Aquaculture risk management and marine mammal interactions in the Pacific Northwest

Abstract

This paper reviews current aquatic farm production in the USA and estimates an annual financial exposure of US$350 million in the marine and coastal environments made up of sales, standing crop value and capital investment. In addition, nationwide aquatic farming creates almost 200,000 jobs and, with secondary and downstream activities combined, contributes about US$5600 million to the GNP. The paper then reviews the increasing risk that elements of the coastal aquaculture industry in the Pacific Northwest face from interactions with populations of marine mammals. These are particularly California sea lions and seals, which have greatly increased in the last 20 years from California to British Columbia. Specifically: (i) shellfish from traditional beds have been contaminated by fecal coliforms from seals and made unfit for human consumption, and have been experiencing increasing losses to river otters and sea otters; (ii) culture-based salmon fisheries, including endangered salmon stocks, have been exposed to heavy predation by sea lions and seals, resulting in both direct losses and reduced market value of wounded survivors; (iii) net-pen farms have been exposed to the same heavy losses from predatory sea lions and seals attacking fish in the pens, together with added financial burdens for anti-predator nets, increased maintenance and labor; and (iv) workers in aquaculture and fisheries, and other waterborne industries, have been observing less fear of humans by sea lions and seals, and more direct damage to servicing facilities. The four issues are discussed both technically and economically, and a number of solutions proposed for managing and controlling these increasing risks.