July 1, 2008

Climate Change Changing Fish Communities

An analysis of 50 years of data from weekly U.S. fish trawling surveys in and near Rhode Island's Narragansett Bay show climate change is affecting the fish.

The University of Rhode Island study shows there is an ongoing significant shift in composition of coastal fish communities -- invertebrates and warm-water species are increasing, while bottom feeders species are decreasing.

Scientists attribute the change primarily to global warming.

Professor Jeremy Collie, who directed the research, said the fish community has shifted progressively from vertebrate species (fish) to invertebrates (lobsters, crabs and squid) and from benthic or demersal species -- those that feed on the bottom -- to pelagic species that feed higher in the water column. In addition, smaller, warm-water species have increased while larger, cool-water species have declined, he said.

This is a pretty dramatic change, and it's a pattern that is being seen in other ecosystems, including offshore on Georges Bank and other continental shelf ecosystems, but we're in the relatively unique position of being able to document it, said Collie. These patterns are likely being seen in estuaries around the world, but nowhere else has similar data.

The research appears in the Canadian Journal of Fisheries and Aquatic Sciences.