Paul Naylor is smitten by one of the UK’ s most fragile and least understood marine habitats
UKDIVING CRITTERCONFIDENTIAL
The marvels of Maerl
Thornback Skate
Paul Naylor is smitten by one of the UK’ s most fragile and least understood marine habitats
Picture the scene: a large ray takes graceful‘ flight’ across a backdrop of dazzling pink coralline scenery that’ s dotted with sea anemones, starfish and the swaying arms of sea cucumbers. Are we in the Mediterranean, the Indian Ocean or the Caribbean? Nope, it’ s the Fal Estuary in Cornwall, home to England’ s best-known bed of Maerl.
Maerl is a very unusual type of red seaweed that forms free-living nodules.
These grow unattached on the seabed and incorporate calcium carbonate from seawater into their cell walls to produce a hard coral-like structure. A single nodule or‘ twiglet’ of maerl can look pretty but a dense bed of them is spectacular. As well as their striking colour, the nodules combine to create a complex three-dimensional structure that provides shelter and attachment for a huge range of species.
It’ s the rich variety of animals and the enjoyment of seeing them go about their lives in such attractive surroundings that has given me countless happy underwater hours around the Fal over the years. Filming the activity of a filter-feeding sea cucumber or an excavating starfish, I get distracted by an unusual small swimming crab tucking itself into the maerl nearby. Or, while trying to capture the mating antics of sea hares, a‘ gang’ of gobies start to
A Dragonet with reddish colouration matches the Maerl
Happy hunting ground – Spiny Starfish with empty clam shells scattered over the seabed
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A Gravel Sea Cucumber extends feathery tentacles to catch passing food