Strong population structure deduced from genetics, otolith chemistry and parasite abundances explains vulnerability to localised fishery collapse in a large Sciaenid fish, Protonibea diacanthus

As pressure on coastal marine resources is increasing globally, the need to quantitatively assess vulnerable fish stocks is crucial in order to avoid the ecological consequences of stock depletions. Species of Sciaenidae (croakers, drums) are important components of tropical and temperate fisheries and are especially vulnerable to exploitation. The black-spotted croaker, Protonibea diacanthus, is the only large sciaenid in coastal waters of northern Australia where it is targeted by commercial, recreational and indigenous fishers due to its food value and predictable aggregating behaviour. Localised declines in the abundance of this species have been observed, highlighting the urgent requirement by managers for information on fine and broad-scale population connectivity. This study examined the population structure of P. diacanthus across northwestern Australia using three complementary methods: genetic variation in microsatellite markers, otolith elemental composition and parasite asse...