The photos below show River Lampreys Lampetra fluviatilis trying to pass Annacotty weir on River Mulkear, March 2017. This is in the Lower River Shannon SAC and these lampreys are on their spawning migration. Warm weather brought on this run of River Lampreys during late-March 2017.
However, these lampreys cannot pass this artificial barrier – which serves no purpose. The lampreys try repeatedly to pass this obstacle and get heavily predated on by herons. One lamprey here got dropped by a Heron as we approached the weir.
There was €1.75 million available in EU Life funds to sort this problem out. The money was spent by Inland Fisheries Ireland yet here we are today.
This weir also blocks the migration of the critically endangered European #eel and even salmon have difficulties, See: https://youtu.be/-FHM1Yjxml0.
The River lamprey has declined markedly decline over the past century. They are poor swimmers and cannot jump, so barriers to migration such as weirs often confine them to the lower reaches of rivers. Indeed they can’t even pass crump weirs placed in rivers to facilitate hydrometric gauges and salmon counters. There is a crump weir salmon counter located 1km upstream from Annacotty weir. This crump weir has a vertical slot fish pass on one side which may allow lampreys to pass upstream. However, the efficiency of this pass has never been assessed and it is quite possible that River Lampreys would also have difficulty at this barrier also. As this fish counter does not even produce accurate counts it may have to be removed or modified also, if we really do want to restore the Lower River Shannon SAC.