Pollution such as run offs from argriculture and effluent from sewage treatment plants and septic tanks are deoxygenating the water in the lake and compromising fish life. The pollution creates a blue/green algae known as algae blooms to develop on the surface of the lake especially during the summer months.
In the 1920's Ardnacrusha hydroelectric dam was constructed on the Lower Shannon, the result of this was a disruption to the migration patterns of salmon to and from the Atlantic, sightings of this fish are now very rare.
Foreign invasive species such as the Zebra Mussel native to the Caspian Sea found it's way into the lake in the 1990's. This mussel filters the water causing more sunlight to penetrate resulting in dense weed growth. The waste it produces has choked the native mussel to extinction.
Roach a none native coarse fish introduced to the lake is particularly triving to the detrenent of native fish which compete for the same food. Nutall’s Pondweed, Asian Clam and the bloody red shrimp are other non-native species found in the lake.
Unfortunately the fragile eco-system of the lake has been damaged forever and there is always the potential of more non-native species being introduced in the years to come. The birdlife is thriving however as shown in the amazing footage captured by English last year.
Murmuration Starlings over Lough Derg