Reproductive biology of Cyprinella camura, the bluntface shiner, in Morganfork Creek, southwestern Mississippi

Abstract– I collected bluntface shiners, Cyprinella camura , once or twice monthly from February to November 1991 in Morganfork Creek, southwestern Mississippi. Examinations of mean largest oocyte diameter (LOD), female mean relative gonadal index (RGI), ovarian developmental condition, and male secondary sexual characteristics indicated that C. camura spawned from late March through mid-August. There were significant positive correlations between mean LOD and mean daylength, mean maximum temperature, and mean minimum temperature (environmental variable means were calculated for the 28 day period prior to each sampling date). Mean day length and mean RGI were significantly positively correlated, but there was no significant relationship between mean maximum and minimum temperatures and mean RGI. Clutch size, RGI, and mean mature oocyte diameter (MMOD) of mature females were significantly correlated with length (standard length). Mean length, clutch size, and RGI of mature females in individual collections decreased significantly over the reproductive season. The corresponding decrease in mean MMOD was not significant.