Archive for March, 2008

Lochaline, Easter 2008

Thursday, March 27th, 2008

This year did not promise the best, with a pretty dreadful weather forecast, and driving hail on the journey North. In the event, however, the North wind, while cold, gave us long cloud free periods, with small snow flurries in between, and raised few problems with the diving.

Lochaline offers some excellent, easily accessed, shore dives with a diverse range of habitats and marine life. The wall off the Hotel beach is a favorite with the group, as this offers a white sand beach access to one of the most impressive walls in the UK, dropping almost unbroken from about 15m to 80 or 90m depth.

Corphella browni

It is here that we did most of our diving over the Easter break, extending our surveys of previous years towards the mouth of the Loch. This encompassed a new beach, and boulder slope, and a number of additional species have been added to our list for the site, including the sea pen Virgularia mirabilis. The organisms on the wall are all currently getting into gear for the year ahead – top shells and sea slugs are grazing the Tubularia, and laying eggs in great coiled masses. Mermaids purses are to be found on anything that they can cling to!

Virgularia mirabilis

Our dive to the East of the fish farm at Fiunary was a bit more exposed, which caused a few problems leaving the water, but it offered a rather different habitat – a short boulder slope to 10m or so, followed by a fairly steeply sloping mud bottom. This area usually has a luxuriant kelp forest over the boulder slope, home to a wide range of organisms, including snakelocks anemones.

At this time of the year, however, the kelp has been thinned by the winter storms, but equally (or perhaps more importantly) it cannot keep up with grazing pressure over the winter months, as it gets eaten faster than it can grow! This makes hunting in the base of the kelp forest a lot easier, and Rob managed to find a sea mouse in between the boulders, while more sea pens (again Virgularia) were spotted in deeper water.

The final dive location was at Drimnin – this was by my request as my 200th dive. I have fond memories of Drimnin, with its simple access and sunlit shallows. In the event we were all a bit under-weight for the dive (which maxes out at about 6m), and for once the sun remained hidden behind high clouds, so the dive was a bit of a disappointment. Still, it is different again, an almost flat muddy bottom with occasional boulders in shallow water offering an excellent habitat for a range of weeds, fan worms and hermit crabs. Later in the year the area will have long trailing sea whips (Chorda filum – this plant has a host of other common names!), for the moment and spring arrives, it is dominated by smaller red algae and the green sea lettuce, while the boulders provide safe anchorages for large kelp plants – furbelows and sugar kelp.

Pennate diatoms

The group also fitted in a number of rock-pooling surveys close to our base at the Old Post Office walks, and a number of longer walks, including to the old castle and estate house at Ardtornish.

We took one plankton sample from the beach area. The first blooms of phytoplankton have not really got going yet, so this was a bit sterile, with just a few pennate diatoms. A wider range of diatoms was to be found epiphytic on some of the seaweed samples taken by the rock-poolers.