The Ecology of the Lough Ine Rapids with Special Reference to Water Currents

Abstract

Lough Ine is a sea lough in Co. Cork, Ireland. It is joined by a narrow channel, known as the Rapids, to Barloge Creed, which in turn opens into the Atlantic. Strong currents are set up in the Rapids by the rise and fall of the tide. The tops, sides, and bottoms of a number of sublittoral boulders from various parts of the Rapids area have been examined, and the quantities of the various non-motile animals have been estimated. A fauna of 156 spp. is listed. 13 spp. show a preference for the main stream of the Rapids; 11 prefer sheltered bays; 25 show no obvious preferences in this respect. 5 (or possibly 9) spp. prefer the tops of boulders; 12 prefer the bottom; 28 show no obvious preference for either. Failure of spp. to occupy current-swept boulders on the Sill is ascribed to a mechanical effect. Restriction to the main stream, with failure to occupy sheltered bays, is thought to be due mainly to an unfavorable influence of sediment, which perhaps affects the microclimate surrounding boulders or clogs feeding and respiratory mechanisms. Restriction to sheltered bays is possibly due to a better supply of organic detritus or bacterial food. Preference for tops is ascribed in some cases to feeding on algae, and in others perhaps to a lack of sufficient room for growth on the bottoms. Preference for bottoms is ascribed to an unfavorable influence acting on the tops. This latter may be competition with algae at all stations, mechanical effect of current in the main stream only, or settling of sediment in sheltered bays.