Environment Agency Wales investigations show a big decline in insect life in the River Teifi between Pontrhydfendigaid and Lampeter. This confirms reports by local anglers of a decline in fly hatch.
These insects are the food for brown trout and the decline of fly hatch has probably contributed to the decrease of this fish species in the Upper Teifi. At the same time, samples taken from the river at Tregaron and Lampeter show levels of Cypermethrin-based sheep dips which could be damaging to invertebrate life.
Sheep dips are designed to kill unwanted insects on sheep and they are particularly toxic to the insects that live in rivers. Dips can enter watercourses from several sources: either directly through the drain holes, from drain down areas, from dipped sheep being allowed access to streams before they are dry, or from the land when the dip is spread.
Since 1999 Agency authorisations have been required to dispose of sheep dip onto suitable farmland, even if there is only a small quantity left after using a mobile shower unit or jetters. The Agency is concerned that, for the Upper Teifi catchment, only 30 farms have such authorisations, when there must be many sheep farms in this area. The Agency would encourage all farmers involved in dipping or showering sheep to take extra care to prevent chemicals from entering watercourses. If they do not have the appropriate authorisation, they should contact the Agency’s Lampeter office for further advice and an application form (01570 422455 ext. 3704 – standard office hours 9am – 5pm).
Agency officers will address these issues by undertaking extensive work in the catchment in the coming weeks, which will include visiting local farms to work with farmers to investigate and resolve any potential problems.
Paul Varallo, the Agency’s Area Environment Manager, said: “The Agency is also undertaking similar investigations into the effects of acidification and metal pollution from abandoned mines on the insect life. The upper part of the Teifi has historically supported a widely acclaimed fishery for brown trout. If this fishery can be returned to its former status there will be considerable economic benefits for the local community.”