WW March - ESTUARIES

Abstract

ESTUARIES Cover story St Lucia at an ecological tipping point? When this will occur, we do not know – it depends on estuarine channel connectivity, episodic river floods, sea-level rise, and the rate at which sediments accumulate in the existing St Lucia Estuary, Narrows, South Lake, North Lake and False Bay. But there are already strong indications that the system is on the cusp of switching from an estuarine lake system to a predominantly freshwater coastal lake and swamp system, with only a very small estuary component – comprising the existing Narrows, St Lucia Estuary and a small portion of the lower uMfolozi River that receives some saline inputs when the joint mouth is open to the sea. This article describes how this once thriving estuary, which should act as a crucial nursery for marine fish stocks along a large proportion of the South African coastline, is rapidly losing its estuarine functionality.

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