Population Structure, Genetic Stock Identification and Potential Impact of Farm Stocking - Lough Sheelin Brown trout

Karen Delanty, Caroline Bradley, Rosaleen Hynes, Martin O'Grady, Paulo Prodohl*

*Corresponding author for this work

Research output: Book/ReportCommissioned report


Brown trout (Salmo trutta) populations are sensitive to alterations of the physical and natural environment (Elliott 1994). Over the past century, urban growth and associated discharges, farming activities and agricultural run-off, arterial drainage, introduction of alien species, and stocking of farmed fishes, have all contributed to the alteration of the natural aquatic environment and the loss of suitable spawning, nursery and feeding areas for brown trout. These anthropogenic-mediated factors, which have changed both the demography and ecology of local populations, have often led to declines in brown trout productivity in many river catchments in Ireland.

One of the main challenges in the management and conservation of biological resources is to preserve genetic variability (particularly adaptive variation) within and among populations. Adaptive genetic variation is the key feature of populations that enable them to cope with environmental changes and, hence, ensures their long-term sustainability. Since habitat degradation and other anthropogenic activities pose a serious threat to the maintenance of adaptive genetic variation within and among populations, routine genetic monitoring of populations provides important information for the effective development and implementation of both management and conservation plans.

During the late 1950s, an extensive brown trout hatchery stocking programme began in the Lough Sheelin catchment. The impact that such a programme could have had on the wild brown trout population was not known. In 2012, IFI, in partnership with QUB, carried out a genetic study, based on microsatellite DNA profiling, to examine the putative consequences of this management strategy on the population structure of the Lough Sheelin brown trout.

The project was supported by the Lough Sheelin Trout Protection Association (LSTPA), who contributed financially and supplied adult trout scale samples to the project.
Original languageEnglish
PublisherInland Fisheries Ireland / Iascach Intíre Éireann
Number of pages27
ISBN (Print)IFI/2021/1-4537
Publication statusPublished - 2020


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