After a string of possible dates this year that we were unable to get in at Roa Island we finally managed a dive on Friday (we had to bring it forward a day to miss the worst of the weather). It was well worth the effort. Visibility was only 2 to 3 metres at best but that is plenty to search the reef for interesting macro life. Our species list – which for invertebrate species goes back to 1968 – grew by at least 2 new species. First to be found were several Goldsinny (Ctenolabrus rupestris), unusual not just as a first for that species, but the first species of wrasse to appear on the list.
The next was a nudibranch (that’s a fancy name for a sea slug) called Jorunna tomentosa (pictured below) – it doesn’t have an English name. Both are common species around the coasts of the UK, so of course may have been here all the time, but this is the first time we have them on record here.
There are many predators in the marine ecosystem and animals have a variety of strategies to help them find food, and avoid being eaten. The Long-spined Scorpionfish is a master of disguise – hiding in plain site by blending its skin colour in with its background; if a crab or small fish comes too close they will be grabbed at lightening speed, predators large enough to tackle it will need sharp eyes to see it, and if they do this fish has a back-up plan – the eponymous long spine on its gill cover, just visible in this picture.
Perhaps the most suprising thing about the dive was the water temperature – depending in depth it ranged from 18ºC to 20ºC. I don’t think that I’ve dived in water that warm either at Roa Island or anywhere else around the Irish Sea. Unfortunately I can’t check my dive logs after a computer glitch trashed them a couple of years ago.
Thanks to Philip and Rebecca for providing shore cover!
Lewis Bambury, July 2019.