Lack of acclimation in Ophionotus victoriae: brittle stars are not fish

Acclimation is possibly the most important criterion deciding an animal's ability to survive change. Species with poor abilities to acclimate to small environmental change are likely to be the most vulnerable in future warming scenarios. Two separate assemblages of Ophionotus victoriae were slowly acclimated from 0A degrees C to either +2 or +3A degrees C and then held at these higher temperatures over a prolonged timescale. None of the animals were able to acclimate; with failure occurring from day 19 at +3A degrees C and day 24 at +2A degrees C, indicating that this species is very sensitive to small long-term seawater temperature increases. These data indicate that O. victoriae has probably the poorest ability to acclimate to elevated temperatures of any species studied to date. Given previous data showing some Antarctic fish can acclimate to +4A degrees C, the predicted effects of increased seawater temperatures on the Antarctic food web and ecology must be assessed at the individual species level and interpreted with care.