Why snakes are disappearing from Southeast Asia’s largest lake
Cambodia’s Tonle Sap Lake is one of the most biodiverse bodies of water on Earth. Zeb Hogan, a biologist and National Geographic Explorer, is examining how fishing in Tonle Sap is affecting aquatic life. Fish stocks in the lake have dramatically declined over recent decades. Large-scale commercial fishing is regulated by the government, although not effectively. Hundreds of thousands of fishermen operate on the lake. As large, valuable species such as giant catfish disappear from overfishing, fishermen target smaller species.
According a study in 2000, around 7 million water snakes were collected from Tonle Sap each year. The population of water snakes, some of them vulnerable species, has been declining since the 1990s. The non-venomous snakes are used for food, leather, and traditional medicines. Water snakes are important to the life of the lake—they eat fish and frogs and provide food for birds. The effects of the declines of water snakes and other species aren’t yet known.
Transcript
TOS (Text-on-screen):
Cambodia’s Tonle Sap Lake is one of the most biodiverse bodies of water on Earth.
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Fish stocks in the lake have dramatically declined over recent decades.
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Zeb Hogan, a biologist and National Geographic Explorer …
is examining how fishing in Tonle Sap is affecting aquatic life.
Zeb Hogan off-camera VO:
Tonle Sap lake is southeast Asia’s largest lake.
Zeb Hogan to camera:
One of the things that makes Tonle Sap special is that it expands in the rainy season and contracts in the dry season.
Zeb Hogan off-camera:
I’ve come out with some fishermen, to see what they’re catching.
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Subsistence fishing such as this has been an important food source for centuries.
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Large-scale commercial fishing is regulated by the government,although not effectively.
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Hundreds of thousands of fishermen operate on the lake.
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As large, valuable species such as giant catfish disappear from overfishing, fishermen target smaller species.
Zeb Hogan on camera:
So the fishermen set out a trap last night, and right down here in the boat is what they caught.
Zeb Hogan off-camera:
One thing that strikes me almost immediately is that these are almost all juvenile fish.
Zeb Hogan off-camera:
So not only fish, but turtle, shrimp, snails, and… check this out – aquatic snake.
And so this is one of the things the Tonle Sap is famous for.
Zeb Hogan off-camera:
The Tonle Sap is home to the world’s largest aquatic snake harvest.
And this time of year, the aquatic snake harvest peaks—the waters come up and it forces the snakes into the trees and into the vegetation.
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According a study in 2000, around 7 million water snakes were collected from Tonle Sap each year.
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The population of water snakes, some of them vulnerable species, has been declining since the 1990s.
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The non-venomous snakes are used for food, leather, and traditional medicines.
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As fish and snake populations shrink, fishermen have begun collecting mollusks, such as snails.
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Water snakes are important to the life of the lake—they eat fish and frogs and provide food for birds.
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The effects of the declines of water snakes and other species aren’t yet known.
