School of Life Sciences

The need to break urban surfaces to restore fish migration

The need to break urban surfaces to restore fish migration

World Fish Migration Day that highlights the plight of migratory species across the globe, was marked globally on 25 May 2024.  The Palmiet River Valley Conservancy and the Palmiet River Watch co-hosted a World Fish Migration Day event with UKZN and the Institute of Natural Resources on the Palmiet River in Pinetown, KwaZulu-Natal. The river is home to several important migratory species, most notably the KwaZulu-Natal yellowfish commonly known as “scallies” and the globally important African freshwater eels.

Since 2018, Mr Lee D’Eathe of the Palmiet River Valley Conservancy and Dr Matthew Burnett of UKZN’s School of Life Sciences have led research on the presence, abundance and communities of fish and freshwater eels. A WhatsApp group with 50 members, functions as a communications, chat, and security backbone over the entire length of the Palmiet River, reporting on water pollution and habitat degradation that impact the river’s ecological health.

There are four African freshwater eels in South Africa, all of which occur in KwaZulu-Natal. Freshwater eels are known to be catadromous migrators that have five morphological phases throughout their life cycle of 20 to 40 years. They spawn in the western Indian Ocean around the Mascarene Trench and their larvae drift with ocean currents to the African continent, where they morph into glass eels and enter the rivers through estuaries. Once in the river, they morph again into elvers to migrate up the river, morphing into yellow eels that can grow to a length of more than a metre. They live their final phase as silver eels and move down rivers into the ocean, returning to the Mascarene Trench where they spawn and die.

Words: Matthew Burnett