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Seines were hung with double weighted lead lines so they would • stay on the bottom in all anticipated water velocities. Catch per effort was determined by dividing the number of fish captured in a given area by the area (square meters) sampled. Several boat sizes were used but the unit that was the best adapted to general river use was a 16-foot (4.9-meter) flat-bottom boat powered. with a 25-horsepower outboard. White water river reaches were traversed with 18-foot (5.5-meter) rubber rafts. Special Investigations Abundance and distribution of young Colorado squawfish The Vernal field office initiated a special investigation in the late summer-early fall of 1979 to obtain information about early life history of Colorado squawfish. Directed toward "filling in" needed information not obtained by the standardized sampling program, this special effort was designed to evaluate the distribution and abundance of (young-of-the-year) Colorado squawfish. Collections were made from RM 363 (kilometer 581) at the upstream end of Dinosaur National Monument and extended to RM 22 (kilometer 35.2) near the confluence of the Green and Colorado Rivers. Due to limited manpower, a knowledge of young squawfish behavior • (based on field work and information from others) was applied in devel- oping a sampling program. In 1979, all backwaters encountered were sampled. In 1980, a limited sampling of shoreline habitat near the sampled backwaters was added and the number of backwater/shoreline habitats sampled was restricted to approximately one location per 2 miles (3.2 kilometers) of river. After sampling the first backwater no more samples were taken for 2 river miles (3.2 kilometers), then the next backwater encountered was sampled and so forth. In addition, seine hauls were made in shoreline habitats near the mouth of each sampled back- water. Collections in 1979 were made with 1/4- (0.6-centimeter) and 1/8-inch (0.3-centimeter) mesh seines. However, little was gained at the expense of extra effort; therefore, in 1980, only 1/4-inch (0.6-centimeter) mesh seines were used as a standardized collection tool. Data obtained from these collections were recorded in the same manner as in the standardized program. In 1981, additional changes were made in the sampling design in order to make this investigation more compatible with work in progress by the Colorado Division of Wildlife. Larval fish collections were made in addition to collections for the larger (30 to 70 millimeters) young Colorado squawfish. The larval collections were made as follows: 1. At the top of each stratum, each team proceeded downstream 5 miles • (8 kilometers) and initiated sampling at that location. All required habitats were sampled with a larval seine (about 0.2-centimeter mesh) in the first initial 0.5-mile (0.8-kilometer) reach. If all habitats were not available in the initial 0.5-mile 13