As if Lake Victoria didn't have enough problems...

Overfishing due to increased demand for and increased export of Nile Perch (Lates niloticus) to EU countries, Australia, and the Middle East has forced President Jakaya Mrisho Kikwete to halt "...all fishing activities on the Tanzania side of Lake Victoria for the next three months."

 "Speaking to the Ministry officials in Dar es Salaam during his working tour, last week, Kikwete said the order is meant to give a room for the fish species to increase after over fishing. He said fish had disappeared from the lake.

Victoria is the large. round-ish lake in the center

Nile Perch (Lates niloticus)

Well ain't that a bitch. Nile Perch are exotic and invasive in Lake Victoria, introduced in the 1950s to supplement native, sustenance fisheries (which didn't need it). This introduction lead to the decimation of the very diverse cichlid fauna (>500 of species) that evolved there over the last few million years.

When teaching ichthyology and/or evolutionary biology, I often cite the radiation of Haplochromin cichlids in Lake Victoria (and other East African rift lakes) as one of the few examples of sympatric speciation...

...and the introduction of Lates and subsequent extinction of cichlids as one of the worst environmental disasters to have occurred on the planet, of which there are (sadly) too many examples.

"fish biomass of the lake has decreased from 80% to less than 1% since the introduction of the Nile perch, and that some 65% of the Haplochromis species were driven to extinction in the process, an event which may well represent the largest extinction event amongst vertebrates in the 20th century (link)"

So, not only did we destroy one of the most amazing, real-world evolutionary/ecological experiments on the planet but now that damn plague-of-a-fish is going extinct too! (I'm ignoring the economic impacts to the $250 million East African fishing industry). 

I am going to have to agree with (and severely paraphrase from memory) something that one of my very good fishing buddies (and former college advisor) said...

"Those with intentions of "improving" should never be allowed within 1000 feet of an aquatic ecosystem..."

 Lake Victoria is and continues to be a very large and obvious example of this statement.