Inferred family structure and dispersal patterns of a Critically Endangered species, Pinna nobilis, using molecular analyses: implications for conservation

Knowledge of the genetic structure and dispersal patterns for keystone and vulnerable species is essential to the establishment of conservation strategies. Since autumn 2016, the Critically Endangered Pinna nobilis bivalve has suffered mass mortality events throughout the Mediterranean Sea, causing mortality of up to 100% in affected populations. To propose appropriate reintroduction programs for its recovery, the present study sought to determine the genetic structure and local dispersal patterns from a well-documented population of P. nobilis. Using 19 microsatellite markers, we obtained genotypic information for 771 individuals from 9 localities within Cabrera National Park (CNP). The CNP population of P. nobilis was a single and homogeneous population, with nearly half of the sampled individuals being related through 333 half-sib and 14 full-sib relationships. The siblings belonged to 126 different family clusters composed of 2-8 individuals recruited during several recruitment events from up to 4 different localities. No evidence was found to suggest that the population was self-sustaining, since no parent-offspring dyad was found. However, the fine-scale dispersal patterns observed in Santa Maria Bay highlight the importance of this locality for the sustainment of the population as a whole. These findings suggest that the CNP could be a good choice for future reintroduction programs. Future studies that compile data from this and other studies conducted in CNP should be considered when modeling for reintroduction.