Assessment and conservation of whitefish (Coregonus lavaretus (L.)) in the U.K.
Winfield, Ian J.; Bean, Colin W.; Gorst, John; Gowans, Andrew R.D.; Robinson, Maggie; Thomas, Rhian
The whitefish (Coregonus lavaretus (L.)) is of high biodiversity value in the U. K., where it exists as a total of only seven native populations in England (Brotherswater, Haweswater, Red Tarn and Ullswater), Scotland (Loch Eck and Loch Lomond) and Wales (Llyn Tegid also known as Bala Lake), and is protected by national conservation legislation. However, an absence of fisheries means that information on its populations is scarce and must be obtained by dedicated surveys and associated activities. A standardised national assessment protocol using hydroacoustics and survey gill netting is described and results are presented from its use on the three whitefish populations of Scotland and Wales. For the remaining four English populations where the assessment protocol has not yet been specifically applied, comparable data are available from similar surveys, augmented by long-term fish entrapment records at one lake. These surveys revealed that the whitefish populations of Loch Eck, Red Tarn and Ullswater were in favourable condition. However, the condition of whitefish in Brotherswater, Haweswater, Llyn Tegid and Loch Lomond was considered to be unfavourable. Conservation measures specific to the whitefish populations of greatest concern in Haweswater, Llyn Tegid and Loch Lomond are described, including the management of water levels, local control of nesting cormorants (Phalacrocorax carbo (L.)) and establishment of refuge populations.
population monitoring • hydroacoustics • gill netting • entrapment • eutrophication • species introductions • water level fluctuations • gwyniad • powan • schelly • Bala Lake • Brotherswater • Haweswater • Llyn Tegid • Loch Eck • Loch Lomond • Red Tarn • Ullswater