Artificial shelters (casitas) as habitats for juvenile spiny lobsters Panulirus argus in the Mexican Caribbean

Abstract

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 associated 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-casita occupancy by juveniles and the association between habitat and lobster size groups suggest that availability of natural habitats had an 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 carapace length, CL) and post-algal (26 to 35 mm CL) juvenile stages recruited mainly to vegetated habitats, with larger lobsters occupying patch reef habitats. Mini-casita occupancy was dominated by transitional and post-algal early juvenile stages (41.1 and 34.6% respectively). The fact that the highest percentage of mini-casita occupancy is by transitional juvenile P. argus is considered to represent a 'population bottleneck' effect.