Effects of light spectrum and tank background colour on Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) larvae performances

Abstract

Light is a key environmental cue involved in the entrainment and regulation of fish development and physiology. Species specific spectral differences in sensitivity are believed to be an adaptation to the species' ecological niche and therefore fish larvae are predisposed to perform better under specific light environments. This study investigated the effects of light spectrum including blue (455nm), green (530nm), red (640nm) and white on larvae performances of two temperate marine species, Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus). In both species, larvae exposed to shorter wavelengths (blue and green spectrums) showed significantly enhanced growth in comparison to larvae exposed to longer wavelengths (red). However, green spectrum appeared to reduce survival rates for both species. Larvae performances in the colour background experiment differed between species with cod larvae survival enhanced when exposed to a blue background but growth performances reduced. No significant impacts of background colour were seen in turbot. The results of the present study highlight the importance of considering light environment in marine larvae rearing protocols to enhance larval performance and survival.