The Olifants River harder fishery

The Olifants River harder fishery (Lisa richardsoni)

  The fishery:  The Olifants River harder fishery is a subsistence fishery. Fishing is carried out with gillnets. The harders provide a source of protein for the Ebenezer community living along the banks of the Olifants River (about 500 km north of Cape Town), and, sold locally as a salted dried product, a source of income.

  Management issues and OLRAC's involvement:  OLRAC provides scientific input for resource management as a free community service. The initial impetus for OLRAC's involvement was a severe downturn in catch rates in 1991. There is a strong perception in the community that this was caused by the presence of seals in the river mouth, physical obstructions in the river mouth, and the harbouring of marine diamond mining vessels near to the mouth. Initial scientific input by other parties has suggested that these factors are not important, but that the reduction in catch was caused by an increase in fishing effort.

  OLRAC, in collaboration with a team of social scientists, put together a research proposal to identify factors impacting on the fishery. OLRAC's input has dealt mainly with the importance of gillnet mesh size regulations. As a result of this work, a catch monitoring system for the fishery has been put in place, and a series of mesh size experiments aimed at determining the relationship between catch rate, catch size structure and gillnet mesh size have been carried out. The mesh size experiments have shown that catch rate is exceptionally sensitive to gillnet mesh size. Because of this, there has been a more careful assessment of the impact of past changes in mesh size regulations on fishing performance. The initial problem with poor catch rates in 1991 is now thought to have been caused by an increase in the regulated mesh size from 51 mm to 54 mm. OLRAC immediately recommended a return to the 51 mm mesh size. For the moment it seems that this measure has enhanced catch rates to levels acceptable to the community.

  OLRAC is providing ongoing support to determine whether the enhanced catch rates experienced by the community are sustainable, and to enhance the community's ability to manage the resource on a co-management basis with the responsible government department.