Lake Titicaca Threatened By Invasive Fish, Overfishing, Pollution

By on December 10, 2015
Lake Titicaca. (Credit: Alexander Fiebrandt via Creative Commons 2.0)

Lake Titicaca, which sits between the countries of Peru and Bolivia, isn’t in great shape. The highest navigable lake in the world is full of pollution and overfished. It serves as an important channel for shipping and suffers a lot of overuse because of it.

Some of these problems have come with good intentions, as in people are just trying to provide for themselves by fishing or shipping goods across the lake. But others, namely a large invasive species problem, was precisely planned from the outset.

In the 1930s, the governments of Peru and Bolivia were working together to leverage the economic potential of Lake Titicaca. To that end, they contacted representatives from the United States to help them make the waterway more useful as an economic engine.

An expert with the U.S. Fish and Wildlife Service’s Division of Fish Culture was dispatched not long thereafter to survey the scene and make recommendations. And after an investigation that spanned parts of 1935 and 1936, the rep, M.C. James, sent a letter of report to the U.S. government suggesting that the lake be stocked with North American fish.

Among the fish that James put forward as possible additions to Lake Titicaca were trout and whitefish. A few years later, the U.S. sent 500,000 trout eggs and 2 million white fish eggs to be stocked in the lake, the environmental effects from which are still being felt today.

A common whitefish. (Credit: Apple2000 via Creative Commons 3.0)

A common whitefish. (Credit: Apple2000 via Creative Commons 3.0)

The whitefish eggs weren’t stout enough to survive stocking in the lake, but the trout eggs were. And many of the lake’s native species are under threat today thanks to the dominance that trout populations have grown to have in Lake Titicaca. These include threatened and endangered species of killifish, as well as some species of catfish that are getting harder to find in fish markets, tourists say.

The effects are compounded by another fish that was stocked in the lake, Argentinian silverside, in the 1950s. It’s not clear how they got into the lake, but some say they could have been brought by boaters or others wanting to fish them for sport.

Pollution in the water is also harming Lake Titicaca’s native species of frogs. These impacts are mostly caused by a rise in fertilizer use around the lake that is spurring algal blooms that choke fish and wildlife.

Perhaps by design, or simple luck, Lake Titicaca has become a very important water body for the economy of the two nations that share its water. But the rise of trout and Argentinian silverside have not been good ecologically for the lake.

Representatives from both the Peruvian and Bolivian governments are planning meetings to address Lake Titicaca’s issues. Expectations for the cost of the remediation works that it needs range in the tens of millions of dollars.

Top image: Lake Titicaca. (Credit: Alexander Fiebrandt via Creative Commons 2.0)

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