Seafood Watch Seafood Report

Seafood Watch Seafood Report Farmed Pacific White Shrimp Litopenaeus vannamei © Scandinavian Fishing Yearbook/www.scandfish.com Mexico Final Report January 7, 2010 Peter Bridson Aquaculture Research Manager Monterey Bay Aquarium and Irene Tetreault Miranda, Ph.D. Independent Contractor 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 (831) 647-6873 or emailing [email protected]. 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. 2 Table of Contents I. Executive Summary……………………………………………………………… 4 II. Introduction………………………………………………………………............. 8 III. Analysis of Seafood Watch® Sustainability Criteria for Wild-caught Species Criterion 1: Use of Marine Resources………………………………………… 22 Criterion 2: Risk of Escaped Fish to Wild Stocks…………………………….. 28 Criterion 3: Risk of Disease and Parasite Transfer to Wild Stocks…………… 32 Criterion 4: Risk of Pollution and Habitat Effects…………………………….. 42 Criterion 5: Effectiveness of the Management Regime……………………….. 56 IV. Overall Recommendation and Seafood Evaluation……………………................. 60 V. References………………………………………………………………………… 62 VI. Appendices………………………………………………………………………... 69 3 I. Executive Summary Mexico supports a major shrimp farming industry and produced 114,000 tons of farmed shrimp from 66,000 hectares of ponds in 2007. Ninety percent of this production came from two northwestern states bordering the Gulf of California: Sonora and Sinaloa. Production is exclusive to the Pacific white shrimp, Litopenaeus vannamei, and is rapidly increasing. For example, both the quantity of shrimp produced in Sonora has more than doubled in the five-year period from 2003 to 2008 and the total pond area has nearly doubled in the same time. Data from 2008 show that Sonora alone now produces over 80,000 tons from 22,000 hectares of ponds. In keeping with the dominance of these two states (especially Sonora) and their significance among U.S. imports, this report focuses only on production in Sonora and Sinaloa. The Gulf of California coastal environment hosts a unique set of habitats and is considered to be an environment of high conservation status. The great majority of Mexican shrimp farms interact directly with this environment. Tropical mangrove forests are found in the lower two-thirds of the gulf, while a variety of intertidal habitats exist throughout the Gulf. The interaction of shrimp farms with these habitats, particularly mangrove forests, has been the subject of considerable controversy on a global scale. While the bulk of Mexican shrimp production occurs in Sonora, the greatest shrimp pond coverage in terms of area is in Sinaloa and Nayarit to the south, where more extensive wetlands and mangrove forest occur. A number of protected RAMSAR wetlands sites are located in Sinaloa. Although 95% of the Gulf of California’s mangrove-associated lagoons have been developed for shrimp farming, there is little documentation regarding the possible impacts of the construction of these farms. Despite the fact that relatively few mangrove-forested areas have actually been cleared for ponds, most ponds have destroyed or impacted adjacent wetlands and tidal/salt marsh habitats, and many (perhaps most) farms drain directly into mangrove lagoons. The tidal marsh habitats of the Gulf are threatened wetlands that contain a diversity of plant and animal life, much of it unique and endemic to the local habitat. It is well known from studies around the world that shrimp farm operations can have many negative impacts on mangrove forests and other sensitive habitats, particularly due to pond effluent. Considering the proximity of most Mexican shrimp farms to sensitive coastal habitats and the rapid expansion in total pond area, the risks to habitats are considered a high conservation concern. Effluent from shrimp farms has the potential to negatively impact the environment at local and regional scales due to nitrification, sedimentation and changes in hydrology. With daily pond water exchanges of 10–30% or more, even though the concentration of pollutants in the effluent water is likely to be low, the volume of effluent discharge is high, and the system is considered to be open in this respect. The level of nutrients being discharged untreated from shrimp farms into the Gulf of California is substantial, estimated to be equivalent (in terms of nitrogen and phosphorous discharge) to the untreated sewage from 1.7 and 1.9 million people per year, respectively. Researchers who have measured shrimp farm outputs suggest that the large volume of discharged nutrients and sediment is having negative local effects, particularly on Mexico’s “esteros” or estuaries. Effluent from shrimp farms can also contribute to the regional problems 4 associated with increasing nutrient input to the greater Gulf of California. Nutrient input to this semi-enclosed sea has been generally increasing and is associated with various environmental concerns including Harmful Algal Blooms (HABs). Agriculture and other anthropological nutrient inputs to the Gulf of California are substantial, and the significant nutrient discharges from Mexican shrimp farms further contribute to these regional impacts. Nevertheless, it appears that Mexican shrimp farming is a relatively minor contributor to regional impacts when compared to agriculture and other anthropological sources. The growing number of shrimp farms has the potential to contribute more strongly to regional impacts. The pollution effects of shrimp farming are therefore considered to be local, even though they also contribute to the larger gulf- wide problem of agricultural and anthropological pollution. Overall, discharge of untreated effluent via daily water exchanges, local impacts, and pond siting in areas of ecological sensitivity, in addition to the continued expansion of shrimp farms into sensitive coastal, wetland, and estuarine habitats, creates a high conservation concern for pollution and habitat effects. Due to the daily water exchanges and therefore the ‘openness’ of the production system, and despite good management and biosecurity protocols, a risk of escapes exists and loss of stock is probably inevitable. Although the majority of escapes may be small trickle losses, the failure of key components such as outlet screens and filters, or catastrophic events such as dyke failures or flooding, do allow significant numbers of farmed shrimp to escape. Anecdotal evidence suggests that trawl fisherman regularly catch farmed white shrimp, but in general the frequency of escapes is unknown. After many generations of domestication and selective breeding for desirable traits such as increased growth rate and disease tolerance, farmed shrimp in Mexico display significantly different biological

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