HON ALISON XAMON (North Metropolitan) [6.37 pm]: I have previously stood in this place and raised concerns about our resident population of Indo–Pacific bottlenose dolphins in the Swan and Canning Rivers. I have more to say about that tonight. It is estimated that about 20 to 25 wild dolphins call our Swan River home and are much loved. I think members would agree that they are an iconic part of Perth. They have an integral role in the river ecosystems and, importantly, are a vital indicator of how the overall health of our rivers is tracking. However, over the last 50 years the community of dolphins has come under sustained pressure. In 2019 alone, a male dolphin calf died from entanglement in a crab pot in April, health warnings were issued due to toxic algal blooms in May, and five dolphins died in August. The vulnerability of our dolphin population reflects the vulnerability of our Swan and Canning River systems.
River health is nothing new. It has been a concern as far back as the 1880s, but the impacts of current and past land use, combined with changing climate, means that the future of our rivers and our dolphins is, unfortunately, quite uncertain. In line with the recommendations of the Auditor General’s 2014 report, the long-awaited 2015 “Swan Canning River Protection Strategy” prioritised key threats to the river and laid out the most effective actions that needed to be undertaken to address these. All 33 of these priority actions were to be undertaken within five years and are due for review in 2021. I note that the 2018 biennial report stated that all recommendations were listed as completed or at least in progress. The Department of Biodiversity, Conservation and Attractions’ assessment of the river’s health contained in the biennial report measured water quality, oxygenation and nutrient levels. Although 77 per cent of targets were met, it is my view that these targets, which were developed as far back as 1998 and 2001, will need to be reviewed. We need to have an increased suite of data on the health of our rivers. Serious issues continue to plague our river system. The Canning and middle and upper Swan estuaries have low dissolved oxygen levels. This has been a problem for a very long time, and chlorophyll a levels are far above the maximum threshold. Long-term reductions in rain and, as I mentioned before, the changing climate, have also contributed to less flushing out of those nutrients and contaminants.
The Ellenbrook catchment, after the Avon, remains the largest contributor of nutrients to the Swan–Canning River system. Much of the catchment has been cleared for agriculture and urban development. This, along with seasonal flows, makes it very challenging to address nutrient run-off issues in the short and long term. Ellenbrook has met neither the long term nor short-term targets for nitrogen or phosphorus levels; thus, it remains a priority for water quality improvement and will require some long-term management solutions. This has been an issue for four years, since 2015. The fertiliser action plan and partnership has still not phased out highly soluble phosphorus fertilisers. Unless farmers are basically persuaded or required to change their approach to fertiliser use, I am concerned that current practices will simply continue.
As experts have contended, despite relative improvements in river health over the past few decades, it is still an ecosystem that remains under threat. A strategy that has managed only to keep our river in reasonable health is not good enough. It is not good enough, and certainly not for our dolphins. Changing rainfall patterns, excess nutrients and organic matter, as well as decreased oxygen levels and macroalgal blooms, act as stressors on our river’s flora and fauna systems. This is exacerbated by more direct human threats caused by poor fishing and boating practices. It is absolutely unacceptable that a dolphin calf’s death was caused simply by entanglement in a crab pot. I was also really dismayed to hear of the deaths of five dolphins a few months ago from cetacean morbillivirus. That virus has been identified as the most significant cause of cetacean sickness and death globally. Although the government stated that no direct link could be found between the contaminants in the Swan River and the deaths of these dolphins, researchers contend —
We suspect that the contaminant levels are a factor in the immunosuppression of the dolphins ...
I do not find that particularly surprising. Research in 2012 showed that the dolphin population of Perth has some of the highest build-ups of perfluorinated compounds commonly found in banned carcinogenic chemicals. It has previously been reported that these dolphins had the highest PFC levels in the country, over 100 times more than dolphins in Bunbury. Many domestic and international case studies from around the world—from the United States in particular, and the United Kingdom—have demonstrated a clear link between water quality, pollutants and dolphin and other fauna health. It is clear that our very small dolphin community is vulnerable to the pressures of living in an urban estuary and major harbour and that we are not doing enough to help them.
We have gaps in our reporting, planning and monitoring that are still hampering efforts to clean up our river ecosystems. The failure to prioritise river health in all elements of land use across the catchment only exacerbates these issues, especially as climate change impacts come into play. It is imperative that pollution is prevented from entering our waterways in the first place. I am concerned that our rivers are on life support, and hence our dolphin population remains at serious risk. We cannot keep implementing bandaid solutions that simply attempt to treat the symptoms of a deteriorating environment. We need to start addressing the root causes.