Sub-Surface Sub-Antarctics: What’s Below the Surface?

I’m in the second year of my Masters degree now – and expected to write a thesis before the year is through. I’m writing it about Marine Metre Squared – a citizen science project that’s all about getting communities involved with marine biology. I have tried to find ways to tie that in with my interest in the Sub-Antarctic Islands and so when the picture below popped up on my Twitter feed, I was inspired to do some research on what one might find in the Southern Ocean surrounding the Sub-Antarctic Islands of New Zealand.

“Playing host to larval fish at a depth of 24m off subantarctic Campbell island, a large Cyanae sp. looks like an exploded ball gown.” (Photo: New Zealand Geographic).

New Zealand’s Sub-Antarctic Islands play a vital role in maintaining the ecological health of the Southern Ocean. Marine mammals and penguins rely on them to stop, rest and breed. But the ocean surrounding them is just as important – it feeds the wildlife that stops to populate the islands.

The Light-mantled Sooty Albatross relies on the Southern Ocean for sustenance (Photo: Kimberley Collins).

We often think of the ocean as foreign – not many of us interact with it daily despite it being within reach for most New Zealanders. So how do we expect to experience what’s below the surface in the remote Sub-Antarctic Islands?

NIWA researchers have found that marine biodiversity and levels of endemism around the Auckland Islands, Campbell Island, the Bounty Islands, and the Antipodes Islands are higher than it was originally assumed. In April 2005, surveys of the subtidal ledges around the Bounty and Antipodes Islands drew comparisons to the biodiversity found in tropical and North Pacific environments. They suggested that Sub-Antarctic marine biodiversity was 25% higher than that in the Hauraki Gulf and 20 – 30% lower than that in Fiordland, which is renowned as one of the most biologically diverse areas in the world.

While the Southern Ocean is home to everything from plankton to cetaceans to fish – the first species I think of when someone mentions the region is bull kelp. It’s one of the more stunning sights surrounding the Snares and, as I recently wrote in a blog post for Marine Metre Squared, has some novel applications in New Zealand culture.

Bull kelp (Photo: Froots).

On the rocky shores you will find a number of endemic species such as the whitefoot paua (Haliotis virginea huttoni) – a subspecies of the paua commonly found in New Zealand that is endemic to Campbell Island and the Auckland Islands.

White-footed paua (Haliotis virginea huttoni). (Photo: Mollusca NZ)

The species that we see on the surface impact those in the ocean. The Southern Blue Whiting (Micromesistius australis) is relied on heavily by seabirds. A study in 1997 revealed that the majority of food caught and fed to Campbell Island Albatross (Thalassarche impavida) chicks during the breeding season was Southern Blue Whiting.

The Southern Blue Whiting (Micromesistius australis) that feeds the Campbell-Browed Albatross (Photo: United Fisheries).

And so it is no wonder that there have been calls from concerned citizens, scientists, and politicians to change the way the oceans around the islands are managed. The Sub-Antarctic Marine Reserves Bill had its final reading in parliament in late 2012, and proposes to create two more marine reserves around the Bounty Islands and Campbell Islands. They will cover 58% and 39% of those islands’ territorial ocean, effectively protecting a total of 435,163 hectares. When added to the marine reserve that already exists around the Auckland Islands, nearly a million hectares of ocean around the Sub-Antarctic Islands will be protected – which is great news for the birds, cetaceans (whales), and pinnipeds (seals) that rely on them.
What species do you know of that are found in the Sub-Antarctic marine environment?

Why the Sub-Antarctic Islands Need the Department of Conservation

Last month, it was announced that 140 full-time positions will be cut from the Department of Conservation. In the last two years, the department has had $54 million dollars slashed from its budget – as Tom Scott illustrated, it’s the same as sucking fat from a skeleton. In an attempt to show the government the value that we as New Zealanders place on conserving our environment, Forest and Bird has announced that this Thursday the 11th of April will be their first Love DOC Day.

It’s pretty self-explanatory – they want us to show the government and the Department of Conservation that we care and how much we appreciate all that they do to conserve our precious species.

I fell in love with birds in my first year of university. I fell in love with DOC when I first worked for them as a volunteer and saw how hard they work to save my first love of the feathered variety. Most encouraging of all was that the hard work was happening at every level of the department and wasn’t limited to those with “ranger” in their job title. I’ve seen everyone from programme directors, to researchers, to cooks, to the five-year old son of an island ranger help out in some small way – by setting a trap, monitoring a stream, or cutting out an invasive plant species.

I fell in love with the Sub-Antarctic Islands when I visited them in 2010. They are managed by the Southland Conservancy who have played a critical role in conserving them as wildlife hotspots. The species you will find there today simply could not and would not have survived without their pest control efforts or breeding programmes.

These islands are New Zealand’s diamonds in the rough – home to species found nowhere else in the world. Think of them as tiny life rafts for birds, seals, and rare plants that are anything from 3.5 to 112 square kilometres in size. Without DOC, these life rafts could sink. It’s the Department of Conservation who carry out the pest control. It’s the Department of Conservation who monitor the streams. It’s the Department of Conservation who set up breeding programmes that can and have saved species from extinction.

While the future may look bleak, I want to look at the past – at the evidence – of why the Sub-Antarctic Islands need the Department of Conservation and to show you some of the species that could actually be affected by these changes.

1. They eradicated the Norway Rat from Campbell Island and saved a species from extinction.

You will find Campbell Island 700 kilometres south of Bluff. It’s remote, it’s exposed to extreme weather conditions – and it was once covered in rats. It is also home to the Campbell Island Teal – a nocturnal, flightless duck that was thought to be extinct until it was rediscovered by DOC staff in 1975. The reason for their assumed extinction – rats.

Campbell Island Teal (Photo: Kimberley Collins)

The remaining birds were quickly removed and the Department of Conservation spent twenty years trying to figure out how to remove rats from the island despite hearing cries of “crazy” and “impossible” from conservationists around the world. Nothing could deter them, and the island was declared rat-free in 2003. Not only did they break the record for the largest island eradication (previously held by the Kapiti Island project), they returned Campbell Island Teal and gave them a fighting chance at re-populating the island.

Read more about the conservation of Campbell Island Teal here & more about the eradication here.

2. They’re looking out for New Zealand’s most endangered marine mammal.

There once was a time when the New Zealand Sea Lion was found all over New Zealand’s south-east coast. Today 80% of a declining population are found in the Auckland Islands. The Department of Conservation has run an annual research programme since 1994 that provides valuable scientific information to the New Zealand government in an attempt to assist them in enforcing fishing protocols that will benefit the survival of this species.

New Zealand Sea Lions (Photo: Phombo)

They examine the survival rates, foraging behaviour, and productivity of populations and count the number of pups born at a number of breeding sites all over the Auckland Islands. They do this by “tagging all pups born on Enderby, and a sample on Dundas to facilitate monitoring of how many return each year. This data is used to estimate survival and reproductive rates for the population. Satellite transmitters and time depth recorders are used to find out where the mothers go to feed and how pups and teenagers learn how and where to feed. Biopsy samples are taken to look at nutrient levels, as this may change with changes in diet.”

Read more about DOC’s NZ Sea Lion Management Plan here.

3. Because look at all these rare, endemic and endangered species!

They’re all endemic to their own islands. I can’t stress this point enough: without DOC they’d be gone. Forever – as in no bringing them back. I can almost guarantee that if they could talk, they would tell you how much they love DOC. I know I love DOC on their behalf, and I hope you will help me to show it on April the 11th!

The Auckland Island Banded Dotterel is found only in the Auckland Islands (Photo: Kimberley Collins)

A large proportion of the Southern Royal Albatross population nest on Campbell Island (Photo: Kimberley Collins)

tThe Antipodes Island Parakeet is endemic to the Antipodes Islands (Photo: Kimberley Collins).

The Snares Crested Penguin is found only on the Snares Islands (Photo: Kimberley Collins).

The Bounty Island Shag is endemic to the Bounty Islands (Photo: Bird Quest Tours)

The Sea Lion and the SLED

You may remember a post that I wrote a few months ago about the New Zealand sea lion. It was about how the largest population of this New Zealand endemic is declining rapidly on their Sub-Antarctic refuge in the Auckland Islands. While writing my e-book about Campbell Island I thought I would head across the road to interview Dr. Bruce Robertson from the University of Otago’s zoology department.

Dr. Robertson has written a number of papers about the New Zealand sea lions; their decline, population structure, genetics, and the bycatch management system. I spoke to him about the use of Sea Lion Exclusion Devices (also known as SLEDs), specifically whether or not they are effective. I was interested to hear about how the government (the Ministry for Primary Industries) have gone about testing these devices to ensure that they are working and successfully protecting this vulnerable species.

Here is his answer: