August 26, 2014 — More than 100 researchers and three dozen projects are underway to find clues as to why Alaska’s Chinook salmon production has declined since 2007.
The ambitious effort marks the start of a state-backed five year, $30 million Chinook Salmon Research Initiative that includes 12 major river systems from Southeast Alaska to the Yukon. And while it will be years before the project yields definitive data, the scientists have pinned down some early findings.
“It’s not the fresh water production of the juvenile Chinook that is the reason this decline is occurring, it’s being driven by poor marine survival,” said Ed Jones, the lead for the Initiative and Sport Fish Coordinator for the Alaska Dept. of Fish and Game.
“We don’t know why, but once these juvenile Chinook salmon are entering the ocean they are not surviving at the rates they once did,” Jones added. “And at the same, we also are seeing younger and smaller Chinook returning to spawn and this obviously results in smaller fish being caught.”
At each river system, the Chinook team is estimating how many young fish are going to the ocean, refining estimates of how many older fish are returning to spawn, and tracking the marine catches.
“That’s an effort to estimate the harvests of these 12 indicator stocks in detail,” he explained. “So we’re going to implement tagging programs on the juveniles and as they go out to the ocean they’ll be marked with an adipose fin clip. We also will include a tiny coded wire tag in their heads and those will be sent to the Juneau lab where we can tell when and where those fish were released. With those three components we can do full stock reconstruction.”
Jones said his primary focus is on the Kuskokwim and Yukon Rivers because of the importance of Chinook salmon to subsistence users.
“A major part of this initiative is to make sure we can help those folks fish when there’s fish around and pull the reins back when they are not around. But we need to gather the information that allows us to do that accurately each and every year. We are trying to learn from the users and gather information on historical harvests, what the people know and what they’ve learned for centuries. We’ll feed that information into our stock assessment program,” he said.
Read the full story from The Fish Site