Reproductive Schedule of the Largescale Stoneroller (Campostoma oligolepis) in North Alabama, USA

Understanding the reproductive patterns and strategies of a species is an important step in establishing the species’ life history. Campostoma oligolepis, the Largescale Stoneroller, is a species that has received little attention in the 90 years since it was first identified, and the work that has been done has been localized in the American Midwest. Collections of C. oligolepis were made monthly from the Flint River in Madison County in northern Alabama, USA, from March, 2014, to September, 2015. A total of 768 fish were collected over the collection period including 492 adults, 268 females and 224 males. We found strong evidence that the peak spawning time for C. oligolepis in the Flint River is March and April. Ovarian maturation, gonadosomatic index for both sexes, and monthly clutch size all support this conclusion. Two unexpected features were found. The first is how few females of mature size were found to carry either oocytes or a clutch except in the peak observed reproductive month of April, 2014. The second unusual feature is the prevalence of asymmetric ovaries, with the left the larger if a difference exists. Campostoma oligolepis may have unusually strong inter-annual responses to abiotic factors such as water temperature and river discharge.