Marine biodiversity surveys and habitat mapping

Diver surveys

Specially trained divers from DEWNR and the University of Tasmania conduct underwater surveys to record the distribution and abundance of marine plants and animals. The divers assess reef fish, invertebrate and algal communities.

These diver surveys provide information on reef communities, which are expected to change inside the sanctuary zones. These changes may take many years to occur and multiple surveys are planned to detect the changes.

Around Maria Island in Tasmania, these survey techniques have been used to document increases in the abundance and size of rock lobster and fish that were previously caught by commercial and recreational fishers.

In March 2015 a team of divers from DEWNR and the University of Tasmania surveyed reefs in the Nuyts Archipelago. On this expedition, the divers surveyed 5 sites outside and 5 inside sanctuary zones. Many of these sites were surveyed in 2009, before the sanctuary zones were implemented in October 2014.

The reef surveys support an on-going global collaboration between DEWNR, the University of Tasmania, and other research and conservation organisations involved in the monitoring of marine protected areas.

Baited Remote Underwater Video Systems (BRUVS)

Baited Remote Underwater Video Systems (BRUVS) are used to sample fish communities across a broad range of depths and habitats. Cameras with bait in front of them are placed on the seafloor in numerous locations inside and outside sanctuary zones. The bait attracts fish in the vicinity and the camera records the ones that swim past the camera lens. This data provides information on fish abundance, diversity, and size, enabling the monitoring, evaluation and reporting program to track changes inside and outside of sanctuary zones.

BRUV surveys were first developed in Australia, and are now used around the world for marine monitoring and research.

Swath mapping

Swath mapping technology enables us to undertake rapid assessments and collect detailed information of a wide strip, or swath, of the seafloor - ranging from 5 metres to more than 50 metres.

Mapping involves sending acoustic sonar beams to the seafloor from shipboard computers. We then analyse the reflected signals to generate images of the depth and shape of the ocean floor and determine the seafloor roughness and hardness. 

Swath mapping survey outputs are detailed 3D models and this along with the hardness roughness information then enables us to classify areas into habitat types - such as sands, seagrass and reefs.

The information we collected in the above techniques will be used to assess whether the parks are changing in the way we expect.

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