Artic char faces extinction in Co. Mayo

Ireland's ‘last survivor' of the Ice Age faces extinction in local lakes

An ancient species of fish that has been found in lakes in counties Mayo and Sligo since the last Ice Age is on the verge of extinction.
A new survey has revealed that the Arctic Char population of Lough Easkey are now most likely extinct and the Lough Talt char are also in trouble.
The char is an ancient species of trout found in northern latitudes. It is believed to be the only surviving vertebrate that inhabited Ireland at the end of the last Ice Age, about 18,000 years ago.
The demise of the char in Lough Talt would have huge implications for Lough Conn where the fish disappeared in the early 1990s due to pollution.
Lough Talt the sole remaining population in the Moy catchment (effectively a genetic bank for Lough Conn), and the trout's extinction there would end any future propspects of char reappearing in Lough Conn
The survey was carried out by the Irish Char Conservation Group, assisted by The North Western Regional Fisheries Board.
Researchers failed to record any char in Lough Easkey even though the species was recorded in the lough as recent as 1991.
“When the survey nets were retrieved from Lough Easkey they were covered in filamentous algae”, said eminent Scottish fisheries scientist Mr. Ron Greer, who led the surveys. “Clearly, the absence of char and the presence of a substantial amount of algae illustrates ecological changes in the loch. This is very shameful indeed.”
Thankfully, a survey on Lough Talt did record some specimens of Arctic char. However, not all appears to be well with the Lough Talt population either. Substantial algae growths were noted on the gravels used by char for spawning in November 2003.
This contrasts with the other char loughs such as Lough Melvin and Eske, which were also surveyed only a few days later by the char group scientists, and found to be clear of any growths.

Algae
Research from Lake Windermere in Cumbria, England, has shown that excessive growth of algae on Arctic char spawning grounds, due to organic enrichment by human waste, was responsible for a decline in Arctic char stocks.
The algal covering in Lough Talt was extensive and seemed to smother most of the gravels. In light of the November findings, Lough Talt was again surveyed last week by Irish Char Conservation Group and the Fisheries Board with the assistance of students on a fisheries course in Sligo Regional Technical College. This time, not only were high levels of algae discovered but, alarmingly, dead char eggs where found where the char had spawned.
Dr. Fran Igoe scientific adviser to the Char Group, said that “although it is normal to find some dead char eggs on spawning beds, particularly in spring, the high percentage recorded in Lough Talt, together with the extensive algal growths, is a cause for concern”.
Professor Professor Mike Power, a char expert from the University of Waterloo, Canada commented on the recent findings adding that “Overgrowth, even to a small extent would inhibit oxygen exchange and promote mortality of char eggs”.

Good news

Dr. Fran Igoe said the good news, however, was that the char did spawn in the lough this year and the fish survey nets showed the presence of a few Arctic age classes still present in the lough.
However, he said there was no room for complacency as the population in Lough Easky now appeared to be extinct and the warning bells are ringing loud and clear in relation to Lough Talt.
Dr. Igoe said The North Western Regional Fisheries Board was very concerned about the findings and he understood the Board would be investigating the matter further. He said that the findings had also been brought to the attention of Sligo Co. Council and the EPA.
And while conservationists, the fisheries authorities and anglers are all interested in saving the char, Dr Igoe is eager to make the wider public aware of the fact that a species that has been part of our environment since long before man came here is on the verge of extinction.
He compared the national campaign to reintroduce the Golden Eagle with the present lack of interest in saving the char population.
“The char has been around much longer than the Golden Eagle and yet they are letting it go to the wall,” he commented.


How we can save Lough Talt's unique Arctic char

Dr Fran Igoe says there is a number of immediate measures all of us can take to save Lough Talt's Arctic char population.
Simple things such as emptying septic tanks regularly, nutrient management planning and a fresh look at water abstraction from the lough are all areas that can probably be improved upon, without causing a major inconvenience to the general public.
If we stand still our legacy will be that we stood still and did nothing, and the Arctic char population of Lough Talt will go the same way as that in Lough Easky and nearby loughs such as Lough Conn, according to Dr Igoe.
The importance of the Lough Talt can be measured at a number of levels. Firstly it is the most alkaline of Irish loughs still holding Arctic char in Ireland and appears to have a late spawning population, all of which is of interest to scientists.
More importantly however, it is the last lough in the Lough Conn or Moy catchment to still hold Arctic char. The high profile extinction of Arctic char from Lough Conn occurred approximately 10 years ago and in Castlebar Lough the population disappeared some time earlier.
“Scientists attribute the extinctions to enrichment due to human and livestock wastes entering the loughs. Algal accumulations were also noted on the gravels of Lough Conn in the early 1990s. Scientists believe that if these external pollutants can be stopped, then suitable conditions should return to Lough Conn to reintroduce the Arctic char.
Lough Talt is the only population surviving in the Lough Conn Catchment and so are the obvious population to stock from. In other words they currently function as a reservoir of genetic material for Lough Conn Arctic char type. This is important as Irelands Arctic char populations have been isolated to their catchment areas for over 18,000 years and therefore have evolved unique genetic differences.
Lough Talt also holds an unusual type of fish eating trout known as the ferox trout, which feeds mostly on Arctic char.

Source:
Western People
Wednesday, May 3, 2004
http://www.westernpeople.ie/news/story.asp?j=18490