Marine fauna observations offer crucial insights into the spatial and temporal patterns of species distribution in offshore environments. Through industry partnerships, the Australian Institute of Marine Science has compiled a dataset of marine fauna sightings recorded by Marine Mammal Observers aboard vessels operating in the Otway Basin, Australia. The data provide an opportunity to investigate the spatial and temporal patterns of the reported species in this region. Data were collected during daylight hours over a period of up to seven months, capturing species identity, distance, bearing, and behavioral context. Recorded species included marine mammals, sharks, and marine turtles, along with ecological indicators such as bait balls and seabird aggregations. By applying density surface modelling, we aim to quantify habitat use, particularly for threatened species like pygmy blue whales, and assess the impact of offshore infrastructure on marine megafauna. The findings contribute to marine spatial planning efforts, including the management of proposed offshore renewable energy developments in the region.