Body growth and mortality of the spiny lobster Palinurus elephas within and outside a small marine protected area

Abstract

Following the establishment of a small marine protected area (MPA) located off western Sardinia (Mediterranean Sea), a long-term survey was conducted on a spiny lobster ( Palinurus elephas) population inhabiting the MPA and adjacent fishing grounds. Between 1998 and 2005, median carapace length increased by 1.9 mm year −1 both within and outside the MPA. On the contrary, body size dispersion (IQR) increased by 0.9 mm year −1 within the MPA and decreased by 0.6 mm year −1 outside. Mark-recapture data were used to develop and calibrate a body growth model explicitly accounting for sexual dimorphism and inter-individual variability. Median asymptotic carapace length was equal to 116 mm in females and 185 mm in males. Age frequency distributions, derived from size distributions through the body growth model, were used to estimate mortality rates inside (ca. 0.41 year −1, natural mortality) and outside (ca. 0.78 year −1, natural + fishing mortality) the MPA. Results provide new estimates of key life history traits for this species and suggest that the MPA is effective in protecting lobsters despite its small dimensions.