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Ponding: When juvenile salmon moves from incubators to raceways

Spring means the crew at Trail Lakes Hatchery begins to encourage salmon fry spend their time outdoors.

by | April 12, 2024

Every March, the Trail Lakes Hatchery crew looks forward to early signs of spring. March brings longer days, warmer weather, and the first direct sun of the year at the hatchery.

The Trail Lakes Hatchery is located just outside the town of Moose Pass and is surrounded by beautiful mountains, which happen to be great at blocking the sun for almost the entire winter. Even though the initial glimpse of sun is worthy of celebration, the real highlight of March is ponding season for the first emerging salmon fry of the year. 

Sunrise at Trail Lakes Hatchery
The highly anticipated first glimpse of sun from the back side of Trail Lakes Hatchery. Troy Pierce, CIAA

Moving juvenile salmon outside

During the summer and fall, we collect the eggs, fertilize them, and put them in incubators at the hatchery where they will remain until early spring.

Over the winter salmon hatch and bury themselves beneath artificial substrate until they absorb their yolk sacs. After the yolk sac is gone, salmon fry emerge out of the substrate to forage for food. When we determine that the fish have reached this stage of development, we begin the ponding process.

At Trail Lakes Hatchery, we don’t literally use ponds as some may envision. Ponding for us means moving juvenile salmon from incubators to large concrete raceways where they will reside until it’s time to release them into the wild.

The raceways at Trail Lakes Hatchery.
The outdoor raceways at Trail Lakes Hatchery that the salmon will call their homes until it’s time to move them to their various release sites. Troy Pierce, CIAA

Ponding: Step by step

When we decide that an incubator full of fry is ready to pond, we attach hose to the incubator’s assigned raceway. This setup allows the fry to move out of the incubator voluntarily. This benefits juveniles that have not yet absorbed their yolk sac and can move when they’re ready.

We periodically expose the fish to light to encourage them to swim out of the artificial substrate and down the hose to their new home.

After a few days, most of the fry have left their incubators and are now swimming in the much larger raceways. We use nets, siphons, and buckets to move the remaining fish that haven’t left the incubators.     

Hoses connected to the effluent of the incubators.
Hoses are attached to the effluent of the incubators to provide the emerging fry the ability to move out to the raceways on their own terms. Troy Pierce, CIAA

New season, new duties

Ponding creates new tasks and responsibilities for staff members. To name a few:

  • Feeding the fry
  • Tracking growth
  • Monitoring raceway dissolved oxygen
  • Measuring flows 

Trail Lakes Hatchery participates in several release programs. This means the release destination and duration of stay at the hatchery varies. Some salmon will be moved in a matter of a couple months through fry release programs, while others will call the hatchery home for another year before we release them as smolt.

The Circle of Life

Learn more about the salmon life cycle by visiting the Cook Inlet Aquaculture Association website. You can also see salmon in freshwater homes by visiting one of our hatcheries.

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