Lake Wilhelm is a 1,740 acre reservoir located in M.K. Goddard State Park in Mercer County. The staff from the Fisheries Management Area 2 Office returned to Lake Wilhelm to set trapnets during the week of April 19, 2004. We set 4 trapnets for 3 nights each for a total of 12 net sets and 277.25 hours. We caught a total of 5,173 fish (431 fish per net or almost 19 fish per hour).

Area Fisheries Manager Al Woomer with a 28” walleye

The walleyes that were difficult to find night electro-fishing on April 7th did show up in the trapnets. We captured 71 walleye ranging from 9 to 28 inches (Table 1). Several year classes were noted in the sample. We also captured 14 muskellunge ranging from 33 to 49 inches. These results indicate our walleye and muskellunge stocking programs are successful and should continue.

Table 1. Length frequency of gamefish and large panfish captured April 19 - 22, 2004 in 12 trapnets set for 277.25 hours in Lake Wilhelm, Mercer County.

Our catch of panfish was impressive. Black crappies ranged from 4 to 14 inches and white crappies ranged from 6 to 13 inches. As is typical though, the populations of black and white crappie showed the cyclical nature of these species with alternating strong and weak year classes. About 64% of the black crappie and 86% of the white crappie were three years old. These fish ranged from about 6 to 10 inches. This large year class from both species will provide the bulk of the fishery for the next couple of years. Growth rates appear to be good for these fish so they should grow to a desirable size as the year progresses.

Table 2. The length frequency of panfish and forage fish captured April 19 - 22, 2004 by 12 trapnets set for 277.25 hours in Lake Wilhelm, Mercer County.

Also captured were good numbers of sunfish (bluegills and pumpkinseeds), yellow perch and bullheads (brown and yellow). All in all, the catch rates in fish per hour and fish per net were very high and show that Lake Wilhelm’s reputation for excellent panfish is well deserved.

A couple of nice crappies

A common sight during our week at Lake Wilhelm

You will note on Table 2 that a new fish species, gizzard shad, is now established in Lake Wilhelm. It is not known how these fish came to be in this lake and we will have to wait and see what impact they may have on the other fish populations. The spread of new and exotic fish species between waters is a serious problem for fisheries managers.

We will be returning to Lake Wilhelm in May to sample the largemouth bass population by night electrofishing.

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