Turbulence, larval fish ecology and fisheries recruitment : a review of field studies

Fish recruitment varies widely between years but much of this variability cannot be explained by most models of fish population dynamics. In this review, I examine the role of environmental variability on fish recruitment, and ill particular how turbulence affects feeding and growth of larval fish, and recruitment in entire populations. One of the main findings is that field studies show contrasting effects of turbulence on feeding, growth and mortality rates in nature and on recruitment. Coincident and multiple variations in ecosystem processes, lack of understanding of how some of these processes (e.g. larval diet composition, feeding behaviour, growth rates, prey patchiness) respond to turbulence, and unavoidable sampling artifacts are mainly responsible for this result. Upwelling as well as frontal processes appear important for larval fish growth and survival, and turbulence levels vary both within and across these features. Process-oriented studies of some of these interactions could provide more definitive links between turbulence and biological responses in future. (C) 2000 Ifremer/CNRS/IRD/Editions scientifiques ct medicales Elsevier SAS.