Freshwater fish face extinction

Freshwater fish are an 'aquatic version of the canary in the coalmine' for Africa's rivers, lakes and wetlands, a report notes

- Sheree Bega

From the tiny galaxiids of South Africa to the 2m-long Nile perch, Africa's extraordinary biodiversity of freshwater fish have evolved to thrive in the various habitats in the geographically, climatically and topographically diverse continent.

They are found in sediment-rich rivers, shallow ponds, the great lakes, caves, canyons, mountain streams and forests. Yet they are often overlooked in global conservation conversations.

This is according to a new report on Africa's forgotten fish, which WWF Africa released in the lead-up to the Ramsar COP15 — a United Nations wetlands conference which gets under way in Zimbabwe from 23 July.

The report reveals that 26% of Africa's assessed freshwater fish species are threatened with extinction, but there are data gaps so the true number is likely to be much higher.

Africa is home to more than 3 200 species — more than a quarter of the world's total freshwater fish.

It's also a "hotspot of risk", said Eric Oyare, the freshwater lead for WWF Africa. "When these fish disappear, we lose much more than species: we lose food security, livelihoods, ecosystem balance and resilience to floods and droughts. These declines are a red flag for the broader health of Africa's freshwater ecosystems, which are the very life support systems for people and nature."

These lifelines are collapsing under the weight of multiple threats, including habitat destruction from dams, deforestation, mining and land conversion; pollution from agriculture, urban areas and industry; invasive species and overfishing, including with destructive gear like mosquito nets; and climate change, which alters rainfall patterns, dries out rivers and heats lakes.

Freshwater fish populations are in freefall across the continent. In the Zambezi floodplain, catches of key species have dropped by up to 90%. At the same time, Lake Malawi's “chambo” tilapia, a staple food, has declined by 94%.