The European spiny lobster, Palinurus elephas, occurs in the Mediterranean Sea, and from the northwest African coast to Norway in the Atlantic. In the Mediterranean, peak moulting occurs in December-January and May to June. U.K. females moult from July to September and males moult mainly in winter. Moult frequency declines with size, pronouncedly in females of > 6 years. Percentage post-moulting growth is inversely proportional to size, especially in females, which have lower asymptotic size than males. For specimens of equal carapace length (CL), females are longer (TL). Eggs are released 10 days after nocturnal deposition of spermatophores during July-September. Berried females occur from September onwards. Incubation lasts 5 months in the Mediterranean and 9 months in the Atlantic. Fecundity is proportional to CL, with one clutch carried annually. Berried females measured a minimum 67 mm CL in the Mediterranean and 70 mm CL in the Atlantic. Fifty percent female maturity occurs at 82-86 mm CL. Eggs hatch in spring in the Mediterranean and early summer in the Atlantic. Phyllosomas measure 3 mm and moult 10× before metamorphosis to natant pueruli. Pueruli measure 21 mm TL, with convex carapaces and well developed abdomens and pleopods. After three moults, pueruli become post-pueruli, also measuring 21 mm, visually similar to adults. Pueruli and post-pueruli records are rare, and juveniles are seldom observed. Post-embryonic development to the post-puerulus takes 5-6 months in the Mediterranean. Attempts at larval culture have been unsuccessful. Adults feed preferentially on echinoderms and molluscs. Offshore migration occurs after egg-laying, with a return to shallower water in spring. Social behaviour is poorly understood. Regionally important fisheries are based in Corsica, Brittany, and southwest Britain and Ireland.