Unprecedented footage captures thousands of catfish climbing a waterfall in southern Brazil. This is the first detailed observation of the migrating species.
Bumblebee catfish (Rhyacoglanis’ delusion) acquires its name from its orange body and small-sized black spots, with the fish reaching 3.5 inches (89.2 mm) in length. Small jumpfish photographed slippery rocks 3.3-13.1 feet (1-4 meters) high behind the Akidauana River Falls.
Scientists know virtually nothing about the behavior of this rare fish species. However, in 2024, members of the Environmental Military Police in Brazil’s Mato Grosso do Sur State noticed the sight before calling out a team of scientists. Their findings were published in the Journal of Fish Biology on August 8th.
You might like it
The genus Rhyacoglanis contains nine small catfish species that live throughout Amazon, Orinoco, and La Plata River Basins. “[This genus] “The large tally reported is very prominent,” said Manoela Marigno, a biologist at the Brazilian Mato Grosso do Sur de Sur and the first author of the new study. “This science is a part of this scientific history.
In a new paper, scientists report that Bumblebee’s catfish only climbed later that day. On a hot afternoon, the fish found shade under the rocks. However, at about 6pm local time, thousands of them began to rise as the sun set.
Starting from a small pool connected to the river, the catfish jumped up the steep, vertical stretch of the rock. On the flat rock there were so many fish that they were seen climbing above each other. In the midst of their climbing frenzy, some of the catfish climbed a scientist’s plastic bucket.
Related: The giant 9.4-foot-long catfish is the biggest ever acquired
The catfish climbed by keeping the fins straight and using left and right locking and tail flipping movements to advance. Scientists also speculate that it could create a suction mechanism that sticks to the rock as it climbs by forming a small cavity between the body and the rock.
The researchers don’t know why catfish are climbing the waterfall, but I think they are moving upstream to breed. The climbing group included men and women, most of whom were adults. This behavior also began in November, when the wet season began, especially after dry winters.
“All signs refer to this as a reproductive gathering,” Marigno said. “It appears that it happened shortly after a long, severe drought in the area, and a sudden rise in water levels caused species to lay eggs, bringing together a large number of fish we’ve never seen before.”
Researchers say that the movement behavior of small fish is not well understood in Brazilian rivers. This is because most studies focus on large fish species that are important for the fisheries. The lack of information on small fish species in the area is because movement occurs under fast and very specific environmental conditions, making it easier for scientists to overlook.
The findings show how important river habitat is to the cycle of small fish life, according to researchers, in light of river damization projects that fragment Brazilian river habitat and threaten to interfere with fish migration.
“Recording and sharing this type of behavior highlights the need to maintain natural habitats, especially the rapidly flowing streams,” Marigno said. “These habitats are often submerged by hydroelectric reservoirs, completely eliminating species adapted to these environments.”
Source link
