XXI.—Studies in the Scottish Marine Fauna. — The Crustacea of the Sandy and Muddy Areas of the Tidal Zone

Abstract

Summary1. An attempt is made to indicate the quantitative distribution of the Crustaceans inhabiting certain Scottish intertidal areas.2. Certain areas in the Clyde, notably Cumbrae, show a rich Amphipodan fauna which exhibits zoning by species.3. Bathyporeia guilliarnsoniana is the dominant amphipod on the Tellina-Nephthys grounds (clean sand) and Corophium volutator is indicative of a muddy to brackish environment.

A Quantitative Study of the Fauna of the Sandy Beach at Port Erin

“…In large numbers, high up on the beach, near and above M.S.L., and in greatest abundance on lines Band C. It was not recorded at all in the samplings taken in April, 1929. This is paralleled by observations at Millport (Elmhirst,5), where the species is found, in winter, in shallow water below L.W: Springs, while in summer it is found further inshore.…”

The sublittoral fauna of two sandy bays on the Isle of Cumbrae, Firth of Clyde

“…The volume of debris collected by the trawl at high tide when most of the movable debris is above station I and in the intertidal zone is given below. Elmhirst (1931), Stephen (1928Stephen ( , 1929Stephen ( , 1930 and Watkin (1942), who, between them, have described in considerable detail the zonation of animals in the intertidal part of the bay. The lowest station of Stephen (1928) corresponds approximately with the highest station in the present survey.…”

The Preservation of Fishing Nets, Trawl Twines and Fibre Ropes for Use in Sea Water

“…This investigation shows that both habitats contribute to the migrant population. To complete the analysis of the migrant fauna it is necessary to obtain samples of the microfauna, which in addition to the usual plankton organisms will consist of such forms as Harpacticids (E1mhirst, 1935), and also to obtain a knowledge of the fishes which both as adults and ./ in their young stages may migrate inshore at night-time in varying numbers at the different seasons of the year (Elmhirst, 1935;Marshall et al 1939). By such studies it will eventually be possible to build up a picture of the extensive activities which occur in intertidal waters at night-time.…”

“…basis shows two definite peaks of density; the first over the 5th-8th day and the second over the 20th-23rd days, thus suggesting an association with lunar illumination of a certain intensity. Elmhirst (1932), in a series of samples taken every three hours from 6 p.m. to 6 a.m. on a night in March and again in June, shows that this species is abundant in the surface waters at low tide; but at high tide, when the lowwater level is covered by 2 fathoms of water, itis abundant near the sea floor and practically absent from the surface. His data further show that very few are carried in with the tide to high-water mark.…”

“…Attention may be drawn to Dexamine thea, seventeen individuals from six samples, and Stenothoii monoculoides, seven individuals from five samples, as adding to the list of algal dwellers which may be included under the species performing a night migration. The data for the sand dwellers Megaluropus agilis (Table III) and Periculodes longimanus, six individuals from two samples, does not represent the extent of their migration, since Elmhirst (1932) has shown that samples taken at two fathoms depth near the low-water mark of spring tides yield these two species in considerable numbers. The samples were taken on a night in March and again in June and successive sampling at 3 hr.…”