Hatcheries are used to produce salmon to augment the number of fish available for harvest, and to supplement wild populations that may be threatened with extinction. Although traditional hatchery rearing methods can produce many fish, they can pose risk to wild populations because they tend to produce salmon with lower fitness than wild counterparts. As wild salmon populations continue to decline, researchers and managers continue to explore alternative methods with potential to affordably produce large quantities of salmon with higher fitness and survival to adulthood.
In this study, we evaluated two devices designed to artificially boost juvenile salmon abundance with limited rearing cost: instream hatchboxes and streamside incubators. We installed these devices into four artificial stream channels at the Oregon Hatchery Research Center, then supplied them with a total 30,000 fertilized Chinook salmon (Oncorhynchus tshawytscha) eggs. We compared egg-to-fry survival rates, cost per fry and fry size for the two methods. Our results suggest that hatchboxes delivered higher egg-to-fry survival (79.8%) than incubators (68.1%). We also found that hatchboxes and incubators produced fry at similar costs ($0.064 and $0.056 per fry, respectively). Finally, we found that fry produced with hatchboxes were 21.4% heavier than those produced with incubators. We suggest that managers and conservationists consider benefits and limitations to the application of these methods as tools for conservation or fisheries augmentation.