Fish Stock Survey of Lough Macnean Lower, August 2022
Lough Macnean Lower is a large freshwater lake located in County Fermanagh, at an altitude of 51m a.s.l. (Plate 1.1, Figure 1.1). It is a mesotrophic lake, with a surface area of 456ha, mean depth of 1.5m and maximum depth of 12.7m. The lake is categorised as typology class 6 (as designated by the EPA for the purposes of the Water Framework Directive), i.e., shallow (<4m), greater than 50ha and moderately alkaline (20-100mg/l CaCO3).
Lough Macnean Lower is fed by the Belcoo River which flows from Lough Macnean Upper into the lake near the village of Belcoo (Figure 1.1). Lough Macnean Lower contains two islands, Cushrush Island which is the larger of the two and Inishee or Jinny’s Island, which is smaller and is completely forested. A causeway was built onto Cushrush Island in the 1960’s to allow animals to be moved on to the island. The shores of both the lower and upper loughs have good examples of wet woodland and of extensive fen and reed bed communities (NIEA, 2009b). The islands in both loughs are important breeding sites for lapwing (Vanellus vanellus), snipe (Gallinago gallinago) and curlew (Numenius arquata) (NIEA, 2009b).
Both Lough Macnean Upper and Lough Macnean Lower were formed by a process of glaciation. Glaciers excavated deep basins in the carboniferous rocks, creating steep valley sides and rocky cliffs (NIEA, 2009a). The lower lough is enclosed by a steep limestone escarpment. Agricultural usage along the shorelines of Lough Macnean Lower is more developed when compared to the upper lough. The underlying limestone soils produce good quality grassland, and the southern shores and lower slopes are farmed intensively (NIEA, 2009a).
The shape of Lough Macnean Lower was changed dramatically during the 1960’s when a major dredging operation took place. The level of the lake was dropped by approximately 1m resulting in wide areas of shallows as well as exposure of a lot of soft and barren shoreline (IFT, unpublished data).
In a survey carried out in 1969, perch (Perca fluviatilis), pike (Esox lucius), rudd (Scardinius erythrophthalmus), roach (Rutilus rutilus), bream (Abramis brama), rudd x bream (Scardinius erythrophthalmus x Abramis brama) and roach x bream (Rutilus rutilus x Abramis brama) hybrids were all recorded in Lough Macnean Lower (IFT, unpublished data). The lake was again surveyed in 2006, 2010, 2013 and 2016 (Kelly et al., 2007, 2011, 2014 and 2017). During the 2016 survey perch were found to be the dominant species present in the lake, followed by roach. Roach x bream hybrids, rudd, pike, eels (Anguilla anguilla) and bream were also recorded.
This report summarises the results of the 2022 fish stock survey carried out on the lake using Inland Fisheries Ireland’s fish in lakes monitoring protocol. The protocol is WFD compliant and provides insight into fish stock status in the lake.
Topics: Lake Surveys 2022 , Lough Macnean Lower |