Translocation Causes Extinction of a Local Population of the Freshwater Shrimp Paratya australiensis

Abstract

In 1993, as part of another study, we translocated freshwater shrimp ( Paratya australiensis ) between pools from two different subcatchments within the same drainage system in southeast Queensland, Australia. Subsequent analysis of the mitochondrial COI locus revealed that populations in the two subcatchments represented monophyletic lineages that were 6% divergent. Thus, we decided to determine the effects of the translocation on resident populations. After only 7 years, representing seven generations, the resident genotype was extinct at one of the sites. Evidence from analysis of nuclear genes ( allozymes ) and mitochondrial genes ( COI ) suggests that this extreme result may be explained by a mating preference of all females ( resident and translocated ) for translocated males and a low viability of crosses between resident females and translocated males. There is no obvious morphological or behavioral reason for a mating preference. The results of our study provide evidence that deliberate translocations and interbasin water transfers should be treated with caution.