Conservation genetic status of Gila trout

Authors: Thomas F. Turner, Maureen B. Peters, Wade D. Wilson

Year: 2008 (xl)

Abstract

Gila trout occur in semi-isolated populations in the Gila River basin of New Mexico and Arizona. This species has been actively managed for over four decades to prevent extinction from catastrophic events and hybridization from non-native trout species. Here, we present data from mitochondrial (mt) DNA, microsatellites, and non-neutral genetic markers (MHC class II) to evaluate relationships between extant lineages of Gila trout. Of these, Main Diamond and South Diamond lineages are most closely related, followed by Whiskey and the most distantly related Spruce Creek lineage. Phylogenetic analysis of mtDNA-ND4 indicated that Gila and Apache trout form monophyletic group with respect to rainbow trout and Mexican trout. Management actions have successfully maintained the genetic integrity of Gila trout lineages. We discuss the implications of a potential trade off in managing for genetic integrity versus management for genetic diversity within lineages. Future research will attempt to evaluate demographic and genetic connectedness of Gila trout introduced into the newly renovated West Fork of the Gila River in an attempt to make recommendations about maintenance of within-lineage diversity.