Quantifying the contribution of small-scale turbulence to the encounter rates between larval fish and their zooplankton prey: effects of wind and tide

Abstract

Simulation suggests that the contribution of small-scale turbulence to encounter rates depended strongly on wind and tidal velocities, prey density and distribution, and larval fish swimming speeds. Failure to consider the influence of small-scale turbulence when prey density ≤35 l-1 can result in up to an 11-fold underestimation of the frequency of contacts between fish larvae and prey under conditions prevailing at fronts in waters over the NW European continental shelf during summer, and up to 112% for larvae at depth 20 m during wind velocities of 5 m s-1. These biases increase when prey densities are lower and when prey are heterogeneously distributed. Turbulence may slow the rate of starvation among larval fish because weak, slow-swimming individuals are more likely to benefit from turbulence than faster-swimming larvae. -from Authors