Trawl gear damages fragile coral reefs, so why is the Government sanctioning more hauls?

Monday, 28 September 2020

Scientists in Jordan are developing techniques that could help repopulate coral reefs.

Vast fishing nets have hauled up 29 species of delicate coral from the still, dark depths of New Zealand's oceans.

And conservationists are warning that the Government has abandoned protection of the sea bed in favour of expanding bottom trawling.

Of protected species dredged up by vessels in the last 18 months, 59 were deep sea corals. Photographs of the brightly coloured, fragile invertebrate animals were taken by fisheries observers after being retrieved from fishing nets. The photos were released under the Official Information Act.

One of 29 species of coral trawled up from New Zealand's ocean floor over the last 18 months.

Conservationists say dragging heavy nets on the ocean floor destroys fragile marine life, such as sponges and coral, that grow painfully slowly and can take decades, or even hundreds of years, to recover.

* Fishing vessels 'bulldozing' oceans, destroying 3000 tonnes of coral in one year

* Bottom trawling for fish causing 'permanent damage' to deep sea forests

Now conservation organisation Forest & Bird is questioning why the Government recently increased catch limits for orange roughy caught by trawling in the deep seas of the Chatham Rise, east of New Zealand.

Fisheries Minister Stuart Nash has increased catch limits for 26 fisheries, beginning in October.

But the commercial fishing industry argues only 2 per cent of the seabed in New Zealand’s exclusive economic zone (EEZ) is trawled. And about 30 per cent (over 1.2 million square kilometres) of the EEZ is closed to bottom trawling.

Earlier this month, Fisheries Minister Stuart Nash said the commercial catch would increase by 18 per cent. That’s in line with similar rises in the previous two years.

New Zealand takes about around 95 per cent of the world’s orange roughy catch.

The fish, which has a firm, sweet, easy-cook flesh, is slow-growing and can reach a maximum age of 230 years.

The population almost collapsed due to overfishing in the 1980s and 1990s, and catch limits were put in place to allow stocks to recover.

Nash said the increase reflected updated science and stock assessments. “An estimated $15.2 million gain in export earnings is expected as a result of the 1195-tonne increase in catch,” he said.

Fisheries NZ manages and regulates fish stocks, and aquaculture from within the Ministry for Primary Industries.

A discussion document released by the agency in May did not mention the impact on coral.

New Zealand is the world's most prolific orange roughy catcher, responsible for around 95 per cent of the global catch.

“The trawl footprint in [the fishery] is estimated to have contacted 11 per cent (5298 km2) of the seabed … between 800-1600m depths from 2008-2018,’’ the document says.

“Most fishing occurs within areas that have been fished for a number of years, and it is estimated that there is very little ‘new’ area trawled each year.

“Therefore, increasing the TAC [total allowable catch] and TACC [total allowable commercial catch] under either of the proposed options is unlikely to increase the trawl footprint significantly.”

The agency says it closely monitors bottom trawling and controls include closed areas, regular monitoring of where vessels have fished and the type and quantity of marine species caught.

“Where there is evidence that commercial fishers are bottom trawling in prohibited areas, we take action,” a Fisheries NZ spokeswoman said.

She cited a recent case where Sealord was fined $24,000 and ordered to forfeit a US$16 million vessel for an illegal deep-sea trawl in a protected zone about 200 nautical miles east of Christchurch.

Kevin Hague believes bottom trawling causes largely irreversible destruction of the seafloor.

Forest & Bird believes that indicates the Government has “given up” on conserving the seabed.

“The incredible photos from MPI’s own observers show the fishing industry is continuing to haul up dozens of coral species. So despite what the Government says, their own observers show that the damage is ongoing,” chief executive Kevin Hague said.

For conservationists, coral reefs are an important ecosystem for underwater life. Many want bottom trawling banned on marine ecosystems like seamounts because of the destruction of vital habitats which underpin the health of the ocean.

Last year more than 40,000 people signed a petition calling on the Government to ban bottom trawling on seamounts.

“The Ministry of Fisheries has given up on our deep ocean ecosystems,” Hague said.

“The ministry appears to be saying that expanding the catch for orange roughy makes no difference to the environment, because the sea floor has already been trawled to destruction.

“This is surely the nail in the coffin for any claims to sustainability from the bottom trawling industry.”

George Clement is chief executive of the Deepwater Group, an advocacy group for deep sea fishing.

Conservation groups also argue that the trawl footprint actually grew by 800 km² between 2013 and 2018.

Fisheries NZ says this is an overestimation because it doesn’t include historical fishing before 2007 and any increase would not be significant or extend into previously unfished areas.

The agency also disputes claims that the New Zealand commercial fishing vessels destroyed up to 3000 tonnes of coral and other vulnerable species through bottom trawling in 2017-18, saying there were questions about the methods used to make the estimation.

It has pledged to map and monitor the trawl footprint of the orange roughy fishery annually.

An updated stock assessment “showed increased abundance of orange roughy in the area,” the spokeswoman said in a written statement.

“Importantly, orange roughy fisheries are generally focused on particular locations where the fish aggregate to spawn. This means that increasing the catch limit is highly unlikely to increase the area contacted by fishing.”

Orange roughy fisheries were previously much larger, with catch limits over 30,000 tonnes compared to the catch limit of 7967 tonnes in 2020-21.

Bottom trawling is an industrial fishing method that involves dragging a large, weighted net along the seafloor.

“We don’t expect limits will ever come near those historical levels, meaning fishing effort and distribution is likely to continue to be smaller and remain well within previously fished areas,” she said.

The Deepwater Group represents fishing companies that fish mainly within New Zealand waters. Chief executive George Clement, says those in the deep water fishing industry value the marine ecosystem.

“Our livelihoods, businesses and future depends upon healthy marine environment,” he says.

In context, all forms of food production necessitate some form of environmental change.

A deep sea trawler in the Tasman Sea. Bottom trawling is the most common trawl method used in New Zealand.

“Even organic farming requires the wholesale removal of native fauna and flora to be replaced by food-producing plants – almost all of which are non-native to New Zealand. All primary food producers have a duty to mitigate their impacts on the environment and deep water fishing is no exception.”

Clement says fishing will have “minor impacts” on the environment.

“It is a question of balance – while occasional interactions with individual protected animals will occur, we must ensure that these are so infrequent that they do not upset their natural population sizes.”

But protected species will be captured. “The sustainability test is to determine whether or not these occasional interactions cause adverse effects on the ecosystem,” he says.

Deep-sea corals are among the slowest growing and longest-lived animals in the ocean.

“Industry’s focus has been to reduce these interactions to as few as is possible. Our obligation, one which we take seriously, is to avoid these interactions and to mitigate harm wherever we can.”

Coral is at risk from bottom trawling, oil and gas exploration, and extraction, the laying of cables and telecommunications links, plastics, waste disposal, climate change and ocean acidification.

Most corals are protected under the Wildlife Act 1953.

There are approximately 110 deep water coral species in New Zealand waters, representing about a sixth of the world’s described species.

A Niwa report, published last year, warned that disturbance of corals by bottom trawl gear is “the most obvious and dramatic source of impact”.

It’s an efficient way to catch deep sea fish, but many environmentalists want the practice banned, comparing the impact on centuries-old coral to the destruction of kauri forests.

The method involves dropping a large net on the seabed, sometimes in depths up to one kilometre, and dragging it behind a ship, scooping up everything in the wake.

The animals have been broken by longline weights or a mainline cutting through them during fishing or hauling.

Corals are also smothered by sediment plumes in the wake of nets, which can be 2-4 metres high and up to 150m wide.

As few as 10 trawls can reduce a coral cover of 15-20 per cent of the sea bed to nothing visible.

“Most coral species have attributes that make them highly sensitive to impact, with low recovery potential,” The State of knowledge of deep-sea corals in the New Zealand region report concluded.

But Clement argues that 98 per cent of orange roughy tows undertaken with an MPI observer on board have not encountered coral.

The weight of coral taken in the observed tows has averaged about 8kg, he says.

“Most trawling occurs year after year over the same locations and most of this is on muddy or sandy sea floor … which are not suitable habitats for corals, which require hard substrates to attach to, such as rocky ground.”

He says the industry recently trialled underwater cameras in a project to routinely record bottom habitats in orange roughy trawl pathways.

“Industry recognises the vulnerability of coral communities to bottom trawling, supports and funds scientific studies to further overall knowledge.

“However, as corals are very widely distributed, the orange roughy fishery interacts with only very small parts of their distribution and corals are only occasionally encountered during orange roughy fishing, scientists consider the overall impact on corals to be slight.”