The Salmon and Steelhead

Hatchery Fish Controversy, Part III

Ernest L. Brannon, University of Idaho--January 24, 2005


Management not Propagation


The major problem responsible for much of the controversy about hatcheries has been confusing the effects of artificial propagation with the effects of fisheries management. Managers routinely used excess hatchery production to support weaker runs in other streams for the sole purpose of providing greater harvest opportunity. This resulted in the introduction of fish poorly adapted to the receiving environment, and little sustained natural production would occur. In other cases, for management objectives, hatchery populations were artificially selected to return earlier than the original stock. This resulted in the hatchery fish being displaced from the temporal synchrony necessary for good survival under natural conditions. In other cases performance was exacerbated by releasing large numbers of fish in one location with no thought about stream carrying capacity, wild fish in residence, or water conditions. The reduced effectiveness of the hatchery fish to reproduce naturally in those instances was not from the influence of artificial propagation, but rather from management decisions that disregarded the biological requirements for fish to successfully reproduce in those river systems. Hatchery fish became the scapegoats for poor fisheries management.



Consequently, to accurately assess hatchery fish performance in the wild, it is necessary to remove the influence of management from the equation, and look only at those differences in performance related to the process of artificial propagation. If the process of hatchery propagation results in substantive reduction in survival, then that is the critical information needed to reassess or reform the application of hatchery technology. If the problem is the negative influence of management policy on hatchery fish performance, that problem has nothing to do with hatchery propagation.



The confusion between process and management has caused much of the near hysteria we witness in some of the sportsmen’s literature. An example is a recent article in the Osprey, the newsletter of the Federation of Fly Fishers. They reported the poor performance of hatchery steelhead released in Forks Creek, in the Willipa River basin , compared to wild steelhead. The wild fish outperformed by the hatchery fish, and the difference was attributed to artificial propagation. However, the hatchery fish were not from the Forks Creek population, but rather a Bogachiel River/Chambers Creek stock hybrid that spawned earlier than the native fish. Therefore, attributing poor performance to the affects of artificial propagation was nonsense. The hatchery fish did not originate from Forks Creek, and thus it was not possible to measure the influence of hatchery experience because the fish were poorly adapted to the receiving stream in the first place.



The difference between process and management is not confusing just to the sporting public, but we find a similar problem among some fisheries scientists. This was exemplified in an article published in Fisheries by the Independent Scientific Advisory Board to the National Marine Fisheries Service. In response to a question about letting excess hatchery produced salmon and steelhead spawn in the wild, they advised against it, and listed several publications in support of their position. They felt that the earlier return and spawn timing of hatchery adults, and their frequently younger ages at spawning, were evidence of domestication. Domestication is unintentional natural selection of traits while in captivity changing the genetics of the population, However, they were mistaken. Hatchery populations that return earlier do so because brood fish have been selected consistently from the earlier part of the returning run. Spawn timing, as a genetic characteristic, can be altered simply by what segment of the returning population is selected for breeding in the hatchery. Therefore, spawn timing can be maintained by using the correct breeding protocol. Early return and spawning is not the given result of artificial propagation.



Similarly, younger age at return is not an inherent property of artificial propagation. The use of warmer temperatures during incubation accelerate development rates, resulting in earlier onset of feeding. Warmer temperatures and higher feeding rates promote rapid growth, and large fingerlings size for their age at release hastens maturation, causing fish to return a year sooner than what would be common in the natural environment. However, timing and growth rate of hatchery fish can be controlled to mimic that of the wild fish. Younger fish at return is not the given result of artificial propagation.



The overriding problem in both the sportsmen’s misinterpretation of scientific information and in the misapplication of scientific literature by fisheries professionals examining artificial propagation of salmon and steelhead, is the negative preconception about hatcheries before they look at the data. In the cases cited above, and common in a large part of the literature on hatchery fish performance, there is a bias that hatchery fish are inferior before the evaluation process begins. Consequently, careful reading of the reports or examination of the original data from reference studies is not exercised, and conclusions of the original investigator and the experimental design used in the original study are not critically examined. In the case with the Federation of Fly Fishers, they didn’t realize they were comparing apples and oranges. In the case of the Independent Scientific Advisory Board, they were not careful in discerning what was actually being tested in the literature cited. In both examples, poor performance of hatchery fish was attributed to artificial propagation when the presence of other overriding variables was overlooked. This has been a common problem in research on hatchery fish, and it has biased our understanding of artificial propagation. Further discussion about these problems will be conducted next time when laboratory studies are examined.



Dr. Ernest L. Brannon is a professor at the Center for Salmonid and Freshwater Species at Risk, University of Idaho, Moscow. He is also Chairmen of the Salmon Committee for the Salmonid Foundation.