Meet the extraordinary catfish that travels the width of South America

The dorado catfish swims more than 7,200 miles, making it the world champion of freshwater fish migration.

There is an incredible fish that lives in the Amazon River. Called the “dorado" catfish for its shimmering skin, 6-foot long Brachyplatystoma rousseauxii comes from a family of “goliath” catfish species long suspected of achieving great feats of migration.

Those suspicions have now been confirmed by an international team of scientists who have proven that the dorado holds the record for the longest exclusively freshwater fish migration in the world. The epic life-cycle journey reads like a wanderlust-bitten adventurer’s dream, stretching nearly the entire width of the South America continent.

The study looked at four species of goliath catfish that spawn in the western headwaters of the Amazon. The journey of our long-distance hero here, the dorado, starts with adults and pre-adults making the long trek upriver from the Amazon River estuary to spawning areas in or near the Andes Mountains. And while the breeding fish do not return to their nursery areas, the newborn catfish do, migrating thousands of kilometers in the opposite direction to complete the cycle.

Migration map© Scientific Reports - Nature

All told, the dorado was found to have a life-cycle migration of approximately 11,600 kilometers … more than 7,200 miles.

The four species studied are among the most important commercial species in the countries they inhabit; and they are under threat from, wait for it … development plans. A flurry of dams, mining operations, and the constant soul-suck of deforestation (specifically in the Amazon’s headwaters) could hinder these stalwart travelers, not to mention the people who rely on them.

“One of the biggest threats to the dorado catfish and other fish species is headwater infrastructure development in the Andes that could heavily impact the spawning grounds of the world’s longest freshwater migrants,” says Michael Goulding, study co-author and Wildlife Conservation Society (WCS) aquatic scientist.

But given the extraordinary conclusions of the new research, conservation efforts will hopefully have more support in the form of data.

“This is the first time that scientific research has linked the full range of these fish species, some of which stretch from the Andes to the Amazon River estuary abutting the Atlantic Ocean,” says lead author Ronaldo Barthem of Museu Paraense Emilio Goeldi of Brazil. “These findings can now inform effective management strategies for these fish, some of which are important for fishing industries in the region.”

“Many questions remain about these incredible fish, such as why they travel so far to reproduce and do they return to place of birth to spawn,” adda Goulding. “Now we have a baseline that will help direct the trajectory of future research and conservation efforts.”

The research was conducted by WCS’s Amazon Waters Initiative, sponsored by the Science for Nature and People Partnership hosted by WCS, The Nature Conservancy (TNC) and the National Center for Ecological Analysis and Synthesis (NCEAS). It was published in the journal Scientific Reports-Nature.

Tags: Amazonia | Conservation | Fish

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