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f: COMMUNICATIONS 199 TABLE I.-Growth and survival of razorback suckert fed five commercial fry diets from 5 to 45 d posthatch (three replicates of 40 fish for each diet). Means within a column followed by the same letter are not significantly different (analysis of variance, P > 0.05). Diet A verageb Mean (SO) survival, 'lb 59.2 (5.2) y 31.7 (12.3) z 20.0 (2.5) z 78.3 (12.6) 1I 78.3 (5.8) 1I 5.0 AP-lOO A-250 4200 LlV B-250 Pooled SEC Mean (SO) fish weight," g 0.036 (0.004) yz 0.092 (0.014) 1I 0.066 (0.030) lIY 0.026 (0.016) z 0.031 (0.018) yz 0.011 Total length, mm 16.5 22.5 19.5 15.2 17.9 Range 13-23" 18-27 16-23 11-20 13-25 "Initial average weight, 0.005 g. b Average of largest and smallest fish from each of three replicates. C Pooled SE - (error mean squarcl3 replicates per treatment)!h. survival; r == 0.44, P == 0.10 for growth) indicated that particle size alone did not explain observed differences. Although wet particle size may have influenced results, we presume that differences in growth and survival reflected differences in food palatability and nutritional needs of the tish. This study demonstrated that razorback sucker larvae can be successfully reared with commer- cially available diets as first foods. Additional study is needed to more fully evaluate the performance of these or similar diets. Effects offood palatabil- ity, wet panicle size, and other factors on growth and nutrition should also be evaluated. Until more definitive work is done, we recommend diets pro- ducing maximum survival (LIV or B-250) as tirst foods for razorback sucker larvae. Acknowledgments This study was supponed in part by funds from the Bureau of Reclamation and the U.S. Fish and Wildlife Service. We thank J. Johnson for help with tank construction and tish care. The Boze- man (Montana) Fish Technology Center conduct- ed proximate analysis of diets. We thank the Wild- life Supply Company (Saginaw, Michigan) for supplying the netting used for feed sieving. G. B. Haines aided in statistical analyses. C. A. Karp, J. H. Williamson, and two anonymous reviewers improved an earlier version of the manuscript. References AOAC (Association of Official Analytical Chemists). 1984. Official methods of analysis. 14th edition. AOAC, Arlington, Virginia. Hamman, R. 1.. 1987. Survival of razorback suckers cultured in earthen ponds. Progressive Fish-Cultur- ist 49:138-140. Lanigan, S. 1.., and H. M. Tyus. 1989. Population size and status of razorback sucker. North American Journal of Fisheries Management 9:68-73. Minckley, W. 1.. 1983. Status of the razorback sucker (Xyrauchen texanus) (Abbot), in the lower Colorado River basin. Southwestern Naturalist 28:165-187. ;.' ~,.....:. . .', TABLE 2.-Composition of commercial fry diets tested as first foods for razorback suckers. All values are means. Diet Component AP-lOO A-250 4200 UV B-250 Proximate analysIs Protein ('lb) 49.8 51.8 55.2 50.6 57.0 Fat ('lb) 12.5 20.1 6.4 30.2 14.6 Moisture ('lb) 5.2 6.0 8.3 3.8 4.3 Ash ('lb) 11.6 10.0 18.3 4.6 10.9 Total carbohydrates" ('lb) 20.9 12.1 11.8 10.8 13.2 Panicle size Larger than 43 I'm ('lb) 59.1 83.2 3.3 0 50.0 153-243 I'Dl ('lb) 38.1 14.0 75.8 0 37.3 103-153 I'Dl ('lb) 2.9 1.9 17.6 0 11.8 Smaller than 103 I'Dl ('lb) 0 0.9 3.3 IOOb 1.0 Average size (pm) 257.0 284.0 185.0 50.0 240.0 · By difference. b Fine brush used to break clumping.