Impacts of multispecies parasitism on juvenile coho salmon (Oncorhynchus kisutch) in Oregon

By: , and 



We are studying the impacts of parasites on threatened stocks of Oregon coastal coho salmon (Oncorhynchus kisutch). In our previous studies, we have found high infections of digeneans and myxozoans in coho salmon parr from the lower main stem of West Fork Smith River (WFSR), Oregon. In contrast parr from tributaries of this river, and outmigrating smolts, harbor considerably less parasites. Thus, we have hypothesized that heavy parasite burdens in parr from this river are associated with poor overwintering survival. The objective of the current study was to ascertain the possible effects these parasites have on smolt fitness. We captured parr from the lower main stem and tributaries of WFSR and held them in the laboratory to evaluate performance endpoints of smolts with varying degrees of infection by three digeneans (Nanophyetus salmincola, Apophallus sp., and neascus) and one myxozoan (Myxobolus insidiosus). The parameters we assessed were weight, fork length, growth, swimming stamina, and gill Na+,K+-ATPase activity. We repeated our study on the subsequent year class and with hatchery reared coho salmon experimentally infected with N. salmincola. The most significant associations between parasites and these performance or fitness endpoints were observed in the heavily infected groups from both years. We found that all parasite species, except neascus, were negatively associated with fish fitness. This was corroborated for N. salmincola causing reduced growth with our experimental infection study. Parasites were most negatively associated with growth and size, and these parameters likely influenced the secondary findings with swimming stamina and ATPase activity levels.

Publication type Article
Publication Subtype Journal Article
Title Impacts of multispecies parasitism on juvenile coho salmon (Oncorhynchus kisutch) in Oregon
Series title Aquaculture
DOI 10.1016/j.aquaculture.2011.07.003
Volume 362-3
Year Published 2011
Language English
Publisher Elsevier
Publisher location Amsterdam, Netherlands
Contributing office(s) Oregon Cooperative Fish and Wildlife Research Unit
Description 9 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Aquaculture
First page 184
Last page 192
Country United States
State Oregon
Online Only (Y/N) N
Additional Online Files (Y/N) N
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