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Indigenous fishermen and scientists reveal 144 fish species in remote Santiago River
Deep in Ecuador's Amazon, the Shuar community of Kaputna has helped biologists document 144 fish species-including five never before recorded in the country-in a stretch of the Santiago River long shrouded in local legend. One newly identified species, still under study, may be entirely unknown to science, while another, Peckoltia relictum, marks its first appearance in Ecuadorian waters.
The findings, published in a scientific study co-authored by Kaputna fishermen, challenge the region's reputation as a scientific blind spot. Until 2021, researchers had warned of a "staggering" lack of data on Ecuador's freshwater fish, despite the country's status as a biodiversity hotspot. The collaboration between the Wildlife Conservation Society (WCS) and local fishermen-who used traditional knowledge alongside mobile apps to log catches-has now filled critical gaps.
From myth to discovery: The river's guarded secrets
For generations, the Santiago River's lower reaches were said to "swallow" canoes, earning Kaputna-"area where the river is fast-flowing"-its name. The 145-person Shuar settlement, accessible only by a grueling 10-hour drive from Quito followed by a motorized canoe ride, had long relied on the river's bounty but lacked scientific documentation of its aquatic life.
Fisherman Germán Narankas, a study co-author, described the river as more than a waterway: "For the Shuar, it's a guide," he said, recalling a 2017 ayahuasca vision that foreshadowed his role in the project. "I saw myself traveling to other countries-though I didn't understand it then." Four years later, he and fellow fishermen began collecting specimens, photographing them, and uploading data via the Ictio app, noting details like location, gear used, and physical traits.
"Their knowledge of the territory is essential for discovering new species."
Jonathan Valdiviezo, biologist, National Institute of Biodiversity (Inabio)
Breakthroughs in a 21 sq km stretch
The study's scope was modest-just 21.2 sq km (8.2 sq miles) of the river-but its impact was outsized. Researchers identified 77 species previously unreported in the broader Morona Santiago ichthyographic zone, a 6,691 sq km area. Among the standout finds:
- Five species new to Ecuador, including Peckoltia relictum, a rock-clinging catfish with a suction-cup mouth and armored plates instead of scales.
- A potential new species with distinctive black stripes, currently under DNA analysis in Canada.
- A meter-long catfish and others with striking features, like a "yellow belly" or silver sheen, remembered vividly by participants.
Biologist Fernando Anaguano (WCS) called the collaboration a "landmark" for recognizing Indigenous contributions, noting that such credit is rare in scientific publications. "Freshwater fish are often overlooked for mammals or birds," he said, "but they're vital to ecosystems and Indigenous food security."
Fieldwork in a living laboratory
In Kaputna's makeshift lab-a zinc-roofed shelter-fishermen like Liseth Chuim and Johnson Kajekai measured, weighed, and preserved samples in formaldehyde. "I felt like a scientist," Chuim said. The team's meticulous labeling, Valdiviezo noted, prevented errors in species recording-a critical step given the region's complexity.
DNA analysis later revealed that one "new" species had been described in 2011 but misidentified. Genetic testing confirmed it as Peckoltia relictum, previously unknown in Ecuador. The process, Valdiviezo explained, resembled "determining paternity"-comparing tissue samples to global databases.
Threats and hopes for the Amazon's hidden biodiversity
The study underscores the Amazon's fragility. Freshwater fish populations have declined 81% globally in 50 years, with a 91% drop in Latin America, per the Living Planet Index. Mining pollution, overfishing, and climate change threaten rivers like the Santiago, where the Shuar's sustainable practices offer a model for conservation.
For Narankas, the project's impact is personal. Seeing his name in print brought tears: "I feel proud." Inspired, he returned to high school in 2025 and plans to study biology. "The river's story is just beginning," he said, as a second paper-again co-authored by Kaputna fishermen-prepares for publication.
"We seek not only to conserve fish but to ensure fishing remains sustainable for generations."
Jonathan Valdiviezo, National Institute of Biodiversity (Inabio)
Why it matters
The Santiago's 144 species represent 17% of Ecuador's freshwater fish and 20% of the Amazon's-a remarkable density for such a small area. With an estimated thousands of undiscovered species across the Amazon basin, the study highlights the urgency of Indigenous-led research.
As global leaders convene at COP30 in Belém to address climate crises, the Kaputna project exemplifies how traditional knowledge and science can unite to protect biodiversity-one canoe trip at a time.
