Are trunk lateral line anomalies and disoriented scale patterns in European seabass (Dicentrarchus labrax) influenced by genetics?

Abstract

Different kinds of defects are observed on farmed fish, and while a lot of research has concentrated on skeletal abnormalities, little is known on scale anomalies. We carried out a survey for lateral line shape anomalies and disorientated scale patterns on a batch composed of crosses of 5 different wild populations of European seabass, in order to find out whether there is a genetic basis to these anomalies. Lateral line shape was standardized coupling geometric morphometrics with advanced warping procedures based on thin-plate splines. Genetic variation between and within populations was found for lateral line shape, which was also affected by vertebral anomalies to a certain extent. Conversely, no significant genetic variation was found for scale disorientation, either between or within populations. We conclude that the shape of lateral line is probably not a decisive factor to externally evaluate spine anomalies; further, its variation is more likely linked to a general variation of fish shape than to impaired early development, while the cause of scale disorientations is more environmental than genetic.