Cornish Coral

A couple of weeks back I went for a boat trip and snorkel over Maerl beds with friends on the other side of the Fal Estuary, just north of St. Mawes.  I did not post about it at the time, as my photographs were quite crap and I reckoned I could go back to try and come home with something better. However, there hasn’t been any time for that, nor will there be in the near future, and as it was such a cool experience I reckoned it would be nice to write a little post about it for now anyway. The beach was fringed with sea grass, but the Maerl beds started very near the coast, at around two meters depth at low tide. Maerl is something special; it must have taken early biologists a while to figure out whether it was mineral, animal or plant. It is actually a calcareous alga that (very slowly) grows in fist-sized nodules or thalli. The Fal and Helford estuaries are one of the few places in the country where it occurs, and the Maerl beds here are under threat of dredging. Although Falmouth has the third deepest natural harbour in the world, big cruise ships cannot land close to the town centre which makes it unattractive for ships to stop. Falmouth would be a very pretty last port of call sailing west and cruise ships are of course good for business, hence the dredging plans. I will save the debate on economy versus conservation for a future post, as it will require a lot more text. I was able to take some pictures of the Maerl with my old Canon Powershot in plastic housing before the new batteries decided to quit on me prematurely:IMG_3280As you can see the Maerl really looks more like a coral than a seaweed (and dead pieces of Maerl form a type of coral sand, see here and here). It provides an ideal structured habitat for all kinds of organisms to live in and on (for instance fine seaweeds and snakelocks anemones). Besides various fish, crabs and sponges and small things darting to safety in general, we saw a big hermit crab in a Buccinum undatum shell with the large anemone Calliactis parasitica on top. Very cool, and apparently not very commonly encountered (this was of course after my batteries had run out). What was striking as well, were the very large (one of them measured half a meter across), very fat and very pale Spiny starfish Marthasterias glacialis:IMG_3279Maerl with a sponge growing through it (or possibly the other way around):IMG_3276Maerl is protected, so not an option for the aquarium, although I am sure it would make for a fantastic looking display (moreover potentially a very stable display as Maerl is not seasonal but grows for centuries). Hopefully more and better pictures later this year!

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