The islands of the Torres Strait are of particular environmental and cultural significance. TropWATER conduct a wide variety of projects in Torres Strait. This work is all done in close partnership with the Torres Strait Regional Authority (TSRA) Land and Sea Management Unit. We work closely with their indigenous Land and Sea Rangers, who participate in nearly all our fieldwork. Our seagrass team have been mapping, monitoring and studying seagrasses, reefs and coastal habitats in the region for 15 years. This work lead by Michael Rasheed, Alexandra Carter and Helen Taylor includes establishing that the region contains the largest continuous extent of deep water seagrass mapped anywhere in the world. Our seagrass work in Torres Strait covers developing a seagrass atlas for the region, planning for shipping accidents, studying dynamics and recovery of seagrass beds, resilience to climate change, assessing the health of seagrasses in the Dugong Sanctuary and in the Port of Thursday Island.
A community seagrass monitoring program - the Torres Strait Observer Program led by Jane Mellors, has operated for 9 years, using Land and Sea Rangers from 8 islands and also involving local school children.
Through a National Environment Research Program (NERP) grant, we have assessed the condition of 463 km of shoreline on 20 islands, via boat and helicopter. Every single day of this work has been conducted with the field assistance of Land and Sea Rangers from each of the 20 islands assessed. In addition, we have established a Mangrove Watch program with the rangers, whereby, after completing a 2-day training course, they collect data on mangrove and shoreline condition in our absence, sending the data to ourselves for further analysis. To date, over 20 rangers from a dozen islands have received our Mangrove Watch training and have recorded video footage of mangrove condition along 151km of shoreline across 15 islands. We have assessed biomass and carbon stocks of mangroves across 31 plots on 5 islands, showing them to have carbon stocks comparable to that of some of the major mangrove forests of South East Asia. Biodiversity surveys of 20 islands have more than tripled the number of mangrove tree species recorded on most islands and detected two mangrove tree species new to Australia.
- Climbing perch
The southern coastline of Papua New Guinea has established populations of numerous pest fish species from all over the world and these may potentially enter Australia via the Torres Strait. TropWATER confirmed the first populations of one of these species – climbing perch (from South East Asia) on two islands in the northern Torres Strait. Continued surveys, led by Damien Burrows and Nathan Waltham, conducted jointly with TSRA and local indigenous rangers, has shown these fish populations are well established. Our pest fish survey work has also uncovered 31 native species of fish, 8 of which are new records for the region. TropWATER is developing ongoing community education programs with local agencies in order to prevent further pest fish incursions. Reports and pest fish fact sheets are available from the Torres Strait - A New Frontier for Freshwater Fish Invasions into Australia
, pages of the TropWATER website.
Helene Marsh and Mark Hamann have for many years, led programs into the ecology and sustainable use of dugongs and marine turtles, respectively. Nine aerial surveys of dugongs, using standard methodology, have been conducted since 1987 and this data was recently summarised in a TropWATER report. The dugong population of Torres Strait is currently estimated at 16,000, a globally significant population. Current ongoing work on marine turtles involves capture mark recapture projects to quantify the reproduction rates of green and flatback turtles, plus satellite tracking to map migratory pathways. Recent tracking indicates that flatback turtles breeding in Torres Strait migrate through International waters and reside in areas as far away as Indonesia and the Kimberley coast of Western Australia.
Eric Wolanski and international collaborators have modified, improved and applied the SLIM model to study the water circulation in the Torres Strait. This model is a non-structured grid model, making it possible to have fine resolution near islands and reefs where the currents vary significantly in a short distance, and a coarse resolution in open waters where high resolution is not needed. In addition, Eric added an oceanographic data set spanning nearly thirty years of his previous work at AIMS, enabling verification of the model. The model predicts that yearly-averaged net east-west flow through the Torres Strait is small to negligible, in agreement with field data. The model also reveals the prevalence of highly energetic tidal flows around shoals, reefs, islands and reef passages, and that the net water circulation in Torres Strait is characterised by events lasting a few days to three weeks, and there is no such thing as a typical ‘mean’ water circulation.
We have also completed an assessment of water quality issues for the Torres Strait. The range of issues covered included discharge of mining-associated metal pollution transported down the Fly River, increasing oil palm plantations, new ports and mines, land clearing, local sewage and stormwater discharge on the islands, and shipping issues (dredging, oil spills, ship groundings, shipyards). The report produced by Jane Waterhouse, Jon Brodie and colleagues, ‘Hazard assessment of water quality threats to Torres Strait marine waters and ecosystems, NERP Project 4.4’
, provides the first assessment of current and potential water quality issues in the Torres Strait Region. Subsequently, we recommended, and have now established the beginnings of a long-term monitoring program for the region using combinations of field data, logging equipment and satellite image processing.