Sunday, 20 July 2014

Diving in Falmouth - Giant Jellyfish

3 great days of diving out of Falmouth with very few other dive boats about, such a change to 10 years ago when a sunny slack tide on the Lizard pinnacles could attract 10 ribs, vying to share shot lines. Dived on the Manacles, East Narrows and Whelps reefs. The water was a bit murky as we were there following the stormy Easterlies and the swell had lifted the silt but we had good viz' on most of the dives, apart from the Helford Estuary where we abandoned the dive as we couldn't see our own feet let alone each other. There was lots of life on the wrecks of the Peterson and the Hera with pollack, many Cuckoo wrasse (Labrus mixtus), Ballan wrasse (Labrus bergylta), conger and shoals of fry. Evidence of spiny starfish (Marthasterias glacialis) feasting on mussels and many of the cuckoo wrasse appeared to be on the turn, between male and female and sporting a cross of gender markings. The dive we did in the East narrows on the first afternoon was interesting as we drifted along the huge and ecologically important Maerl beds, a sort of ground living small fragmented tumbling coral which covers the seabed for a number of miles, each piece grows at 1mm a year and they collectively create important biodiversity-rich habitats. Amongst the Maerl (Coralline algae) I saw some hermit crabs staggering along overloaded with enormous attached plumose anemones and also a micro spider crab riding on a large John Dory fish. I had to come up early and leave the others as they were drifting along the seabed at 20m and I was low on air after the earlier 2 dives, this was unfortunate as they then saw two thornback rays.

 One of the highlights of the trip was seeing two of the huge 'Dustbin Lid' jellyfish (Rhizostoma octopus) that have been in the press recently. They drifted under the boat while we waited for two divers to surface and I was able to get a few shots over the side but wasn't fast enough to get my fins on and get in. These jellyfish, up to a meter in width, have largely disappeared in recent days and we discussed why, perhaps they die off after mating or have all been eaten by the attendant leatherback turtles (Dermochelys coriacea). We sadly didn't see any turtles, but perhaps as evidence of predation we found a single limb of one of these giant jellyfish lying discarded on the wreck of the Peterson and it was surprisingly firm, like a silicon cast, and heavy to hold, stunning creatures.

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