Community-led Marine Biodiversity Monitoring Project – Clashnessie beach: a closer look
On 6th March four members of the Field Club made a second visit to the transect for the Community-Led Marine Biodiversity Monitoring Project at the eastern end of Clashnessie beach (see article on first visit on 14th February). The tide was very low, so we were able to get further down the shore than before.
Barnacles and Seaweeds
We concentrated on some queries from the February visit and the boulder bed. The barnacles on the highest part of the shore, with kite-shaped apertures, were confirmed as Montague’s stellate barnacle Chthalmus montagui. In the shells of some of them were embedded the maritime lichen Collemapsoridium halodytes. We identified those lower down the shore as the northern rock barnacle Semibalanus balanoides (photo 1).
A variety of red seaweeds was collected from upper parts of the boulder bed (photo 2). We found examples of Irish moss Chondrus crispus, clawed fork weed Furcellaria lumbricalis, grape pip weed Mastocarpus stellatus, winged weed Membranoptera alata, false pepper dulse Osmundea hybrida and probably dulse Palmaria palmata. Adhering to the grape pip weed were the bryozoan hairy sea mat Electra pilosa and the hydrozoan sea oak Dynamene pumila. Lurking in the holdfast of one of the red seaweeds was a tiny gastropod mollusc (just 3mm long). It had a striking pattern of darker stripes (photo 3) and was later identified as Rissoa parva, which can be abundant in this microhabitat.
Boulders half way down the bed provided a colourful ragworm, the Greenleaf Worm Eulalia viridis (photo 4), and eggs of the Dog Whelk Nucella lapillus (photo 5).
Boulders in the kelp beds
The higher of the two species of kelp so far found on this shore is Tangle Laminaria digitata (photo 6). Its holdfasts provided a home for juvenile saddle oysters Anomia ephippium. The uppersides of some boulders are covered with the sinuous calcareous tubes of keelworms and the spiral cases of several kinds of Spiral Worms (family Spirorbidae, photo 7).
The undersides of the boulders (carefully replaced after inspection), and searching amongst the seaweed on and around them, provided us with a treasure trove of small organisms. The chitons, or coat-of-male shells, a form of mollusc, were probably Lepidochitona cinerea (photo 8). A spiral egg mass, almost certainly molluscan (photo 9), is not illustrated in the seashore books we have so far consulted.
Crustaceans were represented by juvenile examples of edible and shore crabs Cancer pagurus and Carcinus maenas (photo 10) , a possible tiny hairy crab Pilumnus hirtellus, and numerous juvenile common squat lobsters Galathea squamifera (photo 11). Sponges were represented by the breadcrumb sponge Halichondria panicea, echinoderms by common brittlestars Ophiothrix fragilis (photo 12) and fish by a very lively shanny Lipophrus pholis.
Finally, at the lowest part of the shore were exposed the tops of upright rough-stemmed fronds of Forest Kelp or Cuvie Laminaria hyperborea (photo 13).
A more detailed account of our finds is attached (here). We have only begun to scrape the surface of the biodiversity represented on this beach and realise that, to more experienced marine biologists, our finds are relatively commonplace. However, many are still unfamiliar and wondrous to us, so we shall go on looking.
Ian M. Evans
P.S. About a month after this visit, I was in a local bookshop and happened upon The sea is not made of water – life between the tides by Adam Nicolson (William Collins, 2021). It is the beautifully written story of a fascination with intertidal life which started thirty years ago with a visit to a family house on the north coast of the Sound of Mull. The introduction is entitled The Marvellous; Part 1 Animals then describes aspects of the natural history (previously quite unknown to me) of five common creatures found on that Argyll shore – Sandhopper, Prawn, Winkle, Crab and Anemone. After that, he moves on to wider issues in Part 11 Planetary Connections and Part 111 People. It is described as an account of ‘one of the most revelatory and beguiling habitats on earth’, the breadth of his scholarship is outstanding, and I highly recommend it. IME