Title

DO GROWTH RATES IN SNAKE RIVER CUTTHROAT TROUT AND CUTTHOAT TROUT X RAINBOW TROUT HYBRIDS DIFFER?

Presenter Information

Taylor M. Wilcox

Presentation Type

Poster

Abstract

Historically, non-native rainbow trout (Oncorhynchus mykiss; RT) have been stocked into waters across the western United States, leading to interbreeding with native cutthroat trout (Oncorhynchus clarkii; CT). Hybridization is a well-established conservation threat to CT persistence, but we have yet to fully understand its ecological and evolutionary consequences. One important vital rate in fishes is growth rate because it is related to survival and fecundity. The purpose of this study is to examine if growth rates differ between Snake River cutthroat trout and Snake River cutthroat x RT hybrids in the Gros Ventre River, WY. I have two alternative hypotheses. First, CT may have higher growth rates. One field study has demonstrated that hybrids are less fit than pure westslope cutthroat trout individuals. Second, hybrids have a higher growth rate. Performance studies have shown hybrids have greater swimming capabilities than CT, and that RT had a higher growth potential than CT. In 2007, fish scales and tissue samples for genetic analyses were collected. We have identified the extent of hybridization for these individuals through the presence of RT versus CT alleles at 14CHECK diagnostic microsatellite loci. I am using fish scales to estimate growth rates in approximately 50 fish from one population that ranges from pure cutthroat to first generation hybrids. Each year fish scales lay down an annulus ring, the distance between these annuli are proportional to fish growth rates. I am measuring distances between these annuli and back-calculating growth rates.

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Apr 15th, 3:00 PM Apr 15th, 4:00 PM

DO GROWTH RATES IN SNAKE RIVER CUTTHROAT TROUT AND CUTTHOAT TROUT X RAINBOW TROUT HYBRIDS DIFFER?

UC South Ballroom

Historically, non-native rainbow trout (Oncorhynchus mykiss; RT) have been stocked into waters across the western United States, leading to interbreeding with native cutthroat trout (Oncorhynchus clarkii; CT). Hybridization is a well-established conservation threat to CT persistence, but we have yet to fully understand its ecological and evolutionary consequences. One important vital rate in fishes is growth rate because it is related to survival and fecundity. The purpose of this study is to examine if growth rates differ between Snake River cutthroat trout and Snake River cutthroat x RT hybrids in the Gros Ventre River, WY. I have two alternative hypotheses. First, CT may have higher growth rates. One field study has demonstrated that hybrids are less fit than pure westslope cutthroat trout individuals. Second, hybrids have a higher growth rate. Performance studies have shown hybrids have greater swimming capabilities than CT, and that RT had a higher growth potential than CT. In 2007, fish scales and tissue samples for genetic analyses were collected. We have identified the extent of hybridization for these individuals through the presence of RT versus CT alleles at 14CHECK diagnostic microsatellite loci. I am using fish scales to estimate growth rates in approximately 50 fish from one population that ranges from pure cutthroat to first generation hybrids. Each year fish scales lay down an annulus ring, the distance between these annuli are proportional to fish growth rates. I am measuring distances between these annuli and back-calculating growth rates.