The Diversity of Fish Larvae in the Bons Sinais Estuary (Mozambique) and Its Role as a Nursery to Marine Fish Resources

Abstract

The study of assemblages of fish in their early phases in estuaries is an essential approach to understanding the functioning of these types of ecosystems and their role as nursery grounds for some marine fish species. The main aim of this study was to analyze the ichthyoplankton assemblage in the Bons Sinais Estuary, specifically to clarify the use of this area by species of socio-economic interest. This study identified 22 fish larval taxa among families, genera, and species. Gobiidae (54%), a group of resident species, dominated the community. The larval taxa of socio-economic importance (Thryssa sp., Clupeidae, Sillago sihama, Johnius dussumieri, Pellona ditchela, Pomadasys kaakan, Cichlidae, and Mugilidae) accounted for 23% of the total abundance. Larval density (N°/100 m3) varied spatially and temporally, with higher density and diversity values both in the middle zone and in the wet season. Multivariate analyses revealed that salinity, temperature, and water transparency had a strong influence on larval abundance and density. While most fish larvae were in the post-flexion stage, there was a predominance of pre-flexion larvae in the lower estuary and in the post-flexion stage in the middle and upper zones, especially for marine fish resources, showing the role of this estuarine habitat as a nursery area.