The effects of a single freshwater release into the Kromme estuary Part 4: Larval fish response

Abstract

In total 17 families comprising more than 29 species of larval teleost fishes were recorded in the Kromme Estuary during the study period. Dominant species included Atherina breviceps, Caffrogobius gilchristi, Diplodus sargus capensis, Gilchristella aestuaria, Glossogobius callidus, Rhabdosargus holubi and Rhabdosargus globiceps. The larval fish catch in the estuary indicated a marine dominance with a relatively high species diversity. The introduction of a regulated freshwater pulse of 2 x 106 m3 into the estuary from the Mpofu Dam was monitored. Pre-and post-release collections of fish larvae were made on a weekly basis for a two-month period between October and December 1998. The regulated freshwater release into the estuary resulted in no significant changes to the fish family composition, species diversity or estuarine association of the larval fish assemblage. No significant increase in total larval fish abundance or recruitment response by estuarine-dependent species was recorded.

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