Some Aspects of the Life History of the Black Bullhead, Ictalurus melas (Pisces: Ictaluridae), from an Oxbow Pond in Southwestern West Virginia

Several aspects of the life history, with emphasis on age and growth, of the black bullhead Ictalurus melas from an oxbow pond of Twelvepole Creek, Wayne County, West Virginia were studied. These ictalurids were aged by counting annular rings of pectoral spine cross-sections and vertebra centra. Annular radii of spines and vertebrae were determined with a traveling microscope. Statistical comparisons (95% confidence level) of the two methods of aging indicated no significant differences occurred. Linear relationships were expressed between spine and vertebral radii with total length. Radial measurements correlated highly with total length and with age High variability was seen in ranges of lengths and annular radii among different age classes. Backcalculated growth shows the highest growth to occur in the first age class. A gradual decline in incremental growth with age occurs to age class IV, then an increase in the amount of growth for age classes v VI, and VII is seen. Stunted growth, probably due to overcrowding, is exhibited by this population of black bullheads. Female and male black bullheads exhibited no significant differences in condition factors, however, the K values generally were slightly higher for the females. Condition factors of the oxbow black bullheads were considerably lower in comparison to other studies. The highest K values occurred in spring, summer, and in age classes III and IV. The oxbow bullhead was found to be primarily a planktivore through out its life history in all seasons. Dipteran larvae were a second choice of food, probably due to availability. The black bullhead does very little feeding in the winter. No predation on the bullhead was observed in this study. Spawning was estimated to occur around the first part of June in water temperatures of 20-22 c. Schooling young-of-the-year were collected June 20, 1980. Thefemale-male ratio of the oxbow bullhead was 1:1. The leech Myzobdella lugubris was found attached to the fins of several black bullheads. This is the first report of this ectoparasite occurring in West Virginia