Broodstock Density Mediates Larval Production of Captive-Spawned Loach Minnow and Spikedace

Authors: Kristopher Stahr, Joshua Walters, Hannah Smith

Year: 2018

Abstract

Loach Minnow, Tiaroga cobitis, and Spikedace, Meda fulgida, are two endangered fishes endemic to the Gila River Basin of Arizona and New Mexico. Habitat degradation and the introduction of non-native fishes have resulted in population declines, and as such captive propagation is an important facet for continued recovery. However little information exists on the spawning of these fishes, both in the wild and in captivity. Therefore the goal of this study was to determine whether a relationship existed between broodstock density and larval production to guide future propagation efforts. Three different broodstock densities (low, medium, and high) were used for both Loach Minnow and Spikedace. Both species were spawned in linear raceways (1m × 1m × 4.5m) with each tank receiving separate artesian water flow and programmable recirculation pump to mimic natural conditions. Each spawning tank was prepared identically, respective for each species. We found that lower broodstock densities resulted in the highest larval fish production per raceway for both species. However, future replicates are needed to confirm these results, and thus experiments will continue for at least one additional year.