In New Zealand, hoki (Macruronus novaezelandiae) are typically trawled from depths of 200–800 metres. Between 1990 and 1995, catches averaged a staggering 200,000–240,000 tonnes annually. Hoki, also known as blue grenadier, is now New Zealand’s most valuable export fish. Ling (Genypterus blacodes, belonging to the cusk eel family) are bottom-dwelling fish typically caught by trawls (which are believed to damage the sea floor) or longlines (which may entangle seabirds). Prior to significant coastal fishing in New Zealand, ling were commonly regarded as inshore fish and were frequently caught inside harbours. Today they are regarded as a deep coastal species, usually taken in depths of 250 metres.
Orange roughy (Hoplostethus atlanticus) are trawled from depths of 700–1,000 metres and caught when they come together to spawn. The orange roughy was first reported from New Zealand waters in 1957, when it was given the unappealing name of ‘slimehead’. This was changed for marketing purposes when commercial quantities were taken in 1979. Catches peaked at around 54,000 tonnes in 1988–89. Since then new information about their biology has led to the imposition of quotas inside the New Zealand Exclusive Economic Zone. Most fish biologists now believe that orange roughy are long-lived (up to 150 years) and slow growing; fishing is being managed to take this into account. The biggest fishery is on the Challenger Plateau, while many areas on the Chatham Rise are no longer economic for fishing. There is concern that stocks are being over-fished.
The Patagonian toothfish (Dissostichus eleginoides) lives in waters south of the New Zealand subantarctic islands. To increase marketing appeal it was renamed Chilean sea bass. It grows to just over 2 metres long and 100 kilograms in weight, and can fetch a high price in Japan and the United States. The fish were originally trawled, but longlines are now used for adult fish. As a result many seabirds become entangled in the lines. Most fishing occurs at depths between 400 and 1,500 metres. Poaching of these valuable fish in Australian and other waters may threaten the viability of the fishery. Populations typically survive 2–3 years of harvesting before the fishery collapses. In 2004 the New Zealand government recommended a plan of action to stop illegal, unregulated and unreported fishing of the species.