School of Biology, University of St Andrews

Tag: shark tracking

Tagging tiger sharks in the Caribbean

James Thorburn was recently one of the scientific leads on an expedition at the Saba Bank in the Caribbean Sea to deploy a new type of tag on tiger sharks in an effort to gain more data on their movements and behaviour. Via an invitation from the Dutch Elasmobranch Society, who, along with the Saba Conservation Foundation and Nature Foundation Saint Maarten, organised the expedition – Save Our Sharks 2019.

As well as deploying tags, the team took blood samples and fin clips to help understand the health of the animals, how they fit into the systems food web and how the populations are connected to other areas.

Full blog post can be found here

Something a bit different…..

‘Cassiopeia’ swimming off with her new tag which will provide valuable information that will help protect her, and other tiger sharks on the Saba bank.

I usually save the beginning……

“Imagine being on a boat, just a couple of miles from shore. Below, swarming over the reef, are hundreds of sharks, foraging and hunting amongst the rocks. On board, a team of researchers are preparing to gather data on some of the most endangered species on the planet”

….for introducing our work in Scottish waters. I want the reader’s thoughts to drift to a tropical reef, somewhere they expect to find sharks. Thanks also to some excellent wildlife programs, it is a mental image they can readily form. I would then go on to rather abruptly snatch them far away from the tropics, to the beautiful Scottish coastline where I undertake most of my work.

The realisation that sharks are present in our (Scotland’s) coastal waters often comes as a shock, and the creation of an easily obtained, relatively familiar, mental image in the tropics can help the reader (often to their surprise) visualize similar events regularly taking place around Scotland.  In order to make this analogy work, I often neglect to mention that “the crew are all freezing, huddled into their survival suits as the rain lashes down”… as firstly, this isn’t always true, and secondly, I want the reader to be surprised… imagining we are starting the tale in the tropics somewhere as it’s where they expect to see sharks.

This time it is my turn to be surprised. There is no survival suit in sight, I am warm, the sea is warm and currently the biggest challenge facing me is not getting sunburn, not something I am used to having to deal with!! I am, in fact, where the reader would usually expect me to be, I am lucky enough to be in the Dutch Caribbean

The realisation that sharks are present in our (Scotland’s) coastal waters often comes as a shock, and the creation of an easily obtained, relatively familiar, mental image in the tropics can help the reader (often to their surprise) visualize similar events regularly taking place around Scotland.  The species I’m describing above is the tope shark (Galeorhinus galeus), the UK’s Reef Shark. They can form large shoals in our coastal waters – an amazing, if somewhat unexpected, spectacle. Like all sharks, they are under threat. Their long reproductive cycle means populations are slow to recover and this species, along with many others, are still currently being legally overfished in EU waters.

Saba Island, a volcano (technically the highest place in the Netherlands) rising out of the sea.

My home for the next 10 days is the amazing Saba Island…a truly unique place, a mountain rising out of the sea with bare rock sides plunging into the ocean and a rainforest capping its peaks. On the ferry over I felt a little like Dr Grant and Dr Sattler in the helicopter on the way to Jurassic park! It also has some of the steepest roads I have ever seen!

No photo description available.

I was there as one of the scientific leads via an invitation from the Dutch Elasmobranch Society, who, along with the Saba Conservation Foundation and Nature Foundation Saint Maarten, organised the expedition – Save Our Sharks 2019. This was to be the last expedition as part of a hugely successful project running since 2016.

The main purpose of this trip was to further our knowledge on the shark species that occur over the Saba Bank in the Caribbean Sea, a truly amazing place being the largest submarine atoll in the Atlantic Ocean and, under the “Saba Bank National Park”, a haven for marine life. The overall goal of the research is to gain insight into the role that Saba Bank plays in the life cycle of the species that live here, knowledge that is essential to effectively protect sharks.

To help achieve this, the team deployed a new type of tag on tiger sharks in an effort to gain more data on their movements and behaviour.

Follow this link to read more, but in brief… The European Space agency, in collaboration with AnSem in Belgium developed the Artic microchip, the brain of the new tags designed and built by Star-Oddi. This allows a two-way link between the tag and satellites, helping to optimise battery life. The end game is producing a tag that is smaller and more durable, cheaper, widely available and, most importantly, more animal friendly. The new design is already well on the road to achieving this.

The team hard at work with a beautiful 3.5m tiger shark
I have always wanted to see and work with tiger sharks, they are just the most amazing animals. This expedition was quite literally a dream come true.

As well as deploying tags, the team was taking blood samples and fin clips to help us understand the health of the animals, how they fit into the systems food web and how the populations are connected to other areas. A side project led in collaboration with Mote Marine Laboratory in Florida is investigating the connection between nurse sharks and the lobster fisheries. 

It wasn’t all smooth sailing, the sea conditions were challenging, and a few chilly squalls even had me shivering (the folk more used to a Caribbean lifestyle were positively chilled!).

A squall coming through just at the moment of action. On the other boat, the camera team get ready to enter the water.
One of the Caribbean reef sharks being safely released

However, all in all, the expedition was a huge success with 4 tags deployed, over 50 sharks, including tiger sharks, silky sharks, nurse sharks, and Caribbean reef sharks being sampled.

While I will always love Scottish sharks, to do something different, to work with different species (especially tiger sharks!), and as part of such a successful expedition with such a great group of shark experts was an amazing experience and one I hope to do again! But in the meantime, I am digging out the wellies as it is back to field work on the amazing flapper skate in Scotland next week. However….I think it is fair to say…..

Photo credits go to Peter de Maagt and James Thorburn. All rights are owned by the Save Our Sharks Project and should not be reproduced without prior permission.