Wildlife: Odd walleye eyes right for night vision

February 12, 2012 12:01 am

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According to the 2006 National Survey of Fishing, Hunting and Wildlife Associated Recreation, approximately 143,000 Pennsylvanians considered themselves walleye anglers. That's about 19 percent of those with fishing licenses. Furthermore, though the total number of Pennsylvania anglers declined from 2001 to 2006, the number of walleye anglers increased, and the number of days spent walleye fishing in Pennsylvania has steadily increased since 1996.

The reasons for the walleye's ascent are diligent management by the Pennsylvania Fish and Boat Commission and the fish's excellence as table fare. A fresh, thick walleye fillet is fine food.

The walleye season runs Jan. 1 through March 14, and May 5 through Dec. 31. The split season provides a respite during their early spring spawning season.

Growing to more than 30 inches, the walleye is the largest member of the perch family, which also includes sauger, saugeye (a crossbreed of sauger and walleye), yellow perch and numerous species of much smaller darters.

Walleyes are named for their large, glassy, opaque eyes. This odd appearance is due to a layer of light-gathering tissue at the back of the eye called the tapetum lucidum. This light-sensitive tissue enables walleyes to be largely nocturnal. During the day they retreat to deeper, darker water.

Saugers have similar light-sensitive eyes, but the two species differ in size and markings on the first dorsal fin. Saugers rarely exceed 18 inches in length, and their first dorsal fin is marked by many dark half moons.

Walleyes lack the half moon markings, but have a large dark spot on the rear of the first dorsal fin.

Though originally native to the Ohio River and Lake Erie drainages in Pennsylvania, walleye now occur statewide. Widespread stocking has introduced them to eastern river basins, so there are now self-sustaining walleye populations in the Susquehanna and Delaware river drainages.

Where populations are low, maintenance stocking occurs.

The keys to maintaining walleye populations seem related to zooplankton populations and water quality.

Walleye fry eat zooplankton, but zooplankton densities fluctuate from year to year. When these tiny invertebrates are abundant, stocked fish do well.

Improvements in water quality also enhance fish survival. In a study at the Maxwell Dam on the Monongahela River in 1968, PFBC biologists found just one species of fish. A 2003 survey of the same area found 26 species, including walleye.


First Published 2012-02-11 23:21:06
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