Settlement and juvenile habitat of the European spiny lobster Palinurus elephas (Crustacea: Decapoda: Palinuridae) in the western Mediterranean Sea

Abstract

Settlement characteristics, like timing, depth, microhabitat and density of European spiny lobster Palinurus elephas are described for the very first time. Regular SCUBA-diving surveys were conducted from July 1998 to January 2000 on rocky bottoms of three different geologic origins to assess substratum-dependent differences in recruitment density. Settlement of pueruli took place in June-July, a few weeks after sea surface temperature started to rise. The highest density of juveniles was found at 10-15 m depth. Most spiny lobsters settled in limestone rocks, into empty holes of the date mussel Lithophaga lithophaga, which provided daytime refuge. As they grew, individuals were increasingly found in larger holes and crevices of the rock surface. Sizes were estimated from photographs taken at night when the animals were actively foraging. The smallest observed individuals measured 7.5-8 mm carapace length (CL), but they reached 15-18 mm CL at the end of October. The consequences of our results for the management of the spiny lobster populations in the northwestern Mediterranean are summarily discussed.