Reseeding of mussels on denuded rocky shores: preliminary studies with the brown mussel Perna perna

Abstract

A method is developed to establish clumps of mussels Perna perna in denuded areas on high-energy rocky shores on the south-east coast of South Africa. A total of 20 small (20–30 mm total length) mussels is placed under a 30 cm half-section of perforated PVC drainage pipe bolted to the rock surface. The pipe is left in position for one month before removal to allow the mussels to attach firmly to the substratum. A pilot study in a marine reserve indicated 76% survival of clumps and individuals over a period of a year. Mussels grew at a mean annual rate of 30.1 mm from an initial size of 31.8 mm. A subsequent study of survivorship and growth of three size-classes: 25–35, 50–60 and >70 mm, showed that greatest survivorship and growth were exhibited by the smallest size-class. Apart from the initial drilling of holes, the procedure is simple and inexpensive. Mussels could be harvested after about 12 months and the holes and PVC pipe re-used for repeats of the procedure. The method may be used as a research tool and as a way of rehabilitating areas denuded by other natural or anthropogenic agencies.

Keywords:

• GROWTH
• MARICULTURE
• MUSSELS
• RESEEDING