Review of fish life history strategies associated with warm temperate South African estuaries and a call for effective integrated management

Abstract

Refuge and feeding areas for young fish in estuaries are important for the survival of fish and replenishment of coastal fish stocks, particularly in the temperate south east coast of southern Africa. Larvae and juveniles of important fishery species recruit from the ocean into estuaries, but research has shown that estuaries are one component of broader nursery use patterns. Early stage fish recruit into many shallow water habitats, utilising various niche types, extending into low salinity waters, including rivers, where abundant larval insect prey have been identified in their diet. However, marine and estuarine fishes that use this nursery mosaic are impacted on by various threats transcending traditional habitat boundaries. These include reductions in freshwater supply, pollution, barriers to migration, introduction of invasive species, overharvesting and climate change. Compounding this is the lack of law enforcement, a lack of implementation of effective management covering nursery habitat mosaics and a lack of public understanding of the plight of coastal fish. This review details the life history of estuarine fish and the threats that they face, and how management of these threats, can continue to improve into the Anthropocene, to rebuild coastal fish stocks.

Keywords: early life history stages, Eastern Cape, fish larvae, habitats, juvenile fish, legislation, nursery