A method for sampling sandy beach amphipods that tidally migrate

Abstract

Some sandy beach species display tidally-related, across-beach migrations. Such behaviour can produce false or misleading results when standard sampling methods are used. To address this problem, a novel method was developed for sampling migratory amphipod populations that maintain position in the swash zone. This method provides sampling repeatability at any stage of the tide by locating the water’s edge, defined as the median of the upper limits of 11 consecutive waves, and thus locating the migrating population. Data to test the hypothesis of choice are then obtained via replicate core samples taken at fixed levels above and below the water’s edge.