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10 Ecology of Bonytail and Razorback Sucker ever, this collection technique is still being used in lieu of a more effective method. Trammel netting has been the preferred method to capture bony tail in reservoirs for nearly three decades (Minck- ley and Thorson, 2002, 2003, 2004) (fig. 9). Annual surveys are typically conducted in the spring when fish are suspected to spawn. Trammel nets are typically set at dusk and checked every 2 hours to remove entangled fish. Unfortunately, sampling coincides with the spawning of several other species, including common carp. In the Lake Mohave surveys, several hundred common carp are captured for each bony tail taken (Minckley and Thorson, 2002, 2003, 2004) (fig. 9). Trammel nets are also effective in streams when fished in backwater or along eddy lines where there is a stark contrast in currents. Here bony tail are often captured near the surface, close to shore, especially near areas where fish have access to large submerged rock talus (Paul Badame, UDNR, oral commun., 2005). We have tried other methods of capture, such as large cyclical fish traps, square traps, hoop nets with wings and leads, and electrofishing (table 3). Hoop nets set in the current have proven very effective for other Gila spp. (Douglas and Marsh, 1996), but based on our low catch rates (appears bony tail easily avoid and/or escape traps set in stand- ing water. Fig. 9. Trammel nets are the standard method of capturing bony- tail in Lake Mohave. Arizona State University has been conducting annual "bonytail roundups" for more than three decades. Shown here are Paul Marsh Oeftl and his crew inspecting a carp-laden net for bonytail. Razorback Sucker Larvae Larvae are phototactic and readily captured with lights and small dip nets. w.L. Minckley developed the technique of sitting on a bucket placed upside down in the shallows and attracting larvae with a spotlight. The technique has been improved using underwater halogen lights suspended over the side of a boat which is beached near a spawning area (figs. I 0 Table 3. Capture rates of minnow traps, hoop nets, box traps, tyke nets, trammel nets, and electrofishing used to capture bonytail at Cibola High Levee Pond from 2001 through 2004. Technique Effort (hI Bonytail Bonytail (hI Crayfish' Tadpoles' Minnow 286 115 0.4 251 421 trap Hoop net 366 III 0.3 0 0 Box trap 384 II <0.1 19 15 Fyke net 642 49 <0.1 13 75 Trammel 214 1,174 5.5 0 0 net Electro- 4.6 460 100.0 0 0 fishing 'Includes only partial counts. Initially these organisms were not counted. and II). Often prevailing winds concentrate larvae along shore, making them easier to collect. Under ideal conditions, volunteers have dip netted> I 0,000 larvae in one evening. More than 500,000 sucker larvae have been individually dip netted by Native Fish Work Group (NFWG) volunteers from Lake Mohave during the past decade (Tom Burke, Bureau of Reclamation, oral commun., 2004). Collected larvae are transported to Willow Beach NFH where they are raised to 35 cm before being reintroduced into the reservoir. Larvae can also be captured using light traps (Muth and Haynes, 1984; Mueller and others, 1993; Snyder and Meismer, 1997) (fig. II). Studies conducted in both riverine and reservoir settings have successfully captured larvae using light traps set near or downstream of spawning areas. Mueller and others (1993) examined capture rates using bait and three different light intensities. Traps baited with dog food yielded only <0.06 larvae/hour. Traps illuminated with cyalume sticks produced <0.2 larvae/hour compared to nearly 29.8 larvae/ hour for traps equipped with 12-watt (12 vdc) lights. However, in-trap larval predation by odonates and small fishes proved to be a problem, which became more evident as waters warmed and organisms became more active. Larger fish, especially centrachids, often position themselves at the trap's entrance and intercept unsuspecting larvae as they approach (Horn and others, 1994; Mueller and others, 200 I). Larger Razorback Suckers One of the most bizarre tales of collecting these fish came from a local resident. George Utley reported taking 147 razorback suckers in an hour using a hand axe and .22-caliber rifle in Imperial Valley (Odens, 1989). Razorback sucker have rarely been captured by recreational anglers due to their planktonic diet but they are quite vulnerable to electrofishing, seines, and passive netting such as gill nets, trammel nets, hoop nets and fyke nets. They are most vulnerable when they congregate in the shallows to spawn. Electrofishing is the preferred method to sample streams (Muth, 1995) and has proved to be the most effective at