A new BBC series will see fishing fanatic Will Millard embark on a quest to catch some of Wales’ most iconic fish and first up on his list is the shy sewin and he’s heading west in search of it.

The enigmatic and elusive sewin – or sea trout – can be found in Carmarthenshire and Ceredigion and the episode sees Will hit the banks of the meandering Tywi and the fast flowing Teifi under the cover of darkness in an attempt to land one.

However all is not well with the fish or the rivers that they call home and Will uncovers a range of problems threatening them further. With catches in the region at their lowest in years, Will has a real challenge on his hands as he casts off his latest series.

In addition to the fish that call Welsh waters home, Will hooks up with the anglers that treasure them and in this episode he meets world-renowned casting champion Hywel Morgan, former Welsh international fly fisher Nica Pritchard MBE who has 78 years’ worth of experience, as well as visiting the Llandysul Angling Association to meet the next generation who are being taught the techniques to fly fish.

Speaking about the series, Will said; “With its rugged coastline, wild rivers and mountain lakes, Wales is an angler’s paradise so I’m heading out, rod in hand, to explore the hidden depths of our country and its people, as well as fulfilling a lifelong passion to catch some of the most iconic fish in Wales. I want to meet the people who treasure these waters, hear their stories and make some friends for life.”

Speaking about the episode, he continued; “In this episode I headed to the wild waters of West Wales in search of an enigmatic fish. It’s shy and elusive and you have more chance of catching one under the cover of darkness than in daylight. It was the absolute pinnacle of my angling life. Chasing the sea trout through West Wales was just about the hardest thing I have ever had to do in fishing. Firstly, you are taking one of the most technical disciplines - fly fishing - where your cast has to be perfect and you don’t even use bait; the fly is just a ball of fluff that you are hoping will fool the fish. Secondly, the sea trout are active in the dead of night, which means this highly technical discipline is taking place in absolute pitch darkness. Thirdly, I was contending with the worst sewin season in west Wales’ rivers in living memory. “

The episode will air Friday 21 June on BBC One Wales at 7.30pm and will be available on the BBC iPlayer.