A pressurising system for long-term study of marine or freshwater organisms enabling the simulation of cyclic vertical migrations

A computer-controlled pressurising system enabling large aquatic organisms like marine fishes to be maintained for long periods is described. The paper presents a system that is capable not only of maintaining constant hydrostatic pressures but also of producing any desired cyclic variations of that parameter, allowing the close and reliable simulation of vertical migrations that many species of fishes and other aquatic animals perforin during some stages of their life cycles.