The coastal waters of south-east Tasmania consist of a system of channels and embayments including Storm Bay, the D'Entrecasteaux Channel, the Derwent Estuary and Huon Estuary. The region is a major centre of aquaculture, commercial and recreational fisheries. The Tasman Sea, offshore of these waterways has experienced an increased occurrence of Marine Heatwaves (MHWs, defined as temperatures above the 90th percentile for a period of over 5 days), with particularly notable events in 2015/16, 2017/18 and 2023/24.
In this study we use output from CSIRO’s Storm Bay and ETAS models to quantify how MHW exposure and characteristics such as frequency, duration, maximum intensity and depth of maximum intensity have changed between the 1990s and the 2020s. Results indicate that the frequency and severity of MHWs are increasing with a notable increase in the exposure of benthic environments to MHWs. This result may have significant implications for the management of benthic species (such as Macrocystis kelp, Sand Flathead and Handfish), environments and fisheries.