The Clyde Sea Nephrops fishery produces large amounts of invertebrate discards. Of these, as much as 89% are decapod crustaceans, including the swimmingcrab Liocarcinus depurator (Linnaeus, 1758), the squat lobster Munida rugosa (Fabricius, 1775) and the hermit crab Pagurus bernhardus (Linnaeus, 1758). Theshort-term mortality of these species was assessed following trawling and periods of aerial exposure on deck (16-90min), and ranged from 2-25%, with Pagurusbernhardus showing the lowest mortality. Two experiments were performed to determine the longer-term survival of trawled decapods compared to those withexperimentally ablated appendages. Deliberately damaged decapods had a significantly lower longer-term survival (ca. 30%) than controls (72-83%). Survival oftrawled Liocarcinus depurator that had been induced to autotomize two appendages was slightly lower (74%) compared with intact creel-caught animals (92%).Mortality rates stabilised about 10d after trawling. Our results suggest that post-trawling mortality of discarded decapod crustaceans has been underestimated in thepast, owing to inadequate monitoring periods. Copyright 2001 International Council for the Exploration of the Sea