{"id":60099523,"date":"2025-09-18T17:07:06","date_gmt":"2025-09-18T16:07:06","guid":{"rendered":"https:\/\/dialogue.earth\/?p=60099523"},"modified":"2025-09-30T12:50:21","modified_gmt":"2025-09-30T11:50:21","slug":"inside-the-battle-over-trawling-a-200-year-old-deep-sea-fish","status":"publish","type":"post","link":"https:\/\/dialogue.earth\/en\/ocean\/inside-the-battle-over-trawling-a-200-year-old-deep-sea-fish\/","title":{"rendered":"Inside the battle over trawling a 200-year-old deep-sea fish"},"content":{"rendered":"\n

Down in the deep, dark South Pacific Ocean live grouchy-looking, sluggish fish. Some of them have been around since the Qing Dynasty ruled China and possibly even before the United States was an independent country.<\/p>\n\n\n\n

With a life expectancy of up to 250 years<\/a>, orange roughy live slowly. They reach maturity in their late 20s and early 30s when they can gather and breed mostly on seamounts at depths of 800-1,600 metres.<\/p>\n\n\n\n

Their unhurried lifestyle was largely undisturbed until the late 1970s, when humans began catching them with deep-sea trawl gear. Since then, orange roughy numbers have plummeted. Bottom trawling, the primary method for harvesting the species, is infamous for its destructive impacts on seabed communities. It also involves high levels of \u201cbycatch\u201d \u2013 the capture of non-target animals.<\/p>\n\n\n\n

\"Orange<\/div>
An orange roughy at Atlantis Bank Seamount off the south-east coast of Madagascar, photographed from a remotely operated vehicle (Image: AD Rogers, NERC\/IUCN Seamounts Project)<\/div><\/div><\/div><\/div>\n\n\n\n

These days, bottom trawling and the use of deep-sea resources more generally are both facing growing scrutiny, ranging from the cinema-going public<\/a> to international negotiators<\/a>.<\/p>\n\n\n\n

The stay-or-go debate over orange roughy fisheries encapsulates the tensions in the relationship between humans and the deep sea.<\/p>\n\n\n\n

Deep fishing, deeply damaging?<\/h2>\n\n\n\n

The orange roughy population in part of the largest fishery is now \u201csignificantly below\u201d sustainable levels, with only between 8% and 18% of its pre-fishing biomass remaining, according to recent study<\/a> by the New Zealand government. <\/p>\n\n\n\n

For context, Earth Sciences New Zealand<\/a> (previously the National Institute of Water and Atmospheric Research) states that a biomass level below 20% represents an overfished stock, and one below 10% is deemed to be \u2018collapsed\u2019 and at risk of not recovering.<\/p>\n\n\n\n

As such, the fish may take decades or even centuries to replenish its populations, given its slow growth and maturation. <\/p>\n\n\n\n

No one is starving for lack of an orange roughy meal. It\u2019s not going to people where food security is an issue<\/blockquote>Karli Thomas, Deep Sea Conservation Coalition<\/cite><\/div><\/div>\n\n\n\n

Conservationists also say the fishing causes huge damage to seabed ecosystems, especially on the seamounts where the fish likes to spawn and feed, as trawl nets also scrape up corals and sponges that are known to live for over 10,000 years.<\/p>\n\n\n\n

\u201cOne pass of a trawl net can do significant damage,\u201d says Karli Thomas from the Deep Sea Conservation Coalition. \u201cAs few as 10 trawls can leave just a field of rubble. That\u2019s a private gain on the basis of an environmental destruction that affects everybody.\u201d<\/p>\n\n\n\n

Bottom trawling targeting orange roughy dragged 112.7 tonnes of coral between 2007\/08 and 2019\/20, a report commissioned by the New Zealand government shows<\/a>.<\/p>\n\n\n\n

Bottom trawling in general can be destructive regardless of the fish being targeted. In 2024, an unnamed<\/a> bottom trawling vessel pulled up six tonnes of protected stony coral from a fishing ground, where orange roughy, hoki, hake and other species are fished, according to data obtained by the Deep Sea Conservation Coalition from the New Zealand government.  <\/p>\n\n\n\n

New Zealand exports<\/a> most of its orange roughy catch, keeping only a small amount for local consumption. In 2024, these exports were worth NZD 55 million (USD 31 million), according to NZ Stats. <\/p>\n\n\n\n

Its largest export markets are the US and China. The US usually takes<\/a> the frozen fish fillets, while the whole fish goes to China. <\/p>\n\n\n\n

The fish is usually served on middle-class dining tables, says Thomas. \u201cNo one is starving for the lack of an orange roughy meal. It\u2019s not going to people where food security is an issue.\u201d<\/p>\n\n\n\n

The Deep Sea Conservation Coalition says<\/a> the New Zealand government must end bottom trawl fishing on seamounts in New Zealand and the South Pacific. But fishers in New Zealand, who capture 80% of the global orange roughy catch, refuse to retire their nets. <\/p>\n\n\n\n

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\"surface<\/div>
The surface of a pristine, untrawled seamount south of Tasmania, photographed during a research trip by the\u00a0Commonwealth Scientific and Industrial Research Organisation in 1997 (Image: Tony Koslow \/ CSIRO)<\/div><\/div><\/div><\/div>\n<\/div>\n\n\n\n
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\"surface<\/div>
The surface of a heavily trawled seamount, also south of Tasmania and photographed on the same trip (Image: Tony Koslow \/ CSIRO)<\/div><\/div><\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n

\u2018This keeps us in business\u2019<\/h2>\n\n\n\n

\u201cPart of our job is to keep the fisheries open,\u201d Charles Heaphy, resources manager at Sealord Group, a New Zealand seafood company, tells Dialogue Earth. <\/p>\n\n\n\n

The fishing industry data shows<\/a> New Zealand\u2019s deep-water fishing contributes NZD 2.7 billion (USD 1.6 billion) to the economy and supports around 8,500 full-time jobs. Sealord holds the largest orange roughy fishing quota within New Zealand\u2019s exclusive economic zone (EEZ). It also partly controls one of the few firms still bottom trawling for the species in the international waters of the South Pacific. <\/p>\n\n\n\n

<\/div>
Recommended<\/span><\/span><\/div><\/a>\n\n\n\n

Heaphy says fishing firms have \u201cgood reasons to keep access to these fisheries\u201d. <\/p>\n\n\n\n

Only a tiny fraction of the New Zealand EEZ and the South Pacific allows bottom trawling, he notes. In the last three years, orange roughy accounted for 2.4% of the weight of Sealord\u2019s domestic New Zealand catch, Heaphy says. \u201cBut that\u2019s really, really important to keep us in business.\u201d <\/p>\n\n\n\n

Apart from orange roughy and other white fish, the company also catches<\/a> low-value fish that are directly sold to Africa, he adds. These fisheries often just break even, and the company relies on fishing orange roughy and other higher-value fish to stay afloat, he says.<\/p>\n\n\n\n

But whether the orange roughy fishery can be considered sustainable is an increasingly debated point.<\/p>\n\n\n\n

A boom and a bust<\/h2>\n\n\n\n

For most of history, commercial fishers did little work at depths below 400 metres from the surface. <\/p>\n\n\n\n

But the former Soviet Union\u2019s discovery in 1969<\/a> of slender armorhead on the Hawaiian-Emperor seamount chain marked a drastic shift. The next year, they trawled up nearly 150,000 tonnes of the greyish deep-sea creatures. <\/p>\n\n\n\n

In 1979, the discovery<\/a> of large numbers of spawning orange roughy on the Chatham Rise, an area of ocean east of New Zealand’s South Island, led to a rush for the pale-fleshed fish, which are valuable enough that they were sometimes called \u201cwhite gold\u201d in the country. <\/p>\n\n\n\n

There were so many fish that trawls could catch 10 tonnes per minute and end up throwing some away or even bursting their nets, according to the UN\u2019s Food and Agriculture Organization<\/a>. <\/p>\n\n\n\n

A crash was to come.<\/p>\n\n\n\n

Plummeting population<\/h2>\n\n\n\n

Chatham Rise is home to the world\u2019s oldest and largest orange roughy fishery. Over 60-70% of New Zealand orange roughy catches are from the rise \u2013 particularly the \u201cEast and South\u201d area.<\/em><\/p>\n\n\n\n

In 1997, scientists studied the stock reduction in the north-eastern part of the rise and discovered only 20%<\/a> of the pre-fishing biomass was left. Catches dropped from over 50,000 tonnes in 1989 to fewer than 20,000 tonnes in 1994 and some of the New Zealand orange roughy fishing grounds closed as a result. That includes the Spawning Box<\/a>, an important spawning area, which was closed in the early 1990s, and seamount \u201cMorgue\u201d which has been closed to bottom fishing since 2001.<\/p>\n\n\n\n

For those that remained open, the New Zealand government significantly reduced the amount fishers were allowed to catch. <\/p>\n\n\n\n

\u201cThose mistakes of 40 years ago still haunt us,\u201d says Heaphy. He is referencing a past lack of knowledge on orange roughy\u2019s reproductive cycles and limited stock assessment technology. These blinded regulators and fishers, he says. \u201cFrom my perspective, we\u2019ve got to put that behind us.\u201d<\/p>\n\n\n\n

After the crash in the 1990s, the industry<\/a> heavily invested in building a sustainable reputation. Since then, the stock decline has stabilised and even shown signs of recovery at times, albeit remaining<\/a> far below historic levels.<\/p>\n\n\n\n