Laboratory Study of Foraging by Atlantic Mackerel, Scomber scombrus, on Natural Zooplankton Assemblages

Abstract

This study reports on the behavioural response of captive Atlantic mackerel, Scomber scombrus, to changes in composition and abundance of natural zooplankton assemblages. Filter-feeding activity and swimming speed increase with increasing prey concentration. Swimming speed also increases with increasing prey size. Prey preference shows a size selective pattern that is slightly influenced by the size of the largest available prey, but not by variations in total prey abundance or density of individual size categories. Feeding rates under average natural conditions of prey abundance (0.1 g wet weight∙m−3) indicate that mackerel would be unable to satiate during a foraging period restricted to daylight hours. Although prey aggregation or night feeding may enable mackerel to attain their maximum ration in the wild, a review of the literature suggests that pelagic fish seldom satiate. The dynamic response of mackerel to changes in prey abundance can have important consequences to the impact that mackerel and other planktivorous fish may have on the dynamics of multispecies zooplankton and ichthyoplankton communities.