World’s deepest lake in peril, scientists warn

Lake Baikal is undergoing 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 biodiversity includes over 3,600 plant and animal species, most of which are endemic to the lake. In the past several years, the lake 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, growth of putrid algae and the death of endemic species of sponges across its vast 3.2 millionhectare area.

Starting in October, 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 total biomass of omul in Baikal has more than halved since 15 years ago” from 25 million tonnes to just 10 million, the agency said.

Fishery biologist Anatoly Mamontov said the decrease is likely caused by uncontrollable fish poaching.

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

The Baikal omul, a well-known speciality, was for centuries the main local source of food, eaten salted or smoked, and especially important given the region has no farming.

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, which some scientists say indicates the lake can no longer absorb human pollution without consequence.

“I am 150 per cent sure the reason is the wastewater runoff ” from towns without proper sewage treatment, said Oleg Timoshkin, biologist at the Russian Academy of Sciences’ Limnological Institute in Irkutsk.

The lake, which is 5,580 feet deep, and its tourism now provide a livelihood for many residents to replace fishing.

President Vladimir Putin in August complained of “extremely high pollution” while visiting Lake Baikal, calling its preservation a “government priority”.

The government is putting $452 million into a cleanup programme, which started in 2012, to fund treatment facilities, though experts say much of the money gets wasted.