A HERITAGE WEBSITE FOR  LOUGH CORRIB

Corrib Connect

OIDHREACHT NA COIRIBE

Natural Heritage - Fauna

Tony Whildes Lough Corrib Ecotour privides a good introductory guide to the Corrib Fauna . Another excellent introduction is provided by the Corrib Country Ramblers Guide and Map.

The site is a Special Area of Conservation (SAC) selected for the following species listed on Annex I / II of the E.U. Habitats Directive (numbers in brackets are Natura 2000 codes)  (see also):

As anyone who uses the lake will realise, the Corrib is a very important site for wildfowl and is internationally recognised as such. Up to 38,000 birds have been recorded.

Among the birds listed by the OPW are:

Pochard, Coot, Mute Swan, Tufted Duck, Cormorant, Greenland White-fronted Goose, Common Scoter, Artic Tern, Common Tern, Hen Harrier, Whooper Swan, Golden Plover, and Kingfisher.

Both male and female Mallared can be seen on all parts of the lake as can various Gull species including the Great Black-backed Gull (known to locals as the Faoileán Farraige), a species which preys on other smaller birds such as young ducks. Many of the usual common garden song birds can be seen on the island. If one is lucky, they may come across pheasants on the islands in the upper lake.

Animal species seen along the shores of the lake include the Otter and Irish Hare, both of which are protected by the 1976 Wildlife Act. Otters are rarely seen as they are shy and reclusive animals. Their main diet is fish.

A survey of the Lough Corrib adult fish stock was carried out Inland Fisheries Ireland (IFI)in February/March 2012 - the preliminary observations can be viewed here. Among the species identified as being still present in the lake were the following:

Brown Trout,

Pike,

Perch

Roach

Rudd

Bream

Roach/Bream Hybrids

Rudd/Bream Hybrids

Salmon Kelts

Salmon smolts

The most significant changes compared to the previous 1996 survey are as follows:

  1. There has been a marked decline in trout Numbers.
  2. A very significant reduction in the adult pike population is evident.
  3. A major recovery in perch stocks is evident.
  4. The adult Roach population recorded in both years is similar.
  5. There has been an expansion of the Bream  stock.
  6. A  very  substantial  increase in the Roach/Bream hybrid population is evident.
  7. Regrettably no Char were captured in either the 1996 or 2012 surveys suggesting that this species in L. Corrib, is Probably extinct.
  8. There has been a significant overall reduction in the numerical size of the pike population compared to 1996 and the number of large adult pike has also declined.
  9. There was no information on salmon stocks.

The survey did not attempt to quantify the eel population but it is well recognised there there has been a disastrous reduction in eel numbers over the years and in common with all Irish lakes and rivers, eel fishing is now banned.

A subsequent survey was carried out in June 2014 as part of the fish sampling programme for the Water Framework Directive. The complete report can be viewed here. Despite that fact that IFI was also involved in this survey, no mention is made of the 2012 survey. A 2011 survey is however referred to. The species identified include those listed in the 2012 survey with the addition of 3-spined stickleback, 9-spined stickleback and stone loach. Eels were also surveyed in this survey.

It was found that roach was the must abundant fish species recorded in the lower Corrib while brown trout were was the dominant species in terms of biomass. Perch was the most abundant fish species in terms of abundance and biomass in the upper Corrib. However, in terms of overall abundance and biomass, eels were the dominant species in the upper Corrib.

Dramatic reduction in the roach and perch populations was observed between 2008 and 2011, however perch abundance increased again in 2014. Roach abundance in 2014 only increased in the lower lake and decreased further in the upper lake. A decrease in brown trout abundance and biomass in the upper lake was also observed between 2008 and 2011 and increased again in 2014. In addition there was a decrease in roach/bream hybrids in both the upper and lower lakes in 2014.

The reasons for these lsignificant fluctuations in abundance for certain fish species is not well understood. Factors that might be responsible include the harsh winters in previous years affecting recruitment and the spread of zebra mussels throughout the lake since 2007. The zebra mussel can disturb the food chain by filtering phytoplankton from the water column thus diverting nutrients from open water to the bottom, thus favouring bottom-feeding fish (demersal) species such as brean, roach/bream hybrids and eels over those species that feed in open water (pelagic).

The last report of Artic Char in the Corrib came in the 1980’s and they must now be considered extinct. Char are extremely sensitive to water quality and their demise is a strong indication that the water qualitiy in Lough Corrib has deteriorated since the 1980’s.

In 2010 to 2012, the EPA assigned Lower Lough Corrib an overall draft ecological status of Moderate, based on all monitored physico-chemical and biological elements, including fish and the Upper Lough Corrib an overall draft ecological status of Poor. This is surely and indictment of those responsible for monitoring the Corrib.

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