Ongoing Aquatic Research Projects

in

Rocky Mountain National Park

Managing the fishery of the Park is a difficult task, but the dedicated group of people at the Park Service do a great job of it.

We were involved with the Greenback Restoration project that the Park Service and Fish & Wildlife Service were working on in 2006, but that project has been tabled until some genetic studies can be completed.

Apparently, the greenback cutthroats we have scattered throughout the Park may not be all pure-strain greenbacks.

This photo, which I took at Thunder Lake is a good example.  While it looks like a greenback, it could very well have rainbow trout genes as well.  Rainbows and cutthroats spawn at the same time and they will cross-breed.  The outcome is called a cutt-bow, and since Thunder Lake has a good population of rainbows in the past, it is possible, even likely, that this fish is not pure-strain.

New developments in DNA research indicate that much of the population of greenbacks in the Park have cross-bred with other trout species, and until a source of pure-strain greenbacks can be found no further restocking action will take place.

Here's some other information from Park biologists:

1) Drought conditions promote recruitment in high elevation wild cutthroat trout populations - To investigate the relationship between summer stream temperature and recruitment in native cutthroat trout populations in high  elevation streams in the Southern Rocky Mountain Eco-region using existing climate, stream temperature, and fish population data sets. (No lake sampling. This project uses existing data.)                                

2) Native Trout of North America - This was completed last year. This was just a collection in order to add western trout to a university collection back east. 

3) Using DNA from museum specimens to explore the heritage and native range of Colorado’s state fish - The purpose of proposed research is to use genetic information from museum samples collected in the late 1800s and early 1900s as a basis for evaluating the native range and diversity of Colorado's cutthroat.      

4) The Influence of Fish Stocking on Food Webs in Lakes of Rocky Mountain  National Park - The purpose of the proposed research is to investigate the  differences in community composition and food web structure between lakes with and without fish. This proposed research will be conducted on a set of lakes in Rocky Mountain National Park (Wild Basin, East Inlet watershed, Glacier Gorge watershed ), and will include sampling of phytoplankton, zooplankton, benthic algae (periphyton), and benthic invertebrates.

To test the effects of fish introductions on export to downstream ecosystems, inlets and outlets of the study lakes also will be  sampled. Non-native fish will be sampled by hook and line, and tissue will  be collected for analysis of stable isotope ratios; if any native fish are caught by hook and line, they will be released without collection of tissue samples. Tissue samples of greenback cutthroat trout may be obtained under the direct supervision of the US Fish and Wildlife Service, from fish they have collected. Density of fish populations will be estimated by sonar and by surveys with an underwater video camera.

Analyses of population data and stable isotope ratios will be used to quantify the differences in community composition and trophic relationships between lakes with and without fish. (This is the most intensive fisheries study going on right now. Researcher McCutchan has contacted some of the concessionaires about his  schedule).     

5) Chris Kennedy is always out and about assisting with park fisheries management. He is also involved in any research related to greenbacks(he is the only non-park person approved to take greenback samples in the Park).