Population dynamics and growth rates of the brown mussel (Perna perna) on wave exposed and wave sheltered shores of South Africa

Lindsay, Tracy Lynn

Title: Population dynamics and growth rates of the brown mussel (Perna perna) on wave exposed and wave sheltered shores of South Africa
Creator: Lindsay, Tracy Lynn
Subject: Perna -- South Africa
Subject: Mussels -- South Africa
Date Issued: 1999
Date: 1999
Type: Thesis
Type: Masters
Type: MSc
Identifier: vital:5741
Identifier: http://hdl.handle.net/10962/d1005427
Identifier: Perna -- South Africa
Identifier: Mussels -- South Africa
Description: Population dynamics of Perna perna in low shore mussel beds were investigated over a 15 month period at six sites along the south coast of South Africa, with particular reference to the effects of wave exposure. The degree of exposure was first quantitatively ascertained using the dissolution of cement blocks to measure average wave force and dynamometers to measure maximum wave force. The mean mass loss of the cement blocks was higher at Diaz Cross and Kwaai Hoek than at Mgwalana, Rufanes and Riet River. No data were available for Fish River. The mean maximum wave force encountered at Diaz Cross, Kwaai Hoek and Fish River was significantly higher (p15 mm) were positively correlated with recruit densities (1-5 mm) for both shore types (p15 mm) was significantly lower on exposed (mean of 3 348.m⁻²) than on sheltered shores (mean of 4 796.m⁻²) (pO.05). The effect of exposure on growth rate formed the focal point of this study and was determined using three different approaches. The first technique, mark-recapture, involved filing notches on the growing edges of mussels in the field. After 111 days, mussels were removed and the growth measured. The second approach used internal growth bands to measure growth rates, once the periodicity with which these bands were laid down was established. Thirdly, using Shepherd's length composition analysis (SLCA), growth rates were determined from length frequency distributions in 11 samples taken over 15 months. The general conclusion from all three approaches was that growth rate was twice as fast on the exposed shores as on the sheltered shores (p
Format: 195 p.
Format: pdf
Publisher: Rhodes University
Publisher: Faculty of Science, Zoology and Entomology
Language: English
Rights: Lindsay, Tracy Lynn

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