Highlighting problems on the River Shannon for World Fish Migration Day

World Fish Migration Day is a particular relevant day for the River Shannon; a river with numerous fish passage issues – both due to the presence of the ESB’s dams on the lower reaches of the river and also, perhaps even more importantly, due to the absence of effective fisheries management at these installations. There is no licencing system in Ireland for hydroelectric schemes and the Shannon hydroelectric scheme has never been assessed in relation to its compliance with the EC Habitats and Water Framework Directives. The ESB are the owners and operators of the Shannon scheme and have responsibility for migratory fish populations in the river. This will have to change as it is not reasonable to expect a commercial company to help migratory fish populations when this action will conflict with commercial operations. For World Fish Migration Day 2016 we are highlighting the major fish passage problems at the ESB Shannon hydroelectric scheme.

Ardna 2
Ardnacrusha hydroelectric station on the Lower River Shannon.
World fish migration day 2016
Parteen Regulating Weir on the Lower River Shannon.

There are virtually no salmon in the vast catchment area of the River Shannon (10,400 km2, or around 90% of the catchment) above the Shannon hydroelectric scheme. The River Shannon has an annual conservation escapement limit target though the Shannon scheme of 49,000 adult salmon. However, currently the numbers of salmon passing upstream through the Shannon dams meets <5% of this minimum target – and these are supported entirely by expensive artificial restocking. The Shannon is at the very bottom of the league of Irish rivers in meeting this conservation limit. Beside the ecological impact of having no salmon, the absence of a sustainable run of salmon on the River Shannon and its tributaries is a major loss of recreational opportunities and tourism revenue for the residents of the Shannon catchment.

The Shannon hydroelectric scheme also has a major impact on the European eel, on a catchment with an estimated 425 km2 of rich eel rearing habitat – the largest in Ireland. Access for juvenile eels is blocked, and eel trap and transport programmes are inadequate. In 2014 it was exposed that the ESB was not operating traps on the River Shannon at the peak of the elver run period. The majority of silver eels migrating down the river have to pass though the turbines at Ardnacrusha. The Shannon eel fishery is closed, and hundreds of traditional eel fishermen have been put off the river and its lakes.

Threatened Sea Lamprey populations have also been affected and only a few individuals of this species pass through the Shannon scheme each year, and these are probably accidental movements. Likewise the migration of River Lamprey is also blocked in the river, and other fish species such as migratory Brown Trout are also severely affected.

dead eels
In 2014 the ESB admitted to killing almost 8 tonnes of silver eels at Ardnacrusha hydroelectric station alone, which probably amounts to something like 20,000 silver eels. However, this is almost certainly an underestimate and does not take sub-lethal and delayed mortality impacts into account. The benefits of their trap and transport scheme for silver eels has also been grossly overestimated.
Sea Lamprey are a key conservation interest of the Lower River Shannon SAC and the migration of this threatened species has also been blocked by the Shannon hydroelectric scheme.
After being exposed in 2014 of failing to operate elver traps the ESB have been technically operating elver traps since. However, there is no effective water attraction provided to the traps and elvers can’t find them. The spillway at Ardnacrusha is shown here and elvers are attracted to this – but no traps are provided here. There is a mass unseen elver kill each year in the tailrace of this hydroelectric station.
WFMD 2016 impacts on salmon
The upstream and downstream passage of Atlantic salmon is also severely impacted on. However, salmon stocks have also been compromised genetically through decades of artificial restocking.

The ESB are doing nothing effective to help migratory fish on the River Shannon, either on World Fish Migration Day or on any other. This has never been demonstrated so clearly as when it was exposed in May 2014 that the ESB were not operating elver traps in time for the 2014 record run of elvers. Due to negligence or deliberate actions the main elver runs of April and early May, in a record year, were missed on the River Shannon by the ESB and a chance to restock the River Shannon with juvenile eels was lost. Incredibly this was covered up by Ireland’s state regulators who reported that the traps were down for just two hours maintenance.  The ESB are currently technically operating elver traps at the Shannon dams – but these traps are a very poor effort with no water attraction and elvers just can’t find these traps. Thousands of outmigrating silver eels are killed passing through the turbines each year.

For further reading please see these articles:-

The ESB are doing nothing effective to help migratory fish on the River Shannon, either on World Fish Migration Day  2016 or on any other. We hope that by raising this issue on this important day that things will change in Ireland.

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