Early next week researchers from around the country will gather in Anchorage to address the state’s king salmon puzzle. One of the missing pieces they will attempt to nail down is a lack of consistent data between the state’s king-bearing rivers.
Scientists from the Alaska Department of Fish and Game released a draft version of a document outlining key gaps in the department’s knowledge about king salmon in both freshwater and marine environments statewide.
During the symposium that kicks off Monday, scientists will examine types of research included in the draft analysis and the department will present a final version of the document by the end of the year.
The document identified 12 king salmon-bearing rivers across the state that would serve as “indicator stocks” in what Bob Clark, chief fisheries scientist for the sport fish division of Fish and Game, hopes will result in a centralized database of the state’s king salmon research.
The Kenai River was included in the group and researchers identified several areas of research that could be used to supplement statewide data on king salmon runs.
The four projects include moving the DIDSON sonar site, estimating the abundance of smolt — or juvenile salmon — estimating marine harvest and compiling local knowledge of king trends.
The new research could cost the department more than $400,000 annually to implement, Clark said.
However, the department included the total cost and potential for successful implementation of new projects into account when it considered each of the rivers, he said.
Some projects identified, such as the movement of the sonar site on the Kenai River; or a weir on the Karluk river, have already been launched.
“Some of that (cost) factors into what’s already being measured,” Clark said. “So you’re saving some money because there’s already projects in place.”
The sonar site project on the Kenai river began with capital funding, but needs more funding to pay personnel to estimate run-strength at the new site according to the gap analysis.
The comment period for the draft analysis ends Nov.. 9 and the research plan is due in early December, Clark said, hopefully in time to be included in the governor’s request for funds during the upcoming legislative session.
The research team tasked with developing the gap analysis chose the Unuk, Stikine, Taku, Chilkat, Copper, Susitna, Karluk, Chignik, Nushagak, Kuskokwim and Yukon rivers in addition to the Kenai.
Clark said the team included rivers were disaster declarations had been made following the 2012 fishing season, it also added rivers where very little was known about king abundance and runs.
“There were about 20-25 stocks that were considered, so ... it was just a process of winnowing out places that looked alike,” he said. “Some of it was, ‘Is it conceivable that we can pull off research in this area?’”
Several indicator rivers, such as the Unuk which has the fourth largest run in Southeast Alaska, have king salmon runs that are considered healthy. Others, like the Yukon and tributaries of the Susitna River have stocks that have been classified as stocks of “yield concern” due to low returns, according to the analysis.
The Kenai River met its escapement goals 90 percent of the time between 2006-2010 but has seen uncertain performance since 2009 when changes were made in the assessment of the run strength according to the analysis.
Analysis for each river suggested types of research that could be carried out to improve king salmon knowledge, eventually the researchers hope to use the data to solve the puzzle of low king returns across the state.
“In the past we’ve seen downturns in certain areas in the state but we’ve never seen a concerted downturn across the state,” Clark said of chinook salmon runs. “If you look at the data, this is something unique and ... we need data from a variety of places to figure it out.”
Researchers suggested methods of measuring marine harvest of chinook and salmon bycatch trends which will be discussed during the salmon symposium.
One of the ways researchers suggested determining marine harvest and movement patterns of chinook was to use coded wire tags on juvenile salmon as they leave their rivers.
“That’s one thing that we really lack around the state, we’re trying to figure out what’s causing these downturns and just from adult data its very difficult to tell whether the drop in survival of animals is going on out in the marine environment, or it’s something that’s happening in the fresh water,” Clark said.
In the Cook Inlet, where extensive genetic testing has been done in rivers and allows local biologists to align genetic samples from marine catches with specific local rivers, coded wire tags would serve a different purpose than they do in watersheds were there isn’t good genetic differentiation.
Clark said coding juvenile salmon as they left rivers in the Cook Inlet would give local researchers a chance to track their kings in the marine environment as other fisheries harvested local fish and reported the tag locations.
In other watersheds, the coded wire tags can be used in place of genetic sampling to determine where salmon originated, Clark said.
While the coded wire tags may work in some rivers, Clark said it wouldn’t be the best solution in others and part of the reason of the symposium was to learn about different technologies for tracking chinook.
Part of the research team’s analysis also includes anecdotal data and trends from people who live around each of the rivers.
“Our data on run abundance of chinook salmon really only goes back to the early 1970’s at best. For the Kenai, it’s really only back to the mid-1980’s,” Clark said. “What we’re trying to understand is, ‘Were there downturns like this before?’
“In some places the data go back far enough, you can look. Some other areas they don’t and our best bet is to ask people who have been around a long time. That’s one of the big things I think I’m looking for is asking people to look for patterns and trends in sort of the verbal history of fisheries.”
The research team will take input on the draft analysis through Nov. 9, then a research plan will come out in early December, Clark said.
The 2012 Alaska Chinook Salmon Symposium will be from 8 a.m. to 6 p.m. Monday and Tuesday at the Egan Center in Anchorage. It can be heard by phone at 1-888-655-9647 or streamed live from the Alaska Department of Fish and Game’s website.
Rashah McChesney can be reached at firstname.lastname@example.org