Evaluation of parameters of health in Australian fur seal (Arctocephalus pusillus doriferus) pups during early and mid-lactation

Abstract

Seal Rocks, Victoria, is the largest Australian fur seal (Arctocephalus pusillus doriferus) breeding colony, but has one of the highest rates of decline in live pup abundance for the species. Establishing the current health status in the population is important as a point of comparison for future monitoring. This study aimed to develop haematological reference intervals and assess body condition in pups at Seal Rocks in early and mid-lactation. Pups from the 2021 and 2022 breeding seasons were sampled at 3–6 weeks of age (early lactation, n = 180) and 5–6 months of age (mid-lactation, n = 172). Haematological and morphometric parameters differed significantly (P < 0.05) between early and mid-lactation, but body condition did not. The differences in health parameters between early and mid-lactation relate to normal growth and ontogeny but highlight the increased vulnerability of pups in early lactation. These results provide an important reference point for future evaluations of health parameters in Australian fur seal pups.