Guide to larval and early juvenile cyprinids of the middle and lower Pecos River (New Mexico and Texas)

Authors: W. Howard Brandenburg, Darrel E. Snyder, Steven P. Platania

Year: 2016 (xlviii)

Abstract

The Pecos River, the largest tributary of the Rio Grande, has a diverse but declining assemblage of native cyprinids, including numerous pelagic-spawning species. Anthropogenic alterations to the river (e.g., flow manipulation, river channelization, non- native introductions, and river fragmentation) have negatively impacted native fish abundance and distribution, which has led to extirpations, range reductions, and federal/state protections. The pelagic-spawners have been among the most adversely affected by the degradation of this riverine ecosystem. Conservation activities and species management of these fishes are limited by significant gaps in knowledge about threats affecting their early life stages. An essential tool being developed for fish biologists is an illustrated identification guide, and accompanying computer-interactive key, which describes the early ontogeny of cyprinids found in the middle and lower Pecos River (New Mexico and Texas). Using over 36 morphometric, 18 meristic, and 49 pigmentation characters, along with a suite of size-to-development relationships, the comprehensive guide (to be completed by December 2017) will provide a foundation for robust species identification of the smallest and most vulnerable life stages. The guide will also help facilitate future research and monitoring of the distribution, abundance, reproductive success, and early recruitment of Pecos River cyprinids, which will further the knowledge of larval fishes and their ecology in the desert Southwest.