Sydney Harbour: Beautiful, diverse, valuable and pressured

Sydney's Harbour is an integral part of the city providing natural, social, and economic benefits to 4.84 million residents. It has significant environmental value including a diverse range of habitats and animals. A range of anthropogenic and environmental pressures threatens these including loss and modification of habitats, oversupply of nutrients and introduction of pollutants such as metals, organics, and microplastics, introduction of non-indigenous species and the impacts of recreational fishing. Many people now recognise not only the environmental value of Sydney Harbour, but also the economic and social benefits a healthy harbour provides. Over 80% of residents recognise the importance of maintaining a pollution-free coastal environment and conserving the Harbour's abundant and diverse marine life. A recent review gathered information to make some first estimates of economic revenues and values associated with Sydney Harbour. Port and maritime revenues ($430 million/yr), ferries ($175 million/yr), cruise ship expenditure ($1025 million/yr), major foreshore events such as New Year's Eve and the Sydney Festival ($400 million/yr), and also income from culture, heritage, arts and science (over $33 million/yr) inject considerable funds into the Australian economy. Notably, proximity to the harbour enhances Sydney domestic real estate capital by an estimated $40 billion, equivalent to $3775 million/yr and biological ecosystem services were valued at $175 million/yr. Here we provide i) a synthesis of our current understanding of the natural, social, and economic resources of Sydney Harbour, ii) the threats and pressures these resources face, and finally iii) how a new marine management framework is being used to address these threats to the natural, social and economic wellbeing of Sydney Harbour. This review clearly shows that Sydney Harbour is a valuable and valued environment that deserves continuing scientific, social, and economic research to support management now and in the future.