Response of captive seabass and seabream as behavioural indicator in aquaculture

Abstract

Welfare of cultivate fish at high-density represents an important concern for modern aquaculture. The behaviour of European seabass (Dicentrarchus labrax) and seabream (Sparus aurata) reared in cages was studied in a fish farm of northern Sardinia (Italy) in autumn 2006 to test whether captive condition had an effect on the movement patterns of these two species.Video images recorded before, during and after the manual feeding distribution allowed us to collect data on different behaviours of captive fish. Thus, behaviours indicating the position of fish in the water column, swimming direction and possible aggressive behaviours (aggression, direction change and collision) showed juveniles and adults of seabass and seabream were overall affected by feeding rhythms and captive overcrowding. Seabream had a major tendency to swim towards the bottom and higher frequency of horizontal swimming and collisions than seabass. The overall behavioural difference between two species was explained in terms of their differences in ecological features in the wild

Does fin damage allow discrimination among wild, escaped and farmed Sparus aurata (L.) and Dicentrarchus labrax (L.)?

“…This fact agrees with the assumption that the occurrence of fin damage and erosion is substantially greater under reared conditions than in the natural environment, possibly due to the high densities, feeds provided and aquaculture operations (Mork et al, 1989). Sara`et al (2007) demonstrated that the most frequent movements of farmed seabream inside cages were, apart from horizontal and vertical movements, collisions between fishes. According to this, it was evidenced that the most exposed finspectoral, caudal and dorsalfrom farmed seabream resulted in the highest erosion.…”

“…Sarà et al. () demonstrated that the most frequent movements of farmed seabream inside cages were, apart from horizontal and vertical movements, collisions between fishes. According to this, it was evidenced that the most exposed fins – pectoral, caudal and dorsal – from farmed seabream resulted in the highest erosion.…”

“…Sarà et al. () reported that farmed seabass were horizontal most of the time and close to the bottom under farming conditions, but did not present near‐collisions with nets or surrounding conspecifics, although Person‐Le Ruyet and Le Bayon () found that the dorsal fins on farmed seabass appeared to be mostly eroded by abrasion, probably due to high densities inside the cage. However, our results suggest that such erosion could either be intrinsic to the natural behavior of this species, or be due to lower rearing densities, since such erosion levels in both farmed and escaped seabass were similar to wild individuals.…”

Monitoring marine fishes using underwater video techniques in the Mediterranean Sea

“…In addition to applications to fish ecology and monitoring, video recording techniques have also been used for commercial purposes in aquaculture and fisheries. Aquaculture studies have used such techniques to estimate abundance and biomass of bluefin tuna (Costa et al 2009;Mariani et al 2014) or behavioral changes of captive fish under different conditions (Sarà et al 2007;. Fisheries studies use video techniques to estimate the catchability of fishing gears (Dremière et al 1999;Papadopoulou et al 2015) and record the effect fish aggregating devices can have on fish community structure (Addis et al 2016) or fish behavior (Sinopoli et al 2015).…”