Mussels

White mussels (Donax serra) occur between northern Namibia and the Wild Coast. They are present in high numbers on the sandy beaches of the west and south coasts of South Africa. The zonal distribution of the mussel changes with the tidal cycle. On the west coast, juveniles are found high up on the beach, whereas adults are distributed around and below the mean spring low tide mark. On the east and south coasts, adults are found in the mid-tide region.

White mussels are dominant burrowers on sandy beaches, favouring temperate shores. They are bivalve molluscs that filter-feed and grow to a shell length of 60 millimetres in about five years. The mussels migrate up and down the beach in response to tidal cycles, with juveniles migrating more frequently than the adults.

Commercial exploitation is limited to the west coast where white mussels are particularly abundant owing to the nutrient rich Benguela Current that washes these shores.

Commercial harvesting of white mussels is limited to seven areas along the west coast. The fishery started in the late 1960's but in 1966 it was negatively affected by a red tide that caused massive mortalities of white mussels. The recovery of the population took more than 10 years and led to a dramatic reduction in catch per unit effort ("CPUE"). The total number of white mussels harvested per year has declined steadily since the 1980's. This has largely been as a result of the fishery's lack of economic viability. Surveys conducted in 1988 and 1989 showed that the annual landings amounted to less than one percent of the standing biomass in the relevant areas. Preliminary results from surveys undertaken in 2003 and 2004 support these findings. The resource is therefore considered to be under-exploited.

Currently, commercial right-holders are permitted to collect 2 000 white mussels per month. White mussels are harvested as bait and not for human consumption. A market for human consumption needs to be investigated.

The white mussel fishery is catch- and effort-controlled. A Total Applied Effort ("TAE") of seven right-holders, with bag limits of 2 000 per month and a minimum legal size of 35 millimetres, is enforced. The right-holders either own retail outlets or sell their catch to retail outlets where white mussels realise a price of between R1.00 and R1.50 each.