Life-history traits of the bluenose shiner, Pteronotropis welaka (Cypriniformes: Cyprinidae)
Abstract
Life-history aspects and behavioral ecology of the bluenose shiner (Pteronotropis welaka) were investigated from May 1993 to June 1994 in a small tributary of the lower Pearl River in Marion County, MS. Samples were taken monthly or biweekly to provide information about preferred habitat, reproductive biology, and demography. Observations were made during the breeding season to determine spawning strategy. Except during peak spawning periods, bluenose shiners were located in schools of more than 25 individuals in areas of sluggish flow (0-4 cm/sec) near submerged vegetation. Based on gonadal condition, bluenose shiners have a protracted breeding season, lasting from May to August and including two major spawning bouts. Although the spawning act was not observed, aggregations of adults over sunfish nests and the presence of bluenose shiner eggs and fry in nests indicates that this species is a nest associate. Unlike male bluehead shiners (Pteronotropis hubbsi), male bluenose shiners show an increase in gonadal weight and a gradual increase in the development of secondary sexual characteristics with increased length. Length frequency data and the absence of adults from the study site in the fall and winter indicate that adults die after the breeding.