Tony Browne (left), deputy secretary of New Zealand's Ministry of Foreign Affairs and Trade (MFAT), witnesses US Chargé d'Affaires Robert Clarke signing the Convention on the Conservation and Management of Fisheries in the South Pacific Ocean in 2011. This agreement ensures that fishing from Western Australia to South America is subject to agreed international rules. New Zealand was the depository for the convention, so the US signing took place in MFAT's offices in Wellington. A chargé d'affaires is a senior diplomat of lower rank than an ambassador.