Persistent organic pollutants and trace elements detected in New Zealand fur seals (long-nosed fur seal; Arctocephalus forsteri) from New South Wales, Australia, between 1998 and 2019

Environmental pollution is a growing threat to wildlife health and biodiversity. The relationship between marine mammals and pollutants is, however, complex and as new chemicals are introduced to ecosystems alongside concomitant, interacting threats such as climate change and habitat degradation, the cumulative impact of these stressors to wildlife continues to expand. Understanding the health of wildlife populations requires a holistic approach to identify potential threatening processes. In the context of environmental pollution in little studied wildlife species, it is important to catalogue the current exposome to develop effective biomonitoring programs that can support diagnosis of health impacts and management and mitigation of pollution. In New South Wales, Australia, the New Zealand fur seal (Arctocephalus forsteri) is a resident species experiencing population growth following devastating historic hunting practices. This study presents a retrospective investigation into the exposure of New Zealand fur seals to a range of synthetic organic compounds and essential and non-essential trace elements. Liver tissue from 28 seals were broadly analyzed to assess concentrations of organochlorine and organophosphate pesticides, polychlorinated biphenyls, per- and polyfluoroalkyl substances, and essential and non-essential trace elements. In addition to contributing extensive pollution baseline data for the species, the work explores the influence of sex, age, and body condition on accumulation patterns. Further, based on these findings, it is recommended that a minimum of 11 juvenile male New Zealand fur seals are sampled and analyzed annually in order to maintain a holistic biomonitoring approach for this population.