One unassuming day in the 1950s, a plastic bag of wriggling fish was dropped into Lake Victoria in Africa. Three decades later, the predatory Nile perch dominated the lake as the center of a multimillion dollar export industry, while simultaneously wiping out hundreds of endemic fish species and drastically altering the social fabric of the surrounding countries.
In a world where economic health is treated as a more pressing reality than environmental health, the power of the Nile perch is an apt reminder to the ultimate drivers of societal fate.
As one of the world's most infamous invasive species, Nile perch in Lake Victoria were the stars of the documentary Darwin's Nightmare,"" the film that left the audience of the Nelson Institute's environmental film festival in stunned silence.
The ecological devastation wreaked by Nile perch in Lake Victoria is well documented, but market forces have overridden any thoughts of eradication. By 2000, annual export revenues for perch were measured in the hundred millions of U.S. dollars, while fisherman numbers swelled from 11,000 in 1971 to more than 124,000 in 2000, according to the most recent report by the International Food and Business Agribusiness Management Review (IAMA).
This economic success does little for most residents of the African countries surrounding Lake Victoria. IAMA reported that 34 processing facilities capture 90 percent of perch harvest, and some estimates suggest six to eight job losses in the traditional sector for every job created by the perch industry. Additionally, the expensively processed fish are estimated to feed roughly as many in Europe as are starving in Victoria's surrounding countries, and the concentrated population at the lakes edge hastens the rate of HIV transmission.
The story of Nile perch isn't new. Invasive species enter new ecosystems daily, as a bug here or a weed there is transported through human infrastructure. A millenia of travel becomes compressed into an afternoon. The vast majority of these transfers die in the sudden exposure to new habitat, but those that survive find a new world free from the pressures of competition and predation - a Pandora's box for any creature, ourselves included, whose livelihood depends on the status quo.
That Victoria's fish invasion has any benefit for humans is an exception to the rule. Wisconsin waterways struggle with the introductions of invasive fish that drain millions in management and extinctions, with little benefit from harvest. In the 1890s, common carp were released by the thousands across America in a politicized food fad, only to uproot aquatic vegetation and muddy waters. Sea lamprey exploded onto the Great Lakes in the 1950s, collapsing lake trout, lake whitefish and burbot populations. Recent comers, such as ruffe and white perch, bring an unknown threat to the Great Lakes $4 billion fishing industry.
The conclusion may be one of wonder for the power of breeding and hitch-hiking species to confound the institutions we hold constant. A stowaway snake or a bag of fish can revolutionize not only an unprepared new ecosystem, but our industries and even, in the case of Tanzania, Kenya, and Uganda, the fate of national economies. In the end, it's clear which system's health - natural ecosystems or man-made economy - holds the real power over our fate.
E-mail your comments to Deborah at science@dailycardinal.com.
