Swimming behaviour of the puerulus larvae of the western rock lobster

Abstract

A total of 335 free-swimming puerulus stage larvae of Panulirus longipes* were observed during five nights, using underwater lights, at Seven Mile Beach (29º 10'S., 114º 53'E.) in Western Australia.

All puerulus larvae were found to be swimming alone and no contacts or reactions were observed between individuals. Both the swimming and sinking postures are described.

Swimming speeds of approximately 33 cm/s (maximum) and approximately 15 cm/s (mean) were recorded over a distance of 1 m. Animals were able to swim at these speeds against water currents of between 9 and 13 cm/s, indicating a potential swimming speed with the current of approximately 46 cm/s.

The puerulus larvae was found to be capable of avoidance reactions by a rapid flexing of the abdomen and also of detecting objects in the water.