Age and growth in Peale´s dolphin, Lagenorhynchus australis

BOY, C.C.; GOODALL, R.N.P.; SCHIAVINI, A.C.M.

Hawaii

Conferencia; 13th Biennial Conference on the Biology of Marine Mammals; 1999

Peale’s dolphin, Lagenorhynchus australis, altough a common species off Southern South America, is not well known biologically. We studied growth of this species, using museum specimens (carcasses and complete specimens) ans especially those found on the coasts of Tierra del Fuego, Argentina. Age was assessed for 21 specimens through a study of growth structures present in teeth. Ages ranges from 0 to 13 GLGs. Physical maturuty was established by the degree of fusion of the epiphysis to the vertebral centra. Physical maturity is correlated with the age. The fusion of the epiphysis presents a progressive pattern as the animal grows, advancing from the cervical and caudal sections with the cranial lumbars fusing last. The earliest age at physical maturity was seven years. External and osteological m,easurements were taken for 52 specimens, not all complete, Almost all morphometrical characters increase in value with age. Growth is allometric. The von Bertalanffy growth model was the most appropiate to describe the growth of most of the morphometric characters. Zygomatic width was the craniometrical character most useful to infer the total length of individuals. We could not test sexual dimorph in growth and/or measurements because of the small sample size. This is the first study of growth for this species.