Macroparasites as biological tags for stock identification of the bluemouth, Helicolenus dactylopterus (Delaroche, 1809) in Portuguese waters

In the present study, the macroparasite assemblage infecting Helicolenus dactylopterus (Delaroche, 1809) in three different areas off the Portuguese coast was evaluated in order to assess their use as biological tags in stock identification. Fish were obtained from commercial landings in Azores, Madeira and mainland Portugal (Peniche), and were examined for macroparasites infections according to standard procedures. Parasite assemblage composition and the prevalence and mean abundance of each macroparasite taxa within each area were calculated. Amongst the 20 taxa found, 13 were selected as good biological tags, presenting statistically different infection levels between areas. Anisakidae larvae, which presented different prevalence and mean abundance levels between the three areas, were further identified according to the restriction fragment length polymorphism (RFLP) pattern on TaqI, HinfI and HhaI. The multivariate discriminant analysis applied to the macroparasites species present in more than one area and showing prevalence higher than 10% revealed a high differentiation among the three sampled areas suggesting at least three different bluemouth stocks in Portuguese waters.