Larval and postlarval growth of individually reared specimens of the common shore crab Carcinus maenas (L.)

Abstract

Specimens of Carcinus maenas (L.) from the Isle of Man were reared individually at 15 and 20 °C under controlled conditions from hatching to the puberty moult. Survival was monitored and for every specimen the size and duration of each instar was recorded. Survival with time was better at 15 ° C but survival to a given instar was higher at 20 ° C. Survival was generally good, until heavy mortality followed the puberty moult. The puberty moult was consistently the 11th postlarval moult at 15 °C and the 12th at 20 ° C. The intermoult period was shorter at the higher temperature and the growth rate higher. The moult increment was slightly larger at 15 °C, so following the puberty moult specimens were larger than at 20 °C, despite having had one fewer moult. The coefficient of variation in size did not increase through the sequence of larval instars but increased steadily through the postlarval sequence.