Choked by Hyacinths: Lake Victoria

Hyacinth-choked lakeshore at Ndere Island, Lake Victoria, Kenya. Image from wikpeida

The report, Freshwater biodiversity in the Lake Victoria Basin (2018), assesses the global extinction risk of 651 freshwater species, including fishes, molluscs, dragonflies, crabs, shrimps and aquatic plants native to East Africa’s Lake Victoria Basin, finding that 20% of these are threatened with extinction. Of the freshwater species assessed, 204 are endemic to the Lake Victoria Basin and three-quarters (76%) of these endemics are at risk of extinction.

The African Lungfish (Protopterus aethiopicus), for example, is declining in the Lake Victoria Basin largely due to overfishing, poor fishing practices and environmental degradation as wetlands are converted to agricultural land. The lungfish is considered a delicacy for some local communities and is an important local medicinal product, used to boost the immune system and treat alcoholism. The lungfish is also traded at market, making it important to the local economy.

Lake Victoria is the world’s second largest freshwater lake by surface area. Its catchment area includes parts of Kenya, Tanzania, Uganda, Burundi and Rwanda. Also referred to as ‘Darwin’s Dreampond’, Lake Victoria is known for its high levels of unique biodiversity. The Lake Victoria Basin harbours immense natural resources including fisheries, forests, wetlands and rangelands….

Pollution from industrial and agricultural sources, over-harvesting of resources and land clearance are among the primary threats to biodiversity in this region. Invasive species also present an important threat to native biodiversity in the basin, affecting 31% of all species and 73% of threatened species. The purple flowered Water Hyacinth (Eichhornia crassipes) was accidentally introduced to Lake Victoria from South America in the 1980s, and at its peak covered close to 10% of the lake surface in dense floating mats. These mats reduce the oxygen and nutrient availability in the water column, which negatively affects native biodiversity. Opportunities for harvesting and exploiting the Water Hyacinth, for example by using the species as fuel in bio-digesters for energy production, are under investigation.

Excerpts from Livelihoods at risk as freshwater species in Africa’s largest lake face extinction – IUCN Report, IUCN Report, Apr. 30, 2018

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