Tuesday, September 10, 2013

Manipulating Variables

""When we try to pick out anything by itself, we find it hitched to everything else in the Universe."  - John Muir

Imagine stocking one of the largest lakes on the planet, already lush with life adapted to its unique habitats, with an invasive eating machine capable of reaching more than 300lb.

Couple that with a surrounding population of desperate people, many living hand to mouth.

Add a dash of Russian, Chinese and European exporters taking the commercially harvested fish to markets in their own countries, without trading anything in return.

Sprinkle in some organized crime, both foreign and domestic, more than willing to exploit the desperation of local Africans.

Mix well, let ferment for 60 years.

The emergent stew is Lake Victoria today; a sick giant headed for some dark days.

Confiscated poacher's boats - Rubondo Island National Park

Nile Perch are native to the Nile River and its tributaries. Murchison Falls on the Nile is the geographic barrier that prevented the upstream distribution of the predators from entering Lake Victoria. In its isolation, Lake Vic evolved a host of unique fish; cichlids that diversified to fulfill almost every available niche.

Nile Perch were stocked in the 1950's to build the basis for a commercial fishery. The experiment worked too well. Considered a delicacy in Europe, Asia and Russia, giant, empty cargo planes began landing in Mwanza, a coastal village in Tanzania, filling their holds with refrigerated perch filets carved in foreign-owned processing plants, then flying home.

The introduction of the perch, and their flourishing, knocked the entire ecosystem out of balance. As the food web withers, an entire host of consequences have begun to rear. An even more dire future is forecast for the lake, but from the ruins a new ecosystem will, eventually, rise.

With the big money commercial fishery essentially collapsed, and the 'protected' waters of Rubondo Island National Park within sight of the mainland, desperate locals are lured into poaching by pay from foreign organized crime outfits, mostly from Asia. When chased, they stash their boats in the reeds and disappear into the forest. A night ride back to the mainland is a cell phone call away, and new boats are waiting for them to continue their poaching. If caught, they get bailed out by their employers after a stiff fine of 30,000Tsh ($18).

Poacher Patrol - While we trolled for perch, eyes scanned the horizons for signs of illegal activity.

Our park ranger fishing guide loved showing off his AK. On our first day, he begged us to let him chase some poachers we spotted in the distance. We chickened out, and had him drop us on a rocky outcrop while he gave chase. He returned with a shiny, new wooden boat full of nets. This happened two more times during our stay.

This game is relatively low-stakes. He's never fired his gun, and has never been fired upon. There are almost no consequences for getting caught, and he receives a 10,000Tsh ($6) bonus for each confiscated boat. It's just a game of cat and mouse.

The last thing most fish in Lake Victoria ever see: the gullet of the invasive Nile Perch.

The poachers use nets to capture remnants of the cichlid populations that used to dominate the lake. Each of the hundreds of species unique and endemic, they're now all but gone. If caught, they're used a bait.  Hooked through the back and connected to an unanchored water bottle float, they're set around the island.  Lines between bait and float might be 150ft long, and made of dacron. Perch can't resist, and find themselves connected to a buoyant bottle. If the bottle is seen, it will be hauled up and taken to mainland Uganda or Tanzania, usually for export to the EU or Asia.

The larger perch in the lake cannot be caught by the methods most locals use to fish the lake. Only the young perch are taken using gill nets meant for tilapia. With the demise of their main cichlid prey due to predation, the perch are turning on their own young, and small minnows known as daga. The bottom is dropping out of the fishery as we speak.

A croc with a bleak future. Note the netting entangled in its jaws.

Nile Perch have essentially eaten the tilapia and cichlids of the lake. The prey of those fish, daga, have expectedly exploded in numbers. This has led to a flourishing of snowy egrets, pied kingfishers, short-tailed and great cormorants; all predators of small minnows. The nile crocodile population had previously exploded due to the nile perch, but is now headed for collapse in time with the perch.

The loss of plant-eating cichlids has led to large-scale eutrophication of the lake's waters.

Tilapia were the staple of the diet of the peoples populating the shoreline. Tilapia meat used to be dried in the sun. Now, the fatty meat of the nile perch must be smoked or it will spoil. This has led to heartbreaking deforestation, for wood fuel, along almost the entire lake's shoreline.

Remember, though, that the nile perch fishery is closed to most locals because of the expense of acquiring nets that can handle the giant fish. Instead, they are given the carcasses of the fish that have already been processed commercially. Dumptrucks laden with heads and spines are dumped roadside, to be sifted, sorted and hung to dry in great, smoking arrangements.

The whole complicated thing is a total mess. The aquatic ecosystem is headed for total collapse. But, perhaps this a good thing, for only then will the lake be able to rebuild a new food web, adjusted for the presence of nile perch.

For more photos, check out Pete Stanley's photography website. A skilled photographer can give you a better sense of this part of the planet than a mediocre writer can.  www.photopoa.com


Snuffit said...

A sad series of events, man plays God and...

Feather Chucker said...

Dude, what the hell do you do for a living?

Mark said...

Matt teaches middle school in Tanzania