The Alaska Department of Fish and Game is one small step closer to figuring out the difference between how many offspring hatchery fish produce versus wild stock. The department released a second batch of results this month as part of a long-range study. But there’s some disagreement over how much weight the results should carry.
The Alaska Department of Fish and Game is looking at pink salmon in five streams in Prince William Sound in hopes to answer crucial questions about hatchery fish. The most recent results look at 2014 pink salmon spawners in Stockdale Creek.
“The females are very similar in that they lose about half their relative reproductive success and the males were very different in relative reproductive success between the two streams,” said Alaska Department of Fish and Game Chris Habicht.
Habicht is working on the study and he’s comparing these results with pink salmon spawners in Hogan Bay for the same year.
A potentially concerning finding from the new study is that the male hatchery fish from the Stockdale samples produced roughly a third of the amount of offspring that natural fish did. That’s a change from the first batch of results from Hogan Bay samples where male hatchery and natural fish had roughly the same reproductive success.
The other major takeaway from this study was the reproductive success between different spawning combinations including hatchery and natural, natural and natural, and hatchery and hatchery.
“What was really interesting is that if you look at the relative reproductive success, the hatchery-hatchery origin parents produced the lowest relative reproductive success,” he said. “The ones that were half hatchery and half natural produced intermediate reproductive success. The natural-natural produced the highest reproductive success.”
But Habicht said there are some concerns about how reflective this sampling is of the fish in the stream.
There’s also concern about making conclusions based on just two streams. Bill Templin is the chief fisheries scientist for the Department of Fish and Game and is on the advisory science panel helping to shape the study.
“It'd be like taking a poll of about five people or 10 people and then trying to say something about who's going to win the next election,” he said.
He agrees there is a lot more work to be done and cautions people to wait to make conclusions until the project ends around 2024. But he said it was a requirement of the project’s funding to make these results public.
“So that's why this report is out right now,” he said. “We would really prefer to put all of this information out in context.”
But Peter Westley said the samplings aren’t a huge concern for him. He’s an assistant professor for the Department of Fisheries at the University of Alaska Fairbanks. He’s also on the advisory panel for the study.
“I'll tell you what is a bigger concern for me is really the current results,” he said. “So I'm concerned if indeed hatchery fish have lower success than wild fish. That is a biological concern.”
He said the study does need to go through peer review and adds there needs to be due diligence in making sure that the analytical results are sound. There have also been questions surrounding whether the study is biased.
Westley believes that the results from the study will stand. He adds that there is already overwhelming evidence that hatchery fish don’t do as well as wild fish and that the results from this study points in that direction.
“What is done with that information then is up to the policy makers,” he said. “And there is a need, in my opinion, to very quickly and urgently conduct a study that's going to help inform the trade-offs around those potential decisions.”
But for now, Fish and Game will continue to work on this study. The department said the next batch of results won’t be out for about another year.