Excess piranha by reservoirs

2004/02/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

Piranhas have grown in several rivers in Brazil due to man-made reservoirs. Reservoirs slow down the speed of river water, which facilitates the birth of piranhas. Hence the increase of populations in these rivers.

To reproduce, the piranhas stick the eggs to the plants of the streams, and the force of the water causes many eggs to be released and lost. Therefore, piranhas have to lay many eggs so that the population renews from a few who do not release. But reservoirs slow down river water, so many piranhas are born. According to experts, several rivers have multiplied by ten populations since the construction of reservoirs.