By IFI Staff In Fisheries Research 490 downloads
A genetic study of the mixed trout populations of the Boyne and Suir River catchments
Technical Report for Inland Fisheries Ireland
In 2011, an OPW-funded collaborative project between IFI and the UCD School of Biology & Environmental Science released a report on the genetic structuring of the adult trout stocks in the Boyne and Suir river catchments. The project primarily aimed to compare the genetic diversity of trout populations in a catchment highly impacted by arterial drainage (the Boyne) with those of a more pristine catchment (the Suir). The report’s findings indicate the following conclusions:
- The Boyne trout populations had significant genetic structuring that was heterogeneously distributed across the catchment, with evidence of admixture and gene flow between some tributaries.
- In the Boyne system, the River Mattock population was highly divergent and genetically pure, indicating that it is reproductively isolated; it possibly corresponds to a sea trout breeding stock.
- In the Boyne system, the Kells Blackwater probably contains two sympatric trout populations which are genetically isolated from each other.
- The trout populations of Suir tributaries had a more homogeneous genetic structuring, probably indicating more admixture, more gene flow between tributaries and less genetic drift due to larger effective population sizes.
- In both river systems, the main channel’s adult fish stocks were mixed, comprised of individuals recruited from several of the tributary populations.
- The most important tributaries for recruitment to the main channels’ adult stocks were the Knightsbrook, Trimblestown and Stonyford for the River Boyne and the Nier and the Multeen West for the River Suir.