Habitat and Monitoring

More Than Hatcheries

Salmon cannot thrive without healthy habitat—whether they begin their lives in a hatchery or in the wild. CIAA invests in improving or protecting habitat for all of Cook Inlet salmon.

In 1978, one of CIAA’s first habitat projects was to survey streams for beaver dams and other obstructions to upstream salmon migration.

Since then, we have built water flow control structures and fish ladders. We’ve been on guard against invasive species like northern pike and elodea. We’ve conducted water samples to monitor the status of lakes and streams. We’ve maintained smolt traps to gain accurate counts of juvenile salmon leaving for the oceans.

Good science leads to accurate management and healthier runs that benefit all salmon fishermen and their communities. 

Traps and Weirs

We operate smolt traps and adult salmon weirs to collect data on the numbers of salmon moving up and downstream. Our monitoring crews count every sockeye, coho, Chinook, pink, and chum salmon that may pass through, along with other fish species. The crew may also take samples to help determine ages and origins of the salmon.

There are three main purposes for collecting this information

  1. To evaluate our hatchery programs in stocked systems
  2. To help ADF&G manage fisheries and even open up opportunities
  3. To provide some long-term records of salmon movement that can be used to help determine the health of ecosystems.

For our hatchery programs, we can compare our projections with the actual returns and adjust operations as needed. For fisheries management, our operation of traps and weirs in systems without any hatchery-reared salmon, such as Delight Lake, help open up fishing opportunities that would otherwise be closed. This is due to the fact that ADF&G may not have the resources to run the on-the-ground counting projects.  

Currently we count smolt leaving Bear, Hidden, Shell, Kirschner, and Tutsumena Lakes. Adult salmon are counted returning to Bear, Hidden, and Delight lakes. 

A common aquarium plant causes uncommon threats to our salmon

Elodea can be found in your fish tank at home, but is not native to Alaska lakes and streams. It is a serious threat to freshwater fish habitat all over the state because it displaces native plants and animals. Research shows a 4 to 1 chance that Alaska salmon in elodea-infested habitat will not exist in 20 years. 

We have been surveying for elodea throughout the Cook Inlet region as well as assisting with elodea eradication through funding and staff support.

Other Projects

Northern Pike

Northern pike are native to most regions in Alaska, but not the Southcentral region. They can rapidly take over and decimate native fish, particularly juveniles. Cook Inlet has seen declines salmon runs directly attributed to invasive pike.

CIAA has been working to research, control, and help eradicate northern pike. Projects include pike monitoring,  suppression and/or research at Shell, Whiskey, and Hewitt lakes in the Susitna watershed as well as systems nearer to Tyonek on the west side of Cook Inlet.

Building Fishways

Fishways allow salmon access to spawning grounds, whether by fish ladders or other mechanisms. Paint River Fish Ladder on the east side of Kamishak Bay was built by CIAA in the early 1990s. It allows fish to swim around a 40-foot waterfall to enter the Paint River system and naturally colonize.

CIAA also created a roughened channel at head of Fish Creek. A dam structure at this outlet was impeding salmon fry movement into Big Lake, so an outlet substrate was built  leading to the dam structure, creating a subtle incline as well as resting pools for the fry to use.

Key Terms

Flow Control Structure

A device that alters the flow of water in a stream, such as the use of dam boards

Fishway

A contrivance for enabling fish to pass around a fall or dam in a stream

Invasive Species

Plants or animals that are non-native to an ecosystem and whose introduction is likely to cause economic or environmental harm or harm to human health

Trophic

Relating to feeding and nutrition

Smolt Trap

A box or similar structure placed in flowing waters to capture smolt

Weir

A fence or similar structure placed in flowing waters, that directs the movement of adult fish

Keeping an Eye on Dams

Our field crews will carefully observe what is going on down and upstream of a beaver dam and if the dam is obstructing salmon migration. If the crews determine a dam is blocking salmon, the crew will notch the dam.

The notch is temporary because beaver dams are beneficial for providing habitat to juvenile salmon and it is not CIAA’s intent to take the dams entirely out. The notches allow for adult salmon to pass before the opening is filled in again by the busy beavers.  

Trophic Sampling

Our technicians and biologists collect zooplankton and water samples; and take measurements for temperature, dissolved oxygen profiles, and light incidence. The resulting analysis from the ADF&G lab in Soldotna is used to ensure appropriate nutrient loading and fry stocking into these lakes. It determines the fertilizer application rate to help propagate phytoplankton growth—which in turn increases zooplankton growth, which are major food sources for salmon fry. 

Flow Control

Our habitat projects include maintaining and operating flow control structures to provide adequate flows for salmon migrations. We operate such structures at Bear and Daniels lakes on the Kenai Peninsula; at Packers Lake on Kalgin Island, and on the west side of Cook Inlet at Marten Lake in the Big River Lakes system.