Dive Site: Ynys-y-Moch
Location: Menai Straits, North Wales
Description: Drift or shore dive
Depth: 0 – 15 metres (0 – 50 feet)
Visibility: 4 – 8 metres (13 – 26 feet)
An exciting dive for the marine life in an area awash with dangerous currents. In the northwest of England and North Wales, providing the tides are right the Menai Straits under or around the Menai Suspension Bridge provides the diver with an all-year-round shore dive site, guaranteed! The down side is when the tides are not right it’s running at anything between 6 and 9 knots, but it’s best to dive it at a slack period to appreciate the sheer vastness and bio-diversity of marine life. Screaming drifts can be had but really only with boat cover.
Bangor University of Ocean Sciences regularly make studies of the area, especially under the Menai Suspension Bridge built by Thomas Telford in 1826. The Menai Straits in glacial times used to be estuarial, until afterwards when it became tidal bringing masses of nutrients along its length. The turbo-fed marine life thrives in this area and visibility is reduced as a result.
Under the bridge is a small island called Pig Island and this forms an underwater nature trail usually dived from west to east as the tide flows afterwards. The first thing the diver encounters are sponge cliffs, stepped walls of rocks covered in solidified yellow custard is the best analogy. Look closer and one will find a plethora of filter feeding marine, both sessile and mobile. Lobsters are one thing but hundreds of crabs of differing varieties can be found with an additional load of dragonets, scorpionfish, yellow coloured scorpion spider crabs, gunnell, many pollack and shells.
The depth starts at zero to a maximum of 15m and usually the bottom composition of terminal moraine is covered in dense carpets of very colourful and voracious dahlia anemones. In places huge beds of mussels dangle precariously off rock edges whilst at certain times of year masses of nudibranchs, particularly Dendronotus frondosus can be seen grazing.
The visibility can vary the average being 4m and sometimes it goes up to 8m. With this amount of marine life it’s hardly surprising many of the divers crave this site all year round especially those with cameras with macro lenses fitted!
Scubster 