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Sydney Harbour Organisms

Marine Plants

Mangroves, saltmarsh and seagrass communities are all important components of the ecology of Sydney Harbour. 

Mangroves and saltmarsh are restricted to the intertidal margins of sheltered bays and inlets of the Middle Harbour, Lane Cove River and Parramatta River arms of the upper harbour. Conversely, seagrasses are found subtidally in the lower reaches of the harbour.

Since European colonisation, the area of Sydney Harbour covered by saltmarsh has been drastically reduced, with the largest remaining patch in Newington Nature Reserve. Most saltmarsh patches remain small and isolated, however, meaning that they remain at risk. 

In contrast, mangroves have increased in extent, often displacing saltmarsh habitats.  Although relatively uncommon in the 1870s, they increased from the 1940s and now cover extensive areas around Homebush Bay and the upper reaches of the Parramatta River. Read more here about marine plants in our Sydney Harbour review.

Sydney Harbour Fish Guide

This field guide is an interactive website, enabling you to:

  • Become more familiar with the rich fish diversity in Sydney Harbour and its surrounds
  • Identify species that you have encountered while enjoying the region
  • Contribute new sightings and photographs  

The field guide currently focuses on fish, but over time, with the help of SIMS researchers and public contributions, the coverage will extend to include corals, seaweeds, crustaceans, echinoderms, sponges and other, often remarkably beautiful and bizarre marine invertebrates. To get the most out of the field guide, register now and start exploring the hundreds of species that are currently documented. A help system for using the guide is also available here. This fish guide is an extension of the Gaia Guide system of field guides.