August 3, 2009
Secretary Gary Locke
U. S. Department of Commerce
14^th Street and Constitution Ave. N. W.
Washington, DC 20230

Delivered via e-mail to Jess Beck, Southeast Regional Office, NMFS at Jess.Beck@noaa.gov; and posted electronically to the Federal eRulemaking Portal at http://www.regulations.gov

Re: Proposed Rule 0648-AS65: Fishery Management Plan for Regulating Offshore Marine Aquaculture in the Gulf of Mexico

Dear Secretary Locke:

Thank you for the opportunity to provide a scientific perspective on the environmental risks of open ocean aquaculture to help inform the Department of Commerce’s pending decision to approve or reject the Gulf of Mexico Aquaculture Fisheries Management Plan (FMP). We are a diverse group of academic scientists with experience in marine ecology, aquaculture, and fisheries who have published extensively in the peer-reviewed scientific literature. We identify a range of environmental risks of marine aquaculture, many of which should be addressed at an ecosystem scale to ensure that aquaculture ameliorates, rather than exacerbates, pressure on the oceans. We conclude that a coordinated, ecosystem-based regulatory approach, operating at the national level, is necessary to achieve a sustainable future for open ocean aquaculture in the United States. Without this approach, the piecemeal development of a marine aquaculture industry could result in significant and potentially irreversible environmental consequences. For this reason, we recommend that the Gulf of Mexico Aquaculture FMP should be disapproved.

There are six environmental risks of open ocean aquaculture that are most relevant to decisions about how the United States might proceed with this relatively new method of farming seafood. They are:

1. Use of marine resources,

2. Risks of escaped fish to wild fish and associated ecosystems,

3. Nutrient, chemical, and habitat impacts,

4. Risk of disease and parasite amplification and retransmission,

5. Impacts of drug and chemical use, and

6. Impacts on predators and other wildlife.

Use of Marine Resources
Aquafeed for many of the “carnivorous” species likely to be farmed in open ocean environments (e.g. cod, halibut, seabass, striped bass, yellowtail, and yellowfin tuna) contains very high percentages of fishmeal and fish oil (Tacon and Metian 2008). Average estimates of the ratio of wild fish required to produce farmed fish are 2.2 for “marine fish” and ~5.0 for salmon (Tacon and Metian 2008, Naylor et al. 2009). The wild forage fishes caught for aquafeeds play important ecosystem roles as food sources for higher trophic-level marine predators (Cury et al. 2000, Worm et al. 2006, Alder et al. 2008). As aquaculture has grown dramatically over the past two decades, the total demand for fishmeal and fish oil for use in aquaculture feeds has similarly expanded while the supply has remained relatively constant, thus increasing aquaculture’s share of global fishmeal and fish oil use (Tacon et al. 2006, Tacon and Metian 2008, FAO 2009, Naylor et al. 2009). Additional global growth in industrial fish production has the potential to undermine marine food webs by redirecting food sources away from those wild species most dependent on them (Pauly et al. 2002, Pauly et al. 2005, Karpouzi et al. 2007).

These facts all point to the use of marine resources as a key constraint in a sustainable future for aquaculture. Severing the reliance of fish farming on wild fish requires efficiency improvements at the farm level as well as a regulatory structure that sets overarching sustainability requirements for the industry as a whole, as most of the forage fish used for aquaculture are caught outside of U.S. waters (FAO 2009). Minimizing the use of forage fish in feeds and creating incentives for substitutes for wild-caught fishmeal and fish oil (including seafood processing byproducts, terrestrial plants, animal byproducts, single cell proteins and oils, and marine and terrestrial invertebrates) are needed if these feed sources are to be widely adopted by the aquaculture industry (Naylor et al. 2009).

Risks of Escaped Fish to Wild Fish and Associated Ecosystems
Aquaculture is known to be a major vector for exotic species introduction (Carlton 1992, Carlton 2001), causing concern over the ecological impacts that escaped farmed species can have on wild fish and the environment, whether the farmed species are native or exotic to the area in which they are farmed (Volpe et al. 2000, Naylor et al. 2001, Youngson et al. 2001, Myrick 2002, Weber 2003). Farmed salmon are known to regularly escape from net pen systems, negatively impacting wild salmon stocks by increasing competition for food and breeding sites, as well as reducing the fitness of wild fish through interbreeding (Einum and Fleming 1997, Youngson and Verspoor 1998, Volpe and Anholt 1999, Fleming et al. 2000, Volpe et al. 2000, Jacobsen and Hansen 2001, Volpe et al. 2001, McGinnity et al. 2003, Naylor et al. 2005, Hindar et al. 2006). As compared to salmon aquaculture facilities, which are generally sited in sheltered bays, net-pen systems in open ocean environments face increased risk of failure due to increased exposure to storms and stronger currents.

Developing separate broodstock to allow for selection of desirable growth characteristics is a hallmark of traditional agriculture and livestock production. To date, this has been common practice in aquaculture as well. However, allowing these practices to continue for aquaculture in open ocean environments, where fish will inevitably escape, greatly increases the risk to natural ecosystems of genetically-distinct farmed fish, even if these fish are native to the farming area. If the U.S. is to prevent environmental damage related to fish escapes, explicit regulations for broodstock maintenance and fish escape standards are needed that account for both individual farm-level effects and the cumulative impact of escapes occurring across a large number of farms. In the absence of these regulatory safeguards, permitting open ocean aquaculture in the Gulf of Mexico at this time risks significant harm to the environment and should not be allowed.

Nutrient and Habitat Impacts
Wastes, both dissolved and particulate, from open net pen systems are released untreated directly into nearby bodies of water and can have large impacts on the surrounding environment (Gowen et al. 1990, Beveridge 1996, Costa-Pierce 1996). More than half of the total nitrogen and phosphorus fed to fish in commercial farms is released into the surrounding environment (Beveridge 1996, Fernandez-Jover et al. 2007). In Japan, intensive culturing of finfish and its consequent generation of organic wastes has adversely affected the surrounding environment via deoxygenation (Hirata et al. 1994), outgassing of hydrogen sulfide (Tsutsumi 1991), and blooms of harmful plankton (Yokoyama 2003, Nakamura et al. 1998).

While proponents of offshore aquaculture frequently cite deep water and high flushing rates as reasons for low concern over nutrient pollution in these habitats, emerging science suggests this may be unjustified. A detailed study of a commercial-scale open ocean aquaculture facility in Hawaii found striking changes in benthic species diversity and community structure under and nearby submerged sea cages despite relatively deep water and high current velocity (Lee et al. 2006). High-resolution models of waste transport from aquaculture pens indicate that dissolved nutrients (from excess feed as well as fish excretion) do not disperse as rapidly and as uniformly as was previously assumed (Venayagamoorthy et al. 2009). This evidence suggests that the adage of “dilution is the solution” is not the appropriate framework under which to expand open ocean aquaculture in the U.S., especially in areas such as the Gulf of Mexico which are already under severe nutrient stress. To adequately address the cumulative impacts of nutrient input from multiple aquaculture facilities, aquaculture must be regulated and managed at the ecosystem level, not by relying solely on local-scale, individual permitting decisions such as those allowed by the Gulf of Mexico aquaculture FMP.

Risk of Disease and Parasite Amplification and Retransmission from Farmed Fish to Wild Fish
It is well known that intensive fish culture, particularly of non-native species, has been involved in the introduction and/or amplification of pathogens and disease in wild fish populations (Hastein and Linstad 1991, Nese and Enger 1993, Kent 1994, Nylund et al. 1994, Bakke and Harris 1998, Blazer and LaPatra 2002). In recent years, the issue of amplification and retransmission has received much attention because of the dramatic consequences of the spread of parasitic sea lice from salmon farms to wild salmon (Tully and Whelan 1993; Costelloe et al. 1996; Grimnes and Jakobsen 1996; Gargan 2000; Bjorn et al. 2001; Heuch and Mo 2001; Bjorn and Finstad 2002; Butler 2002; Morton et al. 2004; McKibben and Hay 2004; Penston et al. 2004; Krkosek et al. 2005, 2006, 2007; Morton et al. 2005). Disease outbreaks in other fish grown in open net pens appear to be common as well. For example, yellowtail farmed in the Mediterranean, Japan, and New Zealand have suffered substantial mortalities from monogenean parasites (Whittington et al. 2001; Hutson et al. 2007).

Of the six major environmental risks of open ocean aquaculture, disease is the one for which ecosystem-level management is most critical. Disease at the farm level is a husbandry issue, but it is the transfer of diseases from farm to farm and back to the wild that poses the largest environmental risks. Chile’s experience with Infectious Salmon Anemia in farmed salmon (Mardones et al. 2009, Vike et al. 2009) is a cautionary tale. Farm-level management led to numerous salmon farms being sited too closely together. Only after the salmon industry was decimated by the spread of this disease did Chilean authorities take the first steps toward breaking the disease cycle by developing “neighborhoods” to limit both farm-level and regional fish production (Intrafish 2009). If the U.S. is to prevent these types of disease dynamics, it must develop an ecosystem-based approach to aquaculture management that plans for expansion within an explicitly spatial context. As such an approach does not currently exist, approving the Gulf of Mexico aquaculture FMP risks significant harm not only to the environment, but to the aquaculture industry itself.

Impacts of Drug and Chemical Use
Most aquaculture operations use a variety of chemicals, including antifoulants, pesticides, and antibiotics (Tacon and Forster 2000), which can have negative effects on marine ecosystems or human health. Copper-containing paints, commonly-used antifoulants in the aquaculture industry, are toxic to many marine organisms, including seaweeds, mollusks, and Atlantic cod embryos (Andersson and Kautsky 1996, Granmo et al. 2002, Braithwaite and McEvoy 2004). Use of antibiotics has been shown to result in bacterial resistance in some aquaculture environments and to influence antibiotic resistance in humans (Kerry et al. 1996, Sapkota et al. 2008). Pesticides whose residues are known to be harmful to other marine life (Abgrall et al. 2000, Grant 2002) are sometimes used to control sea lice levels on farmed salmon (Roth 2000). In order to minimize the deleterious effects these chemicals have on the marine environment, their responsible use in aquaculture must be regulated by national agencies under a coordinated plan.

Impacts on Predator Populations
Expansion of open ocean aquaculture in the U.S. may also pose environmental risks to predators and other wildlife. In coastal salmon farming, a range of techniques, including the use of predator nets and underwater acoustic deterrent devices, are commonly used to reduce the impact of predators on stocks of farmed fish. These techniques, while generally successful at reducing losses of farmed fish, can have dramatic unintended consequences for the predators themselves, including alteration of natural behavior and the entanglement and subsequent drowning of large numbers of these air-breathing mammals (Morton and Symonds 2002, Wursig and Gailey 2002, CBC News 2007).

In open ocean environments, little is known about the potential impacts of fish farms on predators and other wildlife, but experience with farmed salmon suggests this will be an important concern. Limited evidence suggests that sharks and other large pelagic predators are attracted to submerged net pens (Galaz and de Maddalena 2004, NOAA 2005) and that predators that have become habituated to the presence of net pens, and hence a threat to human safety, have been killed (Lucas 2006). Should this practice become commonplace as the U.S. industry expands, this could put already vulnerable shark populations (Stevens et al. 2000, Baum et al. 2003, Myers and Worm 2005, Camhi et al. 2009) at further risk. Finally, submerged net pens and their associated mooring lines could pose entanglement risks to whales and other cetaceans, whose migration routes or foraging behavior bring them in close proximity to fish farms (Upton et al. 2007). Mitigating the effects of a young and growing aquaculture industry on predators and wildlife will require additional research on the interaction of farms and marine wildlife as well as the population consequences of the cumulative impact of those interactions.

A Final Note on Cumulative Impacts of Multiple Aquaculture Facilities

When the impacts of a single aquaculture operation are considered in isolation, they may be considered to be relatively mild. However, as the aquaculture industry grows, and should facilities be sited in close proximity to one another for economies of scale, the effects of their combined impacts may be greater than the sum of their individual impacts. This can be the case with nutrients, as well as with disease transfer, impacts of escapes, use of marine resources, and impacts on predators. To avoid these cumulative impacts and help avoid or ameliorate many of the risks discussed above, the precautionary approach should be a central tenet of the planning, management and permitting of aquaculture facilities.

Due to the scientifically documented, serious risks of offshore marine aquaculture outlined in this letter, we conclude it is critical for the U.S. to develop a consistent, precautionary set of environmental standards and implement regulations designed to protect the nation’s federal marine waters. In their absence, the development of a marine aquaculture industry in a piecemeal fashion, such as through approval of the Gulf of Mexico aquaculture FMP, could result in significant and potentially irreversible environmental consequences, including water pollution from waste products and chemicals, threats of disease transmission to wild fish populations, harmful effects on native marine species from escaped farmed fish, and ecosystem impacts of the increasing use of wild forage fish for aquaculture feeds.

Thank you for the opportunity to provide this scientific analysis on the ecological risks of marine finfish farming to help inform your decisions on how the U.S. should address this important issue. We conclude that an ecosystem approach to aquaculture management is critical to the long-term future of a sustainable domestic offshore aquaculture industry and incompatible with approval of the Gulf of Mexico aquaculture FMP at this time.

Sincerely,

Rosamond L. Naylor, Ph.D.
Professor, Environmental Earth System Science
Stanford University

Felicia C. Coleman, Ph.D.
Director
Florida State University Coastal & Marine Laboratory

Ian A. Fleming, Ph.D.
Professor, Ocean Sciences Centre
Memorial University of Newfoundland

L. Neil Frazer, Ph.D.
Professor, School of Ocean and Earth Science and Technology
University of Hawaii at Manoa

Les Kaufman, Ph.D.
Professor, Biology
Boston University Marine Program

Jeffrey R. Koseff, Ph.D
Professor, Civil and Environmental Engineering
Stanford University

John Ogden, Ph.D.
Director, Florida Institute of Oceanography
University of South Florida

Laura Petes, Ph.D.
Postdoctoral Associate
Florida State University Coastal & Marine Laboratory

Amy R. Sapkota, Ph.D., MPH
Assistant Professor, Maryland Institute for Applied Environmental Health
University of Maryland College Park, School of Public Health

Les Watling, Ph.D.
Professor, Department of Zoology
University of Hawaii at Manoa

References