|Title:||Salmon rancher's manual|
|Author/Editor:||William J. McNeil, Jack E. Bailey|
|Institution:||Northwest Fisheries Center Processed Report, July 1975. National Marine Fisheries Service. Seattle, Washington|
The North Pacific Ocean is a vast nursery ground for the Pacific salmon that spawn in streams and lakes in North America and Asia. These salmon reproduce in fresh water, but most of their growth occurs at sea. When mature they return to their freshwater ancestral spawning grounds, where tens of thousands of genetically separate stocks segregate for reproduction.
Man has helped to precipitate a general decline of salmon by overfishing and by polluting spawning and nursery grounds. Even though the oceanic waters where salmon spend most of their life are vulnerable to pollutants, there are encouraging indications that such pollution has not seriously impaired the capacity of the ocean to grow salmon. The problem then is to restore the runs themselves—something that might be accomplished through aquaculture.
Public agencies now produce most of the juvenile Pacific salmon through artificial propagation (hatcheries and spawning channels). However, recent advances in technology for salmon aquaculture and removal of legal barriers to private ownership of salmon in California, Oregon, Washington, and Alaska have combined with a scarcity of wild stocks to stimulate private investments in the ocean ranching of Pacific salmon. Several pioneering business ventures are now in the process of evaluating the economic feasibility of ocean ranching.
Despite a long history of artificial propagation of salmon, the causes of the success or failure of ocean ranching are not fully understood, and many problems remain unresolved or only partially resolved. Therefore, this manual does not attempt to provide answers to all questions. Instead, it attempts to identify the more serious impediments to successful ocean ranching and the precautions that will reduce the risk of failure.
Production of healthy fry is the "core" of any salmon aquaculture system because the success of ocean ranching will depend largely upon the quality of juvenile fish released into the ocean. The primary purpose of this manual is to assist salmon ranchers with planning, constructing, and operating systems for artificial propagation of salmon fry. The methods described are not necessarily the only suitable ones available, and considerable latitude usually exists for modification of equipment and techniques. Salmon ranchers will soon adapt their systems to suit their specific requirements.
Some comments on the use of chemotherapy to control disease in salmon hatcheries is pertinent here because federal, state, and local agencies have rigid regulations governing the use of chemicals in controlling disease in animals raised for human consumption. In fact, only a few of the chemicals recommended in publications that discuss treatment of diseased fish are approved by the federal government. Those approved for salmon include salt, glacial acetic acid, sulfamerazine, and oxytetracycline. In most instances, proper control of the environment and observance of high standards of sanitation are the only means of minimizing mortality from disease.
To simplify the organization and content of the text, publications are not cited in the manual, although many statements are based largely on interpretations of and conclusions from the voluminous pertinent literature (more than 400 reports were reviewed). The authors recognize that alternative interpretations are often possible and also that the conclusions given are subject to change. Trade names are frequently used in the text, but the National Marine Fisheries Service does not endorse any of the products mentioned.