For Great Lakes' Sakes, continued
Turns out that’s just the tip of the iceberg. Four hydroelectric dams downstream of the lake supply 90 percent of Malawi’s electricity. The country is considering proposals to increase water withdrawals from Malawi for irrigation. Climate change aside, “the level of irrigation they’re talking about could result in the level of the lake dropping to the level of no outflow rather frequently,” says Johnson. “It would have dramatic and immediate economic impact on the country.”
Johnson and Malawian colleagues have applied for funding from the National Science Foundation to determine how best to share water between irrigation and hydropower and to determine circumstances under which one should take precedence over the other.
“There are also implications for tourism. There are implications for fisheries in the lake,” says Johnson. “There are a lot of very complex questions to be addressed.”
Cooperation and Differences
International cooperation opens new vistas in the quest to protect the world’s great lakes. But collaboration also reveals cultural differences among people who live by these lakes.
Consider Lake Victoria, bordered by Tanzania, Kenya and Uganda. Second-largest freshwater lake in the world by area—bigger than Lake Huron or Michigan—Victoria is only 260 feet at its deepest. It once had a tremendous number of cichlids fish species, many of which provided subsistence to the people on its shores. But none was large enough to support a commercial fishery. So during the 1950s, fish managers introduced Nile tilapia and Nile perch, a freshwater giant that can weigh more than 400 pounds. The effect on native cichlids was disastrous. With habitat changes, such as the spread of exotic water hyacinth across shallow bays, Nile perch and tilapia were blamed for the extinction of 150 species of cichlids. Says MacIntyre at UC–Santa Barbara, “It was considered one of the largest ecological catastrophes to ever happen.” The International Union for the Conservation of Nature has labeled the Nile perch one of the world’s 100 most invasive species.
Yet local residents see it differently. The two exotic fish support a commercial fishery that lands $590 million of fish a year, including the annual export of $250 million worth of Nile perch—and this in an area with an annual income of about $1,200, where the average fishing boat consists of a two-man canoe. Victoria fishing employs 2 million and provides household incomes to nearly 22 million. According to the Lake Victoria Fisheries Organization, “Lake Victoria is the most productive freshwater fishery in Africa… an immense source of income, employment, food and foreign exchange for East Africa.”
“On the African lakes fish production is everything,” says Dobiesz. U.S. biologists “look at the health of our systems as how well they mirror historic populations. In Africa, they consider healthy ecosystems to be ones that provide them with a lot of fish.”
Disregard for clashing perspectives can lead to the failure of aid and collaboration over the management of fish, lakes and other resources. As Dobiesz notes, some non-governmental organizations “exist solely through support of donors from outside of Africa who contribute financial assistance for specific community projects. Such groups can alienate the local community by ignoring social norms and traditional structures.”
Dobiesz recalls walking with a Ugandan researcher who was in the United States to help with the study of ecosystem health. At one point, Dobiesz explained the American conservation concept of catch-and-release fishing.
The Ugandan scientist stopped, dumbfounded. “I could never explain that to anyone in Africa,” she stammered. “No one would ever take the time to catch a fish and throw it back. If they didn’t need it for dinner, they would give it to someone who did. Or they would sell it to someone. But they would never, ever throw it back.”
If research will continue to inform and benefit management of the world’s big lakes, researchers will have to be keenly aware of the values and needs of the people living on the shores of those lakes.
GREG BREINING writes about travel, science and nature for Momentum, the New York Times and many other publications. He paddled around Lake Superior to write the book Wild Shore: Exploring Lake Superior by Kayak.
Great Slave Lake
Canada’s Great Slave Lake, like all large lakes, provides life support to a spectrum of unique natural communities.
Most of the animal protein consumed by people living along Lake Malawi’s shores comes from fish such as these native usipa.
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Last modified on January 23, 2012