Interesting news release on early smolt release from Spring Creek Hatchery

[Pete]

Early Release of Salmon From Spring Creek National Fish Hatchery Justified

During the week of April 4, news releases appeared in the Portland, Vancouver and Seattle newspapers describing the emergency release of millions of “ill” salmon into the wild from the Spring Creek National Fish Hatchery, located on the Columbia River above Bonneville Dam. The fish were infested with a protozoan parasite, Ichthyopthirius multifilis, commonly know as “ich”. Virtually all freshwater fish are susceptible to infestation by this parasite. Wild fish can also carry infestations of the parasite, which is a natural inhabitant of the aquatic environment.

The decision to release the infected fish was misrepresented Bill Bakke, President of the Native Fish Society, as a ploy by the U.S. Fish & Wildlife Service to “Save Embarrassment” wanting the fish to die in the wild rather than in the hatchery. Nothing is further from the truth. Undoubtedly, Bakke has a poor understanding of fish diseases and host-pathogen interactions in general.

The presence or detection of any infectious agent does not imply that fish are diseased. Simply put, infection – defined as invasion of a host (the fish) by a pathogenic agent-is a more common event. In contrast, disease – is defined as the condition that results in morbidity (diseased state) and possibly mortality in the individual host or population as a consequence of infection.

Releasing the fish from the hatchery into the Columbia River 10 days earlier than normal was a prudent management strategy. Ich is a very common parasite of fish, has a broad temperature tolerance, and has been recorded from tropical regions to the Artic circle. Man has been aware of ich for many years and was first described as a disease of carp in China as early as the Sung Dynasty (960 – 1200s AD) and in the middle ages in Europe. Ich can have a very severe effect in artificial culture operations if it is left unchecked. The news releases described above had many inaccuracies. There was no disease but the fish did have a low-level ich infestation. The best thing for these animals was to be released which should significantly enhance fish survival. Nobody likes to release infected fish, but given the distribution of this very common parasite and the need to address the welfare of these animals, this action was justified. In fact there will probably be less
of a potential impact of the parasite to the environment by releasing the fish rather then maintaining them in an artificial culture situation where the parasite could potentially increase in numbers and cause disease. Additionally, ich does not survive well in saltwater, which is just where these fish and the water they reside in are headed.

Disinfection of the fish passage facility is totally unwarranted and a waste of time and money. While this was not a scheduled release it seems justified given the pathogen that was involved and the need to address the welfare of these animals.

The Spring Creek Tule Stock is one of the few genetically pure and native species of salmon left in the Columbia River. Undoubtedly, this stock would be on the Endangered Species list had it not been kept and raised for the past 100 years at the Spring Creek National Fish Hatchery.

Dr Scott LaPatra, Certified Pathologist and Past President, Fish Health Section/American Fisheries Society

Charlie E. Smith, Certified Pathologist and Past President, Fish Health Section/American Fisheries Society