Collier, C.J., Carter, A., Shepherd, L., van de Wetering, C., Coles, R., Evans, S., Barrett, D., Willan, R., and Groom, R. (2023) Benthic habitats of Marra Sea Country - Gulf of Carpentaria. Report. TropWATER, James Cook University, Cairns, QLD, Australia.

PDF (Published Version) - Published Version Restricted to Repository staff only

Abstract

Marra land and sea country includes coastal waters in the southern Gulf of Carpentaria in the Northern Territory (NT). The Limmen Marine Park (Commonwealth Government) and the Limmen Bight Marine Park (NT Government) are in Marra country. The co-management aspirations identified within the two Marine Park Plans of Management and the Marra Healthy Country Plan include a need to improve information on habitats and key species because they have not been previously mapped. Benthic habitats were assessed for 2072 sites during October 2021, with a primary focus on seagrass. Intertidal habitats were surveyed using a helicopter to assess the large, exposed banks, islands and reef tops. For subtidal waters a combination of drop and towed cameras, van Veen grabs and benthic sleds were used for surveys. At each site, a visual estimate of seagrass, as well as benthic macroinvertebrates, algae and open substrate were made. Seagrass was found at 21% of the sites surveyed. The majority were within the coastal strip of the Limmen Bight Marine Park adjacent to the Limmen Marine Park. Seagrass in this region formed a meadow 65 km long to 9.7 m depth below mean sea level (dbMSL), extending 7–8 km from shore and including areas of very high seagrass biomass. Seagrass also occurred around the Roper River mouth, at sites around Maria Island, and to depths of 21.1 m dbMSL within the Limmen Marine Park. Seven seagrass species were documented in the area. Eighty species of mobile (non-habitat forming) and sessile (habitat-forming) invertebrate species were identified. Soft corals, hard corals and sponges formed habitat through much of the Limmen Marine Park and Limmen Bight Marine Park, though all became sparser as distance from the coast increased. Coral reefs fringed the eastern and southern sides of Maria Island. Ascidians, crinoids, and hydroids were also present and so dense at some sites that they dominated the benthic communities. Diverse fish assemblages, as well as dolphins, dugongs, sea snakes and turtles were also observed on the survey. This is the first comprehensive survey of the benthic habitats of Marra sea country and the southern Gulf of Carpentaria marine parks. This information is essential for natural resource planning and to establish a monitoring program that incorporates Traditional Owner and Custodian knowledge and values, and western scientific knowledge. Ongoing monitoring is required to understand variability in the habitats such as seasonal and inter-annual changes in abundance and composition, the environmental pressures influencing habitats and the effect of these changes on species that depend on them including dugong and turtles. Marra sea country is part of the highly connected southern Gulf of Carpentaria meaning local actions to protect habitats need to be embedded within regional strategies to protect the resilience of the cultural-ecological system.

Item ID:	87668
Item Type:	Report (Report)
Keywords:	Seagrass, Seagrass mapping , dugong, turtle, fish habitat, Sea Rangers, coral, algae, subtidal segrass mapping, seagrass meadows, benthic habitat, Marra land and sea country, Limmen Marine Park, Limmen Bight,
Copyright Information:	© James Cook University, 2022.
Funders:	Australian Government, Mabunji Aboriginal Resource Indigenous Corporation, Northern Territory Parks and Wildlife Commission, Charles Darwin University (CDU), James Cook University (JCU)
Projects and Grants:	Our Marine Parks Grants
Date Deposited:	08 Sep 2025 22:10
FoR Codes:	41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring @ 100%
SEO Codes:	21 INDIGENOUS > 2104 Aboriginal and Torres Strait Islander heritage and culture > 210402 Aboriginal and Torres Strait Islander connection to land and environment @ 50% 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180501 Assessment and management of benthic marine ecosystems @ 50%
Downloads:	Total: 1 Last 12 Months: 1
	More Statistics