Reproduction by June Sucker in a Refuge Population: Successful Spawning in a Lake Habitat

Abstract

Abstract The June sucker (Chasmistes liorus) is an endangered lake sucker endemic to Utah Lake, Utah. As part of recovery actions, June suckers were introduced into Red Butte Reservoir, Utah, as a wild grow-out site. Since their introduction, June suckers have successfully reproduced in Red Butte Reservoir, producing a large population in this refuge. I used passive egg collectors (egg traps and nets) and observational surveys to determine the location of spawning sites within the reservoir, and larval light trapping to determine successful recruitment (i.e., egg survival through larval swim-up) at these sites. Eggs were collected between 18 June and 15 July at 2 general sites along or near the reservoir's dam, although spawning was only observed at 1 of these sites. Suckers were not observed at, and eggs were not collected in or around, the mouth of Red Butte Creek as expected. At the site where spawning was observed, suckers were spawning over gravel substrates (mean diameter = 32 mm) at depths of 0.5–1...