Aspects of the population dynamics and ecology of the white spotted stingaree, Urolophus paucimaculatus Dixon, in Port Phillip Bay, Victoria

Abstract

The ages of U. paucimaculutus were determined using sections of the centra of the vertebrae; as many as 10 age classes were present. Females grow to a greater length (57.3 cm) than males (42.8 cm) and live to a greater age. The sex ratio in the population is approximately unity. Parturition was observed in females 34 cm long. or 3 years of age. Fecundity is estimated as a maximum of 12 offspring per year for females older than 7 years. Biomass of the population appears to be higher in summer than in winter and suggests seasonal migration or changes in behaviour patterns in relation to trawls. The diet of juveniles consists primarily of amphipods and isopods, but that of adults consists mainly of polychaetes and caridean and brachyuran crustaceans.