Study: Total fish biomass could take 20+ years to recover inside reserves

A new study in the journal Marine Ecology Progress Series finds that total fish biomass inside no-take marine reserves could take more than 20 years to recover to its maximum level following closure of the area. The study, by Tim McClanahan of the Wildlife Conservation Society (an international NGO) and Nicholas Graham of the University of Newcastle (UK), examines the size structure and biomass of total fish populations in four coral MPAs in Kenya, repeatedly sampled from the 1980s onward. Analyzed across the four sites, biomass of the fish assemblages reached a peak between 21 and 22 years after closure.

“The study suggests that the time to recovery can be slow, more than two decades, which makes it important to have permanent and full closures so that countries have areas that represent relatively undisturbed ecosystems,” says McClanahan. “Given that this study was in the tropics and near the equator, it would suggest that this might actually be one of the faster recovery times expected. As one moves farther from the tropics, colder water and greater seasonality should produce a shorter growing season and therefore slower inter-annual growth rates.”

McClanahan says spillover of adults or larvae from reserves to fished areas would be expected to be proportional to the recovery of biomass inside the reserves. Therefore, spillover could take a similar amount of time – 20 years or more – to reach its full effect. “Reserve planners must, therefore, convince stakeholders to have a long view of the expected reserve effects on fisheries,” he says. For a copy of the paper, “Recovery trajectories of coral fish assemblages within Kenyan marine protected areas” (Marine Ecology Progress Series, Vol. 294:241-248, 2005), e-mail McClanahan at

For more information:

Tim McClanahan, Wildlife Conservation Society, Coral Reef Conservation, Kibaki Flats no.12, Bamburi, Kenyatta Beach, P.O. Box 99470, Mombasa, Kenya. Postal Code: 80107. Tel: +254 41 548 6549; E-mail:

Managers recommend trawl ban for US Pacific coast waters, reserves for Channel Islands

In a move intended to prohibit expansion of bottom trawl fishing and protect deep-sea habitats and groundfish species, federal fisheries managers for the US Pacific coast recommended in June that all regional waters beyond the 700-fathom depth contour be closed permanently to such gear. (That depth contour is equivalent to 1280 meters.) The recommendation, if approved by the federal fisheries agency (NOAA Fisheries), would ban bottom trawling in an area of 845,000 km2, amounting to roughly 75% of US waters between the Canadian and Mexican borders.

The recommendation by the Pacific Fishery Management Council was developed through a collaborative process involving trawl fishermen, other fisheries representatives, conservationists, and Pacific coast states (California, Oregon, and Washington). The ban on bottom trawling is not expected to affect the trawl industry in the near term, as most current trawling activity occurs in areas slated to remain open.

The collaborative process also resulted in recommendations to close several ecologically important sites in nearer-shore waters to various fishing gear types. Among these recommended closures were several areas within existing national marine sanctuaries, including the multiple-use Channel Islands National Marine Sanctuary (CINMS). The proposed closures for CINMS, intended to apply to all gear types, are consistent with those recommended by stakeholders and experts in 2002 as part of a process to plan a network of marine reserves within the sanctuary (MPA News 4:6). If approved by NOAA Fisheries, the closures would largely represent the culmination of that earlier planning process, and would raise the percentage of the sanctuary that is no-take to approximately 20%. (A complementary set of reserves in state waters of the sanctuary already took effect in 2003.)

A summary of the council recommendations, with a map of all affected areas, is available at

The trawl ban recommendation reflects similar management moves elsewhere this year. In February 2005, managers of US North Pacific fisheries voted to prohibit bottom trawling in 950,000 km2 of waters around the Aleutian Islands in an effort to minimize impacts on sensitive coral and sponge habitat (MPA News 6:8). Also that month, the main intergovernmental fishery management body for the Mediterranean voted to prohibit bottom trawling in all areas of the Mediterranean and Black Sea deeper than 1000 m – a closure estimated to be 1.63 million km2 in size (MPA News 6:9).

For more information:

Kit Dahl, Staff Officer, Pacific Fishery Management Council, 7700 NE Ambassador Pl., Suite 200, Portland, OR 97220, USA. Tel: +1 503 820 2280; E-mail:

Journal publishes issue on acoustic tracking of fish in MPAs

The Spring 2005 issue of the Marine Technology Society Journal is devoted to the subject of acoustic tracking of fish and its implications for the design of MPAs, with 11 articles on the topic. Access to the journal is free to members of the Marine Technology Society; non-members may order a copy of the Spring 2005 issue for US $20. Information on the journal and how to order the issue is available at For background on the subject of acoustic tracking and marine protected areas, MPA News reported on the subject in April 2004 (MPA News 5:9).

Report identifies priority conservation areas for Pacific waters of North America

A new report identifies 28 priority conservation areas that experts consider essential to protecting the marine biological diversity of much of the Pacific coast of North America – from Baja California in Mexico to the Bering Sea. Part of an ongoing project to develop a network of MPAs spanning the jurisdictions of Canada, Mexico, and the US (MPA News 1:4), the report recommends that these priority conservation areas serve as nodes around which such an MPA network could be built. The sites, representing roughly 8% of the three nations’ exclusive economic zones within the Baja California to Bering Sea (B2B) region, are not necessarily intended to serve as a prescriptive MPA network design.

The report was published by the Marine Conservation Biology Institute (a US-based NGO) and the Commission for Environmental Cooperation, an organization established by Canada, Mexico, and the US to address transboundary environmental concerns. The publication represents the data and opinions of hundreds of scientists, managers, and resource users from throughout the three countries, gathered during a five-year process. The ecology and human-use patterns of each priority conservation area are described, including notes on existing MPAs in each.

Report co-author Lance Morgan of the Marine Conservation Biology Institute says the next step is to match the report with community-based conservation planning involving stakeholders within the priority areas. “The report targets two groups,” he says. “One is the public, to give it a sense of the connectedness of the North American seascape and the ecological jewels in this region. Two are the managers of MPAs and individuals working on MPA issues at the local and regional scales to provide a larger framework to assist their efforts.” The report is available in PDF format (14 MB in size) at

For more information:

Lance Morgan, Marine Conservation Biology Institute, 14301 Arnold Dr. Suite 25, Glen Ellen, CA 95442, USA. Tel: +1 707 938 3214; E-mail: