Florida has comparatively few species of large predatory freshwater fishes. Many lakes of the state have an abundance of forage fishes. Therefore, niches may be available for additional desirable predatory species. As far as I know, there is no record of walleye (Stizostedion vitreum) occurring naturally as far south as peninsular Florida. People not familiar with walleye may have the mistaken impression they require cold, deep water. If this were so, an attempt to introduce them into Florida would be absurd. However, there is a strong superficial resemblance between many lakes there and warm, shallow Midwestern lakes that have good walleye populations. Because of this resemblance, I decided to see if walleye could survive in Florida. Permission was obtained to use a privately owned, dug pond, about 0.3-acre in size at Vero Beach, Florida (latitude 27 0 39'). Rotenone was applied for a complete kill, but no fish were found. On May 10, 1960, several thousand sac-fry, courtesy of the Iowa State Conservation Commission, were received by air and stocked in the pond. No forage fish were stocked. In succeeding months several unsuccessful attempts were made to recapture some of the fry with nets and an electric shocker. Pond conditions made both gear types inefficient, so rotenone for a complete kill was applied on March 9, 1961, 10 months after stocking. Three walleye, measuring 215, 231, and 240 mm total length were recovered. Their gonads did not show signs of development. The experiment was repeated. Several thousand sac-fry were received on May 17, 1961. The ice had melted in transit, bag water was 24.40 C. and many fry were dead. The fry were stocked immediately; Gambusia were later stocked as forage. Recovery attempts were unsuccessful and rotenone was applied on February 19, 1962, nine months after stocking. Two walleye, 320 and 326 mm total length, were recovered. Both were males and, as can be seen in Figure 1, the testes were nearly mature. The small number recovered each year does not necessarily indicate walleye could not be established in Florida. It may be that most fry died immediately. On the other hand, walleye are cannibalistic. Even in intensively managed rearing ponds, walleye density is normally low in number and/or biomass. Walleye fingerling harvest in Minnesota is reduced to about 10 fish per acre-foot if they are allowed to grow to 115 mm. Minnesota fingerlings between 1953 and 1958 were harvested at a much shorter length. Intensively managed ponds produced an average of 2259 walleye fingerlings per acre-foot, but averaged only 48 mm total length and 2.2 kg per acre-foot (Dobie; 1956, 1959).
