Some species, or their signs, were familar from last year, such as the shells of Haminoea sea slugs, the Snakelocks Anemone Anemonia viridis, and the introduced North American bivalve, the Quahog Mercenaria mercenaria. Many others were different however - some are presented here and I hope you enjoy them. The first group I want to cover are the molluscs, starting with some primitive armoured species (the chitons) and then a larger (and edible) introduction.
|The fairly common Acanthochitona crinitus (family Acanthochitonidae). The valves are less smoothly arranged than in L. cinerea and there are 18 tufts of coarse bristles. This specimen is about 20mm long - the maximum is about 34mm.|
Chitons (class Polyplacophora) have a mantle skirt which forms a toughened 'girdle' around the whole edge of the animal and this is where the fringing spines etc are found. The head is small and covered by the girdle and the dorsal surface generally has armoured 'valve plates' as seen here. They graze plant and algal material from hard substrates and, like limpets, are able to withstand wave shocks without being dislodged.
|OK, this probably is quite familiar - it's the common hermit crab Pagurus bernhardus, using the shell of a Netted Dog-whelk Hinia reticulata. Gotta love hermit crabs! Note the larger right claw which is covered in small knobs or 'tubercles'.|
|The Leathery Sea-squirt Styela clava. This is an introduced Pacific species and can be found attached to stones (as here) and pilings around the south-west coasts of Britain.|
As with last years post, this is only a snapshot of what can be found on a diverse section of intertidal habitat, but hopefully an interesting one. However, it does illustrate how important volunteers are for recording wildlife, especially less 'popular' groups like many in marine and intertidal habitats - and with knowledge comes at least the potential for conservation.
Crothers, J. & Crothers, M. (1988). A key to the crabs and crab-like animals of British inshore waters. Field Studies 5(5): 753-802 (revised reprint).
Gibson, R., Hextall, B. & Rogers, A. (2001). Photographic Guide to the Sea & Shore Life of Britain & North-west Europe. OUP. Oxford.
Hayward, P.J. & Ryland, J.S. (eds) (2000). Handbook of the Marine Fauna of North-West Europe (2000 revision). OUP, Oxford.
Crothers, J.H. (1997). A key to the major groups of British marine invertebrates. Field Studies 9(1): 1-177. Very useful if you are new to marine invertebrates.
Hayward, P.J. (1988). Animals on Seaweed. Richmond, Slough. For those interested in generally small intertidal species found attached to seaweeds.
Hayward, P.J. (1994). Animals of Sandy Shores. Richmond, Slough. Not used here although Calshot Beach is sandy in places and supports some of the species in this book.
Hiscock, S. (1979). A field key to the British brown seaweeds (Phaeophyta). Field Studies 5(1): 1-44. Useful alongside Hayward (1988).