Environmental Salinity Affects Growth and Metabolism in Fingerling Meagre (Argyrosomus Regius)

Abstract

The meagre (Argyrosomus regius), a farmed fish in Mediterranean countries, seasonally migrates from offshore areas to estuaries for reproduction. During the first two years of life, the meagre evidences a certain grade of euryhalinity by staying in brackish waters close to the shore. The aim of the present study was to establish if fingerling growth in brackish water is improved compared to seawater, where current culture procedures are conducted. Three-month-old fingerlings were maintained for 45 days under two different salinity regimens (12 and 39 ppt). Several growth parameters as well as osmoregulatory and metabolic variables were assessed. Specific growth rate and hepatosomatic index values revealed that fingerlings performed better in brackish waters (12 ppt) compared to 39 ppt. This study contributes to optimizing meagre rearing conditions, thereby supporting the role of A. regius in aquaculture diversification.

Effects of salinity level on the survival, growth, feed utilization, carcass composition, haematological and serum biochemical changes of juvenile Meagre (Argyrosomus regius) (Asso, 1801) grown in ground saltwater

“…The results of the current study congruent with the findings of Sardella, Matey, Cooper, Gonzalez, and Brauner, (), Sardella and Brauner (), and Perez‐Velazquez, Urquidez‐Bejarano, and González‐Félix, (), indicating that meagre is a very good osmoregulator. That was confirmed by Ruiz‐Jarabo et al () with no variation in plasma osmolality between 12 and 39 ppt salinity levels. Furthermore, decreased salinities up to 8‰ were accompanied by reduced water contents.…”

“…According to Tinoco et al () and Ruiz‐Jarabo et al (), juvenile meagre, Argyrosomus regius , exposed to 39‰ salinity presented lower growth, condition factor and feed utilization than those reared at 12‰. The previous studies tested only two levels of salinity with a substantial variation in salinity of 27‰, which made it difficult to recommend one salinity level.…”

“…This result agrees with the results of Laiz‐Carrion et al () for gilthead seabream Sparus aurata under different osmotic conditions. Environmental stressors, such as hyper‐salinity or hypo‐salinity, and disease infection can reduce the serum protein level (Magnadottir, Gisladottir, Audunsdottir, & Bragason, ; Ruiz‐Jarabo et al, ). This reduction in protein level is due to the decreased appetite of fish, reducing the capacities for synthesis and absorption, or increasing protein loss through haemodilution (Patriche, Patriche, Bocioc, & Coada, ) or protein losses in osmolality.…”

“…Only two studies were conducted to investigate the effect of salinity on meagre performance. The first study dealt with the effect of salinity on growth and metabolism in fingerlings (Ruiz‐Jarabo et al, ; Tinoco, Rúa, Calvo, & Cárdenas, ) where two levels of salinity (12‰ and 39‰) were tested. The second one dealt with the evaluation of molecular performance of prolactin (prl), growth hormone (gh), insulin‐like growth factor (igf1) and β‐actin (actb) of meagre acclimated to different rearing salinities (Mohammed‐Geba et al, ).…”

Physiology: An Important Tool to Assess the Welfare of Aquatic Animals

“…Moreover, in catch-and-release fisheries, it is important to minimize stress on animals so that they can fully recover from the process and return to their natural environment [ 31 , 57 , 60 , 67 , 68 ]. Keeping aquatic animals in the best possible conditions during research experiments is mandatory, since the results may be affected by the care conditions [ 69 , 70 , 71 , 72 ]. Finally, the legislation seems to be less strict in aquatic organisms that serve as pets or are used in exhibition centers, such as aquaria.…”