Journal of the Southeastern Association of Fish and Wildlife Agencies

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.