The wonders of the Celtic deep will be revealed on our TV screens this evening.

The makers of Blue Planet have taken their cameras under the waters of the Welsh coast to reveal the wonders of what lies beneath, with the Teifi estuary featuring prominently in the first episode, which airs on BBC One Wales at 9pm this evening.

Narrated by Dame Siân Phillips, Wonders of the Celtic Deep showcases the remarkable wildlife that can be found in and beside the sea that surrounds the spectacular Welsh coastline.

In the first episode, Coasts: Life on the Edge meet animals that make their homes in this challenging environment - where the land and the ocean meet - each perfectly adapted to this rapidly changing environment.

Travelling across Wales, from Cardigan Bay to Anglesey and the Teifi Estuary to meet resident dolphins, cameras capture the drama of a guillemot pair trying to raise a chick; follow the exploits of an extraordinary rock pool fish and get up close and personal with seals and estuarine ducklings.

In never before seen footage, filmed in UHD (ultra-high definition), this first programme takes viewers into the glorious and vocal world of the playful and seductive bottle-nosed dolphins of Cardigan Bay.

Filmed throughout an entire year, cameras witness what life is really like for Atlantic grey seals in Wales, from courtship to pregnancy and birth, including the trials and tribulations of an over curious snowy-white seal pup.

In the Teifi estuary, a family of Shelducks must stay clear of a fox on the hunt for ducklings. In a rockpool in Fishguard, as one of the largest tides of the year heads out, we join the antics of a little creature called a blenny. Remarkably this home loving fish can survive out of water, but only for a while – will the tide return in time?

And in Gower, which has one of the largest tidal ranges in the world, oystercatchers show off their bill skills as they forage for seafood on the shoreline.