Comparative ecology and physiology of four South African mussel species with notes on culture potential
type: CreativeWork
description: The objective of this study was to compare the distribution patterns, reproductive cycles, growth rates and physiological processes in four species of South African marine mussels - Aulacomya ater, Choromytilus meridionalis, Mytilus galloprovincialis and Perna perna. The first chapter is a preliminary account of the introduction of the invasive M. galloprovincialis, and its ecological effects. Its rate of invasion is estimated by monitoring changes in the diet of oystercatchers, as well as comparing its resistance to silt and dessication, and its reproductive and its growth strategies with those of other intertidal mussel species. It appears that although presently mainly confined to cool water of the west and south coasts, M. galloprovincialis will soon colonize in the near future the warmer waters of the east coasts. The second chapter consists of a survey revealing the distribution patterns and standing stock of the four species around the South African coasts. The cool upwelled waters of the west coast support the major populations of A. ater, C. meridionalis and M. galloprovincialis, while the warm east coast is mainly colonized by the brown mussel P. perna. The Transkei and Natal coasts are intensively exploited by subsistence gatherers with an annual rate of removal approaching or even exceeding standing stock. The overall wild crop is ca > 1000 metric tons, while aquaculture output is estimated at 800 tons per annum. The third chapter looks at the timing and the intensity of spawning of the four species. Gamete build up and release results in marked variation in flesh yield. The dry flesh weight of M. galloprovincialis can vary three-fold between ripe and spawned conditions at a length of 65mm. Equivalent figures for C. meridionalis, A. ater and P. perna are respectively 2.8, 2.3 and 2.2-fold. It appears that A. ater shows the greatest gamete output with three annual spawnings, followed by M. galloprovincialis and C. meridionalis with two protracted spawning…
abstract: The objective of this study was to compare the distribution patterns, reproductive cycles, growth rates and physiological processes in four species of South African marine mussels - Aulacomya ater, Choromytilus meridionalis, Mytilus galloprovincialis and Perna perna. The first chapter is a preliminary account of the introduction of the invasive M. galloprovincialis, and its ecological effects. Its rate of invasion is estimated by monitoring changes in the diet of oystercatchers, as well as comparing its resistance to silt and dessication, and its reproductive and its growth strategies with those of other intertidal mussel species. It appears that although presently mainly confined to cool water of the west and south coasts, M. galloprovincialis will soon colonize in the near future the warmer waters of the east coasts. The second chapter consists of a survey revealing the distribution patterns and standing stock of the four species around the South African coasts. The cool upwelled waters of the west coast support the major populations of A. ater, C. meridionalis and M. galloprovincialis, while the warm east coast is mainly colonized by the brown mussel P. perna. The Transkei and Natal coasts are intensively exploited by subsistence gatherers with an annual rate of removal approaching or even exceeding standing stock. The overall wild crop is ca > 1000 metric tons, while aquaculture output is estimated at 800 tons per annum. The third chapter looks at the timing and the intensity of spawning of the four species. Gamete build up and release results in marked variation in flesh yield. The dry flesh weight of M. galloprovincialis can vary three-fold between ripe and spawned conditions at a length of 65mm. Equivalent figures for C. meridionalis, A. ater and P. perna are respectively 2.8, 2.3 and 2.2-fold. It appears that A. ater shows the greatest gamete output with three annual spawnings, followed by M. galloprovincialis and C. meridionalis with two protracted spawning…
author: Van Erkom Schurink, Corine
language: eng
date published: 1991
date modified: 2026-07-22T22:22:58Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Department of Biological Sciences

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/14250