|GOOD, CHRISTOPHER - Freshwater Institute
|VINCI, BRIAN - Freshwater Institute
|SUMMERFELT, STEVEN - Freshwater Institute
|SNEKVIK, KEVIN - Freshwater Institute
|ADAMS, IAN - Chelan County Public Utility District
|DILLY, SAMUEL - Chelan County Public Utility District
Submitted to: Journal of Aquatic Animal Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2011
Publication Date: 6/1/2011
Citation: Good, C., Vinci, B., Summerfelt, S.T., Snekvik, K., Adams, I., Dilly, S. 2011. Assessing the suitability of a partial water reuse system for rearing juvenile Chinook salmon Oncorhynchus tshawytscha for stocking in Washington State. Journal of Aquatic Animal Health. 23:55-61.
Interpretive Summary: We assessed performance of juvenile Chinook salmon raised in a pilot partial water reuse system versus in a traditional flow-through raceway, as contracted by the Chelan County Public Utility District (PUD) for their Eastbank Hatchery in Wenatchee, Washington. The PUD are considering adopting water reuse technology for raising their fish, due to increasing water usage constraints in the Pacific Northwest region; however, fish raised in this new type of rearing environment need to be of good quality for stocking in order for water reuse systems to be deemed an appropriate replacement for raceways. A 21-week observational study was conducted by professionals at The Freshwater Institute to provide the fish health data necessary for the PUD to assess the quality of fish raised in a water reuse environment. Fish from the pilot reuse system and a nearby flow-through raceway were sampled on multiple occasions; sampling included screening for listed fish pathogens, histopathology evaluation, blood gas and chemistry assessments, and fin erosion measurement. On the whole, these evaluations provided a broad picture for the PUD to compare reuse and raceway fish, and from the results obtained The Freshwater Institute provided evidence that water reuse technology can be employed for rearing Chinook salmon for stocking purposes without reducing their performance quality and overall health.
Technical Abstract: Health and welfare of juvenile Chinook salmon Oncorhynchus tshawytsha reared in a pilot circular tank-based partial water reuse system in Washington State were evaluated in comparison to fish from the same spawn reared in a flow-through raceway, in order to assess the suitability of using water reuse technology for raising Pacific salmonids for stocking. This observational study was carried out over a 21-week period. Reuse and raceway fish were sampled repeatedly for pathogen screening and histopathology; fin erosion and whole blood parameters were also evaluated. By study's end, no listed pathogens were isolated from either cohort, and survival was 99.3% and 99.0% in the reuse and raceway groups, respectively. Condition factor was 1.28 in raceway fish (vs. 1.14 in reuse fish); occasional differences in feeding rates might have played a role in these values. Fin indices were lower in reuse fish, but fin erosion was not grossly apparent in either cohort. The most consistent histological lesion was gill epithelial hypertrophy in reuse fish; blood analyses, however, did not suggest any corresponding physiological imbalances. Overall, results suggest that water reuse technology can be employed for rearing juvenile anadromous salmonids for stocking purposes.