Spawning Fish at the Hatchery - A Year around Cycle
Early spring marks the beginning of the cycle of life for many of our native fishes. Northern Pike, a dominant predator species, are the earliest of the many North Dakota fishes to spawn. As the ice begins to recede from the lake’s edge and snow melt causes increased flows into the river systems, the pike arouse from their period of winter dormancy and migrate into the flooded shallows to spawn. Frame nets set by fishery biologists capture the adult fish and they are stripped of eggs and milt at the site. The eggs are brought to the Garrison Dam National Fish Hatchery where they are incubated in special hatching jars. The newly hatched fry emerge from the eggs in about two weeks. It will be another week before the fry are able to swim or feed. The ‘swim-up’ fry spend the last month of their stay at the hatchery in ponds which have an abundance of zooplankton, the food necessary to provide for the rapid growth of the fish. At the month’s end, the northern pike fry, now called fingerlings, are a couple inches long and ready for stocking into area lakes. If the fingerlings are left in the ponds any longer, the zooplankton will no longer satisfy their hunger, and the fish will begin to eat each other!
If you have a taste for the prehistoric, stop by the hatchery in June. The pallid sturgeon, a North Dakota native and an endangered species, are approaching their spawning time. These fish are undoubtedly the strangest looking of the North Dakota fish. The fish has a ‘sucker’ type mouth, beady eyes, whiskers (or barbels), and a body covered with ‘scutes’, a scale like structure that gives them the appearance of having a coat of armor. The fish are a long lived fish, probably more than 50 years, reaching lengths of six feet and 90 pounds. Both the paddlefish and the sturgeon have changed little since the Carboniferous to early Triassic times. During the reign of the dinosaurs 200 million years ago, their ancestors were the dominant freshwater fish. Jurassic Park is alive and well at the fish hatchery!
If you’re in the area, northern pike spawning begins in mid-April, followed by walleye through early May. Paddlefish and pallid sturgeon are spawned in early June. Coldwater species, trout and salmon, are at the station year-around, however if you visit the station in October, you will be able to witness the annual migration of chinook salmon up the hatchery’s salmon creek and watch as eggs are collected from these awesome fish.