Distribution of Eastern Indian Ocean pygmy blue whales and potential impacts of offshore wind developments (NESP MaC 4.8)

The offshore renewable energy (ORE) sector is rapidly developing in Australian waters to meet the country’s carbon emission targets. However, new developments in the marine environment pose added risk to threatened species. The Eastern Indian Ocean pygmy blue whale (Balaenoptera musculus brevicauda) was identified as a key species by the Australian Government for understanding the potential impacts of ORE developments. This subspecies ranges from the Subtropical Convergence (~40-45°S) to Southeast Asia (~2°S) with most of its documented distribution within the Australia Exclusive Economic Zone. Pygmy blue whale distribution overlaps various anthropogenic activities across their range, which suggests that some level of exposure to pressure and threats is likely. We compiled all available spatial data to quantify the full and foraging distribution of pygmy blue whales and quantified exposure to individual and cumulative threats across the species distribution. Threat exposure analysis included expert elicitation to gather expert input on the probability of exposure to a threat occurring from the spatial overlap between pygmy blue whale distribution and anthropogenic pressures, with a focus on areas undergoing ORE development. The cumulative exposure assessment indicated a relatively low level of exposure of pygmy blue whales to existing threats within Australian waters, particularly those that occur within declared ORE areas. However, several gaps in data and knowledge were identified that need to be addressed prior to development of the ORE industry. Our results provide a robust baseline that can be directly incorporated by industry and regulators as spatial layers into impact assessments. The study helps inform Government, and proponents of wind farms on the current state of knowledge of pygmy blue whale distribution and exposure to threats in Australian waters for use in decision-making, helping facilitate the sustainable development of the ORE industry in Australia.