A Summary Of Findings On The Nematode, Goezia Sp. In The Southeastern United States

Goezia was first detected in North America at Lake Hollingsworth in Central Florida during June, 1969 (Ware, 1970). A recently introduced population of striped bass, Morone saxatilis, was found to be infected by the nematode. The following year, three additional populations of striped bass were parasitized, located in Lakes Bentley, Parker, and Hunter in the same general area of Florida. The introduction of this parasite into Florida was at first believed to be related to the striped bass stocking program (Gaines and Rogers, 1971). Goezia was reported as a marine nematode and the young stripers had been fed a diet of marine herring during hatchery culture. A similar means of infection had been reported in France (Dollfus, 1935). Later investigations, however, found the worm to be wide-spread in Central Florida and it was apparently endemic to certain watersheds connected with marine environs. The lakes and streams of the St. John River System, which drains to the Atlantic, and the Peace and Hillsborough watersheds of the Gulf Coast were all verified positive for Goezia. Conversely, some landlocked lakes in the same area were negative. A portion of these waters that were positive for worms had never received striped bass. Plus, two of the introduced striper populations were found to be parasite-free, Lakes Talquin and Julianna. Additional fishes diagnosed as positive hosts were largemouth bass, Micropterus salmoides, black crappie, Pomoxis nigromaculatus, redear sunfish, Lepomis microlaphus, brown bullhead, Ictalurus nebulosus, and Tilapia aurea. Fish kills associated with Goezia infections have been limited to the two reported populations of striped bass (Ware, 1970): (I) An estimated 90% kill in Lake Hollingsworth in 1969, and (2) an approximate 90% kill in Lake Hunter during 1970. In both cases, mortality was related to the presence of Goezia under stress conditions created by a low food supply. Following the kill in Lake Hunter, striped bass were reintroduced but at a much lower stocking rate. Although these fish became parasitized, they survived in good numbers as have fish from subsequent stockings. In this respect, a comparison between the physical condition, K (Hile), of an infected striper population (Lake Hunter) and a parasite-free population (Lake J ulianna) found the condition of infected fish to be significantly higher (Student's t =4.65) at the 0.0 I level (df=180). Lake Hunter mean K was 2.06, while the J ulianna mean K was 1.96. There was no significant difference in growth rates between populations (Ware, 1972). The better condition of infected fish was attributed to the greater abundance offood (shad) in Lake Hunter.

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