Last Saturday Les, Ryan, and I travelled over to Loch Fyne for a day’s shore diving at the site known as Drishaig Reef. As well as having an interesting boulder reef which is home to a variety of life this site is also known for Fireworks Anemones.
These were the main reason for choosing to dive this site as I had long suspected that they would fluoresce well under blue (near UV) light. After previous dives in Loch Melfort and Loch Fyne I had seen fluorescence in a wide variety of life (cup corals, squat lobsters, hermit crabs, yarrell’s blenny, dragonets, and burrowing anemones) but had never had the chance to try it out on fireworks anemones.
The first dive was just a regular dive, heading straight out from the shore we descended the silt slope and turned right to find the rocky reef which was covered in sea loch anemones, various squirts, peacock worms, and some unusual sponges. There were also plenty of hermit crabs and squat lobsters around between the boulders. After passing over the reef we came across three large fireworks anemones quite close to each other in about 20m depth. From there we then moved shallower back up the reef and towards the shore, the visibility was next to nothing down to about 4m but beyond this it was much clearer and with water temp still around 11°C this was a really pleasant dive.
For the dives in the afternoon (after a great lunch in Inveraray) I setup the GoPro (thanks Callum!) with my blue light and yellow barrier filter to hopefully film some fluorescent anemones, the barrier filter blocks out most of the blue light that is reflected back, allowing the fluorescence to be seen more efficiently. I also took in some yellow mask filters for me and Les/Ryan so we could all see what was going on.
Thanks to the murky layer of fresh water runoff on the surface blocking out most of the light the dives were dark enough that we didn’t have to wait and do a night dive. On both afternoon dives (one each with Ryan and Les) we were all able to see plenty fluorescing including hermit crabs and squat lobsters with their glowing mouthparts and claws.
By far the most impressive though were the fireworks anemones with the smaller central tentacles and tips of the long tentacles fluorescing very brightly!
A really enjoyable couple of dives and it was great to finally get some footage of these anemones under the blue lights.
This type of diving is also known as Fluodiving and is now regularly offered by dive centres abroad where night dives on coral reefs can be quite spectacular using blue lights (click here for some photos from a night dive in Thailand). The variety of life that shows fluorescence in this way is huge, from corals and anemones to fish, eels, and sharks, and more recently even turtles have been shown to fluoresce!
However there is no doubt that there is also plenty that fluoresces in our own waters. I’m hoping we will be able to get more dives done over the winter to get some more photos and video.
http://firedivegear.com/science/ is a great website that has lots of background info on the science behind this as well as some great photos/videos.