Predicting the Effects of Angling for Nesting Male Smallmouth Bass on Production of Age-0 Fish with an Individual-Based Model

Abstract

We used an individual-based model of dynamics of smallmouth bass Micropterus dolomieu to examine the effect of angling for nesting males on the abundance of age-0 smallmouth bass. Variation in the daily probability of capture, opening date of angling, and probability of a male successfully returning to guard his brood, as well as a contrast between catch-and-keep versus catch-and-release policies were examined. Male body size and the preference of anglers for fish of different size were varied as a demonstration of the complex interactions between the variability in the reproductive ecology of a fish, angler preference, and a fixed management regulation. We found that the abundance of age-0 smallmouth bass decreased as the daily probability of capturing a nesting male increased in both catch-and-keep and catch-and-release policies. Opening dates during the nesting season, when males were guarding broods, also decreased the abundance of age-0 fish. This decrease was dramatic when the opening date occurred early in the parental care period relative to late in the period. Stress resulting from handling time for catch-and-release can have a significant impact on the abundance of age-0 fish because nesting males may abandon guarding behavior. The simulations indicate that closed fishing seasons during the parental care period, particularly during the early stages of parental care, may be a viable management option in areas where anglers target nesting males.