Trawling ban could help stop endangered sea lion deaths at Auckland Islands

Monday, 23 September 2019

John Burke of the NZ Sea Lion Trust, a volunteer group based in Dunedin, explains why the marine mammal is critically endangered. (Video first published in September 2019)

In the sealing age, humans hunted sea lions from mainland New Zealand. Now industrial fishing is threatening to help drive the population from one of its last sub antarctic outposts.

With fewer than 12,000 individuals, New Zealand sea lions - rāpoka - are one of the rarest in the world. The inhospitable Auckland Islands, 500km south of Bluff, is their main breeding location.

But pup production there has declined by approximately 55 per cent in the last two decades.

Now, Forest and Bird is proposing a last-ditch plan to reduce the number of sea lions caught in fishing nets, one of the causes of death for the threatened marine mammal.

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At the main breeding location, the Auckland Islands, sea lion pup production has declined by approximately 55 per cent since 1998.

The southern squid fishery operates around the Auckland Islands and overlaps with the sea lion foraging grounds.

The conservation organisation wants a ban on trawling in a small area around the islands. It would be a temporary measure, in place until 2022.

Before human arrival, sea lions bred from Cape Reinga all the way down to the subantarctic islands.

Katrina Goddard, marine conservation advocate, says the plan is vital to protect adult female sea lions in the rookery.

Although climate change, disease and nutritional stress are also killing off the creatures, bycatch is the only threat that can be tackled in the short-term, she said.

'New Zealanders feel pretty passionate about the conservation of our native species, like kākāpō and kiwi, and the New Zealand sea lion sits right up there,' she said.

'We are not going to recover them if we don't manage the things we can manage. Direct fisheries bycatch is one thing we can manage - the species needs all the chance to recover and this is the only way we are going to that.

'Breeding females are restricted in the area that they forage because they have pups onshore that they must go back to. We know from satellite tracking data where they go, and where they forage - they don't have alternative supermarkets that they can go to.'

Forest and Bird's marine advocate Katrina Goddard.

Nine sea lions were killed in the fishery this year, four were killed by one Sanford vessel.

Fisheries NZ is currently developing a new 'operational plan' for the squid fishery, but this does not include any trawling bans.

NZ sea lions are among the rarest in the world, with fewer than 12,000 individuals.

Fisheries NZ believes the fishery is having less than a 1.5 percent impact on the sea lion population.

Officials are proposing making Sea Lion Exclusion Devices (SLEDs), an escape hatch built into fishing nets, mandatory in the fishery.

However, their efficacy has been questioned as sea lions may have drowned in the net and fallen out, or not had enough air to reach the surface once released.

NZ sea lions are regarded as nationally critical, the highest level of threat and at grave risk of extinction.

The proposal also suggests putting a limit on the number of sea lions that can be accidentally caught in the fishery before it is closed. And they would ensure observers are present on 90 per cent of the fleet.

Forest and Bird says these three options aren't enough to turn around the population decline. So, working with other environmentalists and scientists, they've come up with a fourth option, for an exclusion zone in 17 per cent of the fishery during two breeding season.

Goddard will meet with fishing company Sanford on Wednesday to discuss the plan.

The company confirmed the meeting and said: 'We are really focussed at Sanford on keeping sea lions safe and our Threat Management Plan submission will reflect that,' a spokeswoman said.

A spokeswoman for Fisheries Minister Stuart Nash said the consultation process closed last week. 'All submissions will now be analysed by Fisheries NZ officials who will then report to the Minister on the public feedback and options for next steps later this year,' she said.

The southern squid trawl fishery has been harvested for arrow squid since the late 1970s, but the catch and number of vessels has declined from 63 in 1990 to 17 operating in 2017. Last year, the export value of the fishery was estimated at $56.6 million, down from $68 million in 2016.

Earlier this year officials changed the threat classification for sea lions from 'threatened – nationally critical' to 'threatened – nationally vulnerable.'

And experts have been buoyed by the stabilisation of the sea lion population on Campbell Island, and a new rookery established on Stewart Island last year.