An integrated approach to assessment of seabed habitat &
biodiversity in support of trawl management on the continental shelf of the
Great Barrier Reef.
Pitcher C.R.1, Ellis N.1, Venables W.2, Wassenberg T.J.1, Burridge C.Y.2, Pantus F.1, Smith G.P.1, Browne, M.2, Doherty P.J.3, Hooper J.N.A.4, Gribble N.5, Poiner I.R.3
1CSIRO Marine &
Atmospheric Research, 2CSIRO Mathematical and Information Sciences, 3Australian
Institute of Marine Science, 4Queensland Museum, 5Queensland
Department of Primary Industries & Fisheries
A series of related research projects over the last 15 years in the GBR has assessed the impact rates of bottom trawling for prawns on megabenthos; monitored subsequent recovery rates and measured natural dynamics of sessile megafauna; mapped the distribution of seabed habitats and benthos species, and integrated these results with fishery effort data in a dynamic modelling framework to evaluate alternative strategies for management with respect to their contribution to the sustainability of megabenthos. Methods included sled and trawl sampling, underwater video, and statistical modeling to predict the distribution of species from biophysical relationships with broad scale datasets such as bathymetry, sediments, remote sensing, and oceanographic model output. The modeling framework simulated trawl impact and recovery on the predicted species distributions, based on experimentally measured estimates of rates and industry data on trawl effort distribution and intensity, to estimate the regional scale implications of past trawling. The model also evaluated the expected outcomes for sessile benthos of management interventions implemented over the last 10 years, which showed that effort reductions lead to positive responses in benthos population status, and spatial closures of low effort areas had negligible response.
Contact author: C. Roland Pitcher, CSIRO
Marine & Atmospheric Research,