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I I I I I I I I I I I I I I I I I I I traps (1993-1996), or hand-held dip nets (only two collections in 1993), Drift nets were used in the Echo Park (1993) and Escalante (1992-1993) reaches to collect larvae transported downstream from the two known areas of razorback sucker spawning activity. Seines were 1.2 m deep and 3.0 m long with 1.6 mm mesh, and seine and dip-net collections were made during daylight, Each seine haul or dip-net collection (a composite of one or more samples at a restricted place and time) was considered a single unit of effort. Light traps were floating quatrefoil units (commercially manufactured as the Edlite™ by Southern Concepts, Birmingham, Alabama; modified after the original design of Floyd et al. 1984) with 4-mm wide entry slits. Light traps fished at night are effective for capturing positively phototactic fish larvae and early juveniles (Kelso and Rutherford 1996), and quatrefoil units were successful in collecting razorback sucker larvae from Lake Mohave (Mueller et al. 1993). Numbers of light traps deployed overnight in each habitat per collection date generally increased with surface area of the habitat sampled and ranged from 3 to 12. Light traps were usually set near shoreline (often associated with emergent vegetation, woody debris, or rock outcroppings) in late afternoon or early evening and retrieved before sunrise. Effort was length of time each trap was fished between sunset and sunrise, and catch per unit effort (CPUE) was number of fish per 1 h of sampling. Conical drift nets (4 m long, 0.15 m2 mouth opening, and 560 ,urn mesh) were set nearshore just below the water surface in flowing water, typically less than 1 m deep, 0-1 km downstream of the spawning area. Sampling with drift nets usually occurred at dawn or dusk, and three nets were deployed for up to 2 h on each sampling occasion. Effort was length of time each drift net was set, and CPUE was number of fish per 1 h of sampling. Diel sampling with drift nets at 4-h intervals (ca. 1000, 1400, 1800, 2200, 0200, and 0600 hours) was conducted below the Escalante spawning area on 8-9 May, 21-22 May, and 4-5 June in 1992. After 1993, we decided that light trapping was the most effective and logistically efficient method for capturing razorback sucker larvae in the middle Green River, and sampling with drift nets, seines, or dip nets was abandoned. Most fish were preserved in 100% ethanol (1993-1996 samples) or fixed in 10% formalin (1992 samples) immediately after collection for later laboratory processing. Selected sucker larvae captured with light traps in 1993 were reared to 7