Variabilità della distribuzione di Paracentrotus lividus nell’area marina protetta di Capo Caccia-Isola Piana: interazione tra l’effetto delle restrizioni sul prelievo e quello dell’accessibilità

This study is aimed at investigating whether the effects of harvest restrictions of Paracentrotus
lividus, occurring in rocky reef habitats, interact with the accessibility of locations. P. lividus was sampled at sixteen locations and attributed
in groups of four to 4 combinations of MPA harvest restrictions 1) B zone, 2) C zone and 3) Outside the MPA and accessibility
(boat vs. car), corresponding to a gradient of potential human activity on P. lividus in the ranked order of very low (B-boat-D), low (Bboat-
V), moderate (C-car), and high (F-car). Sampling were done at the depth range of 3-7 m at each location in two 100 m2 areas. The
size of P. lividus (test diameter without spines) was the response variable considered. Human activity has been found to significantly affect
population structure of P. lividus influencing the proportion of individuals larger than 50 mm. Although harvest was restricted by MPA
regulations, a significantly lower abundance of large individuals was found at sites accessible by car. This result highlights that there is an
effect of harvest restrictions in relation to accessibility and emphasizes the need to carefully address the enforcement of the MPA toward
easily accessible sites.