During the Year of Coasts and Waters 2020, SNH staff working along our shorelines and waterways provide an insight into the important and varied work they do. Jane Dodd, a marine operations officer based in Oban, wrote about her time helping James with his fieldwork on the Critically Endangered flapper skate (common skate complex) earlier this year.
It’s been a successful day – the tag data will allow us to check the status of flapper skate within the MPA, while the ultrasound and blood samples will help us learn more about the ecology of this little-understood species.
“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”
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.
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!
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.
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!).
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.
The early morning sunlight glistens gently on the still, deep-blue waters of Dunstaffnage Marina. I’m walking along the pontoon, pushing a heavy cart of equipment down to the boat we’ve hired for the day: the Blue-Fin. The awesome mountains of the west coast stand around us; speckled snow glints on some of the tallest peaks. The nose of Ben Cruachan pokes out of the clouds for a moment, its full face then coming into focus. It’s a view you can’t beat and one of my favourite places in the world.
just here for the view though. You may be aware that populations of
elasmobranchs (sharks, skates and rays) around the world have experienced
worrying declines. But you might be less aware that there are also incredible, large
and threatened elasmobranch species closer to home. We’re here for one of Britain’s
largest and most threatened marine species: the Critically Endangered flapper
skate (Dipturus intermedius). Growing
up to about two and a half metres in size, and weighing up to one hundred
kilograms, the flapper skate is a hidden wonder in British waters. Once found
from the Mediterranean to northern Scandinavian, the flapper skate was fished
almost to extinction – even becoming the first marine species to be declared
‘locally extinct’. But the skate persist in a few small pockets of their former
distribution. And one of those is on the west coast of Scotland, where a
remarkable and inspiring synergy of citizen science, cutting-edge research and
governance is turning the tide. I can’t quite believe I’ve become part of the
slightly, I draw up the heavy cart at the boat. In the humongous, neon-yellow
oilskins and bright yellow boots I’ve borrowed for the day, I feel like a ludicrous
clown, or perhaps a lollypop. Bending over, I start to lug equipment over the
side of the boat: ultra-sound monitors, tape measures, a water pump, hose
piping, electronic acoustic tags, a blood composition monitor, antiseptics,
anaesthetic, syringes, and litres and litres of water – it all has to go in. Everything
we need in the field to catch, health check and tag flapper skate.
How do you
catch a one-hundred-kilogram fish? Amazingly (at least for someone with as much
fishing experience as me), with a hook and line. Indeed, recreational anglers
started the practice of catch-tag-and-release for flapper skate decades ago –
tagging individuals with uniquely identifiable tags, so that the capture
histories of specific individuals could be mapped across space and time. This
pioneering practice has been one of the most valuable sources of information
available to scientists and policymakers regarding the flapper skate. In
particular, it has shown that the same individuals are caught again and again
through time, suggesting that some skate are resident in the same area or at
least frequently turn again and again through time. This was the major insight
that led to the designation of the Loch Sunart to the Sound of Jura Marine Protected
Area, the only body of water in UK waters currently designated specifically for
the conservation of an elasmobranch. However, despite the enormous value of
these capture-recapture data, they don’t tell us about where skate go and what
they do in-between recapture events. And that’s why we’re back in the Marine
Protected Area today.
This is my first time on the fieldwork team, and I’m not quite sure what’s coming. The boat’s engine comes to life and we chug slowly out of the marina. The wind starts to pick up and the sun slips behind a cloud – typical Scotland! Shivering slightly, I pull my oilskins a little tighter, feeling ominous about the weather. We round the bend, out of the marina, and the boat begins to pick up pace. The wind’s rushing past my face, turning my ears and cheeks pink with the cold. A dash of sea spray catches me in the face. I steady myself as the boat begins to sway, grinning in the excitement: we’re off!
South, travelling down a deep channel to an area where skate are often found.
Our aim is to catch, health check and tag flapper skate with acoustic
transmitters. These tags transmit individual-specific acoustic pings every so
often, working in combination with an array of underwater acoustic receivers (special
hydrophones) which listen continuously for acoustic transmissions. When a skate
moves into the detection range of a receiver, the receiver logs any detections
and later, we can work out where the skate were and where they like to be using
cutting-edge statistical modelling. That’s actually my job as part of a PhD
studentship, funded jointly by Scottish Natural Heritage (through the Marine
Alliance for Science and Technology in Scotland) and the Centre for Research
into Ecological and Environmental Modelling in St. Andrews. I’m here today,
though, thanks to valuable support from Shark Guardian.
We’ve reached our site, the anchor has been deployed, the rods baited, and the reels are spinning furiously as the weights sink towards the bottom. It’s nearly 200 m deep here. Vets from the Royal Zoological Society of Scotland, Edinburgh Zoo; Adam and Georgina, are full-stations-go, checking over equipment and rehearsing protocols for when (if!) we catch a skate. Suddenly, that seems to be happening already: a rod’s nodding and Roger (our skipper) is on it, reeling it in to keep the tension, while I don a waist harness into which the rod is clipped. I feel a pull on the harness and realise that my job is to carefully bring the skate to the surface.
We use rod and line to capture skate (as opposed to long-lining) because it means that we only catch one skate at a time. Consequently, skate are brought to the surface as soon as they are caught, minimising the time that they spend on the hook. Barbless hooks also reduce the risk of damaging the skate’s mouth. Bringing the skate up isn’t easy, though, because skate initially anchor themselves to the seafloor when they are caught, before swimming up through the water column. It’s several minutes, and my back is starting to ache, but I finally I feel the skate release the bottom. I start to reel it in, slowly, to avoid bring the skate up too quickly through the different temperature zones in the water column. Sometime later, the skate breaks the surface. It’s a small juvenile female and the first one I’ve ever seen.
Using a specially-designed sling system, we carefully lift the skate onto the deck and rest it on a support pad to make sure that it is as comfortable as possible. A custom-made water pump drives oxygenated sea water through a system of hoses into the skate’s mouth so that it can breathe and the vets are straight to work, scanning the skate for scrapes and marks and taking blood samples for analysis, before surgically tagging the skate under local anaesthetic. This is a remarkably quick and simple procedure, taking just a few minutes. Meanwhile, Jane (SNH skate expert) and I are monitoring the respiratory and cardiac function of the skate; at the moment, I’m measuring the breathing rate (a breath is visible when water is pumped over from the gills) and Jane’s monitoring the heart rate by counting the number of heart beats from real-time ultrasound imaging of the heart.
The tagging is complete and it’s time to measure and photograph the skate. The photograph will be uploaded to Skatespotter: an online database that contains pictures of a large number of skate. Together with the capture-recapture data, this helps us to record the recapture history of skate, their appearance and changes through time, examine parasite loads and timing of biological events (such as pregnancy); all valuable information that can guide management.
It’s only been 15 minutes, but the skate is back in the water. I watch it flap it huge graceful wings, turning slightly as it descends once more into the depths. I suspect I won’t see that one again for a while. But, perhaps, soon enough, we’ll see it start to transmit signals to acoustic receivers that will tell us how it’s using the Marine Protected Area in years to come. I look up, panting slightly. The sun is shining, and another rod is starting to tick…
Edward Lavender is a PhD student at the University of St Andrews and a member of the Marine Alliance for Science and Technology in Scotland Graduate School. Edward acknowledges his PhD funders (Scottish Natural Heritage and the Centre for Research into Ecological and Environmental Modelling) and extends his thanks to Shark Guardian for providing the funding for his participation in the ongoing fieldwork project, designed to monitor skate habitat use in the Loch Sunart to the Sound of Jura Marine Protected Area. You can read more about the flapper skate here.