Anton van Helden: Fishing threat to sea lions needs action

The number of sea lion pups declined by half between 1998 and 2009 at the main breeding grounds in the Auckland Islands.

Opinion

Another two decades of research and monitoring with no sign of any funds will do little to halt their decline.

• Anton van Helden is marine advocate for Forest & Bird.

The New Zealand sea lion was once common around our coast but now is mostly confined to the sub-Antarctic islands and has the same threat status as the kakapo. Why then does the Government's latest plan to reverse the slide towards extinction of the world's rarest sea lion offer little more than research and monitoring over the next 20 years and no firm funding commitment?

In 1997, the sea lion was classified as a threatened species and this was meant to ensure human threats were managed so they could return to non-threatened status within 20 years. Instead of recovering, the number of sea lion pups declined by half between 1998 and 2009 at the main breeding grounds in the Auckland Islands. In 2010 the threat status was changed to "nationally critical".

This tells us we need to do better than commit to two more decades of research and monitoring.

Around 70 per cent of the sea lion pups are born on the Auckland Islands; most of the rest are born on Campbell Island, also in New Zealand's sub-Antarctic region. Comparatively tiny numbers are also born on Stewart Island and in Otago and Southland.

Some natural factors have been implicated in the decline of the Auckland Islands' population. For example, two bacterial disease outbreaks killed many pups in 1998 and 2002.

Although the proposed research into factors affecting the sea lion population could be useful, it is disappointing that no firm commitment has been given to fund either the studies, or any appropriate follow-up action.

The main human threat in the Auckland Islands is the squid trawl fishery, which operates during the same months female sea lions are hunting at sea to feed dependent pups on shore. Many will also be pregnant, so if a female sea lion is killed in fishing nets, two other sea lion lives may be lost.

Fishing boats scoop up squid using massive nets between 4m and 60m high at the opening and 150-200m long.

The Ministry of Primary Industries allows up to 68 sea lions to be accidentally killed by fishing vessels each season as by-catch in the Auckland Island fisheries and in recent years it has more than doubled the fishing activity allowed there.

The main human threat in the Auckland Islands is the squid trawl fishery.

In 2001 the development began of sea lion exclusion devices (sleds) to be fitted on nets. These are intended to give sea lions a chance to escape if they become trapped inside the net.

The fishing industry says the sleds are effective but there is virtually no evidence to show how many sea lions survive the impact with sleds, and then being ejected from them.

There were an estimated 1322 sea lion deaths in the squid fishery between 1992 and 2009. The industry claims there has been only six recorded deaths in the past four years. But we can put little faith in these figures because we don't know how many sea lions are killed, or badly injured to die later, before being ejected from sleds.

The Auckland Islands fishery may also compete for the sea lions' food, which could make them more susceptible to disease and cause some pups to starve to death.

Forest & Bird believes there is insufficient focus in the proposed policy on the impact of commercial fishing on the sea lions, especially given fishing can be more easily managed than disease and other natural hazards.

Recent reports have shown there are strong incentives for the fishing industry not to report by-catch. That applies to unwanted fish and to protected species such as dolphins or sea lions.

After 20 years of going backwards the question must be asked as to why so little management has been proposed in this Threat Management Plan. Why is there no new proposal to manage the greatest known man-made threat?

For 20 years the ministry has had a major role preparing management plans, which are meant to lead to the recovery of the sea lion. However, over the past two decades of declining numbers it has been clear that the ministry has a conflict of interest. It has a focus on promoting the fishing industry's interests rather than managing the fisheries to ensure the survival of a critically endangered species.

The allowable quota of 68 sea lion deaths annually in the squid fishery should be reduced to zero. But although sleds are being used, we may never accurately know how many sea lions are killed by fishing.

Alternative fishing methods that don't kill sea lions should be introduced. Jigging with hooks on lines has previously been used to catch squid in the Auckland Islands and is much safer for sea lions.

Fishing impacts would also be reduced if the existing marine reserve in the Auckland Islands was extended to the continental shelf to cover the entire sea lion feeding range.

Forest & Bird wants to see a plan that sets New Zealand sea lions on a clear path to non-threatened status.

The proposed plan's goal over the next 20 years to simply achieve a higher population than last year's estimate of 11,800 lacks focus and ambition and amounts to little more than holding the line.

Several management plans for their recovery have been produced in recent decades and still the population of these magnificent animals has declined.

More rigorous management of the Auckland Island fisheries is the best way we can make a decisive difference.