The Amazon River
Many tropical rivers experience seasonal flooding, but nowhere as pronounced as in the Amazon River basin of South America, where water levels may rise thirty to forty feet and surge nearly twenty miles inland. Here the drowned forest is known as Varzea.
A forest that becomes flooded offers challenges and opportunities for wildlife. Terrestrial animals must go up—ascending to higher terrain or climbing up trees. But now fish suddenly can swim among the tree trunks. Many of the trees have evolved to drop their fruit and seeds during high water to better disperse them.
And many fish that invade these areas are herbivorous, having evolved to capitalize on the abundance of fruit and seeds.
The Tambaqui Fish
The tambaqui is a large fish that crushed fallen seeds with its strong jaws. These fish often gather beneath trees bearing the seeds they prefer, a fact that fishermen use to their advantage. Some elongated and flattened fruits characteristic of the legume family hang over rivers in South America; these fruit ripen and explode , with fish gathering underneath to eat the seeds.
Indians think the fish hear the fruit explode, others are convinced it’s the sound of the vibrations from the fruit hitting the water, and still others believe the fish sticks its snout of the water to sniff the odors or ripening fruit. According to Amazonian folklore, jaguars prey on herbivorous fish by listening for the thud of falling seeds.
Others claim that the jaguar crouches on a branch over the water and taps the surface to imitate falling fruit, to draw tambaqui and other fish near.
Fish Farming the Tambaqui
To catch tambaqui and other herbivorous fishes, native fishermen feign falling fish food. Of course, harder than using a fish wheel but safer than that of dynamite fishing. In Brazil, fishermen use a gaponga, a weight tied to the end of a line and pole, repeatedly dropping it on the river surface to imitate the sound of falling fruit.
Fishermen spear the fish that are attracted with the expectation of finding rather than being turned into a meal.