ARTIFICIAL SHELTERS (CASITAS) AS HABITATS FOR JUVENILE SPINY LOBSTERSPANULIRUS-ARGUS IN THE MEXICAN CARIBBEAN

The cryptic and shelter-seeking behaviour of spiny lobsters Panulirus argus Latreille prompted the use of artificial shelters to examine the juvenile population structure at Cayos-Contoy, Quintana Roo, Mexico. We tested the hypothesis that habitat type had no influence on shelter occupancy. The artificial shelters used were concrete structures with a PVC frame (mini-size casitas). Macrofauna and potential predators a ssociated with the mini-casitas were also quantified. The size of the lobsters harbored by these structures emphasized the importance of the Cayos-Contoy as a nursery habitat for P. argus. Differences in mini-c asita occupancy by juveniles and the association between habitat and l obster size groups suggest that availability of natural habitats had a n influence on casita occupancy. The periodic removal of all lobsters from the mini-casitas resulted in the vacancies being occupied mostly by a size-specific group of juveniles. Transitional (16 to 25 mm carap ace length, CL) and post-algal (26 to 35 mm CL) juvenile stages recrui ted mainly to vegetated habitats, with larger lobsters occupying patch reef habitats. Mini-casita occupancy was dominated by transitional an d post-algal early juvenile stages (41.1 and 34.6 % respectively). The fact that the highest percentage of mini-casita occupancy is by trans itional juvenile P. argus is considered to represent a 'population bot tleneck' effect.