Size-based variation in somatic energy reserves and parental expenditure by male smallmouth bass, Micropterus dolomieu

Male smallmouth bass show size-based variation in both probability and timi ng of reproduction. The objective of this research was to determine seasona l and size-based patterns of depletion of energy reserves and determine if parental defense is related to males' energy reserves. We sampled male smal lmouth bass in the spring, during the parental care period and in the fall to measure energy reserves (lipid stores in muscle and viscera tissue) over a two year period. Energy stores, which were not built up before nesting, declined to a minimum level by the end of the parental care period. Small m ales had consistently lower energy reserves than larger males and did not u tilize these reserves at the same rate during the parental care period. All parental males complimented endogenous energy reserves by feeding during p arental care, however, small males appear to rely proportionately more on e xogenous energy intake than do larger males. Parental defense by all sizes of males declined over the parental care period, the decline being the most obvious by small males. Small males' lower energy budget may make them les s effective parents and decrease their probability of survival over the fol lowing winter relative to larger males.