Over 100,000 young salmon die at Parteen Salmon Hatchery

It was reported this week that over 100,000 young salmon died at Parteen Salmon Hatchery on the Lower River Shannon. According to the Limerick Leader an incident occurred at the salmon hatchery on the 7th May 2022 that resulted in the mortality of about 100,000 salmon fry – out of a total stock of 120,000. These salmon fry were being reared in tanks at the facility and were due to be released as smolts in the spring of 2023.

The ESB have claimed that “Initial indications are that this incident was due to an algal bloom”. However, there were no reports of any fish dying or any toxic algae bloom in the River Shannon itself.

The fish kill happened at a weekend and ESB has a history of major fish kills occurring at their dams at weekends

The young salmon would have been just transferred to the main rearing tanks at the hatchery. It is possible that the intakes got blocked with algae. This would be have been easily foreseen in a well-managed hatchery. It is not known if the ESB had alarm systems operating at the time that would have altered staff to a blocked intake or water quality issue. The use of water quality and water level alarms is standard practice at salmon hatcheries globally.  

It is understood that there are no qualified or technical staff working at the salmon hatchery.

The fish kill happened at a weekend and ESB has a history of major fish kills occurring at their dams at weekends when no staff are present. In 2014 over 300,000 critically endangered eels died in the traps at Cathaleen’s Fall dam on the River Erne when there no staff were present to check the traps over a bank holiday weekend – and no alarms were being used.

It was also exposed this year that the ESB have failed to operate the salmon counters at any of their dams and claimed that all the salmon counters at all of their dams “malfunctioned” in 2020 and were not operating for all of 2020 and 2021. This points to underlying management failures within the ESB.

Parteen weir and salmon hatchery on the Lower River Shannon

The current fish kill event follows on from a major eel kill that occurred on the Lower River Shannon in December 2021 when thousands of critically endangered eels were killed passing Ardnacrusha Hydroelectric Station. The ESB had no effective mitigation in place to prevent the eels from entering the turbines.

At the time of the fish kill at the salmon hatchery, the last of the wild salmon smolts on the River Shannon were being killed at the turbines at Ardnacrusha Hydroelectric Scheme. In early May 2022, ESB was abstracting >85% of the water in the Lower River Shannon SAC. Downstream migrating salmon smolts follow the water to the unscreened turbines. No efforts are made to reduce the abstraction or use spillways during the smolt run. Indeed the ESB deliberately runs the salmon smolts through the turbines and call it a “smolt generation protocol”. This is presented as if it is a positive for smolts – yet it is the total opposite.

It is understood that there are no qualified or technical staff working at the salmon hatchery

The ESB has said that there will be an “investigation”. The “investigation” into the December 2021 eel kill (completed by Inland Fisheries Ireland who are now under investigation for corruption) concluded that there was no evidence of an eel kill despite the visual evidence to the contrary. As with the Erne elver kill it is likely that there will be no consequences for ESB.

Parteen salmon hatchery has been operating since the late 1950s but has not mitigated for the impact of the hydroelectric scheme. Indeed, runs of salmon through the Shannon dams could not be any lower if this hatchery had never existed. The river was meeting <5% of its conservation escapement target for salmon the last time the fish counters were operating. Releasing millions of hatchery fish has comprised the genetics of salmon in the River Shannon and the broodstock trap has added to the fish passage problems on the river. If there was no salmon hatchery things could not be any worse. Indeed, the salmon stocks would probably be doing much better. It is now time to close this failed hatchery and provide new fish passes and bypasses – and most importantly sustainable water management.

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