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Distribution of Nile perch Lates niloticus in southern Lake Victoria is determined by depth and dissolved oxygen concentrations
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: PC Goudswaard --- , the Netherlands EFB Katunzi --- , Tanzania JH Wanink --- , the Netherlands F Witte --- , the NetherlandsAlthough Nile perch Lates niloticus is assumed to be sensitive to low oxygen concentrations, it was found in deep water in Lake Victoria, where oxygen depletion is common during the rainy season. Since factors determining Nile perch distribution are not... -
Dissolved Oxygen Characteristics of the Gamtoos Estuary, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: M. W. Pearce E. H. SchumannThe fall and recovery of dissolved oxygen (DO) is documented throughout the Gamtoos Estuary, South Africa during dry conditions and following light and heavy rainfall over a 13-month period from November 1992 to November 1993. Hypoxic conditions generally occurred in... -
Maintenance mechanisms of plankton populations in frontal zones in the Benguela and Angola Current systems: a preface
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: HM Verheye W EkauThis preface provides the background to, and synthesis of research findings from, a set of environmental research-driven cruises off southern Angola, Namibia and South Africa during February–March 2002, under the auspices the BENguela Environment Fisheries Interaction and Training (BENEFIT) Programme... -
Influence of oceanographic fronts and low oxygen on the distribution of ichthyoplankton in the Benguela and southern Angola currents
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: W Ekau HM VerheyeThe study focuses on ichthyoplankton populations in the southern Angola Current, the Angola-Benguela Front and the coastal upwelling area of the northern and central Benguela Current. The horizontal and vertical distributions of eggs and larvae of sardine Sardinops sagax, anchovy... -
Cross-shelf biogeochemical characteristics of sediments in the central Benguela and their relationship to overlying water column hypoxia
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AK van der Plas PMS Monteiro A PascallData from two cross-shelf sediment sampling cruises were used to explain reasons for the sediment biogeochemical variability in respect of carbon, nitrogen and sulphur, and how the cycling of these elements governs the biogeochemistry of the overlying water through their... -
Seasonal and sub-seasonal oxygen and nutrient fluctuations in an embayment of an eastern boundary upwelling system: St Helena Bay
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GC Pitcher --- Fisheries Management Branch, Department of Agriculture, Forestry and Fisheries, South Africa TA Probyn --- Fisheries Management Branch, Department of Agriculture, Forestry and Fisheries, South AfricaSeasonal, sub-seasonal and spatial fluctuations in bottom dissolved oxygen (DO) were examined in St Helena Bay, South Africa’s largest and most productive embayment, between November 2013 and November 2014. Alongshore bay characteristics were assessed through comparison of variables along the... -
Triggers of phytoplankton bloom dynamics in permanently eutrophic waters of a South African estuary
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: DA Lemley --- Botany Department and the Institute for Coastal and Marine Research, South Africa JB Adams --- Botany Department and the Institute for Coastal and Marine Research, South Africa NA Strydom --- Zoology Department, South AfricaThe permanently eutrophic Sundays Estuary experiences recurrent harmful algal blooms (HABs) of Heterosigma akashiwo (Raphidophyceae). This study aimed to identify the environmental variables shaping phytoplankton community composition and succession patterns during a typical spring/summer harmful algal bloom (HAB) period. Monitoring... -
Physico-chemical and microalgal gradients change rapidly in response to mouth closure in a predominantly open estuary
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: DA Lemley --- Botany Department and the Institute for Coastal and Marine Research, South Africa JB Adams --- Botany Department and the Institute for Coastal and Marine Research, South AfricaA third of South Africa’s freshwater flow no longer reaches the coast, yet few systems have shifted from being permanently open to temporarily closed. For the first time since 1969, the Gamtoos Estuary mouth closed in June 2018, because of...