A water column sampler for invertebrates in salt-marsh tidal pools

A column sampler for use in shallow (1 m) pools is described. The apparatus is a 10-cm diameter PVC pipe mounted on a base plate. A sliding trap on the base plate is attached to a cable which runs over a pulley to the upper part of the sampler. A whole water column of 78 cm² is sampled and 1–2 cm of substrate can be included as desired. The sampler has been used successfully in salt marsh pools to census gastropods, amphipods, and copepods.