This week on Earth Matters we put the spotlight on the devastating South Australian algal phenomena that is rocking communities and scientists. While the causes of the bloom are becoming clearer, there are many unknowns, making the future difficult to predict. Ngarrindjeri elder Derek Walker is among the many facing uncertainty arising from the bloom. He is a sustainable fisherman harvesting kutis - or pipis - as they are more widely known - on the Coorong.  Shellfishing has been a part of Ngarrindjeri life for millenia. But with toxins infiltrating the seafloor where the kuti grow, operations are in shutdown and the local Ngarrindjeri who work there are off the water. Derek Walker speaks about the impact of the algal bloom on kuti harvesting, cultural tourism and community. In this episode of Earth Matters we speak to:- Ngarrindjeri elder and Kuti and Co director, Derek Walker - Dr Scott Bennett, marine ecology expert from the University of Tasmania (interview conducted by 3CR Breakfast presenter Sonia Randhawa) SA Government Fact Sheet SA Government Advice (including health and food safety advice)