Basic knowledge of social hierarchies and physiological profile of reared sea bass Dicentrarchus labrax (L.)

Abstract

The effects of social hierarchies (dominant/subordinate individuals), such as aggressiveness, feeding order, and territoriality, are some of the characteristics used for describing fish behaviour. Social hierarchy patterns are still poorly understood in European-reared sea bass (Dicentrarchus labrax). In this work, we examine the social interactions among captive fish integrating behavioural and physiological profiles. Groups of three fish with EMG (electromyogram) radio transmitters were monitored for two weeks via video recording. Plasma levels of cortisol, glucose, lactate and lysozyme as well as haematological parameters such as haemoglobin, haematocrit and RBCC (red blood cell count) were measured at the beginning and end of the experiments. Behaviour and muscle activity were monitored daily. The results highlighted that the social hierarchic order was established after one to two days, and it was maintained throughout the experimental period. Dominant and subordinate fish (ß and γ) showed significant differences in muscle activity, hormonal profile (cortisol), aspecific immunity (lysozyme), carbohydrate metabolism (lactate) and behavioural patterns (food order and aggressiveness). This holistic approach helps to provide insights into the physiological status of the subordinate (ß and γ) and dominant individuals. These data have wide implications for aquaculture practice.

Surgical implantation of electronic tags does not induce medium-term effect: insights from growth and stress physiological profile in two marine fish species

“…Jepsen et al [25] reported similar observations in Chinook salmon, where physiological stress indicators were higher up to 24 h following tag implantation, but were comparable with those of untagged fish at most 7 days later. In our experiments, 46 and 95 days after tag implantation in sea breams and sea bass, respectively, the levels of all monitored stress indicators (cortisol, glucose and lactate) were found to be similar to those of untagged fish and consistent with the levels reported in the literature regarding these species [7,28]. Our results confirm that tag implantation does not induce chronic stress in either the sea bream or the sea bass, as observed in various other fish species [25,29].…”

Are tagged fish like others? Insights from growth and stress physiological profile in two marine fish species

“…Same observations were done in Chinook salmon by Jepsen et al [21], where physiological stress indicators were higher up to 24 h following the tag implantation but were comparable with untagged fish at least 7 days following the tag implantation. In our experiments, after 46 days for bream and 95 days for sea bass following the tag implantation, the levels of all stress indicators monitored (cortisol, glucose and lactate) were found to be similar to untagged fish, and consistent with the literature for these species [7,24]. Our results support the fact that the implantation of a tag does not induce chronic stress in sea bream and sea bass, as already observed for various fish species [21,25].…”

Surgical implantation of electronic tags does not induce medium-term effect. Insights from growth and stress physiological profile in two marine fish species

“…Jepsen et al [25] reported similar observations in Chinook salmon, where physiological stress indicators were higher up to 24 h following tag implantation but were comparable with those of untagged sh at most seven days later. In our experiments, 46 and 95 days after tag implantation in sea breams and sea bass, respectively, the levels of all monitored stress indicators (cortisol, glucose and lactate) were found to be similar to those of untagged sh and consistent with the levels reported in the literature regarding these species [7,28]. Our results con rm that tag implantation does not induce chronic stress in either the sea bream or the sea bass, as observed in various other sh species [25,29].…”