A tale of two (threatened) species

03:05, Aug 17 2012

This is a story of two species of native animal that are found only in New Zealand. Both species are large, cute and cuddly animals that live for a long time. Both have adorable babies and both are a part of our national story and identity.

Species number one is well known to many New Zealanders even though most people will never see one. The kakapo is world famous for its endearing physical qualities, curiosity and intelligence and for the story of how rare it is - clinging to the edge of survival.  For 21 years, an unusual alliance has seen a partnership between the Department of Conservation, the New Zealand Aluminium smelter and Forest & Bird, all working together toward the recovery of the species. Our kakapo reached as few as 50 individuals just 20 years ago - the constant victims of stoats, cats and other predators. A predator-free sanctuary home on Codfish Island and a handful of other islands has seen the kakapo make a slow and steady recovery to 125 birds this year.

Cute kakapo chicks get plenty of helping hands (Picure: Sam O'Leary). 

The dedication of conservation workers, scientists and volunteers from the public to help protect kakapo is legendary. People make no complaints about traipsing the steep, muddy and challenging terrain to either feed or keep a watch over breeding kakapo. The opportunity to be a kakapo "nestminder" where you reverse your sleeping pattern, sleeping during the day and lying awake at night in a tent pitched next to a kakapo nest, is so popular, the volunteers list has thousands of would-be kakapo babysitters.

Imagine if you will if the Government allowed pheasant shooters down to Codfish every year (let's pretend that there were pheasants down there), and set a kill limit for the collateral damage to kakapo of a few kakapo a season, in order to allow a few people to keep shooting pheasants, and kakapo chick numbers almost halved as a result over 14 years - there'd be a public outcry, both here and internationally.

Yet that is exactly what is happening every year to our New Zealand sea lions or whakahao - one of the rarest species of sea lion in the world. Large, long-lived and with cute babies and also on the "Nationally Critical" list. But in this instance, instead of camping out at night next to them to ensure their survival, we're contributing to their rapid decline.


Newly born New Zealand pups, Enderby Island, Auckland Islands (Picture: Nicola Toki)

Once found all around New Zealand's coasts, these large pinnipeds were hunted by Maori and later by European sealers, which pushed their population to the edge of extinction. For a long time the only place the sea lions bred was in the Sub-Antarctic Islands, mostly on the Auckland Islands. The Auckland Island population remains their stronghold.  

The Auckland Islands are also in the vicinity of our squid fishery, and every year huge trawlers head down to the area to catch squid. Unfortunately, they are also catching sea lions. Every year the Government sets a kill limit for sea lions - which is essentially a mathematical equation based on the distance the trawlers cover and the number of "tows" they do. e.g. if you travel x kilometres, then y sea lions are presumed to have been caught. Once the total presumed number of sea lions gets caught (z) then the trawlers must go home.

The science is clear on this issue. Globally, pinnipeds are threatened either directly or indirectly by fishing. Between 1998 and 2011, New Zealand sea lion pup numbers declined by 50 per cent. A recent paper by New Zealand's sea lion expert published in Polar Biology predicts the functional extinction of the Auckland Island sea lions by 2035.  And yet we keep fishing for squid. What's the story?

The industry says that the sea lion problem is solved because they are using sea lion exclusion devices (SLEDS). These are a bit like a trapdoor in the net, which is supposed to allow the sea lion to escape alive.  There is no evidence to suggest that sea lions that escape the nets actually survive. And that is the crux of the debate.

The squid fishing industry says that because sea lions are not being observed in the nets, the sea lions are not being killed. But we don't know that. There is no proof that dead sea lions are retained in the nets. The key here is on the question of whether sea lions are being ejected dead from the nets, either by drowning or by hitting the steel bar of the SLED so hard on the way out of the trawl that they are killed or made unconscious, then drown. We know that more female sea lions than males get caught in the nets, which is a problem because often the females are pregnant, and have a pup waiting for them on the shore. Killing her can kill three animals in one go.

The Government has promised more observers on squid boats, but if the sea lions are being ejected out of a net, hundreds of metres underwater in the darkness, no observer will be able to see that.  It's too dark to stick cameras down there on the nets, so what we need is proof that SLEDS are working as they are intended to. 

Maybe we need to put a fake sea lion into a net with a SLED to see if it is retained. There is no plan to do so. In fact, the Minister of Primary Industries is so confident that when he announced the sea lion kill limit for this year he said "Improved scientific research shows Sea Lion Exclusion Devices (SLEDs) that enable sea lions accidentally caught in fishing gear to escape are working". Dr Bruce Robertson, a scientist at Otago University says the minister is wrong.

This week New Zealand was listed as doing poorly on the global "Ocean Health Index". Clearly we are not getting it right with our management of sea lions.  Why is a "nationally critical" (same as kakapo) species being managed by fisheries legislation (instead of conservation)? Why are there no trials to see if SLEDS are actually working? Why are we standing by and watching a species hurtle to extinction when we have the ability to do something about it?

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