Shellear Fish Documented Climbing 50-Foot Waterfall in Congo
A species of fish known as the shellear (Parakneria thysi) has been formally documented climbing a 50-foot waterfall in the Democratic Republic of Congo. This observation, made at Luvilombo Falls, marks the first recorded instance of fish exhibiting such behavior on the African continent, with scientists hypothesizing it is part of an upstream migratory pattern.
This groundbreaking observation at Luvilombo Falls marks the first recorded instance of fish climbing a waterfall on the African continent, a behavior hypothesized to be part of an upstream migratory pattern.
Discovery and Documentation
The phenomenon of fish climbing waterfalls was initially observed 17 years prior by Auguste Chocha Manda from the Université de Lubumbashi.
Subsequent research led by Pacifique Kiwele Mutambala, then a Master's student, and ichthyologist Emmanuel Vreven, along with their colleagues, resulted in the formal documentation of this behavior. Their findings were published in the journal Scientific Reports.
Mutambala spent multiple rainy seasons at the Luvilombo Falls to film and study the fish, confirming thousands of individuals navigating the vertical rock surface, particularly after initial footage was lost.
Mechanism of Ascent
The shellear fish utilize specific anatomical and behavioral traits to ascend vertical rock faces:
- Pelvic Fins: Used for support during the climb.
- Pectoral Fins: Equipped with tiny hooks, enabling grip on the rock surface, similar to Velcro.
- Pectoral Girdle: A robust bone arch that provides support for the musculature necessary for climbing.
- Lateral Undulations: Rapid body movements, described as "power bursts" or "vertical swimming," propel the fish upwards.
The ascent is not continuous, as fish pause on flat surfaces to recover energy. The entire climb can take approximately ten hours and may involve clinging to overhangs and occasional falls.
Conditions and Limitations
Observations indicate that only smaller fish, typically a couple of inches long or less, are capable of making the climb, as larger individuals become too heavy.
The fish also primarily climb in the splash zones at the sides of the falls, avoiding the strongest central current.
Ecological Significance and Conservation Implications
Scientists hypothesize that the shellear fish scale the waterfalls as part of an upstream migratory pattern. This behavior is considered crucial for connecting upstream and downstream fish populations.
The findings have implications for biodiversity and conservation efforts. Potential water diversion for purposes such as dam filling or irrigation could negatively impact the fish by interrupting their migratory route.
Migratory fish species face an elevated risk of endangerment or extinction compared to non-migratory species. Therefore, protecting the habitat across the species' entire range, including waterfalls, is considered essential for their conservation.
Further research is required to fully understand the precise reasons for this vertical migration, such as potential access to better food sources or reduced predation upstream.