Abstract
As the ocean has warmed, in recent decades marine heatwaves (MHWs) have emerged as a major threat to marine ecosystems and ecosystem services, presenting challenges for management of marine fisheries, aquaculture, tourism, and conservation, including for marine protected areas (MPAs). An MHW is a period of unusually high ocean temperatures, often defined as ocean temperatures that are warmer than 90% of the previous observations for a given time of year. MHWs along Australia’s coastal regions have led to mass coral bleaching on the Great Barrier Reef, damage to kelp forests and seagrass meadows in Western Australia, shifts in species, and fish and invertebrate mortality, all creating pressures on fisheries management (as reviewed in Smith et al., 2023). Understanding how climate change influences ocean extremes and impacts societal and natural values is key for evaluating future risks. Growing concerns around the effects of MHWs on marine industries, food security, ecosystem dynamics, and conservation efforts led to the development of MHW response plans for Tasmania and New South Wales during the summer of 2023/24 (Hobday et al., 2024).