Stockers must fit strategy, place

By Cherry Sokoloski
North Forty News

It may come as a surprise to most fishermen, but not all fish are created equal when it comes to stocking rivers and lakes. Like a good headhunter, the Division of Wildlife looks for fish that are suited to particular jobs and stocks them accordingly.

"Return to creel" is a concept used to describe the success of different stocking strategies. It's also a way of matching a type of fish with a particular job.

Return to creel is a ratio, the total number of fish caught versus the total number stocked. In some environments, the DOW is looking for a high, short-term return to creel. In others, the DOW takes a longer-term view, and a lower return is considered acceptable.

Put-and-take

In popular fishing areas such as lakes and reservoirs, when catchable-sized fish (9 to 11 inches) are stocked, the DOW looks for high returns in the weeks and months immediately after stocking occurs. The agency wants fishermen to benefit from these fish, so it's best if they aren't too spooky in order to help produce high catch rates. This short-term return-to-creel strategy is used where natural reproduction does not occur and food or habitat is limited.

Put-grow-and-take

A longer-term strategy is used when fingerlings (small fish, 4 to 5 inches long) are stocked. In this case, the fish may be stocked in the summer of one year but don't start "returning to creel" until the second or third year. The return in numbers is lower with fingerling plants, but the DOW has another goal in mind: the agency hopes to produce more pounds of fish from natural food in the lake than what was initially stocked.

For this type of stocking, it's best if the fish have good survival skills and predator avoidance behavior. In other words, they should be somewhat spooky. The lake must also have abundant food and over-winter habitat. Areas for natural reproduction are not necessary.

The Hofer-cross fingerlings stocked at Parvin Lake last summer (see related article on page 1) are being evaluated for long-term survival and return to creel.

Put-and-reproduce

A third type of stocking occurs in rivers or lake inlets, where spawning areas for fish are present. Fingerling plants in these environments are designed to establish naturally reproducing populations, so that future stocking won't be necessary. Because of this long-term goal, the DOW wants these fish to be very wild or spooky. They should have a long lifespan and have predator-avoidance behaviors that are suited to a river environment. For this type of stocking, return-to-creel numbers are not so important. Since the DOW is interested in establishing viable natural populations with this strategy, it looks for newly hatched fry that appear two to three years after the initial stocking.

Thanks to George Schisler, Ph.D., fishery and wildlife biologist at the Parvin Lake Research Station, for supplying information for this article.