Lake Baikal under threat

Moscow – Lake Baikal is having its gravest crisis in recent history, experts say, as the government bans the catching of a signature fish that has lived in the world’s deepest lake for centuries, but is now under threat.

Holding one-fifth of the world’s unfrozen fresh water, Baikal in Russia’s Siberia is a natural wonder of “exceptional value to evolutionary science” meriting its listing as a World Heritage Site by Unesco.

Baikal’s high biodiversity includes more than 3 600 plant and animal species, most of which are endemic to the lake.

But in recent years, the lake – a major international tourist attraction – has been crippled by a series of detrimental phenomena, some of which remain a mystery to scientists.

They include the disappearance of the omul fish, rapid growth of putrid algae and the death of endemic species of sponges across its vast 3.2 million-hectare area.

Starting this month, the government introduced a ban on all commercial fishing of omul, a species of the salmon family only found in Baikal, fearing “irreversible consequences for its population”, the Russian fisheries agency said.

“The biomass of omul in Baikal has more than halved since 15 years ago” from 25 million tons to only 10 million, the agency said.

Local fishery biologist Anatoly Mamontov said the decrease is likely caused by uncontrollable fish poaching, with extra pressure coming from the climate.

“Baikal water stock is tied to climate,” he said. “Now there is a drought, rivers grow shallow. Baikal’s surface heats up and omul does not like warm water.”

Unesco last month “noted with concern the ecosystem of the lake is reported to be under significant stress” and a decrease in fish stocks is just one observable effect.

The omul, a well-known speciality, was for centuries the main local source of food, eaten salted or smoked.

Another peril to the lake’s ecosystem is the explosion of algal blooms unnatural to Baikal with thick mats of rotting spirogyra algae blanketing pristine sandy beaches. Some scientists say that indicates that the lake can no longer absorb human pollution without consequence.

“The reason is the wastewater run-off” from towns without proper sewage treatment, particularly of phosphate-containing detergents, said Oleg Timoshkin, a Russian biologist. –