Distribution of newly settled western rock lobsters Panulirus Cygnus

Abstract

Little is known about the biology of the post-puerulus stage (l e indlvlduals < 25 mm carapace length) of the commercially valuable western rock (spiny) lobster Panuhrus cygnus, and few have been found In the fleld In the present study, the natural habitat of post-pueruli was discovered through intensive d ~v i n g surveys Additional studies of habitat preference were c a m e d out using a vanety of designs of artificial habitats and the response of the post-pueruli to transferral between shelters was evaluated Post-puerulus P cygnus were found to shelter in small holes on the face, in ledges and in caves on coastal limestone reefs They apparently preferred shelters with additional cover typically seagrass and/or algae Movement between shelters appeared common because 50 % of monitored shelters were occupied for only a single day Post-pueruli occurred In groups of u p to 100 indlvlduals, although 75 "/ U were solitary There was a trend foi larger post-pueruli to be gregarious Two designs of artiflclal shelter were successfully utillsed by post-pueruli those made of Tanikalon which resembled algae or seagrass and those that consisted of holes in limestone blocks covered by seagrass In transferral experiments at least 50 % of post-pueruli refused to enter or r e m a n in new shelters after transfer from their previous shelters This may be influenced by the method of release Discovery of the natural habitat of post-puerulus P cygnus means that it is now possible to study other aspects of thelr biology and populabon dynamics Results of the transfer expenments indicate that future research is needed to determine the best release method to minimlse rejection of new shelters The successful utlllsation of artificial habitats suggests that these habitats may have potential to enhance the survival of post-pueruh In areas where shelter is hmited