Wonders of the Celtic Deep

The series begins by following Atlantic grey seals through the year, from courtship to pregnancy and birth. The film also witnesses a pair of guillemots bringing up their single youngster on a narrow rock shelf and takes viewers into the world of bottle-nose dolphins of Cardigan Bay.

We journey into this strange environment - one that sits remarkably close to shore. In the giant kelp forest, we join a female catshark as she lays an egg deep in the forest floor and watch as we witness a tangled web of hermaphrodite sea hares taking part in a three-day ‘love-athon’.

As the water starts to warm in the summer, marine giants arrive at the Celtic deep. Some have travelled for thousands of miles to feast on plankton and abundant shoals of fish. Visitors include a group of fin whales. At 25 metres long, these majestic submarine-shaped creatures are the planet’s second largest animals. Joining them to hunt sardines are 2 metre long blue-finned tuna. These sensational super hunters have exciting courtship behaviour.

Presented by Welsh acting legend, Dame Sian Phillips, this final episode in the series, looks at some of the biggest challenges and issues facing the marine environment in Wales and the rest of the world today. We meet the conservation heroes from across Wales, each doing their bit in many ways, to help marine conservation and promote the importance of the ocean. From fishermen sacrificing profits in return for sustainability and a plastic-waste campaigner who paddle boarded around Wales to raise awareness about the pollution of our oceans to a group of underwater scuba-diving litter-pickers and a surfer who uses the sea to help people with mental health issues.