Abstract

The current discussion on key issues regarding reef resources such as connectivity and the open vs closed nature of populations, has led to a re-assessment of the value of recruitment measurements at local and regional scales for reef fish and invertebrates. In open populations at local scale, the recruitment is decoupled from the reproductive activity of adult stock. and generally, the recruits come from foreign, often unknown, sources. Due to their life history characteristícs -with early stages having a long pelagíc life, and the complexity of the current systems prevailing in the region, it is very likely that local populations of spiny lobster Panulirus argus (from a bay, island or oceanic bank) behave as open populations. Under these circumstances, it is mandatory to monitor the recruitment because then recruitment becomes equivalent to natality. We present a progress report on the developing of a sampling protocol to estímate the abundance of postalgal juveniles of spiny lobster as a recruitment index at local level. In particular, we deal with an index of (relative) abundance based on the use of artificial habitats as sampling gears. Our results include aspects related to the precision of the index and sampling under restrictions due to sampling cost, expressed as days at sea. The field work has been done at Bahiade la Ascensión, located in the Biospehere Reserve Sian Kaan; hence, we also report the spatio-temporal patterns of the abundance of juvenile lobster at that locality. Finally, we discuss thepros and cons of our sampling protocol.

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