The role of the invasive polychaete Ficopomatus enigmaticus Fauvel 1923 (Polychaeta: Serpulidae) reefs in the recruitment of Cyrtograpsus angulatus Dana 1851 (Brachyura: Grapsidae), in the Mar Chiquita coastal lagoon, Argentin

Abstract

The calcareous reef building Polychaeta Ficopomatus enigmaticus is considered an invader species in Argentina. First mentioned in 1943, it has shown an important expansion up to date. At present, living parts of reefs are the most important refuge to grapsid crab Cyrtograpsus angulatus juveniles in Mar Chiquita, a brackish coastal lagoon in Buenos Aires Province, Argentina. This work assessed the reef|00E2|??s role in C. angulatus recruitment, by estimating the total volume of living reef and the number and biomass of recruits and juveniles that can inhabit it. Total volume of living reef estimated in 1999 was 353,849 m3, 50% more than the estimate made in 1975. The maximum number of juvenile crabs that reefs can host yearly was estimated from the juvenile density in reefs, the number of massive recruitment peaks and the total volume of living reef, in 1.68 |00C3|? 1010, or 1,946 t, expressed as biomass. It is shown that the presence of F. enigmaticus has a high impact on the populational biology of C. angulatus by increasing refuge availability and recruitment success. This impact is extended to the whole community being this crab a key species in the Mar Chiquita Lagoon.