Age and growth of the estuarine-dependent sparid Acanthopagrus berda in northern KwaZulu-Natal, South Africa

INTRODUCTION The riverbream or perch, Acanthopagrus berda (family Sparidae), is widespread in the tropical Indo-Pacific region, occurring from South Africa to India, northern Australia and Japan (Smith & Heemstra 1986; Garratt 1993). In South Africa it is found along the east coast, where its range extends southwards to Port Elizabeth (33°58’S, 25°36’E). It is one of 22 species of fishes found in South Africa that are dependent on estuaries in the juvenile phase of their life cycles (Wallace et al. 1984). Adult A. berda are also estuarine dependent, rarely being found in the marine environment. Like many other members of the sparid family, A. berda changes sex and is one of several known protandrous sparids in South Africa (Garratt 1993). A. berda is a fairly small sparid, and although the maximum length recorded for the species is 750 mm TL, the majority caught in South African waters are <400 mm TL (Smith & Heemstra 1986). Length at 50% maturity has been established at 220 mm TL (Wallace 1975). In South African estuaries, A. berda is harvested by a variety of methods, which include hook and line, gill nets and traditional fish traps. It is a particularly important component of the recreational and subsistence catch taken in the three large northern KwaZulu-Natal estuaries, namely Kosi Bay (26°54’S, 32°53’E), St Lucia (28°23’S, 32°25’E) and Richards Bay (28°48’S, 32°05’E) (James 2001, James et al. 2001; Mann et al. 2002). The reproductive and feeding biology of A. berda have been studied in South Africa (Wallace 1975; Wallace & van der Elst 1975; Harrison 1991; Garratt 1993). Though age and growth of A. berda has been studied in Kuwait (Samuel & Mathews 1987) no work has been published on age and growth of the species in South Africa. The aim of this study was to investigate the age and growth of A. berda in northern KwaZulu-Natal estuaries to provide a basis for assessing the sustainability of this fishery.