Aerial: Negro (on right) & Amazon (Solimoes) Rivers join @ Manaus (back) but don't mix for miles. Brazil

Delta isles at confluence of Negro (left) and Amazon Rivers at Manaus, looking east; in June. Brazil

Boats dock @ cattle corral at ranch on the innundated floodplains of Tapajos River; June- Santarem Braz

Cowboy gazes out chowhouse window at flooded corral & floodplains of Tapajos River; June- Santarem Brazil

Mike Goulding picks blooms off flooded tree from boat; piranhas eat the flowers in flood season. Brazil

Perched in canoe, Goulding sets net; in 250,000 fish, he's found 400 new to science;Tapajos River Brazil

Portrait of fisherman rowing canoe on Tapajos River near Santarem. Brazil

Fisherman in wooden canoe fishes flooded banks of Tapajos; fish are 70% of protein in local diet Brazil

Fisherman in canoe casts net into Tapajos River;fish supply 70% of protein locals eat; Santarem Brazil

Water boils with piranhas that devour butchered cow's head cast into Cuiaba River; Pantanal. Brazil

Woman and two girls clean piranhas in backwaters of Pantanal to sell as dried fish in Corumba. Brazil

Gutted piranhas hang in a row upside-down to dry out and be sold in Pantanal town of Corumba. Brazil

Boats bearing foods and goods cluster along levee of Santarem on the Tapajos River in June. Brazil

Mike Goulding photographs fish in market to document overfishing pressures in Amazon; Santarem. Brazil

Red-bellied piranha, to be fried or stewed, fill a bin at the fish market in Santarem, Para. Brazil

Red-bellied piranha (sp: Pygocentrus nattereri) caught in Tapajos River near Santarem. Brazil

Red-bellied (nattereri) piranha swimming;this infamous species turns vegetarian in flood season Brazil

Red-bellied & a juvenile black piranha meet;these infamous fish turn vegetarian in flood season. Brazil

Wm Fink uses fiber optics, video & computer eqpt to trace piranha dimensions & evolution; Ann Arbor, Michigan

Piranha-filled jars line shelves of Ann Arbor lab where Wm Fink studies fish evolution; Ann Arbor, Michigan