The "school trap": a mechanism promoting large-amplitude out-of-phase population oscillations of small pelagic fish species

Small coastal pelagic marine fishes often form mixed schools containing two or more species. Individuals of a less abundant species, which are entrain ed in schools that are dominated numerically by a more abundant species, ma y be adversely impacted. This may help to account for an observed pattern o f strong alternations in dominance between sardines and anchovies in a numb er of regions of the world's oceans.