A survey of the fish fauna of Transkei estuaries Part Two: The Mbashe Estuary

Abstract

The species composition, seasonal abundance and spatial distribution of the fish fauna of the Mbashe estuary (S km long) was determined by means of gill nets. During the 37 month survey period, 290S fish (2319,S kg), comprising 27 species, were caught. The family Mugilidae, representing 5S,S% of the numbers and 57,4% of the biomass, predominated the catches. In terms of biomass M. cepha/us, A. h%/epidotus and P. commersonnii were the most important species. Seasonal pattems for 10 of the 27 species were observed.M. cepha/us, A. h%/epidotus and L. amia were more abundant in spring/summer, E machnata and V.buchanani in spring, P. commersonnii and L. tricuspidens increased numerically in winter and M. capensis in autumn, Johnius dussumieri and Va/amugil cunnesius were rare in winter and summer, respectively. Largest catches were made in the middle reaches of the estuary followed by the upper and lower reaches, respectively.Die spesiesamestelling, seisoenverspreiding, en voor1<eurgebiede van visse is met behulp van kiefnette in die Mbashe-riviermonding (S km lank) bepaal. Gedurende die 37 maande van die opname is 2908 visse (2319,S kg) gevang en is 27 spesies ge"identifiseer. Die familie Mugilidae het 5S,S% van die aantal visse, wat 57,4% van die totale biomassa uitgemaak het, verteenwoordig. Die vangste is deur M. cepha/us, A. holo/epidotus, L. amia en P. commersonnii oorheers (biomassa). Tien van die 27 spesies hat seisoenspatrone vertoon, met M. cepha/us, A. h%/epidotus en L. amia volop in die lente/somer, E machnata en V. buchanani in die lente, P. commersonnii en L. tricuspidens meer algemeen gedurende die winter en M. capensis in die herts. Johnius dussumieri en V. cunnesius was baie seldsaam in die winter en die somer. Die middelste gedeelte van die riviermonding het die beste vangsresultate opgelewer.

A survey of the fish fauna of Transkei estuaries Part Four: The Mntafufu and Mzamba River estuaries

“…Physico-chemical properties of the estuaries Some aspects of the temperature characteristics recorded in the Mntafufu and Mzamba estuaries differed from those reported for estuaries in the eastern Cape (Marais & Baird 1980;Marais 1981;Marais 1983a;b) and Transkei (Plumstead et al 1985;1989a;b). With the exception of the winter surface water of the Mntafufu, the mean upper estuarine temperatures in both estuaries exceeded those in the lower reaches.…”

“…1991, 26(4) reversed salinity gradient. Although fairly rare elsewhere (Branch & Grindley 1979;Plumstead et al 1985;1989a;b), this phenomenon was the norm in Mzamba bottom waters.…”

“…Day (1981c) mentions that the majority of the fish in southern Mozambique (80%), Natal (70%) and Transkei (59%) extend northwards and are termed tropical, while Branch & Grindley (1979) found that 53% of the fish fauna in the Mngazana estuary have tropical affinities. In comparison to estuaries in the eastern Cape (Marais & Baird 1980;Marais 1981;1983a;b) and others in Transkei (Plumstead et al 1985;Plumstead et al 1989a;b) the Mntafufu estuary has a much greater species diversity.…”

“…The small clear Mntafufu and Mzamba estuaries in the present study yielded 42 and 25 species respectively. An analysis of the data from the Kei (Plumstead et al 1985), Mbashe (Plumstead et al 1989a), Mtata (Plumstead et al 1989b 36% tropical) (Branch & Grindley 1979;Plumstead 1984). Day (1981c) mentions that the majority of the fish in southern Mozambique (80%), Natal (70%) and Transkei (59%) extend northwards and are termed tropical, while Branch & Grindley (1979) found that 53% of the fish fauna in the Mngazana estuary have tropical affinities.…”

“…Gill netting in eastern Cape estuaries yielded an average of 24 fish species per system (Marais & Baird fJ 980;Marais 1981;1983a;b) whilst in the turbid Transkei estuaries 2h-27 fish species were caught (Plumstead et al 1985;1989a;b). The small clear Mntafufu and Mzamba estuaries in the present study yielded 42 and 25 species respectively.…”