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. 31 . inches tota1length) adult fish and has been declining noticeably in abundance since the early 1980s. Juvenile white suckers are virtually nonexistent in the population. At the same time, rainbow trout have improved in growth, while stocking rates have not substantially changed. This situation is presumably the result of northern pike predation on the white sucker population. Northern pike and tiger muskie could be expected to compete for the sucker forage base as well as the trout populations, possibly to the detriment of the trout and salmon sportfisheries. Angler surveys last conducted from May 1 to October 1, 1989, projected angler use at 87,131 hours with a CP AH of 0.3. Tiger muskie would provide a new sportfish species to the area, although the presence of northern pike in the reservoir probably fills some demand for a trophy esocid fishery. Northern pike weighing more than 20 lbs. are taken from Williams Fork Reservoir each year. Tiger muskie escapement would probably be similar to the current situation with northern pike. Northern pike appear to escape from the reservoir during the occasional times when it spills. At other times, the only escapement route is through the outlet which is probably too deep for esocid habitat. In 1983, after the reservoir spilled, CDOW crews extensively sampled the Colorado River in the Parshall to Kremmling area looking for northern pike and found none. No pike were sampled after the reservoir spilled again in 1984. Although CDOW crews have not found any pike in the river after these spill events, anglers reported taking two northern pike from the Colorado River near Radium, one from the mouth of the Blue River, and one from the lower part of Muddy Creek during the spill years and shortly afterwards. In 1993, the reservoir spilled and CDOW did find five 8-10 inch northern pike in the Colorado River near Kremmling. The number of northern pike escaping from Williams Fork Reservoir appears to be small, based on angler reports and actual numbers of fish sampled. Also it appears that northern pike survival and reproductive success in the river is poor, otherwise a population that is expanding in numbers and size classes would be expected, as has occurred in the Yampa River. Periodic river sampling has not indicated that northern pike are impacting riverine fish populations, including Wild Trout and Gold Medal fisheries. The potential impact of large numbers of tiger muskie escaping to Colorado River might be significant, especially if they were to concentrate in a particular area. Conversely, the impact of a relatively small number of fish escaping would probably not be noticeable; much like the current situation with northern pike. The nearest endangered fish habitat is in the Colorado . . . . . . . .