Biological aspects, population and fishery dynamics of the non-indigenous pearl oyster Pinctada imbricata radiata (Leach, 1814) in the Eastern Mediterranean

Abstract The pearl oyster Pinctada imbricata radiata (Leach, 1814) is considered as an invasive species and despite its presence, for more than half of a century in the Mediterranean its fisheries in Greek waters is illegal, unregulated and unreported (IUU) due to lack of legal framework and fisheries exploitation. The present study is based on a three-level approach including a(n): (a) in-situ field sampling of live shell specimens, (b) estimation of biological and population parameters and (c) estimate of population stock state complemented with in-depth interviews conducted to fishers. The specimens of the pearl oyster were collected from two enclosed gulfs in Greek waters from November 2018 to October 2019. Asymptotic lengths (L ∝ ) were estimated at 100.63 mm and 103.04 mm, in the North Evoikos and Saronikos Gulfs, respectively and the growth coefficient (K) was estimated at 0.47 year −1 and 0.34 year −1, respectively. The longevity of the species was estimated at 5 years. Total mortality coefficients (Z) were 1.92 year −1 and 1.44 year −1, in the two areas, respectively and the exploitation levels (E) were computed as 0.68 year −1 and 0.65 year −1, respectively. The results of the present study will fill the gaps in knowledge of pearl oyster to set up a reference base for its exploitation as a fishery resource based on invasive species.