THE RISE OF SHARKS IN BRITISH WATERS
Increasing numbers of shark species are being found in British waters. Why is this happening, asks Ben Garrod – and where can we see them?
If you are looking for sharks, there are plenty to see wherever you are around the British Isles. Dr Ben Garrod will be reporting on sharks for Radio 4's Costing the Earth in May, and reveals the five shark species you're likely to see in our waters.
"My lasting love of sharks was kindled the day I rescued one. Just 11 years old, I was on a deserted beach one cold Sunday morning, with my trusty terrier, Toby. There had been a high spring tide, leaving broad, shallow furrows in the sand. It was in one of these temporary channels that we spotted a fish thrashing desperately about.
"I’d grown up on nature documentaries and had read every one of Gerald Durrell’s books, so I felt prepared for the task ahead. Worried that the water would seep away and that the shark would effectively suffocate, I waited until she was facing away (and yes, it was a ‘she’) and grabbed her tail. I felt her course sandpaper skin and the power in her muscular body, and flung her into the nearby surf, afraid of receiving some terrible injury from her jaws.
"It was over in seconds. As I saw her disappear back into the sea, I had never been so proud or felt as brave. I feel that my achievement should in no way become diminished simply because my shark was a small-spotted catshark and was only around 40cm long.
"As well as introducing me to sharks and their flattened cousins, the rays, my rescue showed me that, like anything, sharks too could be vulnerable and needed our help. In my adult life as a biologist I’ve been lucky enough to meet some fantastic sharks. I’ve dived with majestic tiger sharks off Cuba, seen schooling hammerheads in the Galapagos and fallen in love with gentle leopard sharks on a Madagascan reef – but my love of sharks started here in the UK, and it is still ‘our’ British sharks that fascinate me most."
British waters: a shark’s place of refuge
"As a kid, I learnt that there were 21 species of elasmobranchs (sharks and rays) found in British waters. More recently, this had risen to over 30 and just last week, I learnt that it now might actually exceed 80 different resident and visiting species. At a time when studies are showing that in oceans across the globe, populations of predatory fish (including sharks) have dropped by over 90% largely due to hunting (100 million sharks are killed a year) and overharvesting of prey species, sharks in British waters appear to be doing well.
"Are there more of them or are we just getting better at producing more accurate population estimates? Our knowledge of marine ecology is constantly improvingand research techniques are advancing rapidly. We have a better understanding now about what’s in our seas than ever before."
See Britain’s sharks
Porbeagle (Lamna nasus)
The porbeagle reaches 2.5m in length and weighs around 135 kg.
The great white shark is a close relation.
It is found in both cold and temperate waters, ranging from the oceans in the southern hemisphere to the Northern Atlantic.
It preys on fish such as mackerel, herring, cod and flatfish and also cephalopods (especially squid).
Although not highly manoeuvrable, it is a fast and active hunter, able to maintain a body temperature higher than the surrounding water, giving it the increased power and stamina needed for chasing down its prey.
Basking shark (Cetorhinus maximus)
Average length of 6-8 m (although the largest recorded was over 12 m).
The basking shark is the second largest fish alive, with only the whale shark reaching greater lengths.
It is also known as the elephant shark, hoe-mother and the bone shark.
Despite its huge size, it is one of only three plankton-feeding sharks, along with the whale shark and the aptly named megamouth.
It has many very small teeth but uses specialised adaptations such as a very wide mouth and sieve-like gill rakers to filter and trap food.
For its body size, the basking shark has the smallest brain size of any shark.
Small-spotted catshark (Scyliorhinus canicula)
This is a small shark, growing up to 1m in length and weighing around 2kg.
It is also known as the lesser-spotted dogfish, rough hound and, in Scotland and Cornwall, the morgay.
Found in habitats ranging from a few metres to approximately 400m deep.
One of the most abundant elasmobranchs in the northeast Atlantic and Mediterranean regions. Populations are stable in most areas.
An opportunistic predator, it feeds on a range of species, preying mainly on fish, molluscs and crustaceans but also echinoderms such as urchins and even polychaete worms.
Flapper skate (Dipturus intermedia)
The largest skate in the world has a maximum wingspan of just under 3m.
Critically endangered, it is one of the most threatened species in British waters.
It is found mostly around northern Scotland and the north of Ireland.
A bottom dwelling species, flapper skates are mainly found at depths of 100–200m, but that can be as shallow as 3m and as deep as 1,000m.
It is estimated that the common skate can live up to 50–100 years and reaches maturity at about 11 years old.
The eggcase (or mermaid’s purse) may reach 215mm in length. Its size and woody appearance when dry makes it hard to miss. If you found one washed up on the beach, the Shark Trust is looking for sightings, to understand more about the population – see The Great Eggcase Hunt for more details.
Blue shark (Prionace glauca)
Males commonly grows to 1.8 to 2.8m at maturity, whereas the larger females can range from 2.2m to 3.2m.
Inhabits deep waters in the world’s temperate and tropical oceans.
It migrates long distances, often travelling thousands of miles.
Diet largely focuses on squid but also cuttlefish, lobster and crabs, as well as a large range of fish prey.
Blue sharks have been observed working together as a ‘pack’ to herd prey into a tight group from which they can feed more easily.
These sharks give birth to live young (viviparous) and may have between 25 and 100 ‘pups’ at a time.
Its triangular teeth allow it to easily catch hold of slippery prey.
Republished by kind permission of Countryfile Magazine