BENEATH the still waters of the picturesque reservoir of Xyliatos, a battle for survival has been raging between an aggressive, large-mouthed alien and an unassuming, unassertive native.
On land, meanwhile, ensuring victory for the home-grown underdog has involved turning accepted environmental good practice on its head and redrawn the battles lines between illegal and legal anglers.
The down-trodden native is Natrix Natrix cypriaca, or Cyprus water snake, a critically endangered species of snake that breeds on the banks of the reservoir. The aggressor is the largemouth bass, a non-native fish species illicitly introduced into Xyliatos around 1999.
The water-snakes’ best hope for survival comes in an unlikely form: fishermen.
The Department of Fisheries and Marine Research closed Xyliatos to fishing in 2003 after a German expert determined that the presence of fishermen threatened the survival of the Natrix. From tomorrow, however, anglers will once more be allowed to cast their rods – but this time it’s to save the snake.
Both the water snake and the bass feed on frogs, but while the bass eats an array of other foods, the water snake does not. The bass has no natural enemies expect humans, and so the Fisheries Department hopes that fishing the reservoir will reduce the bass population and allow the water snake to replenish its numbers.
But the Cyprus Freshwater Angling Association believes the six-year closure of the reservoir worsened the snake’s chances for survival because it not only removed the fish’s only predator, it allowed the number of illegal anglers at Xyliatos to increase.
“Illegal angling is a major issue we’re facing,” says fisherman and vice president of the association Rolandos Constandinides. “They don’t care to be careful, to not do any damage, and as a result they use illegal tools like spear guns, nets, and sometimes boats. They drink, light fires and destroy vegetation.”
Constandinides also reports that illegal anglers leave behind “an unbelievable amount of rubbish”, mainly bottles of vodka and beer.
“It was bad that Xyliotis was closed because you can’t see what is going on the lake [because it is covered by trees],” Constandinides said. “Since no one else was going there [due to the closure], no one would ever get the attention of the police or the Fisheries Department to go after them.”
According to Constandinides, police involvement at Kalopanayiotis dam – where fishing is allowed and therefore monitored – has eradicated illegal fishing activity there. Police confiscate equipment, ticket offenders, and send them to the nearest Fisheries Department office, which can slap them with a hefty fine.
President of the Anglers Association Demetris Mina agrees, asserting that the water snake will not survive at Xyliatos if the reservoir remains unguarded against illegal anglers.
The Fisheries Department lacks the resources to patrol the country’s dams round the clock. As a result the Anglers Association asked the Fisheries Department to reopen Xyliatos so that legal fishermen could at least be present to report any illicit activity they encounter.
But Miroula Christoforou, senior officer at the Fisheries Department, disagrees that illegal anglers pose much of a threat to the Natrix. “If there are two or three illegal anglers there, what damage does it do now?” she asked. “All the damage was done before. The fishermen are not the main problem for the snake. It’s the bass.”
But according to Constandinides, 100 to 200 illegal anglers can be found fishing the reservoirs during weekends and late weekday nights.
Christoforou said the Fisheries Department closed Xyliatos to fishing in 2003 because anglers constituted the gravest threat to the water snake at that time. The bass population had not yet exploded and did not threaten the snake the way it does today. The department has now altered its strategy to reflect the snake’s changing situation, she said.
Mina welcomes the reopening of Xyliatos to recreational fishing but believes it will fail to save the snake for two reasons: removing all the bass is impossible, and as long as even a few inhabit the dam they will continue to harm the snake. Even if every last bass could be removed, he says there is no guarantee that someone will not restock the reservoir with the invasive fish.
No one knows for sure who introduced the largemouth bass into Xyliatos, but the consensus is that illegal anglers placed them there because they are easier to fish.
While the Fisheries Department stocks reservoirs with friendly fish such as trout, fish unrelated to the Department’s activities have been discovered all over the country. The Pumpkinseed fish, for instance, a non-native species originating in North America, was discovered in a Nicosia reservoir late last spring but was never officially brought to Cyprus and has no involvement with the Fisheries Department. Yet it can now also be found in Limassol and Paphos.
The possibility that someone will reintroduce the largemouth bass to Xyliatos, even if the fishermen succeed in getting rid of it, has prompted the Angling Association to recommend the water snakes be transplanted to the Kafizes reservoir located in the mountains near Lefka. “Unless you know where [the Kafizes dam] is you won’t find it,” said Constandinides. “No one goes fishing there and we know that no one will consider putting in bass for fishing there.”
The Fisheries Department were quick to dismiss the notion. “It is not so simple and they are not the right people to say what to do with the snake,” Christoforou said. “We are talking about a rare and endemic species. We need to have scientific evidence and research. [This suggestion] is not scientifically accepted.”
On the advice of their expert, the Fisheries Department earlier last decade created five small lakes around the Xyliatos dam to develop an ecosystem with vegetation. Frogs, the snake’s basic food, appeared in the new environment, and a water snake was eventually discovered there. Two new bio ducts containing the water snake were also found recently.
“The situation in the dam is not so favourable, but it is not the end of the world for the Natrix,” said Christoforou.
Cyprus Mail
By Helen Christophi Published on February 14, 2010