Giant catfish are among the most important commercial fishes in the Amazon Basin. A new study suggests that their sensitive life cycle may be interrupted by dams in their last remaining refuge on the Madeira River.
Every year, giant catfish migrate from low-lying estuaries near the mouth of the Amazon River up to the turbid headwaters of its tributaries—a journey that can exceed 4,000 kilometers (2,500 miles). Once they arrive, they spawn. The resulting catfish larvae and juveniles travel the entire distance back to the estuaries, where they mature over the next two years before repeating their parents’ trip upriver.
A new study suggests that the catfish’s sensitive life cycle—complete with long journeys timed to coincide with seasonal river flows—may be interrupted by dams in their last remaining refuge.