"Fossil Trout" Faces Extinction in Balkans, Experts Warn

James Owen in England
for National Geographic News

September 15, 2003

The Ohrid trout, an ancient fish living in Europe's oldest lake, faces extinction due to pollution and overfishing. The warning comes from Balkan scientists who say even a proposed five-year commercial fishing ban won't be enough to save the species.

Lying between Albania and Macedonia, Lake Ohrid was formed some three million years ago. Along with Baikal in southeast Russia and Tanganyika in eastern Africa, it's one of the oldest lakes in the world.

Reaching depths of 950 feet (290 meters), this UN World Heritage site is also known as the "museum of living fossils." It provided sanctuary for creatures from the tertiary period which died out elsewhere during the ice ages. The closest relatives of species like the Ohrid trout (Salmo letnica) survive only as fossils.

The 19 mile-long (30-kilometer) lake contains at least 146 endemic species, including 17 types of fish. Two-thirds of its small crabs, 71 percent of its flat worms and 90 percent of its snails also exist nowhere else on Earth.

Scientists say this unique collection of wildlife, having evolved in isolation over millions of years, is now threatened with extinction because of human pressures. The famous Ohrid trout, a local delicacy which grows to over 25 pounds (11 kilograms), has become the focus of these concerns.

While its numbers have been supported by hatcheries around the lake since the 1930s, the twin threats of pollution and overfishing have put its survival in doubt. The adult population has dropped dramatically, with hatchery workers able to collect only half the eggs needed to supplement remaining stocks.

"It is very clear that the fisheries in Lake Ohrid are in immediate danger and rapid management action is required. All the data suggest that trout populations are in severe decline," stated scientists in a recent report for the Lake Ohrid Conservation Project (LOCP). Funded by the World Bank, the project began in 1996 with the aim of preserving the lake's biodiversity.

Commercial fishermen—there are around 90 of them along Ohrid's northern shore alone—took out about 80 tons of trout last year. Many illegal fishermen also operate in the lake, mainly from Albania. In response to concerns over their impact, the Macedonian government has now backed proposals for a five-year trout fishing ban.

Untreated Sewage

But scientists say this won't save the species unless other problems are addressed. These include a lack of cooperation between Macedonia and Albania, and pollution from discharges of untreated sewage.

Oliver Avramoski, watershed management coordinator for Macedonia, said, "If the current situation regarding the management institutions, laws and powers to enact them is not going to change, the long-term effects of a ban would be negligible."

Dejan Panovski, LOCP implementation director in Macedonia, believes a ban could actually harm the region, saying, "Economic considerations are crucial because tourism relies on the trout as a local specialty. Also, many families depend on fishing to make their living. And what happens after five years?"

Instead, they want to see a sustainable fishery established, based on scientifically determined catch limits, increased restocking with fingerling trout, and effective policing of illegal fishing.

Senior World Bank agriculturalist Aleksandar Nacev said, "Once harvest levels have been determined, then the harvest regulations in both Albania and Macedonia must be harmonized to ensure these levels are achieved. Vigorous enforcement of appropriate regulations will also be necessary."

The other main threat to the lake's ecological stability is pollution.

The lake is currently described as oligotrophic, meaning its waters are clear and low in nutrients. But within ten years scientists fear it could become eutrophic (high in nutrients), leading to summer stagnation and dangerously low oxygen levels. This would radically alter the lake's ecology, wiping out many unique species, particularly its fish.

The chief source of pollution is untreated sewage produced by the burgeoning lakeside population. Now approaching 200,000 people, this growth has been accompanied by new hotels and other tourism development which has also damaged reed beds where the trout spawn.

Particularly Vulnerable

Ohrid is particularly vulnerable to pollution because of its depth and small number of connecting rivers. Fed largely by springs, its waters are replaced only every 60 years. With an estimated 150 tons of dissolved phosphorus entering the lake each year, new sewage treatment plants are urgently needed to avoid an ecological disaster.

"Estimates of the lake's phosphorus balance suggests its total load may be three to five times greater than it should be to keep the lake in an oligotrophic state," said Nacev.

While he says both the German and Swiss governments are funding work to upgrade sewerage systems in pollution hot spots, he added, "The magnitude of the conservation challenges necessitates a major expansion of the environmental mitigation investment program."

A popular tourist destination, Lake Ohrid could now lose its World Heritage status. UNESCO, the international body responsible for bestowing the status, is considering whether the accolade is still merited in light of its deteriorating condition.

This is despite $U.S. 4.2 million in World Bank funds being channeled into the Lake Ohrid Conservation Project over the last six years.

Avramoski said, "The LOPC attempted to act upon some sources of phosphorus pollution [including agricultural runoff] but at the moment the results of those actions are negligible compared to the amount of untreated sewage entering the lake."

Panovski agrees the project has achieved little so far in reducing pollution and illegal fishing, but he added, "Importantly, it's helped to get Albanians and Macedonians communicating again and sharing information for the first time in 60 years."

This has led to a joint agreement for protecting the lake and promoting sustainable development, due to be signed this fall. The agreement "acknowledges very explicitly that Lake Ohrid and its watershed constitutes a single ecosystem and must be managed jointly by all the jurisdictions in the watershed," Nacev said.

The agreement may represent the last chance to save Lake Ohrid's ancient ice age survivors, including its unique breed of trout.