Fish Hatchery

Storm Lake is usually stocked with Channel Catfish and Walleye every year in the spring. (To see other types of fish found in Storm Lake and to learn more about each one, please see These are the big sport fish in the area and the work that goes into it is done by the Iowa DNR.

In Storm Lake, test nets and equipment are set out the last week of March to check numbers, water temperature, and measure photoperiod (daylight hours). Fish are caught at night using gill nets set perpendicular to the shoreline. When an adult fish swims into a gill net, its gills get tangled in the net and it remains caught until untangled by a human and brought back to the satellite hatchery in the Storm Lake Marina. The males and females are separated, and the females are further separated by whether they are ripe or green bellied (eggs are not ready). The milt (semen) is removed from the males, measured, and mixed with extender (a saline solution to keep the milt viable for up to two weeks). It is important to keep the milt dry because once hydrated it only has a lifespan of 30 seconds.

After roe and milt are removed, fish are returned to the lake where they were captured. Males are returned after removing their milt, and females might be kept for 1-3 days depending on if their eggs are ready or not. At the hatchery, the fertilized eggs are incubated in specialized jars that allow the flow of fresh, oxygen-delivering water over the eggs. Once eggs hatch they are either stocked as fry (hatched fish eggs) or reared until fingerling stages, 2-8 inches in length.

Why stock fish?

Many times fish are stocked because sport fishermen want something to catch. Environmentalists also many times are behind fish stocking to make up for losses due to habitat disturbances or to counteract over fishing. Scientists may also do stocking to be able to conduct research.

Problems with stocking

  • Place you want to stock may not be suitable for the fish species you want to stock
  • You may be disturbing the other fish species that are already living in the area which may upset the balance of the ecological system
  • There is the risk of transferring in diseases or invasive species with the fish species you are stocking.
  • Stocking fish may decimate the natural fish population due to over competition and predation.
  • If two species of fish that are stocked together are two closely related and mate, the genetic diversity of the each species may be lost.


For more information, please see:

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