Evaluation of Walleye Introductions into Lake Burton and Seed

Project number: F-25
Study: XXV
Final Report Date:  September 1998
Period Covered: July 1, 1990 to December 31, 1997
Author:  D. Anthony Rabern

Study Objective

To establish and maintain a walleye population and fishery by stocking and to document any measurable impact of these introductions on both forage and game species.  To compare the effects of stocking on forage abundance at two different population densities of yellow perch.

Abstract

Over 12 million walleye fry were introduced into Lake Burton in 1990 and 1991 to supplement limited natural reproduction in the existing low density population.  One million walleye fry and 41,373 walleye fingerlings, ranging from 50 mm to 179 mm total length (TL), were introduced into Lake Seed from 1990 to 1995 in order to establish a walleye population and fishery.  Fry stockings were not successful in Lake Burton.  Limiting factors implicated in this unsuccessful effort included high latent mortality immediately after stocking due to poor water quality in the hauling media, insufficient food availability shortly after stocking, and predation.  Walleye introductions were moderately successful in Lake Seed.  Survival from all fry and fingerling stockings was documented in fall gill net samples.  The primary factor which hindered stocking success in Lake Seed was two dramatic flood events in 1994 and 1995, which displaced significant numbers of stocked walleye into the neighboring downstream reservoir (Lake Rabun).  As a result,  a moderate-density walleye population and minor fishery was subsequently established in Lake Rabun.
Although survival and recruitment was documented from all walleye stockings into Lake Seed, introductions of small fingerlings (50 mm TL) accounted for a majority of returns in annual fall gill net samples.  As a result of walleye stockings in Lake Seed, a small fishery was established, and successful natural reproduction was documented in 1996.  Spawning activity was observed in the headwaters of Lake Seed located in the Lake Burton tailrace and on main channel points with a rubble-gravel substrate.
In both reservoirs, walleye initially consumed yellow perch almost exclusively.  Illegal introductions of blueback herring into the system, however, altered walleye diet composition during the study period and subsequently thwarted efforts to enhance the yellow perch size structure to a more desirable state for anglers.  As a result of this dietary shift coupled with limited expansion of the walleye population, the total density and biomass of yellow perch experienced negligible changes after walleye stocking.  In addition, the annual length and age distributions of yellow perch remained similar over time.  Annual fluctuations in the survival rate of yellow perch were weakly correlated with walleye catch data.

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