Salmon and recreational fisheries monitoring: traps

The Girnock and Baddoch

The Girnock and Baddoch are two long-term study catchments on the upper Aberdeenshire Dee that support spring Atlantic salmon populations. Operating since 1966, the Girnock Burn is Scotland’s longest running study of salmon population dynamics. The Baddoch has been operating since 1988 and contributes to the UK Upland Waters Monitoring Network (UKUWMN). The sites include pairs of fish traps, monitoring returning adult and juvenile emigrant numbers, ages and sizes, with annual electrofishing programmes providing information on juvenile abundance and performance. Taken together these data allow construction of detailed stock-recruitment (SR) relationships from which Conservation Limits (CLs) can be derived or assessments of population status can be made relative to various biological reference points. The data also allow for assessment of return rates (an index of the effects of natural and fisheries mortality) between emigration and return.

Understanding of long-term environmental change is supported by a programme of environmental chemistry and stream temperature monitoring. The Girnock has the longest detailed stream temperature record in Scotland.

The Girnock and Baddoch are two of only three Scottish monitoring sites providing long-term data on the production of silver eels. The Girnock has the only silver eel data set in Scotland covering the period prior to the Europe-wide recruitment collapse in 1979. Together, these data inform reporting on the status of European eels to the EU as part of the Scottish Eel Management Plan.

In addition to the routine monitoring programme, the Girnock and Baddoch catchments are also the focus of substantial programmes of collaborative research in areas including hydrology, hydrochemistry, groundwater-surface water interactions, stream temperature, energy budgets, the effects of salmon stocking and salmon population dynamics. Recent collaborators at the Girnock and Baddoch include The Northern Rivers Institute (University of Aberdeen), The University of Strathclyde (Department of Mathematics and Statistics) and The University of Birmingham (Department of Geography).