The dynamics of Larval fish and Zooplankton assemblages in the Sundays Estuary, South Africa

Sutherland, Kate

Title: The dynamics of Larval fish and Zooplankton assemblages in the Sundays Estuary, South Africa
Creator: Sutherland, Kate
Subject: Marine zooplankton -- South Africa
Subject: Zooplankton -- South Africa
Subject: Fishes -- Larvae -- South Africa
Subject: Estuarine ecology -- South Africa
Subject: Estuaries -- South Africa -- Management
Subject: Environmental monitoring -- South Africa
Subject: Coastal zone management -- South Africa
Subject: Estuarine area conservation -- South Africa
Date Issued: 2010
Date: 2010
Type: Thesis
Type: Masters
Type: MSc
Identifier: vital:10697
Identifier: http://hdl.handle.net/10948/1119
Identifier: Marine zooplankton -- South Africa
Identifier: Zooplankton -- South Africa
Identifier: Fishes -- Larvae -- South Africa
Identifier: Estuarine ecology -- South Africa
Identifier: Estuaries -- South Africa -- Management
Identifier: Environmental monitoring -- South Africa
Identifier: Coastal zone management -- South Africa
Identifier: Estuarine area conservation -- South Africa
Description: The larval fish and zooplankton assemblages were studied in the permanently open Sundays Estuary on the south-east coast of South Africa, using standard boat-based plankton towing methods. A total of 8174 larval and early juvenile fishes were caught, representing 12 families and 23 taxa. The Clupeidae, Gobiidae and Blenniidae were the dominant fish families. Common species included Gilchristella aestuaria, Caffrogobius gilchristi, Omobranchus woodi, Liza dumerilii, Glossogobius callidus and Myxus capensis. Estuarine resident species (Category I) predominantly in the preflexion developmental stage, dominated the system. A total of 19 zooplankton taxa were recorded. Copepoda dominated the zooplankton community. Dominant species included Pseudodiaptomus hessei, Acartia longipatella, Halicyclops sp., Mesopodopsis wooldridgei, and the larvae of Paratylodiplax edwardsii and Hymenosoma orbiculare. Mean larval fish density showed similar trends seasonally, spatially and across salinity zones, with mean zooplankton density in the Sundays Estuary. Gut content analysis of five larval fish species: Gilchristella aestuaria, Pomadasys commersonnii, Monodactylus falciformis, Myxus capensis and Rhabdosargus holubi, revealed species specific diet and prey selection. Although larval fish diet contained a variety of prey items, guts were dominated by P. hessei, chironomid larvae, Corophium triaenonyx, copepod eggs and insect larvae. Physico-chemical drivers and the interactions between these two plankton communities provide information that enables a more holistic view of the dynamics occurring in the Sundays Estuary planktonic ecosystem.
Format: xi, 131 leaves ; 30 cm
Format: pdf
Publisher: Nelson Mandela Metropolitan University
Publisher: Faculty of Science
Language: English
Rights: Nelson Mandela Metropolitan University

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