Study shows dramatic impact of ESB dams on salmon

A new study just published shows that salmon runs on Shannon are less than five percent of what they should be. This is due to the impact of ESB dams. Essentially the salmon run on the River Shannon has collapsed. The ESB has clearly failed in meeting their statutory obligations to maintain the Shannon fishery.

The report published by Inland Fisheries Ireland and Ireland’s independent standing scientific committee on salmon (SSC), confirms that the number of Annex II listed Atlantic salmon passing the ESB’s dams on the Lower River Shannon Special Area of Conservation is currently less than 5% of the conservation limit (CL) escapement target. The CL is the number of salmon that have to run a river before the river is meeting favourable conservation status. It is also the level at which a salmon stock has to exceed before there is a “surplus” above spawning requirements so a river can be opened for recreational angling. On the River Shannon the CL is 49,638 salmon per year, however the average upstream salmon count passing though the ESB’s dams on the River Shannon for the period  2011-2015 was just 2,148 salmon – and most of these were hatchery salmon. The report entitled ‘The Status of Irish Salmon Stocks in 2015 with Precautionary Catch Advice for 2016‘ ‘from the The Standing Scientific Committee on Salmon can be downloaded from here.

DCIM100MEDIADJI_0157.JPG

Ardnacrusha Hydroelectric Station, December 2015.

The River Shannon is bottom of the league of all the rivers in Ireland in meeting this minimum conservation limit escapement target. The figures released by the independent scientific committee are a damning indictment of ESB’s salmon management programmes on the Shannon. Indeed, you have to ask whether things could possibly be worse than this? If there was no salmon hatchery, no ESB “scientific” salmon management programme whatsoever, could it possibly be worse than <5%? It could not – that number of salmon would be present even if nothing was done except leave the salmon pass at Parteen Regulating Weir open. Indeed it is likely that there would currently be be more salmon in the River Shannon if nothing at all had been done as 50+ years of hatchery stocking on the Shannon – along with the impact of broodstock trapping – has almost certainly had a significant negative and counter-productive impact.

After almost 60 years of ESB salmon restoration projects on the River Shannon it is surely now time to call this work a failure.

But it not just the River Shannon. Indeed, salmon stocks in all of the rivers where the ESB operates hydroelectric schemes in Ireland are on the verge of collapsing. The status of salmon stocks above the ESB’s hydroelectric schemes are specifically singled out in Table 5 of SSC report.

Tabke 5 from SSC salmon

It is also not just salmon. The ESB’s trap and transport programme to move juvenile eels around the dams on the River Shannon has been shown to have an efficiency of less than 2%. In mark and recapture experiments carried out at the Parteen ever traps in 2008 and 2009, the recapture rate for juvenile eels released in the river channel below Parteen Regulating weir was less than 2% (see Egan 2011). Indeed, even the recapture rates for eels released immediately beside that trap were still only 8.61 to 15.20% showing the gross inefficiency of the ESB elver traps. This is despite the fact that the ESB should be trapping and transporting at least 60% of eels upstream around this blocked migration pathway to meet the requirements of Council Regulation (EC) No 1100/2007. The fish passes on the River Shannon have also been shown to be unsuitable for use by Sea lampreys which are also a conservation interest of the Lower River Shannon SAC. See more in this post entitled ‘As few as 2% of elvers may pass Shannon dams‘.

  • PS: The failure of ESB fisheries management programmes on the River Shannon is also not an issue for Irish Water to sort out. Irish Water have recently floated a proposal to pay for a new fish pass at Parteen Regulating Weir – to offset the impact of their proposed Dublin Water Supply scheme. This pass would use a proportion of the 10 cumec compensation flow which the ESB provide to the Lower River Shannon SAC.  Sure a new fish pass is needed, but it can’t be assumed that the 10 cumec compensation flow is an immutable scenario.  The bottom line here is that the existing water abstraction from this Natura 2000 river is unsustainable and this matter will have to addressed first before we start planning new abstractions. We need to start managing the Lower River Shannon sustainably before we start adding additional pressures. The existing ESB abstraction from the Parteen Basin has never been subjected to the requirements of the Environmental Impact Assessment, Habitats and Water Framework Directives.  We believe that it is feasible to abstract water from the River Shannon for use as a major water supply, but the future requirements of sustainable water management on the Lower River Shannon will have to be fully provided for first.

One response to “Study shows dramatic impact of ESB dams on salmon

  1. The so called salmon lift on the Fullerton dam in Buncrana has never worked in years. Now they punish the angler by making it catch and release.when we all know one of the main problems is the granting of licences to farm salmon near the mouth of our river.

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