BASKING SHARKS
The second largest fish in the world swims in UK waters, so why is it so hard to spot? Maya Plass goes in seach of our shy and retiring behemoth – the basking shark
Searching the seas to see the gentle oceanic giants that roam our waters.
I’m lucky to have lived by the coast for the vast majority of my life now. For us sea-obsessed bipeds, life without the coast is like a fish without water. Fortunately, my coastal life has resulted in many wonderful wildlife experiences. There was the time I was diving and caught a nudibranch on the tip of my finger, or the moment I discovered a tiny and unusual clingfish. But the one sighting that took the longest for me to find was, ironically, the second largest fish on the planet – the basking shark.
I have spent so many hours out to sea gazing and scanning the horizon for the tell-tale sign of the dorsal and caudal fin of this huge shark breaking the surface of the sea. There would be days where the water was so calm and still that you could see mackerel shoals fizz on the surface of plankton-rich seas – but not a ripple from the behemoth. I started to think that they were, in fact, mocking me.
There was even a time that I was supposed to be out on a family boat trip but, with limited space, I chose to stay in the estuary playing with my daughter on a kayak. This was, naturally, the time that a basking shark nonchalantly swam close to the boat. I would hear stories from my Devonborn relatives of a time, decades earlier, when basking shark sightings were guaranteed off the coast in the early summer months. Visiting Cornwall for dive trips, I would hear how several basking sharks had been seen on a daily basis prior to my visit. Apparently, I was “guaranteed” to see them. This, of course, was not the case. Nature can be cruel.
The truth is that basking sharks are highly tuned to feed on specific plankton prey. They love the oily copepod Calanus finmarchicus, which is capable of sustaining the giant frame of the shark. This tiny plankton is sieved in vast quantities by the gills, which encircle the shark’s gape like a choir boy’s ruff filtering thousands of tonnes of water.
Due to shifts in sea-surface temperatures, the basking sharks’ preferred fatty copepods are now more plentiful in more northern, cooler seas, while the less nutritious
Calanus helgolandicus dominate UK waters instead. Basking sharks will also feed on these lessnutrient-rich copepods, but the fall in sightings of basking sharks coincides with reduction of their prey of choice in waters with rising temperatures.
An example of this reduction in sightings is the Manx Basking Shark Watch, which recorded just 41 sightings in Manx waters in 2014, as opposed to around 800 in preceding good years. It appears the sharks are moving north to locate their preferred prey.
So I migrated with them up to the Hebridean waters. Here, the beautifully clear waters are rich in life and basking sharks. As we crossed the waters from Oban to Coll, I was on deck scouting, as usual, when what should I see but the tell-tale sign of the big-nosed monster (as its scientific name describes) – the triangular fins of the basking shark!
It may have taken me several years to get a sighting but the anticipation and hours of searching made the experience that much more exciting. I was beside myself with joy (as were many others on the ferry) to witness this beautiful creature slowly snake its tail back and forth, huge mouth agape. While nature can be cruel at times, hiding itself away from us, it is exactly this elusiveness that makes an encounter with truly ‘wild’ life so memorable and so very special. WHERE TO SEE BASKING SHARKS Sighting ‘hotspots’ predominantly occur on the west coast of the UK, including the Hebrides, the Isle of Man, Devon, Cornwall and the Isles of Scilly. For shark-spotting tours of the Hebrides, visit www.baskingsharkscotland.co.uk
“THE GILLS ENCIRCLE THE GIANT SHARK’S GAPE LIKE A CHOIR BOY’S RUFF”