Author Information

Nathan J. CarterFollow

Presentation Type

Poster

Faculty Mentor’s Full Name

Andrew Whiteley

Faculty Mentor’s Department

College of Forestry and Conservation

Abstract / Artist's Statement

Native headwater trout species in Montana are often threatened by introduced fish species. One increasingly common management solution is to install a barrier to prevent the passage of non-native species and apply a piscicide chemical treatment above the barrier. This removes non-native species and allows managers to reintroduce desired populations of native species. The effect of piscicide treatment of co-occurring non-game fishes is not well understood. One such species is the Rocky Mountain sculpin (Cottus bondi). This species appears to be able to survive piscicide treatment, which would likely benefit ecosystem restoration following the treatment. However, we hypothesize that piscicide treatment will induce a drastic decline in abundance (i.e. a population bottleneck) that could negatively affect the persistence of the now isolated populations. We predicted that treated populations would have substantially lower genetic variation than populations immediately downstream from installed barriers consistent with a recent and severe population bottleneck. We examined two sites that were treated, Greenhorn Creek and Sixteenmile Creek, and compared the treated (above barrier) and untreated (below barrier) populations. For each sampled population we estimated genetic variation with a set of microsatellite genetic markers. We then estimated the effective population size (Ne) consistent with the observed loss of genetic variation. We found strong evidence of a genetic bottleneck in the treated areas. In Greenhorn Creek, we found a 10.6% decline in genetic variation corresponding to a Ne estimate between 4.7 and 9.1. In Sixteenmile Creek, we found an even larger decline in genetic variation (37%), corresponding to an Ne estimate between 1.3 and 2.4. These results suggest that Rocky Mountain sculpin above-barrier persistence probability might be low following piscicide treatment and management approaches such as translocations might be warranted.

Category

Life Sciences

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Apr 22nd, 11:00 AM Apr 22nd, 12:00 PM

Do piscicide treatments used to restore trout populations have unintended negative consequences on a non-game native fish species?

UC South Ballroom

Native headwater trout species in Montana are often threatened by introduced fish species. One increasingly common management solution is to install a barrier to prevent the passage of non-native species and apply a piscicide chemical treatment above the barrier. This removes non-native species and allows managers to reintroduce desired populations of native species. The effect of piscicide treatment of co-occurring non-game fishes is not well understood. One such species is the Rocky Mountain sculpin (Cottus bondi). This species appears to be able to survive piscicide treatment, which would likely benefit ecosystem restoration following the treatment. However, we hypothesize that piscicide treatment will induce a drastic decline in abundance (i.e. a population bottleneck) that could negatively affect the persistence of the now isolated populations. We predicted that treated populations would have substantially lower genetic variation than populations immediately downstream from installed barriers consistent with a recent and severe population bottleneck. We examined two sites that were treated, Greenhorn Creek and Sixteenmile Creek, and compared the treated (above barrier) and untreated (below barrier) populations. For each sampled population we estimated genetic variation with a set of microsatellite genetic markers. We then estimated the effective population size (Ne) consistent with the observed loss of genetic variation. We found strong evidence of a genetic bottleneck in the treated areas. In Greenhorn Creek, we found a 10.6% decline in genetic variation corresponding to a Ne estimate between 4.7 and 9.1. In Sixteenmile Creek, we found an even larger decline in genetic variation (37%), corresponding to an Ne estimate between 1.3 and 2.4. These results suggest that Rocky Mountain sculpin above-barrier persistence probability might be low following piscicide treatment and management approaches such as translocations might be warranted.