Effects of feeding condition on the morphology, behaviour and nutritional status of

Abstract

Early life stages of migratory fish in rivers rely on physical transport mechanisms to carry them from spawning sites to distant nursery areas where they find food and refuge conditions. Starvation after a prolonged downriver drift could severely affect the colonisation and predator evasion capabilities of the larvae. In this study we investigated differences in the external morphology, nutritional condition and swimming abilities of fed and unfed Prochilodus lineatus early larvae under experimental conditions. After yolk reabsorption on Day 6, larvae were either fed with nauplii of Artemia salina or left unfed for up to 10 days. Larvae from each feeding regime (i.e. fed and unfed) were sampled daily from three aquaria, and the morphometry and routine swimming activity were determined and analysed together with a previously published RNA/DNA ratio dataset. The results were in agreement with previous investigations that indicated that the larvae of this species have starvation endurance; however, prolonged food deprivation is associated with a smaller body, anal depth and head length, as well as lower RNA/DNA ratios and reduced swimming ability.