Journal article
Distribution of Myxobolus cerebralis within a Free‐Flowing River System during the Migration Period for Juvenile Anadromous Salmonids in Idaho
Journal of aquatic animal health, Vol.15(2), pp.158-166
06/2003
Handle:
https://hdl.handle.net/2376/113382
Abstract
To gain a better understanding of the pathogen‐associated risk to resident and anadromous salmonid populations, the distribution, prevalence, and intensity of Myxobolus cerebralis infections were assessed during the smolt migration period in the Salmon, Snake, and Clearwater rivers of Idaho. Sentinel exposures of rainbow trout Oncorhynchus mykiss fry (0.6 g) occurred at 10 locations beginning at the headwaters of the Salmon River and extending downstream to the Snake and Clearwater rivers from April 18–28 and May 15–25, 2001. Following exposure, fish were examined for the prevalence and severity of infection by means of histological, pepsin−trypsin digest, and nested polymerase chain reaction analyses. Infections did not occur in the portions of the Snake or Clearwater rivers included in this study but were found in the Salmon River at five locations during April and seven locations during May. The results during April demonstrated moderate to high prevalence of infection (65% and 75% at 900 and 1,800 Celsius temperature units (CTUs), respectively) at the most upstream headwater site (river kilometer (rkm) 619, measuring from the mouth of the Salmon River), but intensity decreased 28 km downstream (rkm 591) to 10% and 0% at 900 and 1,800 CTUs, respectively. Fish exposed at two sites further downstream (rkm 454 and 416) showed 100% prevalence in both April and May. The most downriver sites at which infections were detected in April and May were sites 5 (rkm 308) and 7 (rkm 86). Significant correlations were not found between M. cerebralis infection and the environmental conditions examined in this study. However, the findings from this study show a temporal (April−May) increase in distribution and prevalence and a trend toward decreasing prevalence downstream of rkm 416. Therefore, resident and anadromous salmonids emerging or migrating through the Salmon River during April and May are probably exposed to the infectious stage of M. cerebralis.
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Details
- Title
- Distribution of Myxobolus cerebralis within a Free‐Flowing River System during the Migration Period for Juvenile Anadromous Salmonids in Idaho
- Creators
- Wade P Cavender - University of IdahoKeith A Johnson - Idaho Department of Fish and Game Eagle Fish Health LaboratoryKenneth D Cain - University of Idaho
- Publication Details
- Journal of aquatic animal health, Vol.15(2), pp.158-166
- Academic Unit
- Center for Reproductive Biology
- Publisher
- Taylor & Francis Group
- Number of pages
- 9
- Grant note
- Whirling Disease Foundation National Partnership on the Management of Wild and Native Coldwater Fisheries (98210‐0‐G642) Eagle Fish Health Laboratory
- Identifiers
- 99900547338501842
- Language
- English
- Resource Type
- Journal article