Angling notes: UCD report on mercury levels in fish offers reassurance to Irish consumers

Plus, plan for major IFI fish farm in Tipperary progresses, and a successful day of trout fishing in Wicklow

In a recent issue of SeaHealth UCD aimed at personnel in fisheries, aquaculture and consumers, attention focused on mercury levels in fish. In a watching brief, it said methyl mercury accounts for about 90 per cent of the mercury content of fish.

Mercury is a naturally occurring heavy metal found in air, water and soil. Mercury from industrial centres can travel miles before raining into the ocean in organic form as methyl mercury. Fish become contaminated, leading to public health concerns about different species and their mercury levels, the e-bulletin said.

In 2004 the EU Commission requested the European Food Safety Authority to consider data collected by member states and published its opinion with emphasis on mercury intake from fish by vulnerable groups such as women of child-bearing age, breastfeeding women and young children.

The EC note of 2004 on methyl mercury was used to raise awareness in all national authorities with responsibility for public health and for providing safety information to consumers.


Large, predatory fish such as shark, tarpon, swordfish and tuna accumulate higher levels of mercury over a long lifetime. These species are often migratory and it is not possible to exclude fish from particular waters where background levels of mercury contamination might be high.

Irish consumption of canned tuna is increasing and pregnant or breastfeeding women and young children are advised not to exceed two 226g cans a week

EU consumers who eat average amounts (300-350g a week) of fishery products are not likely to be exposed to unsafe levels of methyl mercury. Consumers who eat a lot of fish may be at higher risk, but at time of issue of the EC note (2004) there was insufficient data to specify the situation in all member states.

Maximum levels of mercury in fish were amended in 2022. Levels were lowered for cephalopods (eg, squid, octopus, cuttlefish, nautilus) and marine gastropods (eg, abalone, conches, periwinkles and whelks) to 0.5 or 0.3mg/kg. Levels in shark, swordfish, pike and tuna were maintained at 1mg/kg.

Consumption of shark, swordfish, marlin and fresh tuna in Ireland is relatively low. However, consumption of canned tuna is increasing and pregnant or breastfeeding women and young children are advised not to exceed two 226g cans a week. Other adults and young people should continue to eat tuna and fish products as components of a healthy diet.

A monitoring programme was put in place for fish landed at major Irish fishing ports following the introduction of maximum limits for mercury in fishery products in 1993. This programme is now carried out by the Marine Institute. Mercury levels of fish and shellfish landed at Irish ports are low and well within the EU human-consumption tolerance level. However, these catches do not include deepwater species such as shark, swordfish, marlin and tuna.

Current opinion on mercury levels in fish in Ireland is that levels are very low and fish is safe for consumption by the general population. The watching brief on mercury levels in seafood is comforting for the Irish seafood industry and consumers alike, the e-bulletin concluded.

This document was compiled by Prof Ronan Gormley, school of agriculture & food science at University College Dublin. Further information can be obtained from

Fish farm for Tipperary

Inland Fisheries Ireland (IFI) is progressing plans to develop a modern fish farm facility in Tipperary, based on Recirculating Aquaculture System (RAS) technology.

The new farm will be located in Roscrea and is expected to become operational in 2026. The project will shortly enter the design and planning phase and a prior information notice has been placed in the Official Journal of the European Union.

In the intervening period, IFI expects to continue its current fish-farm operations as normal, supplying brown trout and rainbow trout to angling stakeholders. Those interested in the procurement process can register for email alerts on the eTenders website administered by the Office of Government Procurement at

Trout outing

Members of the Dublin Trout Anglers’ Association had a most enjoyable day at Annamoe Trout Fishery in Co Wicklow last weekend. The group of 16 landed and safely returned 43 rainbow trout in conditions described as “near perfect” for this time of year. Results: 1, Cathal McDonnell; 2, Gerry Heaslip; 3, Dermot Flynn.

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