Zebra Mussels and impact on fish stocking in the Public Angling Estate
Date published:
DAERA will recommence the first stocking of the Public Angling Estate from the Department’s Movanagher Fish Farm since June 2023. Stocking was suspended at that time due to the identification of zebra mussels, an invasive species, at the fish farm.
DAERA and the Agri-Food and Biosciences Institute have been working to develop stocking protocols to ensure compliance with the Wildlife Order (NI) 1985. Results from recent sampling at Movanagher and the current low water temperature, typically below that for reproduction of zebra mussels, is allowing limited stocking of some Public Angling Estate waters, which would be part of the usual annual stocking programme. The window for this stocking is likely to be only 4-6 weeks.
The Agri-Food and Biosciences Institute will continue to assess water samples taken from Movanagher for the presence of live zebra mussel veligers and water temperatures to mitigate the risk of spread of zebra mussels to waters being stocked. Should water samples be found to contain live zebra mussel veligers (larva) and/or water temperatures increase to 10°C then all stocking will cease.
The waters stocked, with the number of fish and species stocked, will be provided on the DAERA website after stocking has been completed. DAERA is not able to confirm at this time if any further stocking of Public Angling Estate waters will take place later this year. DAERA continues to work with AFBI to develop a longer-term stocking protocol that will be compliant with the Wildlife Order (NI) 1985.
Below are responses to frequently asked questions regarding Zebra Mussels and impact on fish stocking in the Public Angling Estate.
Why did DAERA stop stocking fish into the Public Angling Estate (PAE)?
Invasive alien Zebra Mussels (Dreissena polymorpha) have been identified in Lough Neagh since 2003 and the Erne system from the 1990’s, however recent surveys show their numbers and the sites where they are found have increased significantly, which now includes the Lower Bann. The species can have significant environmental and infrastructure impacts.
Any person who releases or allows Zebra mussels to escape will be in contravention of the Wildlife (Northern Ireland) Order 1985. The movement of live fish from aquaculture establishments where Zebra mussels exist to other water bodies is identified as a potential vector for this invasive alien species in the Northern Ireland Zebra Mussel Management Strategy.
Zebra mussels were discovered at the Department’s Movanagher fish farm in June 2023. Consequently, the Department has taken a precautionary approach and suspended movements of live fish from Movanagher fish farm for stocking to other fisheries to ensure compliance with the 1985 Wildlife Order. The Department is currently considering Agri Foods and Biosciences Institute’s scientific advice to inform the way forward.
DAERA was able to carry out a limited stocking with 76,000 juvenile Brown Trout fry (young of year) in April 2024 to a small number of Public Angling Estate waters. (These waters were Castlewellan, Lough Keenaghan, Moorlough and Mill Lough Bellanaleck) These fry have been reared on borehole/groundwater. No further stockings to the PAE are planned at present. Borehole water is obtained by drilling a hole in an aquifer to supply water and therefore is not impacted by zebra mussels. The supply available from this source is limited and restricts the number of fish that can be reared on it.
When were you aware of this issue and why was it not communicated to the public sooner?
Zebra mussels were detected at Movanagher fish farm in June 2023. There is no scheduled stocking over the summer due to the warmer weather conditions. In addition, a temporary suspension of stocking into the PAE was put in place on the 19th July. DAERA used the time during the summer to consider additional information to fully assess the Zebra mussel issue and its impact on the fish farm and the Department’s stocking program.
Has DAERA transferred zebra mussels to other sites?
There are several vectors that risk the transfer of Zebra Mussels. The Northern Ireland Zebra Mussel Management Strategy states, “The high-risk vectors are recreational boating, intentional introductions, and the re-opening of the Ulster Canal. Medium-risk vectors include angling activities, fisheries and aquaculture activities, illegal eel fishing and scientific research and conservation work.”
Once Zebra Mussels were identified within Movanagher Fish Farm, suspension of stocking to the Public Angling Estate took place in order to remove the risk of transfer and to comply with the Wildlife (Northern Ireland) Order 1985. No scheduled stocking also takes place during the summer period from Movanagher.
Is Movanagher Fish farm closed?
Movanagher fish farm remains open. The Department is currently considering options in relation to it and the stocking of fish into the PAE waters.
When will PAE stocking recommence?
Stocking of the PAE has recommenced in March 2025.
Will this impact on private fisheries stocking their waters?
Movement of live fish from fish farms on the Lower Bann will not be authorised by DAERA, regardless of where they are being stocked, where there is a risk of invasive species being transferred in order to comply with the legislation.
What happens to the fish at Movanagher Fish Farm if they can’t be stocked out?
The rearing of fish to a size that they can be stocked into the PAE takes place over a 2–3-year cycle. As fish grow, they need more space, and the only way to achieve this is to reduce the number of fish in a single tank or raceway and keep similar-sized fish together. This depends on raceways/tanks becoming free as fish are moved off the farm and stocked into the PAE.
Fish stocks on the farm can reach a critical point that unless these fish are moved off the farm, then the health of a significant number of fish on the farm will become affected, and many will ultimately die due to overcrowding, cannibalism and the outbreak of diseases.
Given these fish cannot be stocked out elsewhere to comply with the Wildlife Order 1985, the Department conducted a limited cull of 28,250 fish between the 6th and 8th of November 2023. A further cull of 44,351 fish was conducted in the week commencing 10th June 2024.
These culls were the minimum number necessary to provide additional space for the remaining fish on the farm at that time. They were authorised and overseen by a veterinarian surgeon.
The Department continues to monitor fish welfare as changing environmental conditions impact the condition and health of the fish.
What action is being taken to enable stocking to commence?
The Department is currently considering Agri Foods and Biosciences Institute’s scientific advice to inform the way forward and to ensure compliance with the Wildlife Order 1985. A range of options will be considered as to how to address the current impasse. Any decision on the future of Movanagher fish farm and stocking DAERA “put and take” fisheries in the PAE will be considered by DAERA in due course.
What will happen to the currently stocked fisheries in the PAE if they can’t be stocked?
DAERA is responsible for the management of fishing rights of Northern Ireland’s PAE, which currently has 89 waters, including both lakes and rivers, where it owns or leases the fishing rights. Only 27 of these waters are stocked from Movanagher Fish Farm. These waters also contain wild fish for angling and these fisheries will remain open but will not be stocked.
Will DAERA refund anglers for their DAERA permit or rod licence fees paid this year?
Unfortunately, DAERA is not able to refund your fishing licence/permit, please see below link to the refund policy for more information:
Conditions of sale for fishing licences and permits | nidirect
The PAE has a variety of fisheries, please see link below for details of fisheries where your licence and permit are valid:
Where you can fish in Northern Ireland | nidirect
Will DAERA reduce rod licence or DAERA permit fees in 2024 season if no stocking takes place in the PAE waters in 2024?
Rod licence prices have not increased for well over a decade.
Permit prices have not increased since 2016, when there was an increase of 1.6% in permit fees (in line with the Retail Price Index). Any price increase would require Ministerial approval.
A permit gives permission from the fishery owner for the angler to fish a water. It does not guarantee the stocking of fish into a water or the level of fish stocks within a water.
A review of permit and licences is currently underway by DAERA which will be subject to a public consultation in due course followed by Ministerial approval.