Long term abundance patterns of potamodromous brown trout in a large lacustrine catchment in County Fermanagh
Royal Irish Academy
Long-term survey data detailing brown trout abundance in the Lough Erne catchment in Co. Fermanagh were tabulated from 1968–2016. These data included redd counts and electric fishing surveys across three key spawning tributaries in addition to gill-net surveys of the lake. The abundance of spawning adults fluctuated widely across the time-series and were examined in relation to various pressures, including a major disease epidemic and the invasion of the catchment by zebra mussels. A functional stock-recruitment relationship between adult spawners and young-of-year juveniles in the spawning tributaries was identified and described. Redd counts were significantly lower for the post-zebra mussel time-series (2000–16) than the pre-zebra mussel time-series (1968–99). The post-zebra mussel invasion period was associated with increased water clarity, reduced plankton productivity and changes to the balance of coarse fish species in the lake. The significance of these changes is discussed in relation to the trout stock.
Publication history: Accepted - 12 February 2021; Published online - 29 September 2021.
Kennedy, Rosell, McElarney, Gallagher and Allen (2021) ‘Long term abundance patterns of potamodromous brown trout in a large lacustrine catchment in County Fermanagh’, Biology and Environment: Proceedings of the Royal Irish Academy. Royal Irish Academy. doi: 10.3318/bioe.2021.11.