As long as humans have existed, our interaction with the environment continues to defy a profound truth about all living things – all life is connected. During this month of April, Why Science will be publishing stories about the environment, and one of the great ways to appreciate the environment is to study our historical role with it. The story below by Hazen & Trefil illustrates the connectedness of all living things.
“Lake Victoria, Africa’s largest body of fresh water, was once the home of hundreds of species of fish. Among the most important to humans was the tilapia, a delicacy vital to the local economy. Africans harvested and sun-dried tons of the fish, which provided the principal source of protein for millions of lakeshore people.
In the 1960s British sportsmen introduced a new species into the lake-the Nile perch, a voracious predator that grows to several hundred pounds. At first the tilapia population survived perch predation by escaping to deep water where the perch’s visual hunting techniques don’t work. But the perch ate other species of fish that limited algae growth. Unchecked, the algae grew out of control, died, sank to the bottom, and decayed, thus destroying oxygen in the tilapia’s deep-water sanctuary. With the bottom zone uninhabitable, the unprotected tilapia population is now all but gone. The perch have also eliminated snail-eating fish, so snails, which carry dangerous parasites, have become a major health hazard.
The shores of Lake Victoria are nearly equally divided among Kenya, Uganda, and Tanzania. Millions of Africans in hundreds of lakeshore towns and villages have been affected by the changing lake ecology. Lake Victoria’s native fishermen have switched from tilapia to Nile perch, but the larger fish cannot be sun-dried effectively. The fishermen must roast the perch over wood fires. Now the lake’s shoreline has been stripped of trees, resulting in soil erosion and more lake damage. The introduction of one new species has drastically altered an entire ecosystem-an unintended result of man’s simple desire for better sport fishing.”
Wangari Maathai, the first African woman and the first environmentalist to win the Nobel Peace Prize, fought fearlessly to restore the natural ecosystem of Lake Victoria. Her death leaves it up to each one of us to ensure her vision is realized.
Like the new species of fish introduced into Lake Victoria, the introduction of new technology has drastically altered our lives. During this month of April we will explore issues pertaining to unintended consequences of man’s interaction with man and the environment through technology.
About Lake Victoria
Lake Victoria (also known as Victoria Nyanza, Ukerewe and Nalubaale) is the world’s second largest fresh water lake by area. It is located in eastern central Africa, straddling the equator, and is shared between the nations of Uganda, Tanzania and Kenya. It is generally considered to be the source of the Nile River, the world’s longest river. Click here to learn more.
Photo Credits: Silverbird Travel
Source Cited: Science Matters: Achieving Scientific Literacy by Robert M. Hazen and James Trefil & Taking Root: The Vision of Wangari Maathai