Sea lion pups falling into holes

Department of Conservation —  22/12/2017

Laura Boren, one of our Science Advisors in the Marine Species and Threats team, tells us about the strange way sea lion pups are dying on Campbell Island, and the team that’s trying to solve the problem.

It was a busy few days, but by 6pm last Friday I had waved goodbye to the team of four setting off on an exciting and, somewhat, daunting journey to monitor sea lions on the Subantarctic Campbell Island.

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Loading the boat, ready to set sail. Photo: Laura Boren

As a part of the New Zealand sea lion/rāpoka Threat Management Plan, the team was travelling south to monitor the two breeding colonies at Davis and Paradise Points in Campbell Island’s Perseverance Harbour. In addition to the standard monitoring, they are undertaking new and exciting work through a collaboration between the Department of Conservation and the Deepwater Group (who represent the commercial deepwater fishing sector).

Pups trapped and falling into holes

The additional work focuses on the causes of sea lion pup deaths at this remote location. While the last three pup counts at Campbell suggested a population increase, there has been incredibly high numbers of pups dying in the population. While we are trying to determine if pups here also suffer from the same disease that Enderby Island pups are dying from; the biggest risk to the pups at Campbell Island is falling into holes.

Sometimes they fall into pools, creeks or muddy bogs; and this means they die from either suffocation, drowning, or starvation because they cannot get back to their mother. The Department of Conservation and the Deepwater Group are seeking to find a solution to this problem to reduce these deaths, and help the population to thrive.

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Sea lion pup being rescued from the bog. Photo: Blue Planet Marine

What we’re trying to achieve

This collaboration will support an overall assessment of pup mortality, along with monitoring pup behaviour in this muddy, boggy environment. Camera traps will be installed at key locations and some pups will be fitted with small GPS tags. Tracking how the pups are interacting with these holes will help us identify the best way to prevent these deaths.

Because Campbell Island is a UNESCO World Heritage Site, we want to find a solution that fixes the holes that pose the greatest risk to the pups, while leaving the island as natural as possible.

Preparing for six weeks on the island

The team came together for the first time on the 13th of December, having travelled from Kaikoura, New Plymouth, Hamilton and Tasmania. The first night we discussed all the last minute logistics and quarantine requirements. At 2am we crawled into bed to get a few hours of sleep before the busy day started.

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Micah the vet getting the post mortem kit ready. Photo: Laura Boren

On Thursday morning we inventoried what gear had made it to Invercargill and shopped for the last items. The team has to be self sufficient as they are camping for six weeks between the two colonies, with each colony a two-day walk apart. To save their backs, they have nearly two full sets of equipment dropped off by boat at the two colonies so they only have to carry their personal gear between the two sites.

We needed to pack and label all food, water, research equipment and camping supplies for the two different locations. They also needed to have a pretty comprehensive medical kit since they will have virtually no other human contact while they are there. We carefully packed up three medical kits, one for each of the two colonies and the third for the hut that they will overnight at when moving between the two locations. This was done so that if there was an emergency, they wouldn’t have to walk 8-16 hours to get to medical supplies.

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Just one of three medical kits. Photo: Laura Boren

Friday was spent completing final tasks, such as quarantining personal gear so no rodents, seeds or other biohazards make it to the island. The team wanted to try to load the boat on a higher tide (which makes it easier passing gear between the wharf and the boat), so the departure time was brought forward. Everyone worked straight through the day without stopping for lunch, but by 5:30pm the boat was loaded along with the gear from another research team heading to Adams Island to study albatross. We all had time to say our goodbyes and marvel at everything we managed to achieve in 48 hours, before I helped the local team return the truck, and do some last bits of tidying up at the Quarantine Store.

After spending such an intense two days with the team I felt rather like a mother hen. I was so relieved to get the satellite phone call to say that they are safely on the island and getting their camps set up. I can’t wait to hear about what they learn from the cameras and GPS trackers

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The Campbell Island sea lion team with quarantine staff. Photo: Laura Boren

The best part of my job is bringing people together, so I am really excited about the work they are doing this year with the additional support from the Deepwater Group. Collaborations such as these allow us to do so much more work and develop novel techniques. All of this will allow us to develop practical solutions to prevent pups from dying, and give this sea lion population a better chance of survival and stability in to the future.

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Gareth waves goodbye. Photo: Laura Boren