Researchers find Bristol Bay salmon smolt thriving in warming waters
Professors and students from the University of Washington's Fisheries Research Institute come to Bristol Bay each year to collect data and analyze the salmon run. On a cool, rainy morning last week the biologists began catching smolt samples from local waterways using a beach seine. FRI houses its team of biologists on Lake Aleknagik, where veteran FRI research scientist Jackie Carter assembled her team to collect the data.
"Today we're going to go beach seining," said Carter.
FRI has been using beach seines to catch and analyze adolescent salmon, known as smolt, since 1962. "The guys who started this research program understood that if you want to learn something about sockeye salmon, you need to know something about the habitats in which they live at all life stages, and you need to know what their competitors are and what they're eating," she said.
Professor Daniel Schindler is one of the UW faculty running the Alaskan salmon program. He says sustained, long-term data collection can be used to learn how salmon react to changes in their environment.
"This year we're seeing very low water levels and warm water temperatures early, and of course, one of the questions is whether this is an abnormal year or whether it's part of a long-term trend, and you can only get perspective on that question if you have long-term data," said Schindler.
FRI research shows the warmer waters are definitely part of a trend over the last 30 or so years, but the salmon seem to be thriving.
"What most people don't appreciate is that those warmer conditions have translated into better growth and survival conditions for salmon. So in fact, during the last 20 years we're seeing more salmon produced out of these watersheds," said Schindler.
Carter and her team drive their skiff from beach to beach makings sets, sealing the smolt in plastic bags and recording the water temperature.
"We're right across from the Agulowak River, so we get a lot of variety. We have two-check sockeye smolt. What that means is they spent two summers rearing in the lake, and we know they're two-checks because they're really big. We're also seeing one pink salmon — very small, very skinny — and two juvenile arctic char," said Carter after pulling in the seine and observing a catch.
After a few hours of work, the smolt are brought to a lab where they are measured and weighed to record trends in growth.
FRI's Alaskan salmon program started in the late 1940s. Not only have they sustained a thorough log of long-term data, but they continue to provide in-season analysis as the run progresses. Professor Schindler says he will interpret the run this summer by recording where fish are caught in the districts, as well as observing test fishery data and escapement numbers.
"Parallel to that effort is work here in the watersheds looking at where the fish are spawning, how the individual tributaries build up fish on the spawning grounds, but also looking at — like I said —the environmental conditions and how the juvenile salmon are growing throughout the year," said Schindler.
Schindler says more scientists are on their way up to Bristol Bay to help with FRI's efforts — many of whom are graduate students coming to study the methodology of managing a fishery — operating this summer from camps at Iliamna Lake, The Wood River, The Chignik River and Aleknagik Lake.