Journal of the Southeastern Association of Fish and Wildlife Agencies

The continued spawning success of striped bass, Roccus saxatilis, within the reservoir during the past three years, in spite of greatly reduced lock operations, is evidence which heavily supports the resident hypothesis. Striped bass feed heavily upon mayfly nymphs during the spring months, but take clupeoid fish almost entirely for the remainder of the year. The results of a three-year creel census ending August 31, 1957, shows that the number of striped bass caught and the percent of the total catch which striped bass represents has approximately doubled for the past two years. The average catch per trip has increased from 1.7 fish to 3.0 fish since 1955. Other data demonstrate a decided change in preference to striped bass fishing from other species by fishermen. An intensive gill net effort between June 5, 1956 and August 6, 1957 took 5,730.4 pounds of fish. Of this total, 60.1 percent was striped bass.

A method is described for sexing striped bass through use of serrated jaw ear forceps. The instrument is used to extract gonads from dead fish in samples of commercial catches, without incurring damage to the fish which affects the market quality. The gonads are examined later in the laboratory and are identified as male or female. The technique has proven satisfactory in large scale sampling of commercial catches. This method also holds promise for use on other species of fish in which sex ratio studies are important.

Seven charges of Nitromon Primer S were exploded at six stations on the Aucilla River. Results of three explosions, each consisting of ten pounds of explosive, at Station No. 1 killed at least 842 shortnose gar, 300 longnose gar and three channel catfish. The successive treatments at this station indicated a reduction of longnose gar in the area. More shortnose gar were destroyed in the third explosion than in the first and second. Variation occurred in the results at other stations. It was noted gar concentrations could be detected by their surfacing activity. At all stations where this activity was noted, large numbers of gar were killed without destroying many fish of other species. At stations where this activity was not noted, frequently, numerous fish of other species were destroyed.

An investigation of the stomach contents of bluegill, black crappie, and redear sunfish was made from specimens collected during several months of 1948, 1949, and 1950, in Lake George, Florida. Major items found in stomachs of 432 large bluegills were: aquatic vegetation, crustacea, insecta, and fish eggs. Fifty-five stomachs from small bluegills contained, principally, Cladocera and Diptera larvae. Dorosoma petenensis vanhyningi (Weed) was the major food organism found in 145 black crappie. An analysis of 69 redear sunfish stomachs showed snails (Amnicola sp.) were the dominant food of this species.

A study of the life history of the black crappie Pomoxis nigromaculatus (LeSueur), from Lakes Eustis and Harris, Florida, was made in 1952 and 1953. A comparison of the age composition of the individual and combined samples of 318 Lake Eustis and 403 Lake Harris black crappie showed a similarity existed between the two populations. The scale reading indicated few crappie reached ttte VIII group or older in Lake Eustis and few reached the VII group or older in Harris. Males and females showed only minor differences in growth. Calculations of growth from scale measurements yielded the following estimates of length at the end of the first eight years of life in Lake Eustis: first-2.0 inches; second-4A inches; third-6.8 inches; fourth-8.3 inches; fifth-9A inches; sixth-10.4 inches; seventh-l1.2 inches; and eighth-l1.7 inches.

Results of four experiments on 5.5-acre Deer Island Lake demonstrated that selective poisoning was a practical method for reducing the gizzard shad population. Past haul seine efforts had effected only a temporary reduction in this lake. A concentration of 0.04 p.p.m. of 5 percent emulsified rotenone killed very few gizzard shad. A 0.1 p.p.m. concentration resulted in a conservatively calculated kill of 4,651 pounds or 846 pounds per surface acre. An application of 0.15 p.p.m. concentration killed larger shad as well as a few bass. A subsequent application of 0.1 p.p.m. concentration produced a large unexplained kill of bass.

Copies of the specialized paper and information available from Information and Education Division, Florida Game and Fresh Water Fish Commission, Tallahassee, Florida upon request.