UK Diving - Kernow, Runnel Stone and Symbiotic Relationships

Location: Latitude: 50°09'22.7"N Longitude: 005°01'51.1"W Harbour: Penzance Max depth: 50m


Located a short boat journey out of Penzance harbour lies the anemone covered granite rocks of the Runnel Stone. A large dive site, many divers know the Runnel Stone as the home of the City of West Minster Wreck, but those divers are missing out on the beauty of the ridges and pinnacles that make up the majority of the site. Ranging from 20m - 50m, this site is ideal for divers just wanting to leisurely dive taking in the colourful Jewel anemones and hydroids that cover granite rocks, and for those more adventurous divers wanting a deep wreck to explore. Runnel Stone should be dived at slack water, ideally an hour before high water in Penzance, although on a neap tide you can often get in two hours before. It is essential that any dives here are properly planned and that conditions are monitored before any divers are allowed into the water, the tides here can be brutal and jumping in at the wrong time will lead to you be swept off the dive site at considerable speed.

Saturday The 17th of June:

The Kernow dive festival consists of a weekend of diving and camping at Cardinney caravan and camping park in Penzance. The Saturday is usually a busy day with over 100 divers wanting to get in the water and go for a dive followed by a massive BBQ in the evening. This was my second year attending and after hearing everybody rave about it the year before, I was incredibly excited to have been scheduled to dive the Runnel Stone. My excitement dampened slightly when I was informed the boat would be roping off at 8:10 in the morning, I mean who decides to go diving at such an unsociable hour? Anyway 7:15 on the Saturday morning after a freezing night of not very much sleep in the tent the night before, there I was staggering around Penzance harbor like a zombie, setting my kit up and loading it onto the boat, ready to go and experience Runnel Stone for myself. There where six ribs heading out to the same site all with approximately 6 divers on board that’s about 36 divers, 18 buddy pairs all jumping in to dive the same site at the same time, I was prepared for mayhem.

Leaving Penzance harbor the sea was flat calm, barely a ripple to be seen, perfect conditions! A speedy 10 minute rib ride later we had arrived at runnel stone and the conditions where not quite as perfect as they had seemed on departure, as we sat waiting for one of the other boats to drop down the shotline, with a one and half meter swell rocking the boat back and forth I started to feel really rather queasy, luckily myself and Andy where the first ones from our boat to jump into the water and as we started to descend down the shot lines the amazing 15 meter visibility only made me more excited for the site I was about to explore. Neither of us knowing the dive site, we weren’t entirely sure as to which direction we should head in, not that this mattered the dive site was so big and so beautiful that whichever direction we headed in and which ever gully we went down there was so much life to see and photograph and as for those 36 other divers? We saw two of them! For approximately 2 minutes, the rest of the time was spent exploring on our own completely undisturbed by any other buddy pairs. Sadly we didn’t find the wreck and the swell wasn’t much better beneath the water so after 45 minutes when we decided to ascend to the surface, I was still feeling incredibly rough. The conditions however didn’t take away from the dive in anyway and I was excited to find so many small critters and marine species to photograph, especially as I was lucky enough to find some more Nudibranchs.

Who Needs Romance When You Can Cave A Symbiotic Relationship?

Whilst not so common in the UK there is a fairly universal and obvious relationship between Nudibranchs and shrimp. This Symbiotic relationship is not only beneficial for the both the Nudibranch and the shrimp but also for underwater photographers as it makes for some interesting images. Mostly observed in the tropics, shrimp have been known to hitch rides and live off the backs of Nudibranchs, that’s not to say they sit lazy and let the Nudibranchs do all the work however, they are constantly on the move catching food using the Nudibranch for not only easy access and fast movement between ideal grazing spots but also for protection, whilst Nudibranchs are not enormous shrimp can be exceptionally smaller and riding around on a host that emits noxious substances and wears bright colours to scare of predators, provides a lot more protection than the shrimp could ever achieve on their own. The Nudibranchs in turn are provided with live in cleaners, warning away and feeding off any parasites the shrimp will also feed off the Nudibranchs fecal pellets, keeping their anal-gill areas clean and fecal free. Whilst admittedly a slightly biased relationship, (the shrimp obviously come out on top here, free transportation and food yes please!) it obviously works for both parties and no harm is caused to either.

#diving #penzance #cornwall #marine #photography #underwater #scubadiver #nudibranchs #shrimp #runnelstone #photographer #macro

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