Effects of hydrostatic pressure on the motor activity of fish from shallow water and 900 m depths; some results of Challenger cruise 6B/85.

1. Two species of benthic fish from 900 m depths (90 atm pressure), Trachyscorpia cristulata echinata and Synaphobranchus kaupi, are shown to be adapted to their normal, high ambient pressure. 2. Their condition improves when they are restored to their normal pressure after experiencing decompression in a trawl and they undergo convulsions at 150 atm. 3. This contrasts with the response of shallow water species (Salmo salar, Pleuronectes platessa, Anguilla anguilla and Gadus morhua) which convulse at 93-114 atm and become immobilized and rigid at 150 atm.