Marion Angelini

University of Tasmania · Institute for Marine and Antarctic Studies (IMAS)

Understanding the threats facing endemic species is crucial to their survival: local extinction could be synonymous with global extinction. The Maugean skate, Zaeraja maugeana, is a restricted endangered species endemic to Macquarie Harbour (MH), although previously observed in Bathurst Harbour, in Western Tasmania. An increase in aquaculture over recent decades in MH has been linked to a degradation of benthic conditions and declines in dissolved oxygen (DO). Until now, studies have focused on the direct impacts of decreasing DO on this skate; in this study, we focus on the indirect threat, namely the response of their prey to the degrading health of the environment. As this skate has a specialised diet, any threats to these prey species could increase the extinction risk of the Maugean skate species, acting as indirect threats. Field assessment of abundance and distribution of two key skate prey species, the crab Paragrapsus gaimardii and the shrimp Palaemon spp., in conjunction with an assessment of the health of the benthic assemblages where these species are sampled, will be examined as a first step. Then, respirometry, blood chemistry and behaviour analysis of these prey species in response to low DO conditions will provide information on how the skate’s prey distribution/abundance may change in response to the changing environment in MH.