Declining catch per unit effort of an estuarine-dependent fish, Rhabdosargus sarba (Teleostei: Sparidae), in the marine environment following closure of the St Lucia Estuarine System, South Africa

Abstract

Monitoring of catch per unit effort of the tropical stumpnose Rhabdosargus sarba in the St Lucia Marine Reserve between 2001 and 2005 revealed a significant decline. A similar decline was evident from shore patrol data collected by Ezemvelo KwaZulu-Natal Wildlife staff in the southern areas of the Greater St Lucia Wetland Park. As the distribution of fishing effort has decreased considerably since the promulgation of a beach vehicle ban in January 2002, this decline in the abundance of stumpnose has not been attributed to overfishing but rather to the closure of the mouth of the St Lucia estuary and lake system. The reason for this is because tropical stumpnose make extensive use of St Lucia as a nursery area and, since the mouth closure in June 2002, there has been no recruitment of juvenile fish into, or adult fish out of, the system. This emphasises the importance of estuarine nursery areas and highlights the need for ongoing catch and effort monitoring.

Keywords:

• CATCH MONITORING
• ESTUARINE DEPENDENCE
• MARINE-PROTECTED AREA
• ST LUCIA ESTUARINE SYSTEM