Decoys to draw sea lions away from people
Don’t be surprised if you see something fishy going on at beaches in the Catlins this summer, as Auckland student Kim D’Souza oversees a Department of Conservation project that aims to make a dummy out of our only endemic pinniped, the New Zealand sea lio
THOSE hoping to spot one of the South’s most striking shoreline visitors in the Catlins this summer may find themselves doing a double take.
Although the New Zealand — or Hooker’s — sea lion (Phocarctos hookeri), known by Maori as whakahao, is officially registered as an endangered species, it remains a relatively familiar sight on Otago and Southland beaches, where it breeds during December and January.
That breeding period overlaps naturally — and somewhat unhappily — with a parallel human migration oceanwards, as holidaymakers from home and away make for the sun, sand and surf.
But a new Department of Conservation project taking place at two popular Catlins beaches this summer hopes to reduce the number of undesirable interactions between the statuesque marine mammal, and its curious bipedal visitors — with an ingeniously simple idea.
Fourth year Auckland University of Technology advanced science student Kim D’Souza was chosen by Doc to oversee the project, which started in late November.
‘‘When I heard I’d been chosen I was thrilled,’’ she said.
‘‘Having the chance to work in such a beautiful environment on a project that will hopefully help make a difference to this endangered species, it means a lot.’’
Miss D’Souza explained the principle behind the project was simple.
‘‘Sea lions are extremely vulnerable to a range of human disturbances, including harass ment, boat strikes, accidental bycatch and overfishing, as well as climate change and diseases.
‘‘Once breeding sea lions have made their way to South Island beaches they become particularly vulnerable to direct human disturbances.
‘‘The breeding season for sea lions occurs between December and January, which also happens to be a popular time for tourism in the Catlins.
‘‘In these populated areas, this invites humansea lion interactions which can be detrimental to the health and survival of the species.
‘‘We’re exploring one possible way to reduce that happening.’’
By using sea lion decoys placed carefully away from the main human activity areas of favoured beaches, the project hoped to attract real sea lions visiting the beach to less busy, ‘‘safer’’ areas, Miss D’Souza said.
‘‘The project aims to deter mine if the decoys could be used as a management tool, by judging if sea lions find them attractive.
‘‘If so, could they potentially be used to recolonise individuals to safer areas on the beaches away from touristdense areas?’’
The mechanics of the project were equally simple.
‘‘We’ve chosen Cannibal and Jack’s Bay beaches for the project, where I’ll be spending five weeks to January 26, split between the sites and making observations of interactions between the real and decoy sea lions.
‘‘Each day, I set up four or five decoys on the beach, including two subadult males, two females and one large adult male. Then it’s sit back and watch.’’
At this stage, the dummy sea lions were of basic construction, and unscented.
However, this did not appear to deter their living, breathing counterparts.
‘‘We’re about three weeks into the study and have seen a variety of results.
❛ Having the chance to work in such a beautiful environment on a project that will
hopefully help make a difference to this endangered species, it means a lot.
‘‘During the week at Jack’s Bay the decoys have been very successful, with the sea lions approaching, investigating and even lying down near them.
‘‘However, so far at Cannibal Bay, there have been surprisingly low numbers, especially considering last year viewings were high.’’
The decoys were made of a resilient canvas material filled with pillow stuffing, and given basic sea lion characteristics.
Although they were unscented at present, this could change in subsequent investigations.
‘‘It seems the sea lions are just generally investigating the decoys through visual cues, probably trying to determine if they’re actually sea lions.
‘‘If the study shows promising results, Doc could well use them as a management tool, potentially scented with sea lion scat [faeces].’’
Despite the concept touching on the realm of ‘‘mad scientist’’, the idea was not a first, Miss D’Souza said.
‘‘It’s an idea that’s been used elsewhere with varying degrees of success.
‘‘There was a 1984 study in the US, in New Jersey, which used decoys to attract least terns to abandoned colony sites.
‘‘They proved attractive and the study concluded they could be used in the management of the species.
‘‘Then the very same decoys we’re using in this study were previously deployed in the Auckland Islands, where the aim was to use female decoys to attract real females to establish new colonies.
‘‘That, too, proved successful.’’ Miss D’Souza said alongside the immediate benefits to local wildlife, she was pleased to be using her skills to further her personal ambitions in science and conservation.
‘‘After completing my studies, I’d like to make a difference by contributing in some way to help reduce environmental degradation.
‘‘There are ways to achieve this, by helping provide tools to reduce the rate of human disturbances, for example, through lifestyle changes, new technologies and further
research.’’
In the meantime, this would go down as ‘‘the summer of the sea lion’’.
‘‘Thanks to Doc, I’ve gained a vast amount of knowledge about our only endemic species of pinniped.
‘‘It’s been a unique opportunity.’’