Preliminary examination of hatching season and growth of Engraulicypris sardella (Pisces: Cyprinidae) larvae and juveniles in Lake Malawi

Abstract

The hatching period and the growth of Malawian cyprinid Engraulicypris sardella larvae and juveniles collected from two sites along the southwestern shoreline of Lake Malawi were investigated using otolith increment information. The lapillus was used to determine the age in days following previous studies. The hatching months of fish estimated on the basis of lapillus increment counts were from November to July (nine months of a year), demonstrating that this species had an extended spawning season. Based on the age analysis, the fish were separated into two hatching groups: fish that hatched in the rainy season and those that hatched in the dry season. The growth rate of the former (0.70 mm TL per day) was significantly higher than the latter (0.52 mm TL per day). This growth difference was considered to be due to water temperature in the lake.

Keywords: Engraulicypris sardella larvae and juveniles, lapillus increments, growth, spawning season, Lake Malawi