Story: Fishing industry

Page 5. Deep-water fisheries

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The fourth-largest fishing zone in the world

In 1978 New Zealand’s Exclusive Economic Zone (EEZ) was established as a 200-nautical-mile radius around the country. Since the 1960s the deep-water areas off New Zealand had been exploited by foreign vessels such as Russian, Taiwanese, South Korean and Japanese trawlers. Internationally, as in New Zealand, the introduction of these zones was driven by countries wanting to protect their fish stocks from foreign fishing vessels and manage them themselves.

Because its territory included the Chatham Islands and other outlying islands, New Zealand’s area was the fourth-largest fishing zone in the world (4 million square kilometres). New Zealand gained a huge potential resource. Due to the large catches made by foreign trawlers in those waters, hopes were high. With inshore fisheries over-exploited, it seemed obvious to search the depths for new species.

In the northern hemisphere the collapse of the cod and other fisheries left trawlers lying idle. New Zealand companies were able to purchase them at bargain prices and refit them, or they took long-term leases on modern trawlers. The collapse of the northern hemisphere fisheries also created a gap in the international market for high-quality white-fleshed fish. New Zealand orange roughy and hoki fitted the bill.

A rough life

In the 1980s, when the orange roughy fishery was established, scientists knew little about the species. A decade later they had a better idea of its life history:

‘A typical orange roughy is probably at least 50–60 years old and has probably been dodging sharks, sperm whales and giant squids since it began life as a 2 mm egg drifting near the sea surface … Spawning is now interrupted by large factory trawlers; tens of thousands of individuals are headed and gutted’. 1

Orange roughy

Orange roughy lives in very cold, deep water, where there is no light. Fished from 600–1,500 metres beneath the surface, it is the deepest commercial fishery in the world. This remarkable fish has a life expectancy of up to 150 years. Its longevity and slow rate of breeding means that only small numbers can be harvested without affecting the size of the population. This was not known in the 1980s, and orange roughy seemed to be a boundless resource. On one occasion 54 tonnes were caught in only 20 minutes’ trawling – but this apparent abundance was an illusion, as the fish had been concentrated in spawning schools.

Big catches were taken in the 1980s, but the boom years could not, and did not, last. The harvest peaked in 1989 at 54,000 tonnes, and has been in decline ever since. Popular in North American restaurants in the 1980s, by the 2000s orange roughy was scarce in New Zealand and commercial quotas were only a fraction of those in the 1980s. Partly this was due to the stocks being fished down for too long when populations were overestimated. Current harvest levels may be about right, or may still be too high, or may even increase slightly once over-fished stocks are re-established.


Hoki grow to about 1.3 metres long and are thin and tapering. They had been caught as early as the 1930s by coastal trawlers, but were not valued because they did not keep well. It was not until the late 1970s that Japanese trawlers off the South Island’s West Coast took hoki in large quantities. As boats moved into deep waters they found new hoki stocks, and the fishery boomed in the 1990s, accounting for much of the growth in New Zealand’s total catch. By the early 2000s hoki were being caught throughout the year rather than just at spawning time (when the condition of their flesh is not at an optimum – good-quality flesh earns more export dollars). By 2001, hoki was earning $346 million in export revenue – the single most valuable commercial species.

Hoki was the first large fin-fish fishery in the world to achieve certification by the Marine Stewardship Council as a sustainable managed fishery. In 2005 this certification was under review.

Other deep-water species

Although orange roughy and hoki dominated the catch figures, other deep-water species were commercially important, including southern blue whiting, oreo dories, squid and ling.


Deep-water trawling is highly mechanised. Only big companies can afford the massive capital investment required in modern factory-trawlers. These factory ships process everything caught on board – even guts and heads are processed into fishmeal, which is so valuable it is known as ‘brown gold’.

Because of the size of the investment, New Zealand companies embarked on joint ventures. Other nations’ trawling crews taught New Zealanders how to fish the deep waters and in return got a portion of the catch. Increasingly over the 1980s and 1990s, New Zealand companies bought their own vessels and began to fish the deep. They also chartered or leased foreign vessels. This practice caused some controversy in the early 2000s, with accusations that foreign crews were being underpaid. However, owners countered by saying they struggled to retain experienced crews, and foreign deckhands had to be brought in.

  1. D. A. Robertson, ‘The New Zealand orange roughy fishery: an overview.’ In Issues and opportunities: proceedings of the Australian and New Zealand southern trawl fisheries conference, Melbourne, 6–9 May 1990, edited by K. Abel and others. Canberra: Australian Government Printing Office, 1991, p. 38. › Back
How to cite this page:

Carl Walrond, 'Fishing industry - Deep-water fisheries', Te Ara - the Encyclopedia of New Zealand, (accessed 14 August 2020)

Story by Carl Walrond, published 12 Jun 2006