Evidence for acclimation to hydrostatic pressure in Uca pugilator (Crustacea: Decapoda: Ocypodidae)

Groups of male Uca pugilator (Bosc) (Crustacea, Decapoda, Ocypodidae), acclimated to sublethal pressure (34 atm) subaqueously for 5 and 10 days, were observed subsequently at pressures up to 272 atm. Behavioral indicators of pressure resistance (“first response” and tetany) were employed to measure degrees of pressure acclimation in comparison with simultaneously and non-simultaneously conducted control experiments. No firm conclusions can be made on the basis of “first response” results, but the pressures required to induce tetany were significantly higher (P≤0.02, one-tailed comparison) in acclimated groups than in non-acclimated groups. These data and earlier studies by other investigators support the assertion that some shallow marine species are capable of at least limited short-term pressure acclimation.