After 50 years of absence, weatherfish once again swims in the Scheldt river floodplain
On 6 October 2023, 520 young weatherfish (Misgurnus fossilis L.) were released in the artificially controlled flooding area of Kruibeke-Bazel-Rupelmonde (KBR). At over 600 ha, this area is the flagship of the Sigmaplan, a plan where flood protection goes hand in hand with wetland restoration.
As a typical fish of flood plains, the weatherfish is one of the symbol species for the restoration of wetlands in Flanders. Before the 1950s, the fish was present with certainty in the many connecting canals to the Scheldt. Its typical former use as a living barometer is still known to some locals. After 1980, the species was no longer seen in the wider area. However, the fish has a hidden existence: it lives on and in the bottom and is mostly active at night. It was therefore not inconceivable that a relict population remained here and there in the Scheldt Valley. Through eDNA analysis, INBO managed to trace the species in an old Scheldt meander (Berlare broek) in 2019 .
However, genetic analyses of known relict populations show that the species is genetically very impoverished due to inbreeding. With the release of genetically healthy animals in KBR, we hope to eventually build a new stronghold. From there, the species can then spread to other controlled flooding areas along the Scheldt river.
The released weatherfish were bred at the INBO's Aquatic Fauna Research Centre in Linkebeek.
This stocking constituted a milestone in the species protection plan for the weatherfish and was made possible with the financial support of Life+Scalluvia (set-up of KBR) and Life B4B (breeding of weatherfish).
Jeroen Van Wichelen, Johan Auwerx, Bruno Picavet and Jozef Couck
Image above: weatherfish (photo INBO)