Overfishing Social Fish

Abstract

Social learning is common among vertebrates, including fish. Learning from others reduces the risk and costs of adaptation. In some longer‐lived species, social learning can lead to the formation of persistent groups that pass learned adaptations from one generation to the next (culture). Variations in learned adaptations are subject to natural selection, leading to a second, fast‐paced, fine‐scale evolutionary process that complements genetics and enables adaptation to the peculiarities of local areas. Socially learned knowledge is stored mainly in the minds of older fish and subsequently inherited (learned) by younger fish. Consequently, the persistence of locally adapted groups of long‐lived fish requires the inheritance of genetic and learned adaptations. Local populations of social learners are not often recognised nor conserved by fisheries managers. Fishing usually reduces the relative abundance of older fish far more than younger. We hypothesise that fishing may impair and eventually erase the learned local adaptations of long‐lived fish, leading to the loss of local stocks of these species and significant ecosystem‐wide changes. Fishing may shift abundance towards species not dependent on learned adaptations, i.e., invertebrates and short‐lived fish. The hypothesis leads directly to the idea that conserving populations of long‐lived social learners is likely best accomplished by protecting age and social structure or, more generally, the natural processes, such as social learning, that generate complexity in an adaptive ecosystem. Local area‐based management is aligned with the local processes of social learners and can capture and learn about the effect of human activity at that scale.