Local-scale mapping of benthic habitats to assess representation in a marine protected area

Abstract

Macrobenthic habitat types were classified and mapped using a compact video array at 78 sites spaced 5 km apart in Moreton Bay, Australia. The area mapped was about 2400 km2 and extended from estuarine shallow subtidal waters to offshore areas to the 50-m isobath. Nine habitat types were recognised, with only one on hard substrate, and their representation within an existing marine protected area was assessed. Only two habitat types were represented in highly protected (no-take) zones, with less than 3% of the total area of each habitat type included. The habitat mapping characterised several habitat types not previously described in the area and located deep-water algal and soft coral reefs not previously reported. Seagrass beds were encountered in several locations where their occurrence was either unknown or had not previously been quantified. The study represents the most spatially comprehensive survey of epibenthos undertaken in Moreton Bay, with over 40 000 m2 sampled. Derived habitat maps provide a robust basis for inclusion of representative examples of all habitat types in marine protected area planning in, and adjacent to, Moreton Bay. The utility of video data to conduct a low-cost habitat survey over a comparatively large area was also demonstrated. The method used has potentially wide application for the survey and design of marine protected areas.