Meeting Abstract

113-7   14:45 - 15:00  Quantifying the evolutionary potential for Delta Smelt persistence in a warming habitat Griffiths, JS*; Mulvaney, W; Finger, A; Davis, B; Hung, T-C; Fangue, N; Whitehead, A; University of California, Davis; University of California, Davis; University of California, Davis; Department of Fish and Wildlife; University of California, Davis; University of California, Davis; University of California, Davis joanna.griffiths4@gmail.com

Long-term persistence of the endangered Delta Smelt (Hypomesus transpacificus) will depend, in part, on whether the species harbors the genetic variation necessary to adapt to changing environmental conditions such as warm temperatures. Temperatures in the San Francisco Bay-Delta are increasing and extreme temperature spikes are becoming more common. The availability of additive genetic variation for traits that affect fitness directly determines the ability to evolve; however, nothing is currently known about the presence of genetic variation for resistance to elevated temperature in Delta Smelt. We performed a quantitative genetics experiment to test whether Delta Smelt harbor the necessary genetic variation for adaptation to elevated temperatures. We established crosses between wild and hatchery-reared (domesticated) fish and raised siblings from each family in both an optimal temperature (15 ?) and an elevated temperature (18 ?). We estimated thermal tolerance and genotyped 1,000 fish raised in these two thermal environments. Genetic variation for thermal tolerance indicated that the species has little capacity to evolve adaptations to warming temperatures in the Delta. Our experiments also show no differences in thermal tolerance abilities between domesticated and wild fish. Together, this information can be used to manage the refuge population and inform supplementation by maintaining genetic variation that may be crucial for resilience in a changing Delta.