Species-specific PCR-RFLP for identification of early life history stages of squid and other applications to fisheries research.

As cephalopods fulfil important roles in marine ecosystems and may be especially susceptible to overfishing the predicted expansion of cephalopod fisheries will require improved assessment and management of stocks to ensure ecosystem compatible exploitation. Genetic markers facilitating high throughput accurate species identification, particularly for early life history stages, would considerably benefit cephalopod fisheries research. Reported here is the development of a PCR-RFLP assay for identification of four squid species (Loligo vulgaris, Loligo forbesi, Alloteuthis media and Alloteuthis subulata) of growing interest as fisheries resources. The assay was used to type morphologically indistinguishable paralarvae collected from Seine Bay and revealed 99% to be A. media despite a priori expectations that L. vulgaris (present at 1%) would predominate. As the method can be applied to various life history stages and tissue types it offers considerable potential for use in studies of life history, stock structure, reproduction, recruitment and abundance that are necessary for sustainable management.