The MOU74 Box, off the northwest Australian coastline, is an area of approximately 50,000 sq. km within the Australian Fishing Zone. It contains five large, shallow reef systems (less than 15 m deep) ranging in size from 227 sq. km (Ashmore Reef) to 4.5 sq. km (Browse Island). They total approximately 560 sq. km in area. Immediately north of the MOU74 Box within the Australian Fishing Zone (Little Area A) is another shallow reef, Hibernia Reef. In addition to the shallow reefs, there is approximately 925 sq. km of shoal areas (15 to 50 m deep) within the MOU74 Box and 301 sq. km of shoal areas in Little Area A.

The reefs and shoals support populations of sedentary reef resources including several species of holothurians (beche-de-mer, sea cucumbers) and trochus, as well as reef-associated fin-fish and sharks. These resources have been fished for many years by Indonesian fishers. Ashmore Reef was declared a Marine Nature Reserve in 1983, banning the removal of fauna and flora to a depth of 50 m. The remaining reefs in the area are under continued, and probably increasing, fishing pressure.

The marine resources of the MOU74 Box are managed by the Australian Government. Under the terms of a memorandum of understanding (MOU) between the Australian and Indonesian governments, continued traditional fishing by Indonesian fishing vessels is allowed, principally for sedentary resources such as beche-de-mer (trepang) and trochus, but also fin-fish and reef shark. Apart from limited catch data collected by surveillance and regulatory authorities, little is known about the catch of the Indonesian fishers and the effects of fishing on the target species. There are concerns that the current level of fishing may be unsustainable.

In September and October 1998, CSIRO Division of Marine Resources surveyed the shallow reefs (0-15 m deep) and shoal areas (15-50 m deep) of the MOU74 Box area and Little Area A to the north. Its purpose was to assess the status of the reef resources in the area, and the environment that supports them. Fieldwork for the survey was completed on 10 October 1998.

Overall, the sedentary marine living resources on the shallow reefs were heavily depleted with the high-value species over-exploited and the lower value species probably either fully or over-exploited. Despite the low density, there appears to be a sustained fishing effort by Indonesian fishers in the area. A drastic reduction in effort would be required to allow for a recovery of the higher value species, and to protect other species from severe depletion.

The exception is Ashmore Reef, where there were significant populations of most target species. However, there is most likely some illegal fishing occurring on Ashmore Reef and there is clear evidence of exploitation of at least the high-value resources. The nature of these fisheries and the depleted state of the other reefs in the MOU74 Box suggests that the remaining resources on Ashmore Reef could be quickly depleted if the protection currently given to the reef is not maintained and possibly enhanced. For many reasons, including the potential for recruitment of larvae to depleted reefs, it is important that these populations are protected. Year round protection of the resources on Ashmore Reef should be considered.

This record describes the following survey data for the Timor MOU74 Box:

• Classified satellite habitat map for Scott and Seringapatam Reefs.

• Classified satellite habitat map for Ashmore, Hibernia and Cartier Reefs.