Seafood Watch Seafood Report U.S. Farmed Hybrid Striped Bass Morone chrysops X Morone saxatilis (Photo by Gerald Ludwig, Courtesy of USDA-ARS) Final Report August 31, 2005 Brendan O’Neill Private Consultant Seafood Watch® Farmed Hybrid Striped Bass Report August 31, 2005 About Seafood Watch® and the Seafood Reports Monterey Bay Aquarium’s Seafood Watch® program evaluates the ecological sustainability of wild-caught and farmed seafood commonly found in the United States marketplace. Seafood Watch® defines sustainable seafood as originating from sources, whether wild-caught or farmed, which can maintain or increase production in the long-term without jeopardizing the structure or function of affected ecosystems. Seafood Watch® makes its science-based recommendations available to the public in the form of regional pocket guides that can be downloaded from the Internet (seafoodwatch.org) or obtained from the Seafood Watch® program by emailing [email protected]. The program’s goals are to raise awareness of important ocean conservation issues and empower seafood consumers and businesses to make choices for healthy oceans. Each sustainability recommendation on the regional pocket guides is supported by a Seafood Report. Each report synthesizes and analyzes the most current ecological, fisheries and ecosystem science on a species, then evaluates this information against the program’s conservation ethic to arrive at a recommendation of “Best Choices”, “Good Alternatives” or “Avoid.” The detailed evaluation methodology is available upon request. In producing the Seafood Reports, Seafood Watch® seeks out research published in academic, peer-reviewed journals whenever possible. Other sources of information include government technical publications, fishery management plans and supporting documents, and other scientific reviews of ecological sustainability. Seafood Watch® Fisheries Research Analysts also communicate regularly with ecologists, fisheries and aquaculture scientists, and members of industry and conservation organizations when evaluating fisheries and aquaculture practices. Capture fisheries and aquaculture practices are highly dynamic; as the scientific information on each species changes, Seafood Watch’s sustainability recommendations and the underlying Seafood Reports will be updated to reflect these changes. Parties interested in capture fisheries, aquaculture practices and the sustainability of ocean ecosystems are welcome to use Seafood Reports in any way they find useful. For more information about Seafood Watch® and Seafood Reports, please contact the Seafood Watch® program at Monterey Bay Aquarium by calling 1-877-229-9990. Disclaimer Seafood Watch® strives to have all Seafood Reports reviewed for accuracy and completeness by external scientists with expertise in ecology, fisheries science and aquaculture. Scientific review, however, does not constitute an endorsement of the Seafood Watch® program or its recommendations on the part of the reviewing scientists. Seafood Watch® is solely responsible for the conclusions reached in this report. Seafood Watch® and Seafood Reports are made possible through a grant from the David and Lucile Packard Foundation. 1 Seafood Watch® Farmed Hybrid Striped Bass Report August 31, 2005 Executive Summary Hybrid striped bass, a cross between striped bass (Morone saxatilis) and white bass (Morone chrysops), is an important fish in U.S. aquaculture. Commercial-scale production of hybrid striped bass for the foodfish market began in the mid-1980s and grew to over a million pounds of annual production by 1990. In 2000, hybrid striped bass production was ranked fifth in U.S. aquaculture production and fourth in value of all U.S. cultured foodfish. Production of hybrid striped bass primarily takes place in pond systems, which are used most often in the Southeast United States, but tank production also makes up a large portion of overall production. In general, the systems used to farm hybrid striped bass are inherently low risk and not believed to cause widespread environmental harm when well managed. The hybrid striped bass aquaculture industry is dependent on marine resources in feeds, leading some to question its overall sustainability. Advancements in feed formulations in recent years, however, have led to decreased dependence on wild fish for feed ingredients, to the extent that the wild fish input to farmed fish output ratio is now estimated to be below 2:1. While no evidence of frequent or large-scale escapes of hybrid striped bass from aquaculture facilities exists, there are potential risks and caution must be taken to ensure that the environment and wild fish populations are not negatively impacted by escapes. Different systems pose different levels of risk, with pond systems carrying a higher level of risk than closed or semi-closed tank systems. Overall, there is little risk of transfer or introduction of diseases and parasites from hybrid striped bass farms to wild fish and the discharge of wastes is not believed to be a major problem. Management of the hybrid striped bass aquaculture industry is effective and well regulated; however, the increased adoption of best management practices could potentially further improve the environmental performance of the industry. Overall, U.S. farmed hybrid striped bass ranks as a “Best Choice” according to Seafood Watch® criteria for the sustainability of farm-raised species. There are no conservation criteria that are of “High” or “Critical” conservation concern and 3 or more criteria are of “Low” conservation concern (3 for pond systems and 4 for closed systems). 2 Seafood Watch® Farmed Hybrid Striped Bass Report August 31, 2005 Table of Sustainability Ranks Conservation Concern Sustainability Criteria Low Moderate High Critical Use of Marine Resources √ (all) Risk of Escaped Fish to √ √ (ponds) Wild Stocks (closed systems) Risk of Disease and Parasite Transfer to Wild Stocks √ (all) Risk of Pollution and Habitat Effects √ (all) Management Effectiveness √ (all) About the Overall Seafood Recommendation: • A seafood product is ranked “Avoid” if two or more criteria are of High Conservation Concern (red) OR if one or more criteria are of Critical Conservation Concern (black) in the table above. • A seafood product is ranked “Good Alternative” if the five criteria “average” to yellow (Moderate Conservation Concern) OR if four criteria are of Low Conservation Concern (green) and one is of High Conservation Concern. • A seafood product is ranked “Best Choice” if three or more criteria are of Low Conservation Concern (green) and the remaining criteria are not of High or Critical Conservation Concern. Overall Seafood Recommendation: Farmed hybrid striped bass (pond culture and tank culture): Best Choice Good Alternative Avoid 3 Seafood Watch® Farmed Hybrid Striped Bass Report August 31, 2005 Introduction In the late 1980s and early 1990s, as commercial catches of wild striped bass were declining, a new fish began to replace it in markets and restaurants. This new fish was a farmed variety of the popular game fish; however, the “farmed striped bass” was actually a hybrid, a cross between two closely related species, one of which was the striped bass. While several types of hybrid striped bass exist, the crosses used most often in foodfish production involve the striped bass (Morone saxatilis) and the white bass (Morone chrysops). There are two of these crosses that are of primary interest to aquaculturists: palmetto bass, which is created when eggs from striped bass are crossed with sperm from white bass (Harrell and Webster 1997); and sunshine bass, which is created when the reciprocal cross is made, striped bass sperm with white bass eggs. Both crosses have improved characteristics over either parent, including faster growth, better survival, improved disease resistance, and greater tolerance for variable water quality conditions (Morris et al. 1999; Harrell 1997a). Most cultured hybrid striped bass are Sunshine bass, primarily because it is easier to obtain and handle female white bass than female striped bass. Both striped bass and white bass belong to the Moronidae family of fishes (Moyle and Cech 2000). This family, also known as the temperate basses, is comprised of six species of fish, four of which are native to North America. Temperate basses are found in freshwater and saltwater and are considered important game fishes. General features of these fish include medium to large size, elongated body shape, a large mouth, small teeth, two opercular spines, and a spiny dorsal fin (Jenkins and Burkhead 1994). The striped bass is the best known member of the family Moronidae. It is a popular sport fish and is often referred to as “rockfish” in the mid-Atlantic region. The native range of the striped bass extends along the Atlantic Coast from New Brunswick to Florida and along the Gulf Coast from Florida to Texas (Hodson 1989a). Its range has been extended through introductions on the west coast of North America, where it has established reproducing populations, as well as through introductions in many reservoirs where it can establish landlocked populations or be maintained through continued stocking (Hodson 1989a). Striped bass can reach sizes of over 70 pounds. Populations of striped bass on the Atlantic Coast went through dramatic declines in the 1980s, but strict regulations and improved management helped restore the populations. Today, striped bass support important sport and commercial fisheries on the Atlantic Coast. The white