35 TONNES FROM THE DEEP: CORAL BYCATCH REIGNITES BOTTOM TRAWLING BATTLE
New fisheries data showing commercial trawlers reported hauling up more than 35 tonnes of protected coral and sponges from New Zealand waters over six and a half years has reignited the debate over the environmental cost of bottom trawling. Data released by the Ministry for Primary Industries shows 35,640 kilograms of coral and sponges were…
New fisheries data showing commercial trawlers reported hauling up more than 35 tonnes of protected coral and sponges from New Zealand waters over six and a half years has reignited the debate over the environmental cost of bottom trawling.
Data released by the Ministry for Primary Industries shows 35,640 kilograms of coral and sponges were reported as bycatch between October 2019 and March 2026. Greenpeace Aotearoa and the Deep Sea Conservation Coalition say the numbers strengthen the case for protecting seamounts and other vulnerable deep-sea habitats from bottom trawling.
CHATHAM RISE ACCOUNTS FOR ALMOST 60 PERCENT
The Chatham Rise, east of the South Island, recorded the largest share, with around 20 tonnes of seabed bycatch — nearly 60 percent of the total.
The Sub-Antarctic and South East fisheries areas were also among the locations recording significant bycatch.
These areas include seamounts and other deep-sea features capable of supporting corals, sponges and diverse marine ecosystems.
Greenpeace says the figures challenge industry arguments that encounters with coral are rare or that fishing vessels avoid important coral habitats.
The fishing industry has previously defended bottom trawling as an important part of New Zealand’s commercial seafood sector and has emphasised the relatively limited geographical footprint of trawling.
MPI says the bottom-trawl footprint during the 2024-25 fishing year covered 1.7 percent of New Zealand’s combined Territorial Sea and Exclusive Economic Zone, and around 5 percent of fishable area. Around 31 percent of the EEZ is prohibited to bottom trawling.
35 TONNES MAY NOT REPRESENT THE FULL IMPACT
Environmental groups argue the weight recovered in fishing nets cannot measure the entire physical impact on the seabed.
Greenpeace and the Deep Sea Conservation Coalition say coral can be damaged or broken by fishing gear without being hauled to the surface and subsequently recorded as bycatch.
Their estimate suggests the physical amount of coral affected could potentially be far greater than the 35.6 tonnes actually recorded in nets, although those higher estimates are an environmental-group calculation rather than a direct MPI measurement of destroyed coral.
The latest figures also follow longer-term research highlighting repeated encounters between trawlers and protected corals.
A previous NIWA report prepared for the Department of Conservation documented more than 13,400 recorded incidents involving protected coral bycatch over 35 years, including encounters around seamounts and other underwater features.
WHY DEEP-SEA CORAL MATTERS
Unlike shallow tropical reefs, some deep-water corals grow extremely slowly.
Environmental groups say individual corals can survive for hundreds or even thousands of years, while the structures they create provide habitat for other marine life.
That makes the argument over bottom trawling about more than the number of tonnes brought back aboard fishing vessels.
The central question is whether areas known to contain vulnerable ecosystems should remain available to a fishing technique involving nets and heavy equipment being towed along or close to the seabed.
FISHING INDUSTRY REMAINS ECONOMICALLY IMPORTANT
Bottom trawling also remains deeply embedded in New Zealand’s commercial fishing industry.
MPI says approximately 68 percent of fish caught by volume in New Zealand is taken by trawling on or within one metre of the seabed.
That means proposals for further restrictions inevitably raise questions about jobs, seafood exports and the economies of coastal communities.
But environmental campaigners argue protecting sensitive habitats does not require shutting down the entire fishing industry.
Greenpeace points to information presented during a 2022 government process suggesting closing all seamounts in New Zealand waters would reduce fishing value by around 6 percent, assuming those fish were not subsequently caught elsewhere.
ORANGA MOANA BACK ON THE ELECTION AGENDA
The argument carries particular significance for Te Ao Māori.
For generations, the moana has provided kai, employment, economic opportunity and cultural connection. Māori are also significant participants in the commercial seafood industry following Treaty settlements.
That means the debate cannot simply be reduced to fishing versus conservation.
It raises a much bigger kaupapa around oranga moana, kaitiakitanga and how Aotearoa balances economic use of marine resources with responsibility for the ecosystems supporting them.
With Election 2026 approaching, Greenpeace is calling on political parties to protect seamounts and other vulnerable habitats from bottom trawling and ultimately transition away from the practice.
The fishing industry and Government will continue to point to existing closures, management measures and the economic importance of trawling.
But 35,640 kilograms of protected coral and sponges appearing in fishing nets over six and a half years ensures one question will be difficult to avoid this election — how much damage to the deep ocean is Aotearoa prepared to accept in exchange for the fish we bring to the surface?
