Vertical Migration of Gold-spot Herring (Herklotsichthys quadrimaculatus) Larvae on Sofala Bank, Mozambique

Abstract

Vertical larval fish movement influences their survival and dispersal, hence recruitment variability. This study presents the vertical behaviour of gold-spot herring (Herklotsichthys quadrimaculatus) larvae observed on the Sofala Bank (Mozambique) throughout a 48-hour period when depth-stratified samples were taken every 2 h, together with CTD profiles, at a fixed station. Their ontogenetic variation was also investigated. Larval catches were greater at dusk and night, probably due to net avoidance during dawn and day periods. Generally, larvae were concentrated in the first 20 m of the water column, though larger larvae were most abundant in the neuston at dusk and night, and smaller larvae frequented the deeper strata up to 20 m. The results are discussed in terms of vertical migration, ontogenic changes, and net avoidance.

Keywords: fish larvae, diel vertical migration, ontogeny, net avoidance.