Journal of the Southeastern Association of Fish and Wildlife Agencies

Handling techniques for x-raying trapped doe deer are described. Myothesia was used as an anaesthetic at the rate of 1.5 cc. per 5 pounds body weight. A portable x-ray machine with maximum output of 30 MA and 80 KV was used to x-ray eight dead and forty-eight live deer. Pictures were made of yearling deer (12-14 cm. width) at 0.5 second exposure time, 36-inch focal-film distance, 25 milliamps and 65 kilovolts. Machine settings were the same for older deer, except kilovoltage, which increased 2 kilovolts per cm. of deer width. Radiographs indicated that 52 deer contained an average of 0.83 fetus and none of the 23 yearlings were shown to be pregnant. The adult does averaged 1.5 fetuses. Aging of fetal images on the x-ray is discussed. Evidence of prenatal mortality was not found.

Three 160 acre deer enclosures were stocked with 2, 4, and 8 deer respectively. Track counts were made simultaneously on prepared surfaces in the enclosures. It was found that the track counts were not directly proportional to population size. Thus it appears that track counts are not a valid measurement of population size, if a linear relationship through the origin between population size and number of tracks is assumed. The track counts were able to detect that there were differences in population size, but it did not tell us the magnitude of this difference.

A two-year study was made of the nesting ecology of the black duck (Anas rubripes Brewster), the gadwall (Anas strepera Linnaeus), and the blue-winged teal (Anas discors orphna Stewart and Aldrich), at their southern nesting limits along the Atlantic coast. Approximate production at Pea Island was: 1959-black duck 230, gadwall 348, blue-winged teal 105; 1960-black duck 144, gadwall 457, blue-winged teal 97. Production at Bodie Island, estimated only for 1960, was: black duck 111, gadwall 28, and blue-winged teal 48. The major rearing areas were the two man-made fresh-water impoundments on Pea Island (1020 acres of water and marsh) and the brackish pond on Bodie Island (500 acres water and marsh). Estimated juvenile mortalities were: black duck 31%, gadwall 48%, and blue-winged teal 23%. Major predators were feral cats (Felis domesticus) and snapping turtles (Chelydra serpentina).

During 1961 adult female wood ducks (Aix sponsa) were removed from nest boxes on three ponds near Raleigh and banded with U. S. Fish and Wildlife Service leg bands. During the 1962 nesting season ducks were again removed from nests for banding and a large percentage of them were found to be ducks returning from the previous year. An analysis of the first two years of the banding study revealed that (1) no nests were deserted as a result of banding during late incubation, (2) survival of adults as measured by the return of nesting birds was 47%, (3) there was a high rate (70%) of return of birds to individual boxes in which they had previously nested, and (4) some females produced two successful broods in a single season.

The food contents of 326 gizzards from 15 species of waterfowl collected on Currituck Sound between 1947 and 1952 were analyzed in detail by the aggregate percentage method. The collection period was a time of generally low and fluctuating waterfowl populations on the Sound. Per cent frequency and per cent volume results are presented for 122 diving ducks (six species), 75 ruddy ducks, 97 dabbling ducks (six species), 17 Canada geese, and 15 coots, both in groups and by species. Plant foods composed 97% of the total. Potamogeton, Ruppia, and Najas were the overwhelmingly important foods for all groups, totaling about 80% by volume for the entire sample (72% identified and probably most of the 11% unidentified vegetative material). Nevertheless, the 7 commonest species--canvasback, redhead, ruddy duck, American widgeon, black duck, pintail, and green-winged teal--each showed distinctive individual differences in types and percentages of foods taken.

Of 162 female striped bass treated with hormones during the 1962 spawning season, 44 (27.2%) were induced to ovulate. Of several preparations used, chorionic gonadotropin proved to be very effective while follicle stimulating hormone was slightly effective. Of 36 million striped bass eggs put into the hatchery only 7.3 percent hatched. The cause of mortality is 1argely unknown.

Lake Shelby, an 829-acre natural lake, located in Baldwin County at Gulf Shores, Alabama was treated with emulsifiable rotenone in October, 1956 to eliminate an undesirable fish population. The lake was restocked with the bluegill sunfish, Lepomis macrochirus; the redear sunfish, Lepomis microlophus; and the largemouth bass, Micropterus salmoides. Subsequent population examinations following restocking revealed in 1958 that a copepod was infesting the gills of the fish. Collection of specimens and identification revealed the copepod to be Ergasilus lizae Krøyer previously reported only from marine hosts. A description and history of Lake Shelby is given. The taxonomy and morphology and observations on the life cycle of Ergasilus lizae are also presented.

Bioassays were conducted with Aqualin, a herbicide manufactured by the Shell Chemical Company, to investigate its possibilities in collecting fishes from lotic waters as well as to determine its relativity to toxicity to five species of fishes. A narrow range of toxicity was found between the largemouth bass, b1uegill, bowfin, mosquitofish, and the fathead minnow. The 24-hour TLm (median tolerance limit) values ranged from 0.062 to 0.183 ppm at 71 º F. Bowfin were the most sensitive fish tested. Aqualin was found to be less toxic than rotenone in short exposures; however, a lethal dose of either was required to effectively repel fishes. It was concluded that there is a narrow range of susceptibility between different species of fishes to Aqualin and that, in no case, was it sufficiently wide to indicate any promise for collecting fishes in lotic waters.

During the period 1960-1962 a state-wide fish tagging program employing substantial rewards to sport fishermen for tag returns was conducted in Florida. A total of 19,470 fish including 5,328 largemouth bass were captured, tagged, and released. There were 24.2 percent of the tagged bass, 4.5 percent of the bluegill, 3.8 percent of the shellcracker, and 8.9 percent of the crappie returned. Little difference in returns was noted between fish which were transported prior to release and those which were released into the waters from which they were captured.

The chemical and physical properties and phytocidal activity of diquat (1:1'-ethylene- 2 :2'-bipyridylium cation) and paraquat (1 :l'-dimethyl-4 :4'-bipyridylium cation) are discussed. Data are presented on the evaluation of herbicidal activity of the various salts of these 2 chemicals under controlled laboratory conditions, in plastic pools, and in earthen ponds. Research indicates that a majority of common submersed and many emergent aquatic weeds may be killed by concentrations of 0.2 to 0.5 ppm cation of these 2 chemicals. Fish toxicity studies indicate a threshold toxic concentration for diquat in excess of 10 ppm cation, and for paraquat in excess of 5 ppm cation. Two new quaternary bipyridyl chemicals, diquat and paraquat, have been subjected to extensive aquatic herbicide evaluation tests for the past 3 years. These tests have been conducted in the laboratory, in plastic pools, and to a limited extent in ponds, lakes, and drainage canals.

The Florida Game and Fresh Water Fish Commission's Fishery Division obtained 3,000 Tilapia nilotica fingerlings from Auburn University on August 30, 1961. These were used as brood fish and were stocked in a 3-acre naturally fertile mined-out phosphate pit in Central Florida at the rate of 1,000 per acre. From time of stocking until May, 1962, there was an estimated 7 inches of growth. During the latter part of May this pond appeared to go into an overcrowded condition. Twelve ponds totaling 65 acres have been stocked with tilapia from the brood pond. Stocking rates have varied from 2 adults to 1,000 fingerlings per acre. Minimum water temperature at the blood pit last winter was 53 º F. Apparently no mortality occurred from this cold. It was estimated that 1,810 pounds of tilapia were produced per acre in the brood pit during a 369 day period. The fish were not fed and the pond was not fertilized.

Two boat-mounted machines for applying herbicides or other similar materials to small ponds are described. A dry materials spreader was assembled from three lawn-type fertilizer spreaders. Powered by a small air-cooled gasoline engine the spreader operated effectively to uniformly distribute granular herbicides, lime or similar materials. Distribution of granular material at rates ranging from 100-1,000 Ibs. per acre was possible. A boat-mounted spray rig employing a 15-foot boom eliminated the need for a two-man crew for treating small ponds with liquid materials. The spraying operation could be controlled by the boat operator once the spray tank has been filled and the sprayer was started. Both of the machines can be assembled from commercially available parts by a good mechanic in a relatively short period of time.

The De1ury Method was used to estimate the number of channel catfish in three ponds of different years from the catch records of 20,790 anglers at the Farm Pond Project, Auburn, Alabama. The ponds were drained, and the accuracy of the estimates was determined. Estimates for each pond were made using the average number of channel catfish caught per angler per hour at intervals of: 1 day, 500 angling hours, 800 angling hours, 1,000 angling hours, and one week. The error of these estimates varied between 0.0 and 10.3 percent from the theoretical true number (the total cumulative catch plus the number recovered upon draining). Estimates obtained using the average catch per unit of effort for the different intervals of effort were not significantly different. The assumptions of the Delury Method were investigated.