Juvenile Sea Bass Dicentrarchus Labrax Research Articles

Acoustic stress responses in juvenile sea bass Dicentrarchus labrax induced by offshore pile driving

Underwater sound generated by pile driving during construction of offshore wind farms is a major concern in many countries. This paper reports on the acoustic stress responses in young European sea bass Dicentrarchus labrax (68 and 115 days old), based on four in situ experiments as close as 45 m from a pile driving activity. As a primary stress response, whole-body cortisol seemed to be too sensitive to ‘handling’ bias. On the other hand, measured secondary stress responses to pile driving showed significant reductions in oxygen consumption rate and low whole-body lactate concentrations. Furthermore, repeated exposure to impulsive sound significantly affected both primary and secondary stress responses. Under laboratory conditions, no tertiary stress responses (no changes in specific growth rate or Fulton's condition factor) were noted in young sea bass 30 days after the treatment. Still, the demonstrated acute stress responses and potentially repeated exposure to impulsive sound in the field will inevitably lead to less fit fish in the wild.

Toxicological Evaluation of Dietary Garlic <i>(Allium sativum)</i> Powder in European Sea Bass <i>Dicentrarchus labrax</i> Juveniles

The effects of dietary garlic (Allium sativum) powder as a feed additive on hematological and biochemical health characteristics of European Sea bass Dicentrarchus labrax juveniles were studied. Experimental fish were fed diets supplemented with garlic powder at 0 (control), 2%, 4%, or 6% levels for a period of 60 days. Results showed that the red blood cell count (RBC), hemoglobin (Hb) concentration, hematocrit (%), and mean corpuscular Hb in fish fed garlic powder diets at dietary inclusion levels of 4% and 6%, were significantly lower than the control values. Serum glucose was significantly lower in Sea bass that were fed garlic powder diets (4% and 6%) compared to the control group. Serum triglyceride and globulin levels in fish fed a 4% garlic powder diet were significantly higher than the control values, whereas these two variables in the 2% and 6% garlic treatments were similar to the control values. The cholesterol levels in the 2% and 6% treatment groups were lower than the value recorded for the control group. As a result, it is suggested that garlic powder supplementation in diets for Sea bass juveniles should not exceed 2%. The present study is the first attempt to examine the effects of dietary garlic powder on the hematological and biochemical status in Sea bass juveniles.

Effects of temperature, salinity and water composition on otolith elemental incorporation of Dicentrarchus labrax

Elemental composition of fish otoliths provides a valuable means to retrospectively determine a fish's environmental history over time. However, to reconstruct the patterns of fish movement and migration using otolith chemistry it is essential to establish the link between changing environmental variables, in particular, temperature, salinity and elemental concentration, and the concentration of elements within otoliths. Using a controlled laboratory experiment we investigated how otolith chemical composition of Sr:Ca and Ba:Ca was affected by temperature, salinity and ambient elemental concentration in juvenile sea bass Dicentrarchus labrax. A total of 18 treatments representing all combinations of temperature (21, 25°C), salinity (10, 20, 30) and ambient water concentrations (Low, Medium, High) were assessed. Otolith elemental composition of Sr:Ca and Ba:Ca were positively related to ambient water concentration. Consistent interactions between salinity and concentration were found for otolith composition, as well as elemental incorporation, for both elements. Positive effects of temperature on elemental composition and incorporation were also detected. The partition coefficient of Ba (DBa) initially decreased with increased water concentration but increased at the highest level of added elemental concentration. Across salinity gradients, DBa increased whilst distinct patterns in variation of DSr occurred within water concentration treatments. Our data highlight the importance of validation experiments to decipher species-specific patterns in otolith chemistry, particularly if the goal is to reconstruct fish life histories and determine fish movement patterns and habitat use.

Dynamics of scale regeneration in seawater- and brackish water-acclimated sea bass, Dicentrarchus labrax

Scale loss is a common occurrence in both wild fish and those in aquaculture production systems, and regeneration of scales has been described in several freshwater species. Relatively little information exists about this process in marine fish, and in the present study, the chronology of scale regeneration was characterized in juvenile sea bass Dicentrarchus labrax, maintained in full seawater (SW; 36‰, 11.2 mM Ca(2+)) or brackish water (BW; 3.5‰, 1.1 mM Ca(2+)). Despite the significant differences in plasma osmolality, plasma calcium (Ca) and phosphorus (P) were similar between SW and BW. Removal of scales (2.25 cm(2)) did not modify plasma osmolality but a significant reduction in plasma Ca occurred in sea bass in BW during early phases of scale regeneration. Scale Ca and P contents changed during regeneration in SW and BW fish, and in fully regenerated scales, their concentration was comparable to ontogenic scales which had a Ca/P ratio around 1.0. Regenerating scales were first visible at 3 days after removal, and by 6 days, the descaled area was covered with new scales in both SW and BW fish. From this stage onwards, while scale area and mass rose gradually, a rapid accretion of calcium crystals was observed over the basal plate, especially in SW, and Ca and P content per scale increased at a very high rate, decreasing only at the later stages, and between 21 and 30 days the newly formed scales had already ontogenic-like morphometric features. Scale tartrate-resistant acid phosphatase (TRAP) or alkaline phosphatase (ALP) activity was initially similar in SW and BW. However, during regeneration, TRAP was significantly higher in scales of sea bass in SW compared to those in BW where ALP predominated; these differences persisted at 30 days.

Impact of climate change on coastal versus estuarine nursery areas: cellular and whole-animal indicators in juvenile seabass Dicentrarchus labrax

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 464:237-243 (2012) - DOI: https://doi.org/10.3354/meps09885 Impact of climate change on coastal versus estuarine nursery areas: cellular and whole-animal indicators in juvenile seabass Dicentrarchus labrax Catarina Vinagre1,*, Diana Madeira1, Luís Narciso2, Henrique N. Cabral1, Mário S. Diniz3 1Universidade de Lisboa, Faculdade de Ciências, Centro de Oceanografia, Campo Grande, 1749-016 Lisboa, Portugal 2Universidade de Lisboa, Faculdade de Ciências, Centro de Oceanografia, Laboratório Marítimo da Guia, Avenida Nossa Senhora do Cabo, 939, 2750-374 Cascais, Portugal 3Requimte, Departamento de Química, Centro De Química Fina e Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal *Email: cmvinagre@fc.ul.pt ABSTRACT: The effects of thermal conditions of coastal and estuarine nurseries, both in the present and in the near future, on juvenile fish were compared. The response of the European seabass Dicentrarchus labrax was investigated through a long-term experiment in captivity, where 0-group juveniles were exposed to temperatures that reflect the average summer temperature that they encounter in coastal (18°C) and estuarine nurseries (24°C), and also the temperature that they endure inside estuaries during heat waves (28°C). The combined expression of 2 heat shock proteins (Hsc/Hsp70) in white muscle was assessed throughout a long-term experiment (30 d). Growth and condition were determined at the end of the experiment. Hsc/Hsp70 levels were constant throughout the first 15 d at 18°C, and then decreased steeply. At 24 and 28°C, Hsc/Hsp70 levels increased considerably after 15 d, particularly at 28°C, and decreased at the end of the experiment. Daily growth was 0.20 mm d−1 at 18°C, it increased to 0.34 mm d−1 at 24°C, and was lowest at 28°C, at 0.16 mm d−1. Condition, assessed by Fulton’s K, was 0.95 at 18°C, 1.00 at 24°C and 0.83 at 28°C. The Hsc/Hsp70 increase at 24 and 28°C is an indication that molecular reparation processes were underway. The peak growth and condition values registered at 24°C suggest that estuarine average summer temperatures are more beneficial for this species’ juveniles than coastal temperatures. Acclimation was observed at 24°C, yet growth rates and condition values indicate that prolonged heat waves (28°C) may result in lower fitness. KEY WORDS: Climate change · Hsc/Hsp70 · Heat stress · Thermal tolerance · Heat acclimatization · Molecular chaperone · Growth Full text in pdf format PreviousNextCite this article as: Vinagre C, Madeira D, Narciso L, Cabral HN, Diniz MS (2012) Impact of climate change on coastal versus estuarine nursery areas: cellular and whole-animal indicators in juvenile seabass Dicentrarchus labrax. Mar Ecol Prog Ser 464:237-243. https://doi.org/10.3354/meps09885 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 464. Online publication date: September 19, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Effects of dietary yeast Saccaromyces cerevisiae on the antioxidant system in the liver of juvenile sea bass Dicentrarchus labrax

The main goal of this work was to determine the effect of dietary live yeast Saccharomyces cerevisiae on the oxidative status of sea bass Dicentrarchus labrax juveniles. Fishes were fed on three diets: the GM group were fed a diet containing lyophilized yeast grown on grape must, the CS group were fed a diet containing lyophilized yeast grown on cornstarch, and the control group were fed a diet without yeast. The activity of the main antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase, glutathione S-transferase (GST), and glutathione (GSH) content, as well as lipid peroxidation, was measured in the liver of sea bass juveniles 90days after hatching. Supplementation of the diet with S. cerevisiae significantly reduced the SOD and CAT activity, increased the GST activity, decreased the GSH content, and had no effect on lipid peroxidation. The results support the already reported radical-scavenging properties of yeast and usefulness of its employment as antiperoxidative agent in fish.

Haematological and Immunological Responses in Juvenile Sea Bass (Dicentrarchus labrax L.) After Short-Term Acute Stress

The physiological effects of acute stress (induced by an intraperitoneal injection) on the haematocrit, haemo- globin, serum cortisol and glucose, haemagglutinins and lysozyme were investigated in juvenile sea bass Dicentrarchus labrax. A total of 40 fish were subjected to an intraperitoneal injection. Eight fish were sampled at 0, 2, 4, 24 and 48 h af- ter acute stress and compared to unstressed fish (controls) sacrificed at the same times. Intraperitoneal injection resulted in significant changes in cortisol and glucose 4 and 2 hours after exposure to stress, respectively, but not in haematocrit and haemoglobin levels. No significant differences between stressed and control fish were recorded for lysozyme content and haemagglutinating activity throughout the experiment. In juvenile sea bass acute stress caused by intraperitoneal injection was mostly associated with the increase in common stress indicators (cortisol and glucose), while no clear response in terms of non-specific immune parameters was evidenced.

Efficacy of a Listonella anguillarum (syn. Vibrio anguillarum) vaccine for juvenile sea bass Dicentrarchus labrax

The efficacy of a commercial bivalent Listonella anguillarum (serotype 01 and 02) vaccine (MICROViB, Microtek International) was tested on prime- and booster-immersion vaccinated sea bass Dicentrarchus labrax juveniles. We carried out 2 challenge tests on the prime-vaccinated fish, 50 and 90 d after initial vaccination. A second group of fish received a booster vaccination 60 d after the prime vaccination, and were tested with a single challenge 30 d later. Relative percent survival (RPS) was 92 and 84% (both p < 0.01) among the prime-vaccinated fish on the first and second challenges, respectively. The RPS of the booster-vaccinated sea bass was 100% (p < 0.01). Antibody titres were tested only among 10 prime-vaccinated and 10 unvaccinated (control) sea bass, 60 d post-immunisation, and were found to rise to 1/32 in the vaccinated fish. Our results demonstrate that MICROViB immersion vaccine can effectively protect juvenile sea bass from L. anguillarum infection.

Differential freshwater adaptation in juvenile sea-bassDicentrarchus labrax: involvement of gills and urinary system

The effects of long-term freshwater acclimatization were investigated in juvenile sea-bass Dicentrarchus labrax to determine whether all sea-bass juveniles are able to live in freshwater and to investigate the physiological basis of a successful adaptation to freshwater. This study particularly focused on the ability of sea-bass to maintain their hydromineral balance in freshwater and on their ion (re)absorbing abilities through the gills and kidneys. Two different responses were recorded after a long-term freshwater acclimatization. (1) Successfully adapted sea-bass displayed standard behavior; their blood osmolality was maintained almost constant after the freshwater challenge, attesting to their efficient hyperosmoregulation. Their branchial and renal Na+/K+-ATPase abundance and activity were high compared to seawater fish due to a high number of branchial ionocytes and to the involvement of the urinary system in active ion reabsorption, producing hypotonic urine. (2) Sea-bass that had not successfully adapted to freshwater were recognized by abnormal schooling behavior. Their blood osmolality was low (30% lower than in the successfully adapted sea-bass), which is a sign of acute osmoregulatory failure. High branchial Na+/K+-ATPase abundance and activity compared to successfully adapted fish were coupled to a proliferation of gill chloride cells, whose ultrastructure did not display pathological signs. The large surface used by the gill chloride cells might negatively interfere with respiratory gas exchanges. In their urinary system, enzyme abundance and activity were low, in accordance with the observed lower density of the kidney tubules. Urine was isotonic to blood in unsuccessfully adapted fish, ruling out any participation of the kidney in hyperosmoregulation. The kidney failure seems to generate a compensatory ion absorption through increased gill activity, but net ion loss through urine seems higher than ion absorption by the gills, leading to lower hyper-osmoregulatory performance and to death.

Comparative effectiveness of 2-phenoxyethanol and Propiscin as anesthetics for juvenile sea bass Dicentrarchus labrax L.

The comparative effectiveness of 2-phenoxyethanol and Propiscin as anesthetics were studied on juvenile sea bass. Both anesthetics showed low toxicity and good hypnotic characteristics, however median survival times at the same concentration of both anesthetics differed. Propiscin showed much lower LT50 than 2-phenoxyethanol, pointing towards its elevated toxicity in juvenile sea bass, even the same concentrations of Propiscin induced slower anesthesia than 2-phenoxyethanol. The most suitable Propiscin concentration for anesthesia was 0.56 ml/l, while the most suitable concentration of 2-phenoxyethanol was 0.32 ml/l for juvenile sea bass. Mortalities after 96 h were induced with Propiscin at lower concentrations then of 2-phenoxyethanol, resulting in the conclusion that the 2-phenoxyethanol is a safer anesthetic for use with juvenile sea bass (Dicentrarchus labrax L.).

The influence of a power station on the survival of juvenile sea bass in an estuarine nursery area

Trawl surveys in the estuary of the River Medway in the autumns of 1987–1991 have shown that the distribution of juvenile sea bass Dicentrarchus labrax is strongly associated with the warm‐water outflow from Kingsnorth power station. In years of low abundance of first‐year bass, very few were caught outside the warm‐water discharge channel, whereas proportionately more fish of abundant year classes occupied the main river. About 15% of the available juvenile bass population died on the cooling‐water intake screens at Kingsworth in the autumn and winter of 1987 and 1988. However, growth and survival of first‐year bass in the Medway Estuary may be enhanced by the power station's warm‐water effluent, such that overwinter mortality due to inadequate nutritional reserves and low temperatures may be considerably reduced.

Feeding and growth of juvenile sea bass: the effect of ration and temperature on growth rate and efficiency

The effect of ration on the growth of pairs of juvenile sea bass Dicentrarchus labrax fed squid mantle was recorded at four temperatures: 6, 10, 14 and 18) C, covering the range typical of Welsh coastal waters. Initial weight of the fish ranged from 2.8 to 15.9 g. A predictive model for the maximum meal size (Mmax) at temperatures between 10 and 18) C, accounted for 95% of the variance in lnMmax. Even when offered excess food, bass at 6) C had a low rate of food consumption [0.19% body weight (BW) day−1] and lost weight (G=−0.04% day−1). Predictive regression models for specific growth rate (G) accounted for 86% of the variance at reduced rations and 70% at maximum meals. The relationship between G (calculated for total biomass per tank) and ration was a decelerating curve. G at maximum meals increased with temperature, at lower rations G decreased with temperature. For a pair of bass with a combined weight of 15 g, predicted maintenance ration ranged between 0.7 and 2.3% BW day−1 and increased with temperature. Maximum meal size was more sensitive to temperature than maintenance ration. At 18) C optimum ration was 7.4% BW day−1. At lower temperatures, the optimum ration was the maximum meal. The maximum gross growth efficiency was 17.4% at 18) C. Mean absorption efficiency was 94.8%. Ration level had no significant effect on absorption efficiency, which was lowest at 6) C. Condition indices (Fulton condition factor, wet and dry liver—somatic indices and body depth index) increased with meal size at all temperatures except 6) C. An increase in temperature between 10 and 18) C generally resulted in a decrease in condition indices at a given ration. When comparisons were made at a given standard length, gut and carcass weight increased with ration. Visceral fat and gut weight decreased with increased temperature.

Feeding and growth of juvenile sea bass: the effect of ration and temperature on growth rate and efficiency

The effect of ration on the growth of pairs of juvenile sea bass Dicentrarchus labrax fed squid mantle was recorded at four temperatures: 6, 10, 14 and 18) C, covering the range typical of Welsh coastal waters. Initial weight of the fish ranged from 2.8 to 15.9 g. A predictive model for the maximum meal size (Mmax) at temperatures between 10 and 18) C, accounted for 95% of the variance in lnMmax. Even when offered excess food, bass at 6) C had a low rate of food consumption [0.19% body weight (BW) day−1] and lost weight (G=−0.04% day−1). Predictive regression models for specific growth rate (G) accounted for 86% of the variance at reduced rations and 70% at maximum meals. The relationship between G (calculated for total biomass per tank) and ration was a decelerating curve. G at maximum meals increased with temperature, at lower rations G decreased with temperature. For a pair of bass with a combined weight of 15 g, predicted maintenance ration ranged between 0.7 and 2.3% BW day−1 and increased with temperature. Maximum meal size was more sensitive to temperature than maintenance ration. At 18) C optimum ration was 7.4% BW day−1. At lower temperatures, the optimum ration was the maximum meal. The maximum gross growth efficiency was 17.4% at 18) C. Mean absorption efficiency was 94.8%. Ration level had no significant effect on absorption efficiency, which was lowest at 6) C. Condition indices (Fulton condition factor, wet and dry liver—somatic indices and body depth index) increased with meal size at all temperatures except 6) C. An increase in temperature between 10 and 18) C generally resulted in a decrease in condition indices at a given ration. When comparisons were made at a given standard length, gut and carcass weight increased with ration. Visceral fat and gut weight decreased with increased temperature.