The Congo River is the deepest river in the world with lots of strange fish
Get to know the Congo River, the deepest river in the world and lots of strange fish
- The Congo River, located in Africa, has been named the deepest river in the world.
Reporting from The New York Times, the Congo River in some parts is around 220 meters deep.
The Congo River, stretches 4,700 km in the Congo.
The depth of the Congo River means that sunlight cannot penetrate the river bed. Thus, the bed of the Congo River is in shadow. This river is inhabited by strange fish, one of which is the Goliath Tigerfish. This Goliath Tigerfish has large and sharp teeth. The sharpness of this fish's teeth is on the same level as piranha teeth. Goliath Tigerfish can grow to a weight of around 45 kg.
The discovery that the Congo River is the deepest river in the world stems from the mystery of the fish that died in the river.
More than a decade ago, scientists found dead fish in this river that were blind and pale.
It turned out that the cause of the fish's death was decompression or bend syndrome, a condition in which air bubbles form in the fish's blood and body tissue.
Reporting from kompas.com, Stiassny, who studies the biodiversity and evolution of fish in the lower Congo, a stretch of 322 kilometers before the river empties into the Atlantic Ocean, said this at a meeting of the American Geophysical Union.
He said there are more than 300 species of fish found in lower Congo alone. The rapids there are so strong that they physically separate fish populations and encourage new species to evolve, even when no physical distance separates the animals from their close relatives.
Of the hundreds of fish species discovered, Stiassny found one species that really stood out from the others.
"In one place, we found this very strange fish. This is a blind and isolated cichlid, very similar to a cave fish, but there are no caves in the river," he said as reported by Live Science (12/01/2020).
This unique species left Stiassny and his colleagues confused because they did not find any surviving individuals of this fish. Moreover, the fish died very horribly.
"When it died in my hands, bubbles formed under its skin and over its gills, a sure sign of decompression syndrome," continued Stiassny. To note, decompression syndrome is caused by a rapid rise from very deep water to shallower depths.
This makes the pressure drop sharply and causes the gas to dissolve, forming bubbles in the body. This species of fish also makes researchers suspect that the bottom of the Congo River is actually deeper than we know so far, and that the fish comes from that deep part.
To investigate, Stiassny and researchers measured the river's depth by sending a kayak or small boat across the rapids in 2008 and 2009. The kayak is equipped with tools to measure river depth.
This research also uses an acoustic current profiler instrument to measure the direction and speed of currents throughout the water column.
As a result, researchers discovered that the Congo River is indeed very deep.
According to research published by the US Geological Survey, the river bed of the lower Congo River lies more than 200 meters below the surface. "The results we got were astonishing: Very deep. Very deep" said Stiassny. Their data also revealed the existence of strong currents that swirl in the Congo River and cause jets of water that spray from the seabed to the surface.
When an unlucky fish is hit by this jet, it will immediately be thrown to the surface hundreds of meters above and experience decompression syndrome.
While the mystery of the dead fish may have been solved, there is still much to be discovered about this unique river and the animals that live there.
One of the highlights is that some fish populations isolated from each other share similar traits, in a process known as convergent evolution. According to Stiassny, how that happens in this unique and extreme environment is the big question he and his colleagues will be navigating. (*)