In January 2016 St Helena welcomed specialists from the Georgia Aquarium in Atlanta USA under an initiative to tag and monitor whale sharks. The party included marine biologist, Dr Alistair Dove, who answers our questions on everything aquatic…
Are you still monitoring the whale sharks that visited St Helena last year?
All of the satellite tags have come off now, but some probably still have acoustic tags on them, which are picked up by receivers that we have put on the sea bed at different places around the island; more of those will be going in this year too. There are other ways to monitor whale sharks as well, and I’m excited that Saints have embraced the research and are continuing to document whale sharks and gather photo identifications for the research effort. Research activities on the island are based at ENRD and “citizen scientists” interested in participating can contact Elizabeth Clingham about how they can help.
What did you learn from the research trip?
To start with, we learned that Saints are some of the most hospitable, helpful and resourceful people in the world! By working together with the support of the Darwin Foundation, we’ve been able to quickly characterise the most newly-discovered whale shark aggregation site in the world. It consists primarily of adult male and female whale sharks, it seems to be reliable and strongly seasonal, and the animals occur all around the island, even though people experience them the most on the leeward side where most small boating takes place. St Helena Government has rapidly translated these sorts of findings into successful conservation measures by putting in place ecotourism codes of conduct and having the entire exclusive economic zone of St Helena declared a Marine Protected Area. Saints should be proud to have taken such decisive action to protect their extraordinary marine resources.
What makes the St Helena whale shark phenomenon special?
The whale sharks of St Helena are bigger than those seen in coastal aggregation sites, and they’re a good mix of adult males and females, whereas most other places have groups dominated by juvenile males. This information, combined with a couple of eyewitness accounts of mating behaviour around the island, leads us to believe that St Helena may play an important role in breeding for this species. That is critically important because we haven’t seen evidence of breeding from anywhere else.
How do the number of whale sharks in St Helenian waters this year compare to the numbers of the previous two years, when you were here for your research?
From what I’ve heard so far, pretty similar. They seem to show up abruptly in mid-late January and then stick around in little groups of 5 or 10, but there may be 30-50 different animals scattered around the island in total. Some tag data from last year says the season may be a bit longer than we thought, with animals resident around the island (maybe a bit further offshore) until April or even May.
What’s your favourite thing about whale sharks?
I love that they challenge everything we think we know about sharks. They’re not all vicious predators. The biggest of all is a peaceful filter feeder, with polka dots no less!
And a little known fact?
That their mouth may be up to 5 feet wide, but their throat is not much bigger than a 1 pound coin, so they couldn’t swallow you even if they wanted to.
What other marine life did you see on your visit to St Helena?
One of the things that makes the island wildlife so special is the number of species you don’t find anywhere else. Take the humble cunningfish for example, which is everywhere around the island. How odd that the single most common fish in St Helena can’t be seen anywhere else in the world! I also love the way oceanic species come right to the island’s doorstep, so you may see rocky reef species on the bottom, with mahi mahi, wahoo, dolphins and flying fish swimming right above them. In most mainland places, you have to go a long way offshore before you see the oceanic species. It’s not just the fish, all the critters on the bottom like feather stars and cup corals and nudibranchs are completely unique. It’s an incredibly special place.
What are you currently working on?
We’re still analysing data from the last two expeditions, planning a new trip to study whale sharks in West Papua, Indonesia in July, and writing up previous research including our whale shark genome project and some long-term behaviour studies we’ve been doing at the aquarium. Every now and then I stop, though, and daydream about plunging into the clear waters next to the Barn or diving along Long Ledge, and then warming up with a hot bowl of plo afterwards. St Helena does that to you. Can’t wait to come back, hopefully next year.
For more information read Dr Dove’s blogs from his previous adventures on St Helena.