9470 - Laserfiche WebLink

Home Browse Search

with alcohol preservation, 15-25 cm is an ideal size range, but larger fish were frozen, although the more large fish we froze, the more dry ice we needed and the less space we had in the cooler(s) for additional collections. 3 . We attempted to collect between 15 and 30 fish per population. If the population numbers seemed very low we collected fewer than our goal, as we are able to obtain data from a sample size of 10-12. As a general rule, if fish cannot be collected from a population and mostly fm clips are taken, it is still useful to have some whole specimen vouchers archived in the museum for future study. For this, about 12 fish per population is adequate. 4. We killed the fish by overdosing them with MS222. 5. We wrapped several fish in a plastic bag and put them immediately on the dry ice. To keep the fish from freezing together we placed one fish in the bottom of the bag, rolled the bag around it, then added a second fish to the bag, etc. Fish placed next to dry ice tend to freeze on one side only, so we periodically checked and rotated the fish to make sure they were completely frozen. This was especially a concern with large fish. Dry ice was kept on top of the fish since it freezes material beneath it better than it does material above it. 6. We prepared labels and enclosed one with each bag of specimens, and placed the entire sample (all specimens) into a single bag and labeled the outside of that bag as well. The labels included the following information. Collector(s): Date: Stream: County: State: Drainage: Number of specimens: Field Sampling Notes We sampled or obtained samples from 27 locations in western Colorado (Figure 1). These excursions took place mainly during 2001, although several agencies provided us with samples collected at other times as well. These 27 stations were assigned site codes (Table 1) to aid in data manipulation and presentation after analysis. Below are field notes for the sampling trips. Trip 1 We began collecting trips to Colorado on August 1,2001. The field crew on the first trip includedM. McKell, J. Kauwe, C. Young, andE. McLaughlin. The first stream selected appeared on the map as a major tributary to the Yampa, the Little Snake River. We chose a site on BLM land at County Road 26, Moffat County. The river at this site, however, was shallow with a sand and gravel substrate. We observed numerous small fish in the shallow, extensive 4