GROWTH AND SECONDARY PRODUCTION OF THE MEDITERRANEAN GORGONIAN PARAMURICEA-CLAVATA

Growth and secondary production of the shallow-water gorgonian Paramur icea clavata (Risso, 1826) were investigated at an infralittoral rocky station located at the northern entrance of the Strait of Messina (Ty rrhenian Sea, southern Italy). Colonies were aged by counting the numb er of annual growth rings at the base of the skeleton. Mean annual lin ear growth rates were calculated both by field measurements (tagging) and by fitting a Bertalanffy growth equation for the species. Growth r ates were 2.7 and 3.0 cm yr(-1) respectively. Secondary production was estimated by means of an increment-summation method. The estimate was quite conservative, because it did not take into account production l ost by nonlethal predation, and yielded 3.0 g ash-free dry weight (AFD W) m(-2) yr(-1). Standing stock biomass was 22.5 g AFDW m(-2). Annual P/B ratio was 0.13, and turnover time 7.5 yr.