Legend says the Santiago River once swallowed any canoe that dared explore it. Today, an indigenous community uncovers surprising species in its waters.
We stepped into a wooden canoe floating on the murky Santiago River, ready to enter one of the Amazon’s least-studied ecosystems. Until recently, scientists had no clear record of which fish inhabited this stretch of water. After a two-day journey from Quito, Ecuador’s capital, photographer Karen Toro and I neared Kaputna, an indigenous community that has revealed new species in these remote waters.
Kaputna, the community at the heart of discovery
Kaputna lies surrounded by untouched jungle, where jaguars, peccaries, and pumas still roam. Its 145 inhabitants belong to the Shuar, one of Ecuador’s 11 indigenous nations. Ecuador holds immense freshwater fish diversity, but in 2021, scientists warned that knowledge about its species was “staggeringly incomplete.” A group of Kaputna residents began filling this gap. They discovered fish camouflaged in shades of brown and silver, feeding from submerged rocks with specialized mouths.
Between 2021 and 2022, combining traditional knowledge and scientific methods, the community identified 144 fish species in the Santiago River. Five species were previously known in other countries but never recorded in Ecuador. One species is still under study and could be entirely new to science. Kaputna fishermen, including Germán Narankas, became co-authors of the scientific publication detailing the discoveries.
“Their knowledge of the river was crucial to discovering new species,” says biologist Jonathan Valdiviezo, who supported the sample analysis. Fernando Anaguano, main author of the study and a WCS biologist, describes it as a landmark in recognizing local contributors in scientific research. “Acknowledging the work of local communities is rare in scientific publications,” he says.
A river that once swallowed canoes
Local legends tell of people disappearing along the lower Santiago before motorboats existed. The river allegedly swallowed their canoes, and strangers never reached Kaputna. The name Kaputna means “area where the river is fast-flowing,” locals say.
Reaching it required a ten-hour drive from Quito to Tiwintza, a border town with Peru, where we stayed overnight. In the morning, Narankas greeted us with a fishing net slung over his back. “Today will be hell,” he warned. “It hasn’t rained in three days, and the heat is intense.” By 9 a.m., temperatures already reached 35°C.
After gathering food, water, and gasoline for his canoe, Narankas guided us to the Peñas port on the Santiago River. Peque-peques, gasoline-powered canoes, provide the only access to Kaputna. Murky waters hid the riverbed, protecting its secrets. Calm stretches offered serene views, while rough currents reminded us of the legend of disappearing canoes. We dodged fallen logs and finally reached Kaputna. Children guided us to a communal shelter where we set up tents.
“Let’s sail before it gets too late,” Narankas suggested. We explored even more remote stretches, where the community made the discoveries that changed their lives.
Flowing with the current
Narankas knows the Santiago like the back of his hand. Before joining the scientific project in 2021, he already recognized different fish species by sight. He learned to identify and record them by their scientific names.
He recalls a 2017 vision during an Ayahuasca ritual, where Shuar people seek guidance from the plant. “I dreamed I would change the system and travel abroad. That man in the vision was me,” he says. Four years later, WCS researchers invited him to participate in biodiversity studies on the Santiago River. Narankas and fellow residents collected fish, photographed them, and uploaded data to the Ictio app, including location, gear used, and species characteristics. “Three of them were new to me,” he says.
Crickets drowned out the canoe’s engine as we glided through the jungle for nearly an hour. Eventually, the water cleared and turned transparent.
“We’ve reached the Yaupi,” Narankas announced. The Yaupi is a Santiago tributary and a local favorite due to its clean, mining-free waters. He, his sister Mireya, and son Josué cast nets and pulled in a fish called carachama, scientifically Chaetostoma trimaculineum. It measures 10 cm, is dark brown with black spots, and uses a suction-cup mouth.
Narankas identified a previously unstudied fish, Peckoltia relictum, measuring 15 cm, which clings to rocks. Its suction-cup mouth and plate-like covering distinguish it from other Loricariidae species.
In Kaputna, residents measured, weighed, and preserved specimens. “I felt like a scientist,” said fisherwoman Liseth Chuim. Johnson Kajekai explained, “We labeled every fish with its number and name.” They remembered a one-meter catfish, a yellow-bellied specimen, and a silver fish. WCS biologists then transported samples to laboratories in Quito.
Revealing the mystery
Biologists finally unlocked an ecosystem long unknown to outsiders. “This basin is one of the least studied. Few studies document its fish diversity,” says Anaguano, who has studied freshwater fish for over a decade. He cites the river’s remoteness and historical neglect of freshwater fish in favor of mammals or birds. Freshwater species, he adds, play key ecological roles and provide vital food resources to local communities.
Previous research recorded 143 species in the broader Morona Santiago ichthyographic zone, covering 6,691 sq km. The Kaputna study found 144 species in just 21.2 sq km, including 77 not previously reported. These species represent 17% of Ecuador’s freshwater fish and 20% of Amazonian species, remarkable for such a small area.
The Amazon hosts the world’s richest freshwater fish diversity. Researchers have recorded 2,500 species but estimate thousands remain undiscovered. Some rivers support the planet’s longest migrations, like the dorado catfish traveling nearly 11,000 km between the Andes and the Atlantic Ocean.
Conserving fish for the future
Freshwater fish face severe threats. The Living Planet Index reports an 81% decline in the past 50 years globally, and 91% in Latin America. Fish are vital for indigenous culture and food security. “We aim to conserve fish and ensure sustainable fishing,” Valdiviezo says. Proper training of Kaputna fishermen in sample labeling ensured accurate species records.
Discovery brought surprises. DNA analysis revealed one fish previously thought new was actually described in 2011. Still, it represented a new species for Ecuador. Researchers continue studying another catfish that may be entirely new to science. A second paper, co-authored by Kaputna fishermen, is expected this year.
Evenings in Kaputna under the stars brought reflection. Narankas felt immense pride seeing his name in a publication. At 34, he returned to high school in August 2025, planning to graduate and study biology. He hopes to continue uncovering the Santiago River’s secrets, where scientific discovery has only just begun.
