An initiative of the
North Atlantic Salmon
Conservation Organization (NASCO)

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Two research surveys were undertaken using Marine Institute research vessels in 2009. The first survey involved the RV Celtic Voyager (9 -12 May 2009) and the second the RV Celtic Explorer (23 June - 2 July 2009). The aim of these surveys was to investigate the distribution and feeding patterns of Atlantic salmon during the early stages of the marine migration. The RV Celtic Voyager surveyed areas West of Ireland and Scotland while the RV Celtic Explorer surveyed an area much further north in the Norwegian Sea six weeks later, in order to capture salmon post-smolts of both southern and northern origin stocks.

The RV Celtic Voyager experienced adverse weather conditions which impeded aspects of the survey. In total, 9 trawls were conducted but 4 of these yielded no post-smolts. In total, 9 post-smolts were caught, an average of 1 post-smolt per haul, having a mean fork length of 18.9cm, mean weight of 68.87g, and a mean condition factor of 1.01. Two of these post-smolts contained coded wire tags (CWTs) indicating precisely the river of origin and the date of migration. All trawls were carried out close to and across the continental shelf in daylight. The lack of post-smolts and by-catch may have been a result of fish dispersing away from the shelf edge migration route as the overall catch of all expected species was smaller than anticipated.

The RV Celtic Explorer conducted 15 trawls, all of which contained post-smolts, with individual hauls ranging from 1 to 69 post-smolts. In total, 455 post-smolts were caught, an average of 30.33 per trawl.  Of these, 4 contained CWTs with 1 adipose fin clipped fish also taken. The mean fork length of the 455 salmon post-smolts was 21.3cm, the mean weight 94.39g and the mean condition factor was 0.95. In total of 10 adult salmon were caught, 8 of which were of wild origin. The mean fork length of these adults was 49.9cm, the mean weight was 1.11kg and the mean condition factor was 0.87.

In summary, despite poor weather that affected the first survey, the sampling conducted in 2009 was succesful and has generated much data that is now being analysed.