DURHAM, N.C. – The number of marine mammals, sea turtles and seabirds killed after becoming ensnared in U.S. fisheries’ gear could be more effectively managed if policymakers applied consistent criteria across species when setting bycatch limits, according to a comprehensive new study led by 91 researchers.

The study, published in the May 2009 issue of the journalMarine Policy, is now available online. It finds that the United States has made important progress toward reducing bycatch, but the success of these efforts has been limited by a focus on federal regulations that generally protect only one species group, or taxa, in one fishery at a time.

Applying consistent criteria across fisheries and taxa – in particular, adopting the legislatively mandated approach currently used for marine mammals to sea turtles and seabirds, as well – would be a good first step toward resolving this problem, the study’s six authors argue.

“The Marine Mammal Protection Act outlines a specific process for evaluating whether a given level of bycatch is likely to have negative consequences for the status of marine mammal populations. In contrast, other protective statutes, such as the Endangered Species Act, provide less clear guidance for determining how much bycatch is too much for protected sea turtles and seabirds,” says first author Jeffrey E. Moore, research scientist at the Center for Marine Conservation at Duke’s Nicholas School of the Environment

“A multi-species, multi-gear approach to bycatch would address the fact that many species interact with multiple fisheries and fishing gears. This would help avoid situations where bycatch regulations merely shift the problem from one species group or fishery to another,” says co-author Bryan P. Wallace, adjunct assistant professor at Duke’s Nicholas School of the Environment.

“It also would help reduce inefficiencies in bycatch management, and identify the species and fisheries where resources and regulations are needed most urgently,” he says. Wallace is a science advisor for Conservation International’s Sea Turtle Flagship Program and a faculty collaborator in the Center for Marine Conservation at the 91 Marine Laboratory in Beaufort, N.C.

The 17-page study brings together a wealth of available information – much of it assembled into one document for the first time – on mortality estimates, regulations, statutes and observer programs for bycatch of marine mammals, sea turtles and seabirds in U.S. fisheries. It identifies pressing issues, along with knowledge gaps and policy limitations that hinder multi-species bycatch reduction.

“Our goal was to create a primer that provides a more comprehensive perspective of bycatch and emphasizes the need to assess its cumulative population impacts,” Moore says.

Seeing the big picture is critical, he emphasizes, because, “many bycatch issues overlap spatially. Yet the current approach of taxon-specific federal legislation has generally led to efforts that are more expensive and potentially less effective than if overlapping problems were addressed together.”

Moore says there are too many cases where incidental take – or bycatch – limits are set without proper understanding of whether they are sufficient, or even unnecessarily restrictive, to protecting wildlife populations. This, he says, has potential consequences for both fishermen and marine conservation.

Co-authors of the study, in addition to Wallace, are Rebecca L. Lewison of San Diego State University; Tara M. Cox of Savannah State University and the Center for Marine Conservation; Ramunas Zydelis of the Center for Marine Conservation; and Larry B. Crowder, director of the Center for Marine Conservation and Stephen Toth Professor of Marine Biology at the Nicholas School.

To download the study, go to  and enter any two of the authors’ last names in the search field.

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Note to media: If you need assistance reaching Wallace, Moore or their co-authors, contact Tim Lucas at 919-613-8084, tdlucas@duke.edu.