After near extirpation by profit-based sealers in the early 1800s, Australian fur seals (Mering-mum in Boon Wurrung language) experienced a moderate recovery from 1975-2007. However, by 2013 pup numbers had declined ~20% and they have not recovered.
Seal Rocks near Millowl (Phillip Island) is the largest breeding site for the sub-species and part of Bunurong sea country. Here, pup numbers have declined by 28% from 2007-2013, and a further 6% to 2017. Threatening processes include fisheries interactions, toxicants, disease, plastic entanglement, disturbance, and climate change. Understanding was hindered by infrequent survey schedules (5-yearly) and limited knowledge of vital rates, for example, pup births and survival and adult female abundance.
Remote Piloted Aircraft (RPA or drones) have been used since 2017 to gather photographic surveys during the breeding season and the seals counted via our global online Citizen Science portal “SealSpotter”.
The results show that ~1,000 pup deaths occur in some seasons, concurrent with a stable adult population; indicating that the pup decline is driven by pup mortality rather than reduced births.
Mering-mum are valued ocean sentinels and indicators of ecosystem health. Without mitigation, reduced future recruitment is expected to exacerbate the decline and shift the population centre further south.