There are nearly 30 species of shark found in UK waters, but the blue shark is certainly one of the most impressive.
With the white underbelly contrasting with its cobalt blue upper body, it's easy to see where this nomadic shark got its name from.
They normally grow up to an average size of 230cm long, however in 2005 a Welsh record was set 25 miles off the coast of Milford Haven, when a fisherman hauled in a blue shark measuring a massive 271cm.
Here they feed on other fish, such as mackerel, herring, squid and some bottom living species and scavenge on other creatures.
That's why WWF Cymru has joined forces with the UK Shark Tagging Programme in the first 'Angler driven' project in the UK.
Volunteer anglers and charter skippers are being asked to record information about the length, weight, sex, condition and location of any shark they catch, before tagging and releasing them. The tag is individually numbered thus making each shark unique.
Any tagged sharks that are subsequently recaptured can provide clues as to their migration patterns and abundance.
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