'Seven-colored lake' sends an SOS
ANTALYA - Hürriyet Daily News | 11/30/2009 12:00:00 AM | BETÜL ÇAL
Lake Eğirdir in Isparta, Turkey's fourth-biggest lake and second-largest reserve of drinking water, is in danger of becoming unsuitable for freshwater fishing, according to a joint study conducted by the World Wildlife Foundation's Turkey branch and Siemens Home Appliances. Unless immediate precautions are taken, the report says, the lake might soon turn into a marsh
Excessive fishing, poorly managed stocking and contamination by agricultural runoff and wastewater have brought Turkey’s “seven-colored lake” in Isparta province to the brink of ecological collapse.
To highlight the danger facing Lake Eğirdir, the Turkish arm of the World Wildlife Foundation, or WWF, has prepared a fishery report titled “Seven-Colored Life for Seven-Colored Lake” in coordination with Siemens Home Appliances.
According to WWF-Turkey General Manager Filiz Demirayak, excessive and careless fishing has caused the most economically valuable fish in the lake, namely crawfish, zander and carp, to become nearly extinct today.
“The suggestions we made in the report to ensure the sustainability of fishing in the lake include extending the ban on fishing, facilitating the multiplication and growth of the lake fish and determining the kinds [of fish] open to fishing,” Demirayak said.
She added that there is an urgent need to prevent illegal fishing, prohibit foreign species of fish and exercise constant control over the agricultural waste being dumped into the lake from nearby fields.
The basic motivation behind all these studies is the protection of the biological richness of the lake, the prevention of water pollution and the assuring of the sustainability of an important means of living in the area, Demirayak said.
[HH] ‘Crawfish population hit bottom’
The worsening situation of Lake Eğirdir has alarmed local authorities, national environmental associations and companies.
In an interview with the Hürriyet Daily News & Economic Review, deputy Eğirdir mayor Süleyman Sağdur said the lake faces the danger of losing both its fish population and its tourism potential.
“Fishing, especially crawfish fishing, was an important industry in the district,” said Sağdur. “However, carelessness and the wrong measures taken in the lake have led to a serious decrease in the crawfish population, killing this occupation for the local people.”
The report by WWF-Turkey and Siemens Home Appliances also noted that crawfish, which used to be exported to European countries, held high economic value for the local economy. Crawfish fishing was banned between 1986 and 1999 in an effort to replenish stocks.
The ban on crawfish fishing worked and production reached 797 tons in 2001. However, the fish became endangered again due to over-fishing, which caused production volume to fall to 11 tons by 2007.
Crawfish, carp and zander fishing was subsequently banned once more in 2008 for a period of four years.
At the same time, the lake was restocked with 2 million baby carp between 2008 and 2009 under the Lake Eğirdir Management Plan.
[HH] No refining system for waste
Another danger the lake faces is the possibility of turning into a marsh due to excessive algae and the deterioration in water quality.
Agriculture engineer Hasan Bostan, the assistant manager of the Eğirdir Fisheries Research Institute, told the Daily News that every lake has a birth, growth and death phase. Although Lake Eğirdir is not in its last phase yet, he said, it is crucial to continually keep an eye on the lake and take the necessary precautions before it is too late.
“Besides agricultural waste, the everyday waste of the 82 residential areas in the lake district is being dumped into the water without any refining system,” said Bostan. Unless a sound purification system is established for the lake, all efforts to increase the fish population will be in vain, he added, noting that the problem is compounded due to the excess number of fishermen in Turkey.
“Some 15 percent of Eğirdir’s fishermen fish as a primary occupation, so they have no other means of living other than this,” he said. “This is also the reason behind the illegal fishing in the district, which [no one] has been able to prevent in a long time.”
[HH] Wrong fishing policy
Lake Eğirdir is a tectonic lake whose depth exceeds 10 meters at only a few points, while the karstic nature of the lake bottom allows water movement both in and out.
The lake is fed by three streams that usually dry off during the summer while the water flows into Kovada Lake through a canal located to the south. The northern parts of the lake are much shallower, so its shores there are usually covered with reed beds.
Lake water is used as drinking water in Isparta and throughout the district of Eğirdir. Today, the main fish species caught in the lake is the pike-perch (Stizostedion lucioperca), which was introduced to the lake in 1955.
Until the mid-1980s, Lake Eğirdir yielded the highest crawfish (Astacus leptodactylus) production in Turkey, with an annual mean of 2,000 to 2,500 tons of crawfish caught. Since then, however, the crawfish population has collapsed and has become nearly extinct.
Either a fungal disease, or an increase in the pike-perch population as a result of the over-fishing of crawfish, is thought to be the main reason behind this decline.
Eight different native species of fish have also become extinct with the introduction of pike-perch.