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Genetic Information Can Shape Conservation Policy

ESF scientist helps identify genetic stock of two species of river herring

A study of river herring populations along the East Coast of the United States has provided genetic information that could provide a basis for conservation management policies aimed at restoring declining populations of economically significant species.

In a paper published this month in Evolutionary Applications, a team of scientists that includes a fisheries ecologist from the SUNY College of Environmental Science and Forestry (ESF), identifies distinct genetic stocks of two species known as river herring: alewife and blueback herring.

"The paper concludes that we have the information for prioritizing conservation methods," said Dr. Karin Limburg of ESF. "We do know where some work needs to be done."

Said the main author, Dr. Eric Palkovacs, assistant professor of ecology and evolutionary biology at the University of California, Santa Cruz: "Our hope is that the next stock assessment will use our information on stock structure throughout the process of evaluating these species for management decisions."

Understanding which genetic stocks fish come from sheds light on which rivers should be grouped together for management decisions and reveals information about where the population declines are most severe and, therefore, what areas need more conservation attention.

In the past, before populations of these species began to decline, Limburg said, they ran in the tens and even hundreds of millions. When the juveniles left freshwater spawning grounds and headed out to sea, where they spent most of their lives, communities of predators would be ready to feed on them. The river herrings' predators include economically significant species such as striped bass and Atlantic cod.

As a link between fresh water and marine ecosystems, river herring take on a special significance, both economically and ecologically, Limburg said.

In recent years, the decline in river herring populations prompted regulatory actions. In particular, the National Marine Fisheries Service declared the fish "species of concern" and several states imposed harvest restrictions.

However, neither species was ever listed under the Endangered Species Act.

The study, funded by the National Fish and Wildlife Foundation, will continue now with Limburg taking the lead on a more detailed analysis that uses earstones, tiny bones within fish heads that acquire chemistry from the surrounding environment. By examining fishes' earstones, she can construct a more detailed story of its origins.

"For example, with earstones, we can break the Hudson down into three parts and we can distinguish among watersheds up and down the coast," she said. That can help fine tune management decisions.

Co-authors on the paper were Daniel Hasselman and Emily Argo of UC Santa Cruz, Stephen Gephard of the Connecticut Department of Energy and Environmental Protection; David Post of Yale University; Thomas Schultz of Duke University, and Theodore Willis of the University of Southern Maine.

-Tim Stephens of the University of California Santa Cruz contributed to this report.