Zooplankton investigations in the Firth of Clyde

Abstract

SynopsisZooplankton investigations in the Firth of Clyde can be considered as starting in 1885, when the Fishery Board for Scotland built a laboratory at Tarbert and the Granton based Scottish Marine Station extended its studies to the west coast. The work of both groups, and their successors, waxed and waned, with a particularly active period starting in the early 1920s, when the Millport Station received government aid.Although the euphausiids Meganyctiphanes norvegica and Thysanoessa raschii are important in the deep waters around Arran and in Loch Fyne, in general, copepods are the most important pelagic crustaceans. Of these Calaims occurs in enormous numbers in surface waters in May and June. Thereafter it is found mainly in deep waters such as those of Loch Fyne. Other abundant copepods are Pseudocalanus elongatus, Acarlia clausi and Oithona similis which are particularly characteristic of the area extending from Kilbrannan Sound via the east of Arran to the upper Firth of Clyde. In these latter areas the peak standing stock of the larger zooplankters (as caught by a 250μm mesh net) is about 5, occasionally 8, g dry weight per 100cum, occurring from April to July. The smaller zooplankters (as caught by a 68μm mesh net) add a further 1.3g dry weight per 100 cu m.