New Zealand orange roughy exports are accelerating as catch limits of the deepwater fish, once a poster child for bad fisheries management, increase amid confidence about improving stocks.

Exports of the slow-growing fish, which can live for up to 130 years, rose 6.9 percent to a three-year high of $36.5 million last year, according to Statistics NZ data. That compares with a high of $170.2 million in 1988 when the fishery was at its peak, and a low of $29 million in 2012 when catch limits were cut back.

Orange roughy exports are expanding again following a slump after three of the fisheries were closed and catch limits were pulled back to 7,000 tonnes during the 2012 and 2013 fishing years, which run from October through September, on concern about overfishing, from a peak of 61,000 tonnes in the 1988 fishing year.

New technology to better measure orange roughy populations has shown two of the three closed fisheries can now support some commercial fishing, allowing the catch limit to rise to 8,700 tonnes in the current fishing year through September 2015.

“The stocks are looking very healthy now,” said Alastair Macfarlane, a fishery consultant to industry body Seafood New Zealand. “Orange roughy catch limits have been starting to gradually increase in a number of fisheries and the outlook over the next five years is for continued capacity to cautiously increase catch limits.”

Still, he said the fishery would never return to the huge volumes of the late 1980s when the stock was being “fished down” to a lower level.

New Zealand boasts the oldest and largest orange roughy fishery in the world on the Chatham Rise, to the east of the South Island, where bottom trawling for the species began in the late 1970s.

Since the 1988 peak in orange roughy exports, China has emerged as a major market for the fish.

In 1998, 90 percent of New Zealand’s orange roughy exports were sent to the US and China wasn’t listed among the 22 export destinations compiled by Statistics NZ. However, last year the US accounted for just 63 percent of orange roughy exports, and China overtook Australia as the second-largest market for the fish, taking 21 percent of the exports.

Seafood was New Zealand’s sixth-largest commodity export last year, increasing 3.6 percent from the year earlier to $1.38 billion.