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 high biodiversity includes over 3,600 plant and animal species, most of which are endemic to the lake.
Over the past several years, however, 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 (7.9 million-acre) area.
The total biomass of omul in Baikal has more than halved since 15 years ago from 25 million tonnes to just 10 million.
The decrease is likely caused by uncontrollable fish poaching, with extra pressure coming from the climate.
Baikal water stock is tied to climate.
Now there is a drought, rivers grow shallow, there are less nutrients. Baikal’s surface heats up and omul does not like warm water.
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 that the lake can no longer absorb human pollution without consequence.
The lake, which is 1,700 metres (5,580 feet) deep, and its tourism now provide a livelihood for many residents to replace fishing.
Foreign visitors often spend time at Baikal while doing a trip on the Trans-Siberian Railway and in recent years more Chinese have been coming as Russia eased visa requirements.
170 types of sponges throughout Baikal’s coast were tested and only 11 percent looked healthy.
A special 1999 law in Russia spells out protection measures for Lake Baikal.
The government is also putting 26 billion rubles (about $452 million, 385 million euros) into a cleanup programme, which started in 2012, to fund treatment facilities.
