Extreme climate change-related occurrences, such Maritime Heatwaves (MHWs), can have a significant negative influence on ecosystems. Thermal stress frequently causes localised die-offs and observable evidence of damage, as organism bleaching. While these effects are frequently reported in shallower habitats, deeper Mesophotic Ecosystems (MEs), where data collection is more expensive, have received less attention. However, these deeper ecosystems frequently exhibit biodiversity and serve crucial ecological functions, making it crucial to comprehend how climate change will affect these depths. Here, we investigate bleaching in a cup sponge' morphospecies' (i.e., morphologically different animals easily detected in imaging) in MEs across eastern Tasmania, an area undergoing fast ocean warming, using benthic imagery taken as part of a large-scale monitoring programme. We observe a rise in the frequency and there is currently no proof of widespread death as a result of bleaching, despite signs of bleaching in surveys following MHWs.
