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14 <br />PREDATION ON LARVAE <br />Predation by introduced fishes has been targeted as potentially <br />responsible for lack of recruitment to the adult razorback sucker <br />population in Lake Mohave (Bozek et al. 1984, Minckley 1983, Langhorst <br />et al. 1985). Preliminary data lack quantification, but clearly indi- <br />cate that predation does occur (Langhorst et al. 1985). We endeavored <br />to examine this factor in greater detail. <br />Potential predatory fishes were captured in areas of known abundance <br />of larval suckers. We were particularly interested in smaller <br />Centrarchidae (green sunfish, and bluegill), rainbow trout, and thread- <br />fin shad since these species were most common in nearshore habitats <br />occupied by larval suckers. <br />Lake Mohave <br />Fish were taken by experimental gill nets.(10 m x 1.8 m, 5 panels <br />ranging in bar mesh size from 6.4 to 38.1 mm) set over night (generally <br />12 hrs) from February through March in Hammerhead Cove. Stomachs of 81 <br />fish were examined (Table 5) and razorback sucker larvae were only <br />identified from stomachs of green sunfish. Frequency of occurrence was <br />low (2.7%) as was average number of larvae per predator (2.0), data <br />which provide little evidence for consumption of significant numbers of <br />larvae. However, it is possible that larvae were eaten in greater <br />numbers, but were undetectable in stomachs since digestion could have <br />continued for up to 12 hours after predators entangled in nets or could <br />have been regurgitated. We investigated the importance of this factor. <br />Green sunfish (mean 91 mm, range 77-119 mm TL) were captured from <br />Hammerhead Cove and a single individual placed in each of 4-4 L glass