Monster Seminar JAM - Conservation Genetics of Delta Smelt (Hypomesus transpacificus): Population Genetics, Hybridization & Captive Population Genetic Management
Dr. Kathleen Fisch, Genomic Variation Laboratory, Department of Animal Science, UC Davis
Delta smelt (Hypomesus transpacificus) are endemic to the San Francisco Estuary. Once abundant, numbers of delta smelt declined dramatically in the early 1980s, and the species has been listed as threatened since 1993. To assess wild delta smelt population genetics and to analyze the genetic signature of the decline, we conducted a population genetic study using sixteen microsatellite DNA markers to assess the geographic and temporal population structure of delta smelt, assessed hybridization between delta smelt and wakasagi and longfin smelt, and genetically monitored the captive delta smelt population. We genetically analyzed samples collected by the California Department of Fish & Game from the 2003, 2005, 2007 & 2009 Spring Kodiak Trawl Survey, consisting of delta smelt collected from fourteen unique geographic locations and from three generations in captivity. For the hybridization study, we genetically analyzed fish using microsatellite markers and sequenced all three species and potential hybrid fish for nuclear and mitochondrial DNA loci. The null hypotheses are as follows: 1. Populations of delta smelt in the San Francisco Estuary do not vary geographically or temporally in genetic diversity and/or population structure, 2. Delta smelt hybridization with longfin smelt and/or wakasagi smelt is not prevalent, and 3. Genetic management of the captive delta smelt population maintains genetic diversity and minimizes mean kinship. The relevance of this study includes the need for dynamic management of delta smelt populations, including hybridization control, as there appears to be an ephemeral population in the Sacramento Deep Water Ship Channel, and low levels of hybridization have been detected. In addition, the genetic management plan has been shown to preserve the genetic diversity and minimize mean kinship in the captive delta smelt population. The results of this study demonstrate the utility of population genetics in prioritizing conservation management of this imperiled species.
Date and Time:
October 14, 2010,
11:00 am - 12:00 pm