The ability of salmon hatcheries to increase wild salmon abundance may come at the cost of reduced diversity among wild salmon, according to a new University of Alaska Fairbanks–led study.
The ability of salmon hatcheries to increase wild salmon abundance may come at the cost of reduced diversity among wild salmon, according to a new University of Alaska Fairbanks–led study.
The number of juvenile salmon released into the North Pacific Ocean by hatcheries increased rapidly in the second half of the last century and remains at over 5 billion each year. Salmon hatcheries have helped push annual pink salmon harvests in Prince William Sound, Alaska, from about 4 million fish prior to hatchery programs to roughly 50 million in recent years.
Using data collected from pink salmon streams in Prince William Sound through the Alaska Hatchery Research Project, researchers determined that many hatchery-raised fish are straying onto natural spawning grounds and interbreeding with wild populations. In a related study, researchers used simulations developed with the real-world data to ask what this continued input of hatchery fish might mean for wild populations.
“Even if only a small percentage of hatchery-origin fish stray into wild populations, a small fraction of a huge number can still be a lot,” said Samuel May, lead author of the newly published study in the journal Royal Society Open Science. “We were interested in exploring the long-term consequences of hatchery straying for wild population recruitment and resilience.”
Read more at University of Alaska Fairbanks
Image: Differences between two male pink salmon highlight morphological diversity in the species. (Credit: Photo by Julia McMahon)
