SEASONAL VARIATION IN REPRODUCTIVE CONDITION OF THE PECOS BLUNTNOSE SHINER (NOTROPIS SIMUS PECOSENSIS)

Authors: Davenport, Stephen R.*, Archdeacon, Thomas P., Blocker, Sara D., Henderson, Kjetil R.

Year: 2015 (xlvii)

Abstract

Reproductive strategies vary among fishes, and information on reproductive characteristics is important for water managers to protect and recover imperiled species. We describe aspects of the reproductive ecology of Pecos Bluntnose Shiner, Notropis simus pecosensis. Gonadosomatic index, ovarian condition, and counts of mature ova were evaluated to determine the seasonal reproductive timing and duration of Pecos Bluntnose Shiner in the Pecos River, New Mexico. Monthly changes in gonadosomatic index, ovarian stage, and number of mature ova per female suggest Pecos Bluntnose Shiner have a reproductive season extending from April through September, with a peak occurring in June and July. In July, 93% (n = 44) of female Pecos Bluntnose Shiner were in reproductive condition, regardless of size. The highest number of mature ova counted (1,498) was observed in a 59.5 mm (standard length) female from June 2009. Peak spawning activity coincides with water releases from reservoirs with higher peaks and longer duration than natural rainfall events. Results of this study provide important insight on the reproductive biology of a threatened fish and may be useful in long-term conservation planning.