Understanding habitats of Marra Sea Country

Marra Sea Country in the western Gulf of Carpentaria is home to rich biodiversity, supported by a range of seafloor (benthic) habitats including seagrass, corals, mangroves, macroalgae, and saltmarsh. Dolphins, dugongs, turtles, and diverse fish communities rely on these habitats.

Improving knowledge of the habitats that support key species is a management priority for Marra Traditional Owners to better protect the biodiversity in these waters, which include the Limmen Marine Park (Commonwealth) and Limmen Bight Marine Park (NT).

We have partnered with Marranbala and li-Anthawirriyarra Rangers to map seafloor habitats using helicopters and boats and to provide training for Rangers to lead ongoing monitoring programs.

First maps and future monitoring

Together with Marranbala and li-Anthawirriyarra Rangers and other project partners, our team is using the following methods to survey the marine habitats of Marra Sea Country:

• Helicopter surveys to visually assess intertidal areas.

• Boat surveys for subtidal areas, including drop and towed video cameras, and van Veen grabs and benthic sleds to collect small samples from the seafloor.

• Baited Remote Underwater Video stations to assess fish populations in different habitats.

During these surveys, we are providing hands-on technical training to help establish an ongoing Ranger-led monitoring program on Marra Sea Country.

We will use data from this project to provide recommendations for biodiversity conservation to all groups responsible for managing this region, including Marra people, Parks Australia, and the Northern Territory Government.

From sponges and seagrass to dolphins and dugongs

We have identified a range of different species types in Marra Sea Country including:

• Dolphins, dugongs, sea snakes, and turtles.

• Eighty species of invertebrates.

• Over 100 species of fish, including sharks, rays, and commercially and recreationally important fish.

• Seven species of seagrass, with most seagrass along the coastal strip of the Limmen Bight Marine Park forming a meadow over 65 km long.

• Soft corals, hard corals, and sponges.

• Ascidians (sea squirts), crinoids (feather stars), and hydroids.

Ongoing monitoring will focus on how these habitats change seasonally and from year to year, the environmental pressures that might be affecting these habitats, and potential impacts on the many species that depend on them.

Project details

This project is led by Dr Catherine Collier, Dr Alex Carter, and Dr Tim Smith in partnership with Namultja Aboriginal Corporation, Mabunji Aboriginal Resource Indigenous Corporation, Marranbala and li-Anthawirriyarra Rangers, Charles Darwin University, Northern Territory Parks and Wildlife Commission, and the Museum and Art Gallery Northern Territory. This work is funded by the Northern Territory Government, Parks Australia, and the National Environmental Science Program Marine and Coastal Hub.