The status of fish populations in the Clyde Estuary

Abstract

SynopsisChanges in the status of fish populations in the Clyde Estuary between Woodhall and Glasgow since 1978 are described and data presented on species composition and distribution, temporal and spatial fluctuations in abundance and biomass and length frequency data for certain species are analysed.The seaward part of the estuary is colonised by marine and euryhaline marine species dominated by flounder, while the ‘city reaches’ have a fresh water component dominated by three-spined stickleback and eel in addition to several euryhaline species, e.g. sand-goby and saithe.The extent of biological recovery of the estuary from severe organic pollution can be gauged from the presence now of thirty-four species, including nineteen in the city reaches which were virtually fishless in the mid nineteenth century. The upper estuary is now able to support resident and migratory fish for much of the year, but species composition and abundance are markedly affected by seasonally variable fresh water flows to the estuary affecting primarily dissolved oxygen and salinity, leading to mortalities among resident species and providing a barrier to migrants.

Disused docks as habitats for estuarine fish: a case study of Preston dock

“…A winter migration also occurs in the Medway (van den Broek, 1979) and the Severn (Potter & Claridge, 1985), although in the latter estuary the influx is of older individuals. A larger peak of 40-44mm 0-group sprat in August-September, as found in the Severn (Claridge et al, 1986), the Clyde (Henderson & Hamilton, 1986) and the Ribble, (Sewell, 1983), was not recorded from the catches of Lundgren nets used in this study. Sea trout were present throughout the year but were most numerous from December onwards, reaching a maximum in February.…”

“…Due to the inherent difficulties of netting, work on estuarine fish communities has generally been confined to sampling of power station intake screens (e.g., van den Broek, 1979;Henderson & Hamilton, 1986;Claridge et al, 1986;Turnpenny & Utting, 1987) although several net surveys, including one of the Ribble Estuary (Sewell, 1983) have been undertaken. Docks, in contrast, are relatively easy to sample using nets, and, despite their semi-enclosed nature, can be used to gain insights into the fish assemblages in adjacent estuaries.…”

Beam trawl surveys as a monitoring tool in polluted estuaries in north‐east England

“…A beam trawl was therefore selected as being inherently more efficient than the Agassiz trawl and easier to handle in the estuary than the otter trawl. Other workers have reported successful use of both Agassiz trawls (Elliott & Taylor, 1983) and beam trawls (Henderson & Hamilton, 1986) for estuary work in the lower reaches of the Forth and Clyde estuaries respectively, while a beam trawl has been used in the upper Forth estuary (Elliott & Taylor, 1986) and in the upper Mersey estuary (Taylor, 1985).…”

An Overview of the Status, Study and Management of Fishes in Estuaries

“…as shown in the clean-up of the Thames and Clyde (UK) and the return of their fish communities (e.g. Henderson & Hamilton, 1986). However, there are still accidental inputs and spillages, such as trace metals into the Donana protected area, southernspain, and oil into the Milford Haven estuary from the Sea Empressaccident in 1995.…”