NZ Sea Lion Research Shows More Action Needed to Address Fishing Threat

New research published today shows that more action is needed to reduce accidental catch of endangered New Zealand sea lions in fishing nets, said environmental organsiation WWF-New Zealand.

NZ sea lions/rāpoka are the most severely threatened and rarest sea lion in the world. They are listed as 'nationally critical' by the Department of Conservation, and without further action this species is at risk of extinction.

The research, undertaken by a team of scientists from the University of Otago, Massey University and the University of Toronto, and published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), uses government data to analyse the impact of fishing on the NZ sea lion population. The scientists conclude that accidental catch in fishing nets poses a greater threat to NZ sea lions than is currently assumed by the government.

Livia Esterhazy, Chief Executive officer of WWF-New Zealand said: “Research like this is vital in helping us to understand the threats to endangered species. Robust science lies at the heart of good management and we urge the government to take this new work on board so that we can ensure the survival of the NZ sea lion.

“Although NZ sea lions are also affected by disease and food shortages, accidental killing in fishing nets is the biggest human threat these precious animals face. The fishing threat can be actively managed, so surely we should do all we can to reduce it.”

Peter Hardstaff, Head of Campaigns at WWF-New Zealand said: “The fishing industry took an important step by installing sea lion exclusion devices, or SLEDs, in squid trawl nets but for years there have been concerns about their effectiveness. This new study provides certainty that fishing remains a significant threat to NZ sea lions.”

In December, the New Zealand government will take decisions on the management of the squid trawl fishery, which poses the most significant by-catch threat to NZ sea lions.

“This research has come at an important time,” Mr Hardstaff said. “The government should take immediate precautionary management action to reduce by-catch of sea lions in the squid fishery, and carry out research to specifically investigate the effectiveness of SLEDs.”

The overwhelming number of New Zealanders – 84% – want the government to do more to protect endangered NZ sea lions from being accidentally caught and killed in fishing nets (Colmar Brunton polling, July 2017).

ENDS
Notes:
1.The research paper “Marine mammal population decline linked to obscured by-catch” by Stefan Meyer (University of Otago), Bruce C. Robertson (University of Otago), B. Louise Chilvers (Massey University) and Martin Krkošek (University of Toronto) http://www.pnas.org/content/early/2017/10/03/1703165114.abstract

The paper looked at the impact of fishing on the NZ sea lion population. They found that the fishery interaction rate (the number of sea lions that come into contact with trawl nets) explained the population trend more than the by-catch rate (the number of sea lions observed to be killed by fisheries – extrapolated to entire fishery). In other words, the by-catch estimate (based on observer data) does not explain the population impact, but the interaction estimate does correlate significantly with it. This means that actual mortality is higher than has been assumed since the installation of sea lion exclusion devices (SLEDs).

Results show NZ sea lions that are released from SLEDs must suffer elevated subsequent mortality or reproductive failure, which would likely be caused by injuries sustained during collision with the exclusion grid or temporary entanglement. In other words, sea lions may die and fall out the ‘escape hole’, or be injured by the fishery interaction to the extent that they die after they escape, or have trouble reproducing at their normal rate.

2. New Zealanders call for better protection for NZ sea lions (Colmar Brunton polling, July 2017). http://www.wwf.org.nz/media_centre/?15101/New-Zealanders-call-for-better-protection-for-NZ-sea-lions

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