During a study of the demographics of the Australian sea lion (Neophoca cinerea), the sex ratio and morphology were obtained from 128 pups at Seal Bay Conservation Park over three breeding seasons (2002-03, 2004 and 2005-06). Gross necropsies were also performed. Dead pups were small and young, averaging 8.0 and 7.0kg in weight, and 75.2 and 71.3cm in length, for males and females respectively, only 1.8kg heavier and 6.7cm longer than newborn pups. There was no sex bias in the dead pups overall or in each cause of death classification. In 49% of mortalities, cause of death could not be inferred from gross necropsy and pups appeared in good condition. In pups in which cause of death was inferred, trauma inflicted by conspecifics was the primary result in both males and females (31.6%), followed by emaciation (10.4%), stillbirth or premature birth (7.6%) and possible shark attack (1.4%). Histopathological examination of tissues and other investigations would be required to determine whether other factors, such as disease or parasitic infection, and pollutant contamination contribute to pup mortality.
- Conspecific aggression
- pup mortality