Mystery at sea

ANGLING NOTES: THE decline in Atlantic salmon stocks over the past 30 years is alarming

ANGLING NOTES:THE decline in Atlantic salmon stocks over the past 30 years is alarming. While major initiatives to curb the problem have been initiated, for example the cessation of drift-netting – which allows for an additional 150,000-plus salmon to return to their native rivers every year – nevertheless, marine scientists remain baffled that wild salmon stocks continue to fall.

While a good deal of information is known about the route and whereabouts of smolts following their departure from rivers, it’s a mystery why so few return. Some of the reasons put forward include a fluctuation in sea temperatures, a problem with the food chain, pollution and predation.

In 2002, Nasco established the International Atlantic Salmon Research Board (IASRB) to address the issue. Its main objectives were to discover the causes of marine mortality, to maintain an account of research and to raise funds to finance research projects.

After a series of meetings, the initial Salsea (Salmon at Sea) programme was presented to Iasrb at its agm in 2005. It was agreed to seek funding in Europe and the US to achieve the objectives outlined in the programme.

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The Atlantic Salmon Trust and Total Foundation showed a keen interest in part-funding the project and under a FP7 programme the EU provided an additional €2.4 million. With matching funding from the private sector, the total figure rose to €5 million.

On April 1st, 2008, the Salsea-Merge programme commenced. By August, three cruises had been completed.

The Irish survey included the use of RVs Celtic Voyager and Celtic Explorer. The latter cruise-ship collected 358 salmon post-smolts taken in 27 hauls from the southern range of the early salmon migration and included data relating to water temperature, depth and salinity. Some 76 post-smolts were taken during the cruise of the Voyager.

The Faroese cruise in July on RV Magnus Heinason accounted for 363 post-smolts, an average of 7.3 per tow. Most were 21cm in length but 11 larger salmon – 10 1S/W and one 2S/W – were also caught. Eleven post-smolts were fin-clipped and when scanned for presence of microtags, four tested positive. The Norwegian cruise aboard RV Eros concentrated on areas not previously surveyed for post-smolts. Although not numerous, a total of 88 salmon were taken in 31 net hauls.

On each cruise, salmon post-smolts were photographed, measured, weighed and, sexed. Scale loss was noted and they were inspected for lice count, cataracts, etc.

The biological examinations included scale samples; pectoral fin for DNA; disease (gill filament, pyloric caeca, spleen and kidney; ISA disease; Isotope (liver, dorsal muscle, adipose fin, heart and caudal fin; lipid (dorsal muscle); stomach and otolith samples. The carcass was labelled and stored.

The above data, from 885 salmon and new material from cruises planned this year, will provide a basis for an analysis to be carried out as part of Salsea-Merge. The results from the programme will be presented at an international salmon summit in 2011 which will examine the results of surveys of Pacific and Atlantic salmon stocks. Details are available at www.salmonatsea. com

*Big seas, strong easterly winds and floating weed made fishing difficult for the first leg of the Leinster Shore League hosted by Raheny District SAC at Kilcoole, Co Wicklow, last Sunday week. Nevertheless, a good turnout of anglers required three zones and by all accounts catches were good considering the wintry weather. The event was sponsored by Henry's Tackle, Ballybough, Dublin 3.

Results: Overall winner: J Farrell (Blackrock). Zone A: J Bermingham (South Shore). Zone B: T Keogh jnr (South Shore). Zone C: J Farrell (Blackrock). Best junior: G Fogarty (Raheny District). Longest fish: L Mooney (Ballybrack), 50cm codling.