Abstract: This talk will outline the synthesis of biophysical effects of dredging, as a resource for ongoing management, followed by an opportunity for discussion of the implications for developing policy on dredging.

• The Report provides an independent and balanced compilation of the full range of views of experts on the topic; rather than aiming for a single, definitive “consensus” view on all matters, it takes the more pragmatic approach of documenting areas of agreed knowledge, agreed knowledge gaps, and areas where the experts don’t agree. This allows progress on all fronts, instead of bogging down in areas of contention.
• We feel that this means the Governments and stakeholders are now in a much better position in terms of the scientific foundation for managing dredge- and the results are already being taken up.Many of the experts consider that the effects of dredging have probably been under-estimated historically. For example, the recently released Long Term Sustainability Plan cites the conclusions of the 2014 Outlook Report that dredging effects were localised compared to land-based run-off; this may well not be the case.
• The main concern is about long-term contributions to fine sediments and turbidity, through ongoing resuspension of dredge material, especially at disposal sites. The direct effects of excavation and burial are severe but only within a very limited footprint.
• There remains considerable uncertainty about the proportion of disposed sediments that are permanently buried, and the proportion that provide ongoing source of sediments. But the total amounts were potentially very significant, perhaps similar to river amounts (depending on methods of comparison, assumptions, etc).
• The report provides a framework for understanding impacts and risks for key habitats and biodiversity values, as a resource for future assessments.

Bio: Laurence McCook works in science-based management of marine ecosystems, especially coral reefs. He has more than 30 years’ experience, including coral reefs in Australia, Indonesia and the “Coral Triangle”, the Pacific and the Caribbean, as well as in temperate ecosystems. For the last 11 years, Laurence worked at the Great Barrier Reef Marine Park Authority, with the aim of ensuring the management of the Great Barrier Reef is based on the best available scientific information, in the face of increasing, cumulative impacts, ecosystem declines and climate change. Laurence led several trans-disciplinary synthesis projects between managers and scientists. Prior to that, he spent 12 years at the Australian Institute of Marine Science, researching the ecology of coral reef resilience and degradation, the effects of water pollution, climate change and over-use. He has a PhD in marine science from Dalhousie University in Canada. In 2005, Laurence was awarded a Pew Fellowship in Marine Conservation. His project focused on management and policy initiatives to protect the resilience coral reefs under climate change, and included developing and delivering a series of workshops on coral reef management across Indonesia, and in Malaysia. He is a Partner Investigator and Adjunct Principal Research Fellow in the ARC Centre of Excellence for Coral Reef Studies.