This is a short video I made following a visit in June 2020 to Ennistymon Falls on the Inagh River, Co Clare. The falls here are natural but have been modified for hydroelectricity production. These modifications have made them almost impossible for juvenile eels (elvers) to pass. Large numbers of elvers are often visible here in the spring each year. However, very few of these elvers survive – they die trying to ascend these falls.
The hydroelectric scheme was refurbished recently but the upgrades to the fish pass did not include an elver pass. Elvers will climb up the first stage of the falls and then eventually get to the outflow of the salmon pass. However, they can’t use this long two-stage denil pass. These are critically endangered young #eels and something should be done to help them. Raw sewage is entering the River Inagh here also via a stormwater outfall. Elvers are blocked by these modified falls and suffer outbreaks of Ichthyophthirius Multifilis (“white spot” disease) every year – brought on by stress due to the migration barrier and poor water quality. It is likely that less than 1% of the elvers manage to pass these falls and millions die here. The elvers trapped here this week were in poor condition and all showed signs of Ichthyophthiriasis.
There is an Inland Fisheries Ireland (IFI) so-called national juvenile eel recruitment monitoring site. I have been highlighting problems with the operation of these traps for over 10 years – and this visit to Ennistymon again illustrates that these traps are not being operated properly and do not provide an accurate index of juvenile eels numbers as they are supposed to. The video here shows how water is flowing through the trap – but it will not catch any elvers. They will repeatedly climb up and be washed out again. This does not provide any data and is also cruel to elvers. A critically endangered species deserves better than this. Trapping and netting should be used below these falls to catch elvers and bring them upstream past the modified falls and hydroelectric scheme. Elvers from here could also be used to stock other eel habitats and the operation could be run as conservation elver fishery. However, an eel passage solution is also required. But questions need to be asked in relation to why every time that I visit these so-called national juvenile eel index traps they are not being operated properly. Data from these traps is fed into European data series.
For more information also see this post from 2017.
I have posted several videos of large elver runs at this site – for example, this video from 2018.