, doi: 10.3354/meps11260