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v y <br />1 <br />2 <br />It thus appears that the razorback sucker is not successfully <br />providing recruits to its adult population. 'Three possible <br />explanations have been suggested: 1) predation by exotic species on <br />eggs and larvae; 2) insufficient foods for larval survival and growth; <br />3) removal from the lake via subsurface currents. To date, predation <br />has seemed the most likely explanation. Predation by introduced <br />species on native, Southwestern fishes is recognized as a major cause <br />in their demise (Mincktey and Deacon 1968). However, it has been <br />difficult to find eggs or larvae of razorback sucker in guts of <br />potential predators, in part because of rapid digestion (Marsh and <br />Langhorst 1988). Nevertheless, coax= carp (Cyprinus carnio) and a <br />number of other non-native species, have been observed feeding in <br />areas of razorback spawning and are suspected predators (Jonez ar4 <br />Sumner 1954). <br />In general, little is ]mown about the early life history of <br />razorback sucker. The role of food availability on survival and <br />growth has not before been examined. However, this relationship has <br />been extensively studied for marine species of ocmmercial importance. <br />'i <br />Laboratory and field experiments have identified insufficient food as <br />cause of high mortality, particularly as larvae switch from endogenous <br />yolk to exogenous sources of nutrition (O'Connell and Raymond 1970). <br />The present study investigated the effect of food availability on <br />survival and growth of larval razorback sucker. In Part I, I report <br />results of a series of controlled laboratory experiments to cbtain <br />baseline data on time to starvation, effects of delayed feeding, and