Fish Stock Survey of Lough Cullin, September 2022
Lough Cullin is a large, shallow lake situated to the west of Foxford, which is connected to Lough Conn by a narrow inlet at Pontoon, Co. Mayo (Plate 1.1, Figure 1.1). The outflow from the lake discharges directly into the River Moy south-west of Foxford (NPWS, 2014). Lough Cullin has a surface area of 1019.3ha with a maximum depth of approximately 3m (O’Reilly, 2007). The underlying geology of the lake is mainly granite with some areas of limestone present in the southern region of the catchment (NPWS, 2014). The lake is categorised as typology class 10 (as designated by the EPA for the purposes of the Water Framework Directive), i.e., shallow (<4m), greater than 50ha and high alkalinity (>100mg/l CaCO3).
Lough Cullin is located within the River Moy Special Area of Conservation (NPWS, 2020). The underlying geology of much of the site is Carboniferous limestone, with areas of Carboniferous sandstone, Dalradian quartzites and schists also present. Some of the tributaries at the east and south of Lough Conn, and all in Lough Cullin are underlain by granite. The site has been selected as a candidate SAC for containing alluvial wet woodlands, raised bog, old oak woodlands (present on the shores of Lough Cullin), degraded raised bog and Rhynchosporion depressions (Rhynchospora alba), all priority habitats on Annex I of the E.U. Habitats Directive. This SAC has also been selected due to the presence of the following species, listed on Annex II of the same Directive – Atlantic salmon (Salmo salar), otter (Lutra lutra), sea and brook lamprey (Lampetra planeri) and white-clawed crayfish (Austropotamobius pallipes) (NPWS, 2020). Lough Cullin is a moderately hard water lake with relatively low colour and good water clarity. The phytoplankton in the lake is dominated by diatoms and blue-green algae (NPWS, 2020). Lough Cullin also supports important concentrations of wintering waterfowl and is designated as a Special Protection Area, as one of the few breeding sites for Common Scoter in Ireland (NPWS, 2020).
Lough Cullin was once regarded as one of Ireland’s premier brown trout fisheries, but was often considered to be the ‘poor relation’ of Lough Conn. Historically, in angling terms, Lough Cullin was noted for supporting a large population of relatively small (<0.5kg) brown trout (Salmo trutta) (O’Grady and Delanty, 2001). The lake was also regarded as a very important salmon fishery and receives a run of salmon during the spring and summer months (NPWS, 2014). In fact, all the salmon, of which there can be many, destined for Lough Conn and its inflowing rivers must pass through Lough Cullin. The early IFI surveys conducted in 1994, 1998 and 2001 captured salmon, sea trout, rudd and roach x rudd hybrids (O’Grady and Delanty, 2001). The lake was previously surveyed on four occasions (2009, 012, 2015 and 2018) as part of the WFD surveillance monitoring programme (Kelly et al., 2010, Kelly et al. 2013, Kelly et al. 2016 and Connor et al., 2019).
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 Cullin |