Fishery studies in the estuary and Firth of Forth, Scotland

Abstract

SynopsisRecent fishery studies in the estuary and Firth of Forth stem from the late 1970s and have largely been carried out by the Institute of Terrestrial Ecology, the Forth River Purification Board and Heriot-Watt University. This paper briefly reviews these studies, which may loosely be divided into work done at power stations, general demersal and pelagic studies of the estuarine fish populations, studies on particular species (lamprey, eelpout, whiting, cod and flatfish, especially the plaice), pollution- orientated studies (hydrocarbons in flatfish and mercury in eelpout) and more general work including ichthyoplankton surveys. Most work has been done on the ecology of flatfish, especially the plaice and it is examined in most detail.A total of fifty species of fish have been recorded of which thirty-six occurred in the estuary and thirty-nine in the firth. Others are however known to occur. Of the twenty-eight species entrained into the intakes of local power stations, the sprat, herring, whiting and sand goby were most numerous, while other common species were sandeels, eelpout and pogge. Sand gobies, whiting, common dabs and sprats were the most numerous species taken by Agassiz trawling with herring, cod, eelpout, butterfish, pogge, flounders and plaice also commonly taken. Only herring, sprat, whiting, cod and fatherlasher were recorded using a midwater trawl and only the clupeoids occurred in all the catches. The catches of the 2 m beam trawl used in sandy bays in the firth were dominated by plaice, common dabs, sand gobies and sandeels. The ichthyoplankton surveys undertaken in 1986 have caught twenty-three species as eggs and twelve species as larvae. The majority of the eggs were those of the common dab, whiting, flounder, rock ling and sprat, while the majority of larvae were sandeels and clupeoids.