Validation trials of a shipboard filter skid (p3SFS) demonstrate its utility for collecting living zooplankton.

Relatively large volumes of water-on the order of cubic meters-must be sampled and analyzed to generate statistically valid estimates of sparsely concentrated organisms, such as in treated ballast water. To this end, a third prototype of a shipboard filter skid (p3SFS) was designed and constructed. It consisted of two housings (each containing a 35 μm mesh filter bag) and its own pump and computer controller.