Granting our fish the right of way

Abstract

Granting Fish the Right of Way Collaborative efforts to determine the correct design of fishways for uniquely South African conditions are bearing fruit. Lani Holtzhausen reports. Mangrove snapper, silver robber, bluespot mullet, thornfish, spotted grunter, longfin eel, mountain catfish, Lowveld suckermouth. These are but a few on a long list of fish species whose free movement has been impeded by man-made structures such as weirs, dams, levees and embankments. In fact, impassable fabricated barriers to migration have been cited as one of the main reasons, along with pollution and the introduction of alien species, for the threatened status of a number of red data species in southern Africa. The harmful effect of barriers to migration is particularly severe on coastal rivers where a number of socalled catadromous species need to migrate from their marine or estuarine spawning grounds into freshwater reaches of rivers for feeding purposes. As these fish migrate upstream as small juveniles even low barriers of less than a metre can be impassable.

Authors

Categories