June 28, 2013

Newsletter: 

A three-week survey of the Oceanic Shoals Commonwealth Marine Reserve (CMR), a poorly known region of the Timor Sea north of Australia, found biodiversity patterns related to turbidity, light and currents.

The survey, by a team of NERP Marine Biodiversity Hub scientists on the Australian Institute of Marine Science Research Vessel Solander, examined mid-shelf habitats of the Reserve, including potential biodiversity hotspots such as pinnacles, banks and shoals.

Field conditions were good throughout the survey period and significant geophysical, geological and biological data were acquired for the seabed and water column.

This included more than 500 kilometres of multibeam sonar and 1.5 km of towed video transects. A total of 763 samples was collected for taxonomic identification, with sponges and cnidarians (hydroids, jellyfish, anemones, and corals) the most abundant type of fauna.

Mobile fish fauna was assessed using baited cameras deployed on the seabed for demersal species, while pelagic species were assessed with baited cameras suspended under floats in the surface waters.

Ocean drifters were deployed to map surface currents via GPS tracking; surface water samples were collected for analysis of chlorophyll-a and suspended solid content to support analysis of MODIS satellite data for the North-west region; and observations of whale and dolphin activity were recorded.

To support the development of a monitoring program for the Oceanic Shoals CMR, the survey applied a standardised technique for selecting sampling sites.

The technique, termed a GRTS (Generalised Random Tessellation Stratified) design, ensures a spatially balanced distribution of sample sites and can be weighted towards known seabed features.

The survey findings will build on recent datasets for shoals closer to the northern and western shelf margins, enabling a regional scale overview of these features and the development of predictive spatial models for shoal biodiversity.

The datasets and models will support marine bioregional monitoring and management by the Department of Sustainability, Environment, Water, Population and Communities.

The survey involved the Australian Institute of Marine Science, Geoscience Australia, University of Western Australia and the Museum and Art Gallery of the Northern Territory.
 


Images:

  • Crew of RV Solander retrieving benthic sled from the seafloor during survey of the Oceanic Shoals.
  • Samples from the benthic sled. (Images: AIMS)

 

 AIMS)

 AIMS)

 


Further reading

Visit the blog for the survey which includes video footage and images

 

Contact

Dr Julian Caley, AIMS