Kutupārera / Gaer Arm is a marine reserve encompassing approximately 433 hectares within Bradshaw Sound in Fiordland, Southland. It is a glacially carved fiord arm characterized by steep underwater rock walls and a relatively shallow basin that deepens to over 100 metres at its entrance. The eastern side features extensive, shaded rock walls with vertical drops of 50-60 metres, while the western side has more broken rocky reef habitat with boulders and a large river outflow. The arm includes significant estuarine habitat at the entrance of the Camelot River, containing large cockle and pipi beds and areas of seagrass flats. The water has a distinctive low-salinity surface layer from tannin-stained freshwater runoff, which filters light and influences marine vegetation. The surrounding landscape consists of dense temperate rainforest growing directly to the waterline on near-vertical slopes.

As a marine reserve, all marine life is protected, and no fishing, disturbance, or removal of any material is permitted. Paddlers must adhere to the Fiordland Marine Mammal Code of Management, which includes specific measures to minimize impacts on the local bottlenose dolphin population. The fiord's deep, dark, sheltered waters create unusual habitats where species like black coral, sea pens, and brachiopods, typically found at greater depths, can be observed in shallower areas. Wildlife in the area includes blue cod, tarakihi, butterfly perch, New Zealand fur seals, and seabirds. The environment is remote and wilderness-focused, with no paddler facilities, launch sites, or amenities. The area is part of Fiordland National Park and the Te Moana o Atawhenua / Fiordland Marine Area.