Habitat use of larval fishes in a southwestern desert stream

Authors: Norman Mercado-Silva, Scott A. Bonar

Year: 2013 (xlv)

Abstract

Fish conservation in North American desert streams requires knowledge of how each species makes use of habitat throughout its ontogeny. Several studies have focused on determining habitat suitability for adult stages, but fewer have investigated how larval fishes make use of stream habitat. We use data from extensive sampling efforts and microhabitat descriptions to identify habitat characteristics that are related to larval fish presence and abundance in a small desert stream in central Arizona. Larval longfin dace, desert and Sonora suckers, speckled dace, fathead minnow, red shiner, and roundtail chub were found in our collections, but were located in different segments of the creek. Longfin dace comprised 81% of collected individuals. Classification tree models were constructed for all larvae (irrespective of species) and longfin dace. These models identified low water velocity, low average depth and short distance to shore as key variables to explain the presence of larval fishes in general, and larval longfin dace. Regression tree models identified two additional variables, presence of algae and dominant substrate, as important to predict larval fish abundance. We present habitat values that can help predict larval fish presence and abundance.