Lateral line deformities in wild and farmed sea bass (Dicentrarchus labrax , L.) and sea bream (Sparus aurata , L.)

Abstract

Summary The lateral line of aquaculture fishes has rarely been studied although it is a very important anatomical organ that could serve as an inexpensive and easy tool to distinguish farmed from wild individuals. In the present study, lateral line deformities were examined in both wild and farmed sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) specimens to try to detail all possible differences between them. In order to do so, the morphology of the trunk lateral line in wild and farmed adults was examined whereby two major deformities were observed in both species: the ‘scale pocket’ deformity (14–40% incidence in all groups) where the specialized scales are missing but the canal underneath is present and the scale print is obvious, and the ‘somatic scales’ deformity (14–56% incidence in farmed individuals only) where the missing lateral line is covered with normal somatic scales. Histological examination confirmed the macroscopic observations in that the lateral line mechanism was present – although damaged – beneath the scale pocket deformity and completely absent beneath the somatic scales deformity. It is argued that the scale pocket deformity is a result of an accident during the life of the fish whereas the somatic scales deformity is an actual deformity in development.

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

“…On the other hand, it could also be that affected fish have slower growth rates, as the observed scale anomalies are the most evident effect of some hidden impaired developmental process. Carrillo et al (2001), by Sfakianakis et al (2013) in farmed seabream and seabass, we never observed missing sectors of the trunk lateral line, associated by Carrillo et al (2001) to the loss of canalized neuromasts, neither additional canal systems observed by Ellis et al (1997) in few wild and most of reared turbots, probably associated with larger number of canalized neuromasts. Then, we can hypothesize that the anomalies in the lateral line shape we detected in seabass could not be associated to variation in the number of canalized neuromasts.…”

“…Further studies at histo-molecular level may greatly help in elucidating which between the alteration of molecular mechanisms controlling the primordium migration (i.e., chemokine Sdf1a and its receptors Cxcr4b and Cxcr7b) and the interaction with underlying muscles (an anomalous growth of muscle could alter the position of the horizontal myoseptum in which the primordium migration occurs) could be the cause of the anomalous shape of lateral line we detected in seabass. We observed alterations in the shape of the lateral line, but not anomalies such as interruptions and branching as described by Carrillo et al (2001) in farmed seabream and by Sfakianakis et al (2013) in farmed seabream and seabass. Andrades et al (1996) had suggested that the shape of the lateral line could be an interesting indicator of spine anomalies (especially lordosis).…”

“…The presence of lateral line anomalies has been observed in farmed and not in wild gilthead seabream Sparus aurata (Carrillo et al, 2001;Sfakianakis et al, 2013) and European seabass Dicentrarchus labrax (Sfakianakis et al, 2013). Anomalies of the lateral line are in some cases linked to vertebral anomalies, although only a few authors have studied them in any detail (Andrades et al, 1996;Carrillo et al, 2001;Jawad et al, 2006).…”

“…Despite the quite large number of studies dealing with skeletal anomalies in farmed fish, lateral line abnormalities (Jawad et al, 2006;Sfakianakis et al, 2013) and disorientated scale patterns (Corrales et al, 2000) have received little scientific attention, seemingly because they do not lower the commercial value of the fish as much as skeletal anomalies do.…”

First records of scale deformities in seven freshwater fish species (Actinopterygii: Percidae and Cyprinidae) collected from three ponds in the Czech Republic

“…Irregular scale shape was a dominant feature amongst the regenerated scales obtained from different body regions of the seven species studied. Scale loss is a common feature amongst fi sh exposed to accidental damage and this usually leads to the development of regenerated scales (Miranda and Escala 2002, Ashley 2007, Sfakianakis et al 2013. Abnormally regenerated scales were observed in the percids (G. cernua, P. fl uviatilis, and S. lucioperca) only, with the highest numbers observed in body regions 6, 3, and 8, respectively.…”