STEP 5: STOCKING In mid-September, FWP employees from the hatchery in Lewistown start hauling fish and releasing them in Holter, Hauser and Canyon Ferry. The fish are about 4 months old and 8 inches in size, big enough that they have a good likelihood of surviving in the wild. “The smaller the fish is, the more vulnerable they are to predation by other fish,” Grant said. They stock both Arlee and Eagle Creek trout. These two strains of rainbows are stocked in Helena-area reservoirs because they grow to a large size quickly, they survive well in these reservoirs and are easily caught by anglers. The fish are transported from the hatchery in large, specially designed trucks that can hold about 9,000 to 11,000 8-inch fish. Oxygen is constantly flowing through the water tanks on the trucks to keep the fish healthy in transit. Once they reach the reservoirs, the fish are transferred into the lake via a long tube that attaches to the trucks’ tanks. In all, the hatchery stocked about 400,000 rainbow trout in Holter, Hauser and Canyon Ferry reservoirs. Another 300,000 fish from other hatcheries around the state are released in the reservoirs.
STEP 4: FISH MARKING By June, the fish are about 4 inches long, and at this point, they’re marked to identify their strain. The Lewistown hatchery primarily raises two strains of rainbow trout – Arlee trout from the hatchery in Arlee, Montana, and Eagle Lake trout, a strain that originated in California. The Arlee trout are marked by removing the fish’s adipose fin. “It’s a non-essential fin on their back,” Grant explained. “It’s a non-lethal mark that’s noticeable to a biologist.” When trout eggs are harvested from Holter, biologists only capture non-Arlee trout. So if they see a fish missing its adipose fin, they throw it back. That means the eggs harvested at Holter are most likely from Eagle Lake trout. To mark the Arlee trout, fish are corralled in an outdoor raceway and then placed into small tubs, where a little anesthetic is added so the fish are easier to handle. Fish marking is a major undertaking. In all, about 230,000 fish have to be handled, and it takes upward of 30 people working most of a week to tackle the task. 16 | BRIGHT MAGAZINE Vol. 1