Abstract
Seasonal values of the critical thermal maximum (CTMax) of eight species of adult marine Crustacea from temperate latitudes were measured and found to range between 20 and 34 °C. The extent to which CTMax was dependent on acclimatization varied with species but for most of the species studied, summer-captured animals had significantly higher CTMax values than winter-captured animals. Heat shock resulted in an increase in thermotolerance in most species in winter-captured animals, but a different pattern was found for summer-captured animals. Then, only
Cancer pagurus and
Pagurus bernhardus showed a positive increment of CTMax on heat shock. Test for Serial Independence analysis indicated no significant phylogenetic autocorrelation between CTMax values in winter or summer-captured animals. Temperature measurements taken by remote data loggers in the intertidal zone of the North-East coast of England are reported. These suggest that several species, whose distribution extends into the intertidal zone, may experience temperatures close to their CTMax in summer.