Pike in Irish waters may have changed their diet preferences according to a new report launched by Inland Fisheries Ireland. The report, entitled ‘Pike (Esox Lucius) in Ireland. Developing knowledge and tools to support policy and management’ looks at new research carried out on Lough Conn, County Mayo and Lough Derravaragh, County Westmeath in 2016 and provides an insight into the dietary habits of pike.
Previous dietary research carried out in the 1960s and 1970s in Lough Derravaragh and Lough Sheelin (located across Westmeath, Meath and Cavan) indicated that pike preferred to eat brown trout and perch. However, this latest research reveals that pike appear to have changed their prey preference and now predominately eat roach. Researchers in Scotland and England have also found similar changes in pike diet occurring in Loch Lomond (Scotland) and Lake Windermere (England). It is thought the changes in diet are due to the invasion of roach in these waters.
The research examines whether pike and brown trout can co-exist in the same habitat. Using statistical models, it found that pike and brown trout could live together within relatively large deep lakes with strong stream connectivity however in small, low-complex systems pike introductions could potentially have a devastating impact on resident brown trout populations.
The practice of pike removal and the impact it has on brown trout stocks is also examined. The findings suggest that pike removal may only be effective in protecting brown trout populations in systems where trout are the only available prey but may have little effect in systems where other prey, such as roach, is available.
CEO of Inland Fisheries Ireland, Dr Ciaran Byrne, said: “This research was initiated to answer some on-going questions relating to the dietary preference of pike and the pike-brown trout interactions in lakes across Ireland. Previous studies in this area were carried out more than 50 years ago which is a long time within our changing lake systems.
“This research is important as it gives an insight into the behaviour of the pike species and provides updated information around their relationship with brown trout. The changing food web and altered preferences of predators in the water systems highlights the need for continued monitoring and updated data to inform effective management strategies.
“This research will now be considered alongside the many historic, socio economic and management factors which all inform fisheries management and development work. Inland Fisheries Ireland uses the best available scientific information to underpin management decision making and advice.”
To view a full copy of the report click: Pike (Esox lucius) in Ireland: Developing Knowledge and Tools to Support Policy and Management (4.61 MB).
For further information see: www.fisheriesireland.ie/pikeresearch.