Marine Benthic Habitats of the Gorgon Gas Development EIS/ERMP - Technical Appendix C8

Brief description

The survey comprised a review of the available information describing the marine environment of the area and field surveys at the locations of proposed infrastructure. Assessment of potential impacts from the proposed development was based on the results of field observations, general knowledge of the area from previous surveys and literature on the area. The major environmental sensitivities within the proposed Development area relate to coral habitats. Protected mammals and reptiles that may be affected by impacts on these habitats are covered in Appendix C6. The coral assemblages on the south-western corner of the Lowendal Shelf are of regional conservation significance. The extensive patch of Acropora in this location is one of the few extensive patches of fragile acroporid corals in the region. Some of the Porites coral bombora in the area are three to four metres high and are estimated to be several hundred years old. These corals support diverse assemblages of fish and invertebrates. The coral reef areas on the subtidal pavement adjacent to Barrow Island are locally significant because they represent a benthic habitat with restricted distribution around the Island. The individual coral bomboras are of low conservation significance as they are very widely distributed along the east coast of the island. The seagrasses in the proposed Development area mainly comprise species such as Halophila and Halodule. The plants are small and the meadows are too sparse to provide habitat for the fauna usually associated with high-density seagrass meadows. These seagrasses are unlikely to be of high importance to local dugong or sea turtle populations. Halophila, Syringodium and Halodule recover rapidly from disturbance and recolonise disturbed areas from sediment seed banks. These genera are widespread throughout the area and the low-density seagrass in the development area has low conservation significance. The Sargassum-dominated macroalgae beds on both the east and west coasts of Barrow Island are of low conservation significance as they are widely distributed and recover rapidly from disturbance. These beds undergo large seasonal biomass fluctuations each year and are adapted to an environment that is periodically buried with sand and thus undergo cycles of loss and recolonisation on the reefs around Barrow Island. The significance of the effects of the proposed Development on benthic primary producer habitats is discussed in Chapter 11 of the ERMP report. KEYWORDS: Gorgon Gas Development, Barrow Island, EIS/ERMP, benthic habitats, seagrass, coral, reef

Lineage

Maintenance and Update Frequency: unknown

Statement: Original record compiled for the Gorgon Gas Development EIS/ERMP.

Notes

Credit
RPS Environment-Jeremy Fitzpatrick

Credit
MJ & AR Bamford Consulting Ecologists.