Conservation & Protection - Shellfish FAQ

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What shellfish are in Lough Foyle and Carlingford Lough?
Lough Foyle is home to many species of wild shellfish. Blue Mussels and native oysters are the most abundant shellfish however brown crabs, velvet crabs, spider crabs, green crabs, lobsters, prawns, winkles, clams and whelks can also be found here. There is a traditional fishery for native oysters in Lough Foyle that has been fished by local people for centuries.

Lough Foyle supports a thriving shellfish aquaculture industry, which produces about half of Ireland’s total production of blue mussels per annum. Pacific oysters are also farmed in Lough Foyle and sold in restaurants around Ireland and other European countries. Carlingford Lough is also home to large populations of blue mussels. These are present in wild beds within the Lough and are also farmed in aquaculture sites within the Lough. Green crabs, brown crabs, lobsters, clams, prawns, winkles and native oysters are also present in the Lough. Pacific oysters, manila clams, native oysters and mussels are all farmed in Carlingford Lough on the seashore and also on the seabed.

Can they be collected by the public and are they safe to eat?
Persons wishing to collect shellfish for personal consumption should be aware of the health risks associated with doing so, they should also be aware of the European Food Hygiene Regulations (EC Regulation 853/2004). Persons wishing to commercially gather shellfish by hand should contact the Department of Agriculture, Fisheries and Food in Ireland, the Department of Agriculture and Rural Development in Northern Ireland or the Loughs Agency for advice.

Shellfish are filter feeders and they eat by siphoning water through their gills and collecting any suspended food particles in the seawater. Their diet contains plant and animal material in the form of plankton. Some of this plankton can sometimes be toxic to humans when it is eaten. For this reason it is important to monitor the levels of these harmful plankton. This toxic plankton can be called red tides or harmful algal blooms and government scientists monitor the levels of these toxins weekly to determine if there is a toxic plankton species present in the water. When there is a toxic species present the shellfish are not harvested and not sold to the human consumption market. These toxic events are very rare in Lough Foyle and Carlingford Lough although they do occur in other bays around Ireland and the UK.

Although red tides do not occur very often in our waters it is best to check with the monitoring body prior to eating shellfish from Lough Foyle or Carlingford Lough so as to avoid eating shellfish during a closed period.

What are red tides/harmful algal blooms?
Shellfish are filter feeders and they eat by siphoning water through their gills and collecting any suspended food particles in the seawater. Their diet contains plant and animal material in the form of plankton. Some of this plankton can sometimes be toxic to humans when it is eaten. For this reason it is important to monitor the levels of these harmful plankton. This toxic plankton can be called red tides or harmful algal blooms and government scientists monitor the levels of these toxins weekly to determine if there is a toxic plankton species present in the water. When there is a toxic species present the shellfish are not harvested and not sold to the human consumption market. These toxic events are very rare in Lough Foyle and Carlingford Lough although they do occur in other bays around Ireland and the UK.

When will shellfish aquaculture licenses be given out to people by the Loughs Agency?
It is anticipated that Loughs Agency will be in a position to start the licensing process for aquaculture in 2010.

Do the oysters in Lough Foyle have a disease? Is it harmful to humans?
A very small percentage of native oysters in Lough Foyle have tested positive for a microscopic parasite called Bonamia ostreae. This parasite can cause mortality in native oysters, especially during spawning seasons and periods of high water temperature.

This parasite is not harmful to humans and oysters can be consumed without any worry by the public.