Friday, May 29, 2015

Study Analyzes Effects Of Supplementation On Natural-Origin Salmon Abundance
Posted on Friday, May 22, 2015 (PST)
A recent study that compared 12 wild chinook salmon populations that had been the focus of hatchery supplementation programs and 10 populations of salmon that had never been the focus of supplementation programs found none to small benefits in natural salmon abundance.

The study analyzed information from a 25-year period and determined that densities of natural-origin spawning adult salmon in the Snake River Basin that had been the focus of supplementation programs had increased just 0 percent to 8.4 percent relative to the 10 salmon populations that had not been the focus of supplementation.

“To put these numbers in perspective, large-scale factors that affect population size, such as hydropower operations or changing ocean conditions, have a much more substantial effect in roughly 9 out of 10 years,” said the study’s lead author Mark Scheuerell, research fisheries biologist in the Fish Ecology Division with the NOAA Fisheries Northwest Fisheries Science Center.

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