Beach and Dune - Gower - page 136

FIG 72. The south-claw hermit crab Diogenes pugilator , as illustrated in Bell's British Stalk-eyed Crustacea , pub-
lished in 1853.
the author for Figures
The early descriptions mention the crab's ability to quickly bury itself in the sand. Because of such
comments and subsequent studies on the ecology of this specialised species, the Gower location where
Dillwyn collected it is more likely to have been Rhossili beach than the mainly rock habitats nearby at
Worms Head. Some 150 years later it still occurs on this and other beaches facing onto Carmarthen Bay
and in general needs gently shelving moderately exposed beaches facing southwest. The waves reaching
these beaches spill when breaking rather than plunging and conditions are less turbulent than on steeper
beaches.Thesandalsotendstobecleanandwellsortedandextendsoffshoreratherthangivingwaysoon
to muddier sediments.
Most crabs generally feed by scavenging or by processing sediment with their mouthparts, and while
thehermit crabcanuseboththese methodsitalsohasanothertechnique. Likethemolecrabs,whichbury
themselves in the sediment, it has pairs of extended bristles along its antennae and it uses these as a net to
catch food. The crab digs itself into the sand so that just the rim of the shell shows and from this position
sweeps its antennae alternately in circles about 30 to 40 degrees from the horizontal.
Another animal found in this habitat is the lesser weever fish Echiichthys vipera , which grows to
around 10 to 15 centimetres. It spends most of its time in shallow water over sandy areas and can often
be found during the summer months on the Gower beaches. This small burrowing fish, which lies partly
buriedonthelowestshore,shouldnotbehandledsinceithasvenomousspinesalongitsdorsalfin.People
walking barefoot along the edge of the sea can be stung and there have been reports of incidents from