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Growth and nutritional condition of anchovy larvae on the west and southeast coasts of South Africa

David Costalago*, Yanasivan Kisten, Catriona Clemmesen, Nadine A. Strydom

*Corresponding author:

ABSTRACT: Cape anchovy is an ecologically and economically important pelagic fish species occurring along the coast of South Africa. A recent eastward shift in Cape anchovy distribution indicates that environmental conditions are becoming more favorable for the species on the east coast. This is particularly important for the sheltered Algoa Bay region, a potential nursery area for fish larvae. However, the relatively low productivity of the Aghulas Current Large Marine Ecosystem on the eastern coast of South Africa may lead to an anchovy population with poorer nutritional condition and slower growth rates compared to the west coast nursery. Using otolith and nucleic acid analyses, the growth rates of anchovy larvae were compared between individuals on the western and the southeastern coasts of South Africa. The otolith analysis results indicated that at any given age, individual growth rates for anchovy larvae were higher on the southeast coast compared to west coast. The RNA:DNA values also indicated that there were higher instantaneous growth rates of anchovy larvae in Algoa Bay compared to samples from the west coast. At the time of sampling, chlorophyll and zooplankton productivity was higher at sampling sites in Algoa Bay than the west coast, potentially due to favorable oceanographic features in the bay. As such, the results suggest that Algoa Bay is a suitable and potentially favorable nursery area for the early stages of anchovy, highlighting the importance of the separate management in the southeast coast region in a changing world.