Priority Species | Fish | Pollan
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Latin name: Coregonus autumnalis
Family: Salmonidae
Description of the Pollan
The pollan is a freshwater fish and a member if the whitefish family. It is silver in colour with a dark green/blue section along its back. They generally live for around 5-6 years, although fish at the age of seven have been recorded in the past.
At 3 years of age the pollan start to spawn, generally leaving their eggs in shallow waters around the edges of the lake. This takes place between December and January and, as the young fish grow, they mostly feed on animal plankton and smaller invertebrates.
Size
The pollan is usually found to be around 170g in weight.
Historical Info
The pollan is thought to have been present in the loughs and rivers of Ireland since the Ige Age, over 14,000 years ago! Four large lakes in Ireland contain the only populations in Europe. They are found in Lough Neagh, Lower Lough Erne, Lough Ree and Lough Derg on the main stem of the Shannon system.
Lough Neagh has the largest population of pollan and commercial fishing of the species still takes place here. Pollan can be found in the local fish markets and shops between March and October. In Upper Lough Erne this fish is now fully extinct and the numbers in Lower Lough Erne have dramatically dropped since the 1970’s. Due to the ever decreasing numbers the pollan are now listed as a UK priority species.
The Pollan's Habitat
Freshwater lakes, occasionally moving along rivers to estuaries.
Diet
Insects and planktonic crustaceans.
Threats to the Pollan
There are many different factors that threaten this species. These include eutrophication (when the environment becomes too enriched with nutrients - often due to farming fertilisers causing algae to grow rapidly and consume the oxygen in the water) and the increase of non-native species, such as roach and zebra mussel - these species decrease the zooplankton available for the pollan to eat. Other factors include climate change and uncontrolled commercial fishing.
