Confirmation of green turtle (Chelonia mydas) foraging grounds in northern New Zealand

The green turtle (Chelonia mydas) is the only sea turtle species to reside year-round in New Zealand waters, with juveniles using shallow coastal habitats as foraging grounds before dispersing throughout the Pacific. Rangaunu Harbour in northern New Zealand was surveyed in the austral summer to assess the feasibility of aerial drones for monitoring green turtles. Across 163 km of drone transects, 27 turtle sightings representing potentially 18 unique individuals were recorded, predominantly in shallow seagrass (Zostera muelleri novozelandica) habitats during high tides. Five green turtles were observed actively foraging on floating seagrass and among the subtidal seagrass beds. These sightings provide visual confirmation that the harbour is a temperate neritic foraging ground for green turtles in New Zealand. The survey also documented diverse marine fauna, including eagle rays (Myliobatis tenuicaudatus), stingrays (Bathytoshia spp.), and several teleost species, confirming the feasibility of drones as a monitoring tool for turtles and other marine megafauna. Anthropogenic pressure to estuaries and coastal New Zealand ecosystems, including Rangaunu Harbour, highlight the need to identify and protect critical green turtle habitat in New Zealand waters as soon as possible. Further drone surveys in nearby harbours are feasible and recommended to locate additional foraging areas for green turtles across northern New Zealand.