Migration and settlement of puerulus of spiny lobsters in southern hemisphere

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The larvae of spiny lobsters hatch out as phyllosoma and metamorphose into puerulus after about a year. Because od difficulties to culture phyllosomas in laboratory and to capture pueruli in the ocean, the puerulus particalarly at the early stage has been a missing link of the life history of spiny lobsters. A number of puerulus of Jasus edwardsii was observed to settle at Castlepoint, New Zealand. Another species Jasus verreauxi occurred in the northern part of New Zealand and southern coast of New South Wales, Australia. We have carried out the survey in order to find migration and settlement of puerulus of siny lobsters.1. Seasonal change of puerulus settlement for J. edwardsii. Total number of pueruli and postpueruli collected with Booth type collectors were 198 and 47 for 18 days with 12 collectors in January and February, and 40 and 13 for 10 days with 20 collectors in November and December 1991. Settlement of the puerulus was much higher in summer compared to spring.2. Distribut … More ion of the puerulus near shore. A number of puerulus was found under the stones on sand beach at low tide. A total of 106 pueruli and 13 postpueruli was collected under 755 stones in February. A number of puerulus was collected at the middle depth of the mouth part of Castlepoint Inlet with collectors. A puerulus was sampled with sledge net on the sandy bottom in the inlet.3. Morphological change of hepatopancreas of the puerulus. The hepatopancreas was not visible for the early stage of the puerulus. It became visible as a pair of white coloured organ at the advanced stage. From histological examination storage of fat was observed at the tip of anterior lobe of the hepatopancreas for the early stage puerulus. The fat was found in the cells of the hepatopancreas after the mid-stage.4. Burrowing behaviour of the puerulus. The puerulus showed the burrowing behaviour on the salty sand at Castlepoint. The early stage puerulus burrowed easily, but the late stage puerulus and postpuerulus could not burrow. The pueruli burrowed into silt at daytime and emerged after dark. Less