Frazer Lake Project
Although Frazer Lake is the second largest lake on Kodiak, it was barren of anadromous fish until 1951 when a stocking project was initiated. Located on the southeastern side of Kodiak, Frazer was chosen as the location to establish a self-sustaining sockeye salmon run. Egg, fry, and adult sockeye salmon from two other systems (Karluk and Red Lakes) were used as transplants to stock Frazer Lake from 1951 to 1971. When adults started to return in 1956, a 10-meter waterfall stood as a barrier for sockeye salmon heading back to their natal waters to spawn. They were backpacked around the falls and up to the lake, bringing the gravel-to-gravel life cycle to full circle. Backpacking the fish continued until 1962 when a fish pass was constructed around the barrier, which allowed fish to autonomously migrate up and access Frazer Lake and tributary spawning habitats.
Many fish still missed the small fish pass entrance and got trapped at the bottom of the falls. In 1971 and 1972, a diversion weir was built across the river, helping to lead salmon to the newly extended entrance. Operation and maintenance of the fish pass and weir at Frazer has been and remains an integral part of sustaining healthy sockeye salmon stocks for commercial harvest in Olga, Moser and Alitak Bays. Frazer Lake is one of the most successful introduced runs in the world and a major producer of sockeye salmon in the Kodiak Management Area, with annual runs exceeding 1 million in recent years. The Frazer Lake project contributes to the Kodiak economy by producing sustainable commercial fisheries as well as bear viewing and tourism. The current goals for the Frazer Lake project are to estimate the number of adult sockeye salmon escaping the system, enumerate the number of sockeye salmon smolt outmigrating from Frazer Lake, and to collect relevant data in an effort to understand the population dynamics of the Frazer Lake stock to optimize natural sockeye salmon production.
Fish Pass Operation and Adult Sampling
Adult sockeye salmon return to their natal rivers and lakes to spawn, thus producing the next generation of salmon. After they have survived numerous environments and avoided predation from various species including humans, they are considered escaped, hence the word ‘escapement’ is used to define salmon that make it to their spawning grounds. Adult escapement as well as age, sex, and length (ASL) of adult sockeye salmon have been monitored since the first successful adult returns in 1956 from the Frazer stocking program. Currently ADF&G and Kodiak Regional Aquaculture Association (KRAA) work in collaboration to operate the Frazer fish pass and weir for the duration of the sockeye return (1 June–20 August). The fish pass has an exit pool, or holding tank, at the top where field personnel lift a gate to identify and count fish before releasing them into the upper reach of Dog Salmon River heading for Frazer Lake. The complex fish pass and supporting structures are exposed to rough elements and bear activity, requiring daily maintenance to assure unobstructed and timely escapement. In addition to adult enumeration and fish pass maintenance, 240 adults are sampled weekly for age, sex, and length data. The collection of this biological data is used by management to help determine future run forecasts and escapement goals.
Historically, Frazer Lake sockeye smolt have been monitored at various levels using several sampling methods including a smolt weir and an incline plane trap placed below or above the falls. Currently an inclined fan trap is placed above the waterfall which is easier to operate and performs well in high water. Field personnel operate the trap three days a week throughout the smolt emigration to randomly collect 40 smolt each day for a total of 120 samples a week. For each individual, scales are collected for aging as well as weight and length. Biological data obtained from these samples are useful in assessing the fitness of outmigrating smolt and help to forecast future runs.
This summer, through a grant project, ADF&G will provide educational outreach about salmon to Kodiak residents and visitors. This project was partially funded by NOAA Pacific Coastal Salmon Recovery Funds administered by the Alaska Department of Fish and Game, Alaska Sustainable Salmon Fund.
Sockeye Salmon Life Cycle
- Eggs Females deposit approximately 2,000 to 3,000 eggs into redds, or gravel nests, along the lake shore and in tributary streams. Proper gravel size and water circulation through the gravel provides a safe environment from predators and protects the eggs from minor changes in climatic conditions, essential for egg survival throughout the winter.
- Alevins During the winter, the eggs hatch into alevins. Alevins cannot swim, so they remain hidden in the gravel, where cool, well-oxygenated water flows around them. These fragile alevins are protected from fine sediment accumulation and predators as they develop, obtaining all their nutritional needs from a yolk sac attached to their bellies.
- Fry Alevins emerge from the gravel in the spring to begin actively foraging as fry. Afognak Lake has an abundance of zooplankton and aquatic insects for juvenile fish to feed on. Summer is a busy time for young fry as they voraciously feed and grow, building up body reserves for the long winter.
- Smolt After 1 to 2 years foraging in the lake, fry undergo chemical and physical changes that prepare them for ocean conditions. Now called smolt, these juvenile salmon will leave Afognak Lake in May and June to continue the next phase of their life in the ocean.
- Ocean Juvenile sockeye salmon feed and grow in the ocean for 1 to 3 years as they mature into adult salmon. Afognak sockeye salmon are some of the first salmon to return to the Kodiak area each year, starting to arrive by mid-May.
- Spawning Mature salmon return to the waters where they were born to spawn and continue the cycle of life. After entering the freshwater environment, salmon stop eating and live off energy stored from their years of ocean feeding. After the salmon spawn and die, the decaying carcasses leave important nutrients that help support future salmon production.
Although tourism is not a part of the ADF&G finfish research program, bear viewing is integral to daily field life out at Frazer. The success of the introduced run at Frazer has created an enhanced food source for the Kodiak brown bear and increased the bear density in the surrounding area. Many local tour operators fly visitors out to Frazer to enjoy the scenery and the opportunity to view bears in their natural habitat within the Kodiak National Wildlife Refuge. The US Fish and Wildlife Service and ADF&G have worked to create a safe environment for both humans and bears, by creating established trails and viewing areas, food storage lockers, and posted signs directing visitors how to view responsibly.