The Atlantic Aquatic Resource Conservation (AARC) project in the Shannon is rapidly coming to a close. Excellent progress has been made in achieving the objectives set out in the project application in 2010. Of particular success was the establishment of relative survival studies in the River Suck to assess the quality of the Shannon (Parteen) hatchery strain for salmon restoration, using the progeny of salmon sourced from several neighbouring wild populations.

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As reported in the last newsletter (June 2011) the eggs were transferred from ESB’s Parteen Hatchery to two streams on the River Suck, namely the Bunowen and Tirur tributaries. Monitoring of the relative performance in the wild of the various candidate populations continued with a survey of salmon fry at the experimental sites using electro-fishing. These surveys were carried out to determine the densities of salmon fry in the rivers and to assess the relative survivals of the different introduced populations. The egg to summer parr survivals were 1% and 1.5% for the Tirur and Bunowen rivers, respectively, which was not brilliant and probably reflected high initial stocking densities. As described in previous issues, because we have genetically profiled the parent fish, we can assign the recaptured fry to a particular family and subsequently to a specific source population. The genetic assignment work is ongoing and will be reported in the next newsletter.

Samples were collected also for body size and shape measurement on the basis that it might help to explain some of the difference in survival that may emerge. We had an expectation that the experiment would end with the smolt migration from the experimental streams in the Spring of 2013, however, much to the surprise of the project scientists, a substantial smolt run of 1-year old fish took place in 2011!

This could reflect an adaptive behaviour for early migration or be triggered by environmental factors, such as food availability. Either way, these samples were collected for genetic profiling and parentage assignment. The fish were trapped using rotary screw traps (thanks to ESB and the Marine Institute for the use of the traps). By early 2012 another significant milestone in the project was the installation of a Passive Integrated Transponder (PIT) tag array in the River Bunowen at Clonbrock Demesne. This equipment enables the absolute monitoring of all tagged individuals and the timing of their migrations.

Significant progress has also been made on the compilation of Shannon specific geographical data into GIS. This database will include all AARC project survey data including: the distribution of potential spawning habitats (an essential element in determining restoration possibilities in the system); elec-trofishing survey results; water quality layers; arterial drainage; barriers data; restocking sites. This map-ping tool will enable the presentation and communi-cation of relevant survey data, and will help inform management decisions relating to Shannon salmon conservation.
Other milestones in the project include:

  • Consultation and information dissemination to all stakeholders (seminars, newsletters)
  • Complete salmonid spawning habitat surveys for the River Suck catchment ( using kayaks and on foot)
  • Morphometric analysis for all salmon sampled during electrofishing and trapping programmes on the Bunowen and Tirur
  • Genetic analysis of archive and contemporary tissue and scale samples from the Shannon

Download the full report here: icon River Shannon AARC Newsletter Volume 2 Issue 1 (718.97 kB)