Integrating Life History Theory and Dispersal in Riverine Fishes

Winemiller and Rose’s life history model (opportunistic, periodic and equilibrium strategies) seeks to explain the adaptations of organisms to a changeable environment. In fishes, these adaptations relate to traits, such as age at maturity, and relative investment in size and number of young. A key element missing from the life history model, however, is dispersal. In this paper, we integrate existing life-history theory with empirical observations of dispersal patterns across life-history strategies to better understand the drivers of recruitment variability. We hypothesize: a) that dispersal mode and dispersal capability are correlated with other life history traits within a strategy; b) that environmental conditions (e.g. flow) will influence dispersal of species from each life history strategy differently; and that c) some environmental conditions may provide advantages to one life history strategy over another. Swimming trials and experimental releases of the larvae of Australian riverine fishes indicated that equilibrium species were the best swimmers, showing orientated, controlled drifting and were retained in fewer numbers in a river reach than periodic species, who were very poor swimmers and drifted passively. We present a conceptual model that explicitly incorporates dispersal into life history and discuss how this will aid conservation and management.