Sound production in the Meagre, Argyrosomus regius (Asso, 1801): intraspecific variability associated with size, sex and context

Many fish taxa produce sound in voluntary and in disturbance contexts but information on the full acoustic repertoire is lacking for most species. Yet, this knowledge is critical to enable monitoring fish populations in nature through acoustic monitoring.Portuguese Foundation for Science and Technology: PTDC/BIA-BMA/30517/2017; SFRH/BD/115562/2016; UID/MAR/04292/2019; UID/BIA/00329/2019; PTDC/BIA-BMA/29662/2017.info:eu-repo/semantics/publishedVersio

Swimming abilities of temperate pelagic fish larvae prove that they may control their dispersion in coastal areas

The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sensorial acuity of temperate fish larvae allows them to find and swim towards coastal nursery areas, which are crucial for their recruitment. To gather further evidence to support this theory, it is necessary to understand how horizontal swimming capability varies along fish larvae ontogeny. Therefore, we studied the swimming capability of white seabream Diplodus sargus (Linnaeus, 1758) larvae along ontogeny, and their relationship with physiological condition. Thus, critical swimming speed (U-crit) and the distance swam (km) during endurance tests were determined for fish larvae from 15 to 55 days post-hatching (DPH), and their physiological condition (RNA, DNA and protein contents) was assessed. The critical swimming speed of white seabream larvae increased along ontogeny from 1.1 cm s(-1) (15 DPH) to 23 cm s(-1) (50 and 55 DPH), and the distance swam by larvae in the endurance experiments increased from 0.01 km (15 DPH) to 86.5 km (45 DPH). This finding supports one of the premises of the SAAB hypothesis, which proposes that fish larvae can influence their transport and distribution in coastal areas due to their swimming capabilities. The relationship between larvae's physiological condition and swimming capabilities were not evident in this study. Overall, this study provides critical information for understanding the link between population dynamics and connectivity with the management and conservation of fish stocks.Funding Agency Portuguese Foundation for Science and Technology SFRH/BD/104209/2014 Portuguese Foundation for Science and Technology UID/Multi/04326/2019 FCT, under the Transitional Norm DL57/2016/CP[1361]/CT[CT0008 CLIMFISH project-A framework for assess vulnerability of coastal fisheries to climate change in Portuguese coast n2/SAICT/2017-SAICTinfo:eu-repo/semantics/publishedVersio

Influence of the lunar cycle on plasma melatonin, vitellogenin and sex steroids rhythms in Senegal sole, Solea senegalensis

24 p., il., y bibliografíaThe effect of the moon light cycle on plasma melatonin rhythms was examined in Senegal sole (Solea senegalensis) exposed to natural outdoor or artificial indoor lighting conditions. Furthermore, in a second experiment, the effect of the lunar cycle on vitellogenin and sex steroids (Testosterone, T; Estradiol, E2; 11-ketotestosterone, 11kt) was studied using mature individuals during reproductive season. In the first experiment, during full moon, plasma melatonin peaked at night in covered tanks (deprived of night illumination) from both outdoor (133.2 ± 12.8 pg ml-1) and indoor (190.6 ± 41.5 pg ml-1) groups. However, for fish in the open tanks, exposed to approximately 0.3 lux of illumination, nocturnal plasma melatonin was significantly reduced (p<0.05), approaching to mid-light (ML) values, (79.6 ± 7.1 and 81.8 ± 14.0 pg ml-1, for outdoor and indoor groups, respectively). During new moon a similar pattern was observed in outdoor group: fish in the covered tank showed higher melatonin values than those in the open tank, which were exposed to the near undetectable night illumination. In the second experiment, plasma sex steroid concentrations were significantly higher during the full moon compared to the new moon. In the case of females, E2 concentration reduced from 2.4 ± 0.6 to 0.4 ± 0.1 ng ml-1 between full and new moon samplings, while T decreased from 0.3 ± 0.0 to 0.2 ± 0.0 ng ml-1. Vitellogenin, however, did not show such differences between moon phases. In males, 11kt exhibited a plasma concentration of 14.3 ± 2.1 ng ml-1 during full moon and 4.7 ± 0.7 ng ml-1 during new moon while T values were 2.6 ± 0.4 and 1.0 ± 0.1 ng ml-1 for full and new moon, respectively. In conclusion, these findings pointed out the high sensitivity to moon light of the Senegal sole, which could be using the melatonin signalling to synchronize their reproduction rhythms to the lunar cycle.This work has been financed by the Spanish Ministry of Education and Science (MEC) through project Reprosolea AGL2004-07984-CO2-01/ACU to FJSV and project AGL2006-13777-C03-01 to EM. CO received an FPI fellowship from the same institution.Peer reviewe

Hormonal induction of Atlantic dusky grouper (Epinephelus marginatus) broodstock

Immature fish and young females were sex reversed using hormonal induction in two consecutive years. In the first year one permanent male was obtained. Collected sperm of both years ranges from 30 μl to 300 μl and cell concentration varies from 3 to 6.5 x109 spermatozoa/ml. Atlantic dusky grouper can successfully be induced to functional males with 17α-methyltestosterone implants

Tyrosine and phenylalanine supplementation on Diplodus sargus larvae: effect on growth and quality

27 páginas, 3 figuras, 5 tablas. The definitive version is available at www.blackwell-synergy.comPhenylalanine is the precursor of tyrosine, which is involved in the synthesis of several molecules with key roles in the regulation of metabolism and growth, stress response and pigmentation. In this study, three experimental diets were tested: an amino acid (AA) balanced diet supplemented with phenylalanine, another supplemented with phenylalanine and tyrosine and a non-supplemented AA balanced diet. Rotifers were enriched with liposomes encapsulating free AA in order to obtain a balanced AA profile. The experimental diets resulted in similar larval survival, growth, enzyme activities of AA catabolism and nitrogen excretion in all treatments. High levels of skeletal deformities were registered and significant differences were found between the control and the phenylalanine treatment for the percentage of vertebral compressions in the trunk region of the vertebral column (30% in the control and 5% in the phenylalanine group). A significantly higher survival to a temperature stress test was found for larvae fed the diet supplemented with phenylalanine and tyrosine. The results suggest that supplementation of phenylalanine/tyrosine in fish diets may be useful in order to reduce skeletal deformities and mortalities caused by stress. The present study confirms that AA requirements may be sufficient for covering growth and survival but insufficient to cover other metabolic processes.This work was supported by the project POCI/MAR/61623/2004 – SAARGO, financed by the programme POCI 2010 (FCT, Portugal), which is co-financed by FEDER. FEDER and PN Project AGL2004-06669-C02-01 (Ministry of Education and Science, Spain) are co-financed by FEDER and project –‘Tecnologias de Produção Aquícola’– (22-05-01-FBR-00014 – QCA IIII).Peer reviewe

Production of the ragworm Nereis diversicolor (O. F. Müller, 1776), fed with a diet for gilthead seabream Sparus auratus L., 1758: survival, growth, feed utilization and oogenesis

A 65-day experiment was conducted to determine survival, growth, feed utilization and oogenesis of Nereis diversicolor (O. F. Müller, 1776), fed with a commercial dry diet developed for gilthead seabream Sparus auratus L., 1758. Worms were reared in three replicate tanks with 50 worms per tank (255 indiv · m_2). Tetramin®, a commonly used diet for ornamental fish and polychaete laboratory experiments, was used as a control. Survival was high (95.3 %) for both treatments, and not significantly affected by diet. Specific growth rates and feed efficiency ratios did not differ significantly between worms fed with either diets, nor were there significant differences in the proportion of individuals in the oocyte size classes.La supervivencia, el crecimiento, la utilización del alimento y la oogénesis de Nereis diversicolor (O. F. Müller, 1776) alimentado con pienso de dorada Sparus auratus L., 1758 fueron estudiados durante 65 días. Los poliquetos se cultivaron en tres tanques replicados con 50 individuos en cada uno (255 indiv · m_2). Como control se utilizó Tetramin®, una dieta común para peces ornamentales y en experimentos de laboratorio con poliquetos. La supervivencia fue alta (95,3 %) en ambos tratamientos y no se vio afectada significativamente por la dieta. El aumento de peso y los cocientes de eficiencia alimentaria no variaron significativamente entre los poliquetos alimentados con ambas dietas. Entre los grupos experimentales no hubo diferencia significativa en la proporción de individuos por clases de tamaño de los oocitos.Instituto Español de Oceanografí

Fish larval performance fed with copepods (Acartia grani) and the dinoflagellate (Oxyrrhis marina) as supplement: the case of dusky grouper (Epinephelus marginatus)

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Vocal repertoire and consistency of call features in the meagre Argyrosomous regius (Asso, 1801)

Passive Acoustic Monitoring (PAM) is a non-intrusive and cost-effective method capable of providing high-resolution, long-term information on the status and health of vocal populations and communities. To successfully monitor the same species over wide geographical and temporal scales, it is necessary to characterise the range of sound variability, as well as the consistency of sound features between populations. The meagre (Argyrosomus regius, Asso 1801) is an interesting case study because recent investigations suggest a wider vocal repertoire than previously described. In this study, meagre vocalizations were recorded and analysed from a variety of settings, ranging from rearing facilities to wild populations to provide a comprehensive characterisation of its vocal repertoire, while investigating the consistency of spawning sound features between populations. All sounds presented a similar acoustic structure in their basic unit (i.e. the pulse), while an important variability was found in the number of pulses; the meagre can emit sounds made of one single pulse or many pulses (up to more than 100). High level of overlap in the Principal Component Analysis made difficult to differentiate sound type clusters. Despite this, two sound types were identifiable: knocks (sounds from 1 to 3 pulses) and long grunts (sounds with more than 29 pulses). Discriminant Analysis carried out on PCA residuals showed that knock had the highest proportion of correct placement (92% of the observations correctly placed) followed by long grunts (80%). All other previously described sound types (intermediate grunt, short grunt and disturbance sounds) could not be separated and presented low levels of correct placement, suggesting that care should be taken when defining these as independent sound types. Finally, acoustic features consistency was found in meagre grunts emitted by different populations during spawning nights; statistical differences could be explained by recording settings and fish conditions. The results of this study provide important information for fostering PAM programs of wild meagre populations, while contributing to the discussion around the definition of fish sound types in vocal fish communities. Studies of this kind, which evaluate both variability and consistency of sound features, are of fundamental importance for maximising PAM efforts in the wild, at both the specific and the community level.info:eu-repo/semantics/publishedVersio

Skeletal quality in Senegalese sole: characterization of fish resulting from environmental and nutritional trials

The Senegalese sole (Solea senegalensis) is characteristic from southern Europe and Mediterranean. It has recently been adapted for aquaculture production since it is well accepted by consumers and reaches high commercial values. After the initial description of the ontogenic events of skeletogenesis, systematic evaluation of the incidence of skeletal malformations by several groups revealed high levels of skeletal deformities reaching up to 90% of the population

Fish larvae quality descriptors: an appraisal of methods for red porgy Pagrus pagrus and grouper Epinephelus marginatus produced under different rearing conditions

Quality control in fish hatcheries is of paramount importance to achieve the desired characteristics of larvae and fry, either for the market or release to the wild. Quality programmes are applied in a day to day basis having direct implications for production management and final costs of product. Most common criteria used for larval quality assessment are morphometrics, condition factor, histometrical indices, lipid analysis, nucleic acid ratios, enzyme activity and stress tests