CLAM SIPHON TIP NIPPING BY FISHES IN THE ESTUARINE CAPE-FEAR RIVER, NORTH-CAROLINA

Over two million fishes within 57 families and 173 species were collec ted between 1973 and 1978 in the Cape Fear River, North Carolina. Samp ling consisted of repetitive six-year, 22 station gill net (2,362 sets ) and otter trawl (8,284 tows) efforts. Stomachs of 82 species contain ed fishes. Diets of 14 species representing nine fish families were fo und to include clam siphon tips, primarily Mercenaria mercenaria. The 14 species comprised 39.7% of the total catch (798,607), and examining 21,732 stomachs found siphon nipping had occurred 453 times by 889 in dividuals (4.1%). Nipping was most intense in 1976 and 1977, years whe n river water temperatures were historically lowest, and shoal areas w ere subjected to large expanses of ice flows. Sampling daily, weekly, and monthly revealed that clam populations were patchy. Most ''nipping '' fishes were less than 126 mm in standard length ((x) over bar = 90 mm SL). Most siphon tip feeding fishes were caught in September, Augus t, and October, and least in December. Nipping behavior was dominated by croakers, hogchokers, southern kingfish, spot, pinfish, and fringed flounders.