Te Whanga Lagoon is the largest waterbody on Chatham Island and is prized for its recreation and food gathering values, as well as having high cultural values. It is predominantly a brackish or saline environment, due to periodic openings to the sea. It has moderate to high nutrient levels and sometimes suffers from algal blooms. Many of the watercourses on the island drain to Te Whanga Lagoon, so its health is linked to the management practices in many catchments. (https://cic.govt.nz/assets/CIC/Documents/Chatham-Islands-Freshwater-Investigation-State-of-the-Water-Resources-Report-June-2020.pdf)