The aim of this study was to address an analysis of spatial distribution, reproduction, population parameters and secondary production of the natural beds of the well-defined morphotypes of the clam Mactra stultorum (brownish and whitish variants) along the SW Spanish coast. The main findings showed that the presence and the frequencies of both morphotypes increased near the estuaries of rivers, particularly the Guadalquivir River. However, subtle differences in habitat preferences have been revealed and the brownish variant showed a wider and deeper distribution. High similarity in the gonadal development was recorded for both variants. It started in January, continued into late winter and early spring and ended with a spawning period from April to August. An energy storage-utilization cycle, coupled to the reproductive and resting periods and driven by seawater temperature variations and food availability, was also observed. The abovementioned period of gamete emissions resulted in a recruitment pattern with a one-time settlement period per year. Von Bertalanffy growth functions provided an asymptotic length of 46.7 mm (whitish) and 50 mm (brownish) and growth constants of 0.55 (whitish) and 0.50 year(-1) (brownish). The mean annual biomass ((B) over bar) ranged between 0.062 (whitish) and 0.076 g AFDW m(-2) year(-1) (brownish) (AFDW: ash-free dry mass). Individual somatic production showed the highest value at 32 and 34 mm shell length, and annual production (P) ranged between 0.075 and 0.113 g AFDW m(-2) year(-1), resulting in renewal rate (P/(B) over bar) values between 1.21 and 1.37 for the whitish and brownish variants, respectively. These results provide basic knowledge about the reproduction and population dynamics of this species along the Atlantic coast, particularly in the sandflats near the estuary of the Guadalquivir River. They could also shed additional light upon taxonomic differentiation and clarify the ecological role of both variants when compared with two bivalve sympatric species of the intertidal and subtidal areas.

Phospholipids (PL) are essential molecules for larval growth and development. In this study, growth, lipid metabolism and gene expression responses associated with different dietary PL levels in pelagic sole larvae were evaluated. In a first trial, the long-term effects on growth and survival of two experimental microdiets (MD) containing high (High-PL) or low (Low-PL) PL levels were tested and compared to a diet based on live prey (rotifers). The MD were supplied from 3 to 10 days post-hatch (dph) and Artemia from day 8 to 29 dph. High-PL fed larvae had higher dry mass (1.2-fold) than Low-PL fed larvae at 8 dph and both MD were smaller (2.9-fold) than larvae fed live preys. However, a compensatory growth (33% between 8 and 20 dph) occurred when MD were substituted by Artemia and by the end of the trial no significant differences in mass or survival occurred between the dietary treatments. In a second trial, growth, lipid metabolism and gene expression profiles of larvae fed with MD up to 8 dph were analyzed. Growth data confirmed that mass of larvae fed with High-PL was higher (1.3-fold) than the those fed Low-PL and they had lower levels of triacylglycerol (2.8-fold), cholesterol (1.2-fold) and cetoleic acid (1.7-fold). Histological analysis indicated an excess of lipid vacuoles in larvae fed with Low-PL and the expression analysis revealed a coordinated response to enhance lipid mobilization since the expression of genes involved in PL intermediate synthesis, PL remodeling as well as eight apolipoprotein was up-regulated. The down-regulation of apolipoprotein apob2 in larvae fed with Low-PL indicated a specific regulation by PL levels. The present work provides insight into the responses associated with dietary PL in early fish larvae, which will be of use for future studies aimed as designing effective larval sole diets.

Event Abstract Back to Event Analysis and damage assessment of discards in the hand dredge wedge clam fishery (Donax trunculus Linnaeus, 1758) in the Gulf of Cádiz (SW Spain Raimundo Blanco1*, Sara Román1, Ana Rodriguez-Rua1, Miguel Coján1, Luis Silva1, Antonio Sánchez2, Esperanza Lisa-García1 and Marina Delgado1 1 Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Spain 2 Facultad de Ciencias, Universidad de Cádiz, Spain Within the framework of the research project VENUS, the aim of this communication is to provide a first insight of the discards associated with the artisanal hand dredging fishery targeting wedge clam Donax trunculus Linnaeus, 1758 in the sandy beaches at littoral of Huelva, in the south west of Spain. Small scale fisheries represent one of the main types of fisheries occurring in the area with a high socioeconomic importance. D. trunculus constitutes a very important fishing resource due to its high economic value and has been exploited over the last decades using primarily either artisanal hand-operated dredges (rastros manuales) in shallow water and commercial boat-operated dredges from subtidal to deeper waters. The hand dredge wedge clam fishery has been regulated by the Andalusian autonomic government since 2008. Several measures for the control of fishing and protection of this valuable economical resource were established in order to maintain its sustainability: licenses (the protect area Doñana NP has a specific license regulation), daily quota, a minimum size limit and a closed season (Silva et al., 2014). In general fishing trawling is one of the most impactful fishery activities on the seabed. The physical and biological impacts in the communities are variable. They depend upon size and weight of the gear as well as fishing practice and ecosystem. In the area of study, there is a lack of scientific information about of some aspects of the wedge clam fishery with hand dredge: discard structure and composition, and damage caused to specimens during the fishing and the manipulations. A basic tenet of the ecosystem approach to fisheries management is that harvesting should be conducted with minimal impact on juveniles, non-target species, and marine habitats. An analysis of discards and damage will be useful for the adoption and assessment of the discard mitigation strategies for this fishery (Bellido et al., 2011). The study area comprised the low intertidal and the upper (2 - 3 m depth) infralitoral zone of the sandy beaches of the Huelva province coast. The area was divided into six units from the mouth of the Guadalquivir river to Ayamonte (mouth of the Guadiana river): Doñana National Park, Mazagón, Huelva, Punta Umbría-La Bota, Isla Cristina-El Rompido, and Ayamonte. Sampling was carried out using a hand dredge similar to those used by artisanal fishermen. It consists in a wood towing arm, dredge mouth of 44.5 cm width by 15 cm height with an even cutting edge, a mesh sieve size of 7 X 7 mm and a length of 58 cm, with a rear net bag of 200 cm length and mesh size of 5 X 5 mm. The gear digs deeply into the sediment up to 10 cm. A total of 17 hauls were performed at 17 stations, between the lower intertidal and 2 m depth of the infralitoral zone in June 2018. At each station the hand dredge was towed diagonally to the shoreline for 5 min. Every transect was geo-referenced by a GPS. The samples were sorted in the laboratory. Macrofauna and megafauna were identified to the lowest taxon level (mainly species level) with the uttermost precision and their respective abundances and weights recorded. Additionally, a damage assessment was performed on the fauna, taking into account the whole fishing process. A three level damage scale was used to assign the level damage to the individuals of each taxon: D0 (no damage), D1 (low damage), D2 (intermediate damage) and D3 (high damage, not survival after their release) (Anjos et al., 2011, Urra et al, 2017). The preliminary study of the 3897 specimens yielded 25 taxa belonging to 5 Classes: Polychaeta (4), Bivalvia (8), Gastropoda (3), Scaphopoda (1), Crustacea (6), Echinoidea (2) and Actinopterygii (1). However, the number of taxa could be even higher, because Paguroidea and Polychaeta could not be identified to species level. Bivalvia was the dominant group in abundance (94.12%) and biomass (95.41), followed by Crustacea with 4.72% and 2.06%, Echinoidea 0.44% and 2.42%, Polychaeta 0.39% and 0.06%, Gastropoda 0.21% and 0.01, Scaphopoda 0.10% and 0.01% and finally Actinopterygii with 0.02% and 0.03%. The targeted species, D. trunculus, represented 83.34 % of the specimens and 76.58% of the biomass of the capture (3248 specimens and 8447.03 g); The discard fraction was composed by 24 taxa and represented the 16.65% of the collected individual and the 23.42 % of the biomass. Discards were dominated by Bivalvia in taxa richness (7), abundance (64%) and biomass (80.39%). Overall, 82.44% of the discarded specimens were undamaged, 0.92% display low damage, 0.15% display intermediate damage, 16.49% display severe damage. Bivalve was the group with more damaged individuals (66.67%), all belonging to Mactra stultorum (Linnaeus, 1758), followed by brachyuran crustaceans (25.44%), irregular sea-urchins (6.14%) and fishes (1.75%). Acknowledgements Study funded within the framework of the project “VENUS” (Estudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de hábitats asociados) (0139VENUS5E; INTERREG-POCTEP). We would like to thank Rafael Donato, Carlos Farias, Eva García-Isarch, Verónica Duque, Jorge Rey and Teresa Montaño for follaborating in biological sampling. We also thank the ranger team of the Doñana national park and Doñana Biological Station (EBD-CSIC). References Anjos, M., Pereira, F., Vasconcelos, P., Joaquim, S., Matias, D., Erzini, K., & Gaspar, M. (2018). Bycatch and discard survival rate in a small-scale bivalve dredge fishery along the Algarve coast (southern Portugal). Scientia Marina, 82(S1), 75. https://doi.org/10.3989/scimar.04742.08a Bellido, J.M., Santos, B., Pennino, M.G., Valeiras, X. & Pierce, G.J (2011). Fishery discards and bycatch: solutions for an ecosystem approach to fisheries management? Hydrobiologia, 670:317–333. https://doi.org/10.1007/s10750-011-0721-5 Coján M., Silva, L., Delgado, Terrón, A., Férnandez, J. & Mártinez, E. (2015). Descripción de la fauna macrobentónica en la zona intermareal del litoral de Huelva donde se desarrolla la pesquería de coquina (Donax trunculus Linnaeus, 1758). In Díaz del Río V., Bárcenas, P., Fernández-Salas, L.M., Palomino, D., Rueda, J.L., Sánchez-Guillamon, O. & Váquez, J.T. (eds) Proceedings of the VIII Simposio sobre el Margen Ibérico Atlántico, Málaga, 21–23 September 2015, p. 349. Gaspar M.B., Santos M.N., Leitão F., Chícharo, L., Chícharo, A, & Monteiro, C.C. (2003). Recovery of substrates and macro-benthos after fishing trials with a new Portuguese clam dredge. Journal of the Marine Biological Association of the U.K., 83: 713-717. https://doi.org/10.1017/S0025315403007690h Pranovi, F., Raicevich, S., Franceschini, G., Torricelli, P., & Giovanardi, O. (2001). Discard analysis and damage to non-target species in the “rapido” trawl fishery. Marine Biology, 139(5), 863–875. https://doi.org/10.1007/s002270100646 Peña Olivas, J.M. & Antón Camacho, A.I. (2013). Estudio de actuación del tramo de costa comprendido entre las desembocaduras de los ríos Guadiana y Guadalquivir. (Informe final) (CLAVE CEDEX: 22- 410-5-001, para la Dirección General de Sostenibilidad de la Costa y del Mar). 82 pp. Rufino, M.M., Gaspar, M., Pereira, A.M., Maynou, F. & Monteiro, C. C. (2010). Ecology of megabenthic bivalve communities from sandy beaches on the south coast of Portugal. Scientia Marina 74(1): 163-178. https://doi.org/10.3989/scimar.2010.74n1163 Serhat Çolakoğlu, S. (2014). Population Structure, Growth and Production of the Wedge Clam Donax trunculus (Bivalvia, Donacidae) in the West Marmara Sea, Turkey. Turkish Journal of Fisheries and Aquatic Sciences 14, 221-230. https://doi.org/10.4194/1303-2712-v14_1_24 Silva, L., Delgado, M., Cojan M.,Martínez, E., Quesada, L., Gamero, J., Fernandez, J. &Terrón A. (2014). Fishery of surf clams Donax trunculus (Bivalvia, L. 1758) in the Gulf of Cadiz (SW Spain). In Ríos, P., Suarez, L.A.& Cristobo, J. (eds) Proceedings of the XVIII Symposium Ibérico de Estudios de Biología Marina, Spanish Institute of Oceanography, Gijon, 2–5 September 2014, p. 203. Urra, J., García, T., Gallardo-Roldán, H., León, E., Lozano, M., Baro, J., & Rueda, J. L. (2017). Discard analysis and damage assessment in the wedge clam mechanized dredging fisheries of the northern Alboran Sea (W Mediterranean Sea). Fisheries Research, 187, 58–67. https://doi.org/10.1016/j.fishres.2016.10.018 Keywords: Discards, damage, Megafauna, macrpfauna, Wedge clam, Small scale fisheries, Ecosystem aproach Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Poster Presentation Topic: Ecology, Biodiversity and Vulnerable Ecosystems Citation: Blanco R, Román S, Rodriguez-Rua A, Coján M, Silva L, Sánchez A, Lisa-García E and Delgado M (2019). Analysis and damage assessment of discards in the hand dredge wedge clam fishery (Donax trunculus Linnaeus, 1758) in the Gulf of Cádiz (SW Spain. Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00091 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 May 2019; Published Online: 27 Sep 2019. * Correspondence: Mr. Raimundo Blanco, Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Cádiz, Spain, raimundo.blanco@ieo.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Raimundo Blanco Sara Román Ana Rodriguez-Rua Miguel Coján Luis Silva Antonio Sánchez Esperanza Lisa-García Marina Delgado Google Raimundo Blanco Sara Román Ana Rodriguez-Rua Miguel Coján Luis Silva Antonio Sánchez Esperanza Lisa-García Marina Delgado Google Scholar Raimundo Blanco Sara Román Ana Rodriguez-Rua Miguel Coján Luis Silva Antonio Sánchez Esperanza Lisa-García Marina Delgado PubMed Raimundo Blanco Sara Román Ana Rodriguez-Rua Miguel Coján Luis Silva Antonio Sánchez Esperanza Lisa-García Marina Delgado Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Event Abstract Back to Event Spatial distribution of Donax trunculus (Linnaeus, 1758) populations along the intertidal area of the Gulf of Cádiz (SW, Spain) Sara Román1*, Raimundo Blanco. Pérez1, Luis Silva1, Ana Rodriguez-Rua1, Miguel Cojan1, Esperanza García1 and Marina Delgado1 1 Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Spain The wedge clam (Donax trunculus Linnaeus, 1758) is widely distributed along Atlantic-Mediterranean exposed beaches at depths ranging from 0 to 6 meters. This species inhabits of the superficial fine sand biocenosis, with beach characteristics such as beach profile, wave energy, tidal range and grain size being important drivers controlling the distribution of the populations (Bayed and Guillou, 1985). This species has high commercial importance on the southwest coast of Spain, and D. trunculus is harvested by licensed fishermen using hand-dredges in shallow waters (IDAPES, 2016). However, it is common to observe unauthorized fishermen hand-dredging and tourists hand-gathering this valuable fishing resource from beaches, making official statistics unreliable and making difficult stock assessment and resource management. Thus, knowledge of resource situation through estimation of abundance by direct methods is essential to improve suitable management measures, and for understanding the ecology of the bivalve beds. In this context, in the framework of the research project VENUS, the main objective of this study was providing a preliminary estimation of spatial distribution for D. trunculus in the intertidal areas along the littoral of Huelva to adopt optimal resource exploitation strategies compatible with its sustainability. The study area comprised the intertidal zone of the Huelva province coast. This area was divided into six sections of sandy beaches from Doñana to Ayamonte (i.e. between the mouths of the Guadalquivir and Guadiana rivers): Doñana, Mazagón, Huelva, Punta Umbría-La Bota, Isla Cristina-El Rompido, and Ayamonte. These beaches included different levels of anthropogenic pressure (fishing, tourism and pollution), fishing reserves and the protected area of Doñana National Park where fishing activity is under control. A total of 58 sampling sites, separated by 2 km, were sampled along the coast during low tide in June 2018. Samples were collected from the lower part of the upper sublittoral area of the beaches. Sampling was performed using a hand-dredge similar to those used by local bivalve harvesters. The hand-dredge has an iron structure with a 44.5 cm wide opening that digs deeply into the sediment (upper 15 cm), using an experimental mesh size (3 x 3 mm) to allow for the collection of the smallest individual and juveniles. At each sampling site, hand-dredges were towed diagonally to the shoreline for 5 min, each transect being geo-referenced by means of a GPS. The number of retained individuals was recorded to estimate population density (ind. m-2) and biomass (g m-2), and shell length (SL) with a digital vernier caliper to produce length-frequency distributions. Environmental variables such a sediment grain size and Tª were analyzed. A total of 18619 individuals were collected and analyzed from the beaches. In general terms, highest values (density and biomass) were reported on Doñana section (National Park), where fishing activity is controlled, particularly in Site 8 (53.6 ind. m-2 and 78.3 g m-2). On the contrary, low values corresponded to beaches with higher touristic and illegal fishing pressures which are clearly affected the wedge clam populations. These values were observed on Mazagón beach (touristic zone together with river mouths of the rivers Tinto and Odiel), in Site 24 (0.04 ind. m-2 and 0.1 g m-2). Additionally, low values were also found on Ayamonte beaches where there is fishing zone (legal and illegal) and touristic pressure. Sedimentary classification ranging from coarse to fine sand. These maximum values reported from D. trunculus were related with fine sand and well sorted fine sediments being the minimum ones associated with medium sand and poorly sorted sediments. Regarding length-frequency distributions, protected areas together low fishing activity zones showed more complete population structure compared to other areas. These results highlighted the important role of protection measures on the population conservation management. In order to preserve this important resource monitoring and new management measure should take into account the different types of pressure: authorized and unauthorized fishermen hand-dredging and tourists hand-gathering. Acknowledgements The present study was supported by “VENUS” project (Estudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de sus hábitats asociados) (0139_VENUS_5_E; INTERREG-POCTEP). We would like to thank Rafael Donato, Carlos Farias, Eva García-Isarch, Verónica Duque, Jorge Rey and Teresa Montaño for collaborating in biological sampling. We also thank the ranger team of the Doñana national park and Doñana Biological Station (EBD-CSIC). References Bayed, A., & Guillou, J. (1985). Contribution à l’étude des populations du genere Donax: La population de D. trunculus L. (Mollusca, Bivalvia) de Mehdia (Maroc). Ann. l’Inst. Océanograph, 61, 139-147. IDAPES, 2019. Sistema de información Andaluz de comercialización y producción pesquera. Consejería de Agricultura, Pesca y Desarrollo Rural. http://www.juntadeandalucia.es/agriculturaypesca/idapes/. BOJA Nº 71. Orden del ORDEN de 1 de abril de 2011, por la que se crea una reserva marisquera en el litoral de la provincia de Huelva y se modifica la Orden de 24 de septiembre de 2008, por la que se regula la obtención, renovación y utilización de los carnés profesionales de marisqueo a pie en el litoral de la Comunidad Autónoma de Andalucía. https://www.juntadeandalucia.es/export/drupaljda/reserva_marisquera_huelva.pdf Keywords: Donax trunculus, sandy beaches, spatial distribution, Bivalves, hand-dredge fishery Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Poster Presentation Topic: Ecology, Biodiversity and Vulnerable Ecosystems Citation: Román S, Blanco. Pérez R, Silva L, Rodriguez-Rua A, Cojan M, García E and Delgado M (2019). Spatial distribution of Donax trunculus (Linnaeus, 1758) populations along the intertidal area of the Gulf of Cádiz (SW, Spain). Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00077 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 May 2019; Published Online: 27 Sep 2019. * Correspondence: Dr. Sara Román, Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Cádiz, Spain, sara.romanm@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sara Román Raimundo Blanco. Pérez Luis Silva Ana Rodriguez-Rua Miguel Cojan Esperanza García Marina Delgado Google Sara Román Raimundo Blanco. Pérez Luis Silva Ana Rodriguez-Rua Miguel Cojan Esperanza García Marina Delgado Google Scholar Sara Román Raimundo Blanco. Pérez Luis Silva Ana Rodriguez-Rua Miguel Cojan Esperanza García Marina Delgado PubMed Sara Román Raimundo Blanco. Pérez Luis Silva Ana Rodriguez-Rua Miguel Cojan Esperanza García Marina Delgado Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

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.

Event Abstract Back to Event Spatiotemporal distribution and growth pattern of Venus nux (Gmelin, 1791) in the Gulf of Cádiz (Southern Spain) Marina Delgado1*, Ana Rodríguez-Rua1, Luis Silva1, Esperanza Garcia1, Miguel Cojan1, Sara Roman1 and Raimundo Blanco1 1 Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Spain The venerid clam Venus nux (Gmelin, 1791) is a species distributed along the Atlantic from southern Portugal to Senegal, and is also present in the Mediterranean (Poppe & Goto 1993). Dense populations seem to be restricted to the Alboran Sea and the Ibero-Moroccan Gulf (southern Spain), usually inhabiting muddy sand bottoms from;30 to 350m in depth (Salas 1996). The decline of catches of commercial bivalves in southern Spain has pointed out an overexploitation of these resources. For this reason, a new research line of shellfish resources have been opened in the last years among them this venerid V. nux (Tirado et al., 2011). In this sense, Tirado et al. (2011) have studied the reproductive cycle of Atlantic and Mediterranean populations of V. nux from southern Spain. The main objectives of the present work are intended to complete this previous study, an particularly were (i) to analyse the spatiotemporal distribution and (ii) to provide an updated age-length key for V. nux from the Gulf of Cádiz (Atlantic waters). First the spatiotemporal distribution of this species was investigated using time series data from trawl surveys conducted in the Gulf of Cádiz. The geographic and bathymetric variability in the population distribution was analyzed. Secondly, an in-depth analysis of the shell and updated estimation of growth parameters of the V. nux population were performed using thin-layer cross section methodolgy. Data on species abundance are derived from 1993-2015 monitoring bottom-trawl surveys (ARSA surveys) conducted to evaluate demersal habitats of the continental shelf and slope of the Gulf of Cádiz. We calculated spatial indices of location in longitude, latitude and depth (i.e. center of gravity, CG) to explore and analyze trends in the 21 yr time series of scientific surveys for each year as decribed by Woillez et al. (2009) and using the RGeostat package in R software (Renard et al., 2014; R Core Team 2015). CG is the mean location of a population and also the mean location of an individual clam taken at random in the field (each data location was weighted by clam density) The inertia is the variance of the location of individuals in the population, that is, the mean square distance between an individual clam and the centre of gravity of the population (Bez, 1997). Additionally, a total of 480 V. nux individuals (size range: 20-43 mm) were collected from 2017. Shell length, height and width from each individual were measured to nearest 0.1 mm with a digital vernier caliper to produce length frequency distributions and to estimate relative growth. To determine the species microgrowth pattern by means of the thin-layer technique, a modified protocol of Schenk et al. (1984) for calcified tissues was applied. The left valve of each clam was embedded in poly methyl metachrylate, and thin sections from the umbo to the ventral edge of 100 µm thickness were obtained using low-speed diamond (ISOMET 4000) and grounding and polishing with sequential grinders (sandpaper from 120 to 1 µm) (Delgado et al., 2017). After the identification of annual growth bands, the distance between the umbo and the annual ring was measured using the image analysis software NIS-Elements AR 3.2. Because these measurements are relative to shell height, they were transformed into shell length using the morphometric relationship. Figure 1 shows the spatial distribution of V. nux densities as well as the center of gravity (CG) and inertia (latitude and longitude) in 2015. Geographical range distribution varied between 36º53’40” and 36º25’31” in CG latitude, and -6º35’3” and -7º5’43” in CG longitude. Figure 2 displays the time series of changes in the center of gravity in depth. CG depth varied between 66 and 103 m and a trend towards deeper waters can be observed. The morphometric relationships between shell height (SH), shell width (SW) and shell length (SL) were: SH = 1.096 SL 0.936 (r2: 0.94) and SW=0.837 SL0.937 (r2:0.85). The embedding in poly methyl metachrylate and the subsequent procedures of sectioning, grounding and polishing until obtain thin sections allowed for highly detailed direct observations and analysis of the inner structure of valves. V. nux shell growth pattern is printed in the external prismatic layer. Growth bands were clearly visible in sections of analyzed shells (Fig. 3). Wide translucent zones alternate with opaques zones, probably showing the alternation of fast and slow growth periods (Fig. 3). Translucent growth lines were also present either on the umbo or close to the edge. Figure 1 Figure 2 Figure 3 Acknowledgements We thank the scientific and technical staff of ARSA surveys and its funding support (project PESCADIZ-IEO). The present study was funded within the framework of the project “VENUS” (Estudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de sus hábitats asociados) (0139_VENUS_5_E; INTERREG-POCTEP). References Bez, N. (1997). Statistiques individuelles et géostatistique transitive en écologie halieutique. [PhD Thesis]. [Paris]: Ecole Nationale Supérieure des Mines. Delgado, M., Silva, L., Gómez, S., Masferrer, E., Cojan, M., and Gaspar, M.B. (2017). Population and production parameters of the wedge clam Donax trunculus (Linnaeus, 1758) in intertidal areas on the south west Spanish cost: Considerations in relation to protected areas. Fish. Res. 193, 232-241. Poppe, G. T., and Goto, Y. (1993). “Scaphopoda, Bivalvia, Cephalopoda” in: European sea shells vol.2, ed. C. Hemmen (Wiesbaden, Christa Hemmen), pp. 1–121. Renard, D., Bez, N., Desassis, N., Beucher, H., Ors, F, and Freulon, X. (2014). RGeostats: the geostatistical package [10.0.8]. Mines Paris Tech/ARMINES, Fontainebleau. R Core Team. 2015. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. www.r-project.org. Salas, C. (1996). Marine bivalves from off the southern Iberian Peninsula collected by the Balgim and Fauna 1 expeditions. Haliotis 25, 33–100. Tirado, C., Rueda, J.L., and Salas, C. (2011). Reproductive Cycles in Atlantic and Mediterranean Populations of Venus nux Gmelin, 1791 (Bivalvia: Veneridae), from Southern Spain. J. Shell. Res. 30(3), 813-820. Schenk, R.K., Olah, A.J., and Hermann, W. (1984). “Preparation of calcified tissues for light microscopy” in: Methods of calcified tissue preparation, ed. G.R.Dickson(Elsevier Science Publishers, Amsterdam), pp. 1-56. Woillez, M., Rivoirard, J., and Petitgas, P. (2009). Notes on survey-based spatial indicators for monitoring fish populations. Aquat. Living Resour. 22, 155-164. Keywords: Venus nux, spatiotemporal distribution, Gulf of Cádiz, Growth pattern, geostatistics Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Poster Presentation Topic: Fisheries, Aquaculture and Biotechnology Citation: Delgado M, Rodríguez-Rua A, Silva L, Garcia E, Cojan M, Roman S and Blanco R (2019). Spatiotemporal distribution and growth pattern of Venus nux (Gmelin, 1791) in the Gulf of Cádiz (Southern Spain). Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00065 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2019; Published Online: 27 Sep 2019. * Correspondence: Mx. Marina Delgado, Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Cádiz, Spain, marina.delgado@ieo.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Marina Delgado Ana Rodríguez-Rua Luis Silva Esperanza Garcia Miguel Cojan Sara Roman Raimundo Blanco Google Marina Delgado Ana Rodríguez-Rua Luis Silva Esperanza Garcia Miguel Cojan Sara Roman Raimundo Blanco Google Scholar Marina Delgado Ana Rodríguez-Rua Luis Silva Esperanza Garcia Miguel Cojan Sara Roman Raimundo Blanco PubMed Marina Delgado Ana Rodríguez-Rua Luis Silva Esperanza Garcia Miguel Cojan Sara Roman Raimundo Blanco Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Event Abstract Back to Event Reproductive and population aspects of Mactra stultorum (Linnaeus, 1758) in the littoral of Huelva (SW Spain) Ana Rodriguez-Rua1*, Luis Silva1, Miguel Cojan1, Raimundo Blanco1, Sara Roman1, Esperanza García1 and Marina Delgado1 1 Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Spain The surf clam Mactra stultorum (Linnaeus, 1758) is widely distributed in sandy bottoms at depths ranging between 1 and 30 m along the Black Sea, Mediterranean Sea and Atlantic Ocean, from France to Senegal. This species is part of the accompanying fauna of commercial species such as Chamelea gallina and Donax trunculus. M. stultorum is presented with two different and well-defined morphotypes, easily distinguishable by the colour of the shell: the white variant and the brownish radiating bands variant (Guarniero et al., 2010). Despite its abundance and commercially importance in many countries, no studies regarding its reproductive cycle have been carried out to date in the Atlantic coasts. The aim of this study is to provide information on aspects of the gametogenic cycle and the population structure of M. stultorum in its two morphological variants by means of histological analysis, physiological indices and length-frequency distribution. To achieve this objective, populations of M. stultorum in its two variants were monitored during one year. Samples were collected monthly from the lower part of the intertidal area of Doñana beach (36°48′20.6 N/6°23′8.29 W) using two hand-dredges, one with an experimental mesh size (3 x 3 mm) to allow the collection of the smallest individuals and juveniles and the other with a commercial mesh size (7x7 mm). Shell length (antero-posterior axis) of retained individuals was recorded using a digital vernier caliper to the nearest 0.01 mm to produce length-frequency distributions. Additionally, twenty five individuals for each morphotype were sampled monthly for histological analysis. A piece of visceral mass was taken for each individual and fixed in buffered formaldehyde (4%), dehydrated through ethanol series and subsequently embedded in hydroxyethylmethacrylate (Technovit 7100). Sections (5 μm thick) were cut and stained with Harris Hematoxylin and eosin (H-E). Histological preparations were observed under a light microscope (Nikon Eclipse 90i) and the stages of gonad development were scored according to the scale proposed by Delgado et al. (2013) for C. gallina. To determine the condition index twenty five individuals for each morphotype were sampled per month. Body soft parts and valves were separated and dried at 100º C during 24 h (until constant weight). Soft tissues and valves were then weighted with a precision balance to the nearest 0.0001 g. The index used was: CI = Soft tissue dry weight/Valves dry weight Data on surface sea water temperature was collected in situ and samples of water were taken for chlorophyll a determination. The reproductive cycle of marine bivalves is influenced by a number of environmental factors including temperature and food availability. Water temperature showed high fluctuations along the study year, with maximum values in August (26ºC) and minimum in December (10ºC). The histological results suggest that spawning occurs during spring and summer when sea water temperature was higher. The condition index showed a similar pattern, with a high peak in spring and a decrease during the summer that can be related to a spawning event. The sexes in M. stultorum were clearly separate and sexual dimorphism was not observed. No significant differences between both morphotypes were found. These results are in concordance with a previous study carried on M. stultorum from Tunisia (Chetoui et al., 2018). Several cohorts were identified in the monthly length-frequency distributions throughout the study period. Acknowledgements The present study was funded within the framework of the project “VENUS” (Estudio integral de los bancos naturales de moluscos bivalvos en el Golfo de Cádiz para su gestión sostenible y la conservación de sus hábitats asociados) (0139_VENUS_5_E; INTERREG-POCTEP) and the project “FEMP_AND_04” (Programa plurianual en el ámbito de la recopilación de datos de la comunidad autónoma de Andalucía: Análisis de la pesquería de coquina en el caladero del Golfo de Cádiz) References Chetoui, I., Telahigue, K., Bejaoui, S., Rabeh, I., Ghribi, F., Denis, F., ElCafsi, M. (2018). Annual reproductive cycle and condition index of Mactra corallina (Mollusca: Bivalvia) from the north coast of Tunisia. Invertebrate Reproduction and Development, DOI: 10.1080/07924259.2018.1529636. Delgado, M., Silva, L., Juarez, A. Aspects of reproduction of striped venus Chamelea gallina in the Gulf of Cadiz (SW Spain): Implications for fishery management. Fisheries Research. 146: 86-95. Guarniero, I., Plazzi, F., Bonfitto, A., Rinaldi, A., Trentini, M., Passamonti, M. (2010). The bivalve mollusc Mactra corallina: genetic evidence of existing sibling species. Journal of the Marine Biological Association of the United Kingdom. 90(3): 633-644. Keywords: Mactra stultorum, length-frequency distribution, Gametogenic cycle, Huelva (Spain), condition index Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Poster Presentation Topic: Fisheries, Aquaculture and Biotechnology Citation: Rodriguez-Rua A, Silva L, Cojan M, Blanco R, Roman S, García E and Delgado M (2019). Reproductive and population aspects of Mactra stultorum (Linnaeus, 1758) in the littoral of Huelva (SW Spain). Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00066 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 May 2019; Published Online: 27 Sep 2019. * Correspondence: Mx. Ana Rodriguez-Rua, Oceanographic Center of Cádiz, Spanish Institute of Oceanography, Cádiz, Spain, ana.rodriguez@ieo.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ana Rodriguez-Rua Luis Silva Miguel Cojan Raimundo Blanco Sara Roman Esperanza García Marina Delgado Google Ana Rodriguez-Rua Luis Silva Miguel Cojan Raimundo Blanco Sara Roman Esperanza García Marina Delgado Google Scholar Ana Rodriguez-Rua Luis Silva Miguel Cojan Raimundo Blanco Sara Roman Esperanza García Marina Delgado PubMed Ana Rodriguez-Rua Luis Silva Miguel Cojan Raimundo Blanco Sara Roman Esperanza García Marina Delgado Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The effect of dietary iron (Fe) and vitamin C (Ascorbic acid, AA) supplementation on development, gene expression and antioxidant status of Senegalese sole (Solea senegalensis Kaup, 1858) larvae was investigated. Larvae were reared from 7 to 28 days post hatching (dph) in triplicate using a recirculation system. Three experimental groups were established: The control group was fed Artemia enriched with the microalgae Tisochrysis lutea (T. lutea), the F group, T. lutea supplemented with Fe and the FP group, T. lutea supplemented with Fe and ascorbyl palmitate (AP). Enriched Artemia of F and FP groups displayed a significantly higher content of Fe than the control (850 mu g Fe g(-1) DW and 350 mu g Fe g(-1) DW, respectively). In addition, enriched Artemia of the FP group also showed a significantly higher content of AA than the control (3.5 mu g AA mg(-1) DW and 0.8 mu g AAmg(-1) DW, respectively). At 28 dph, Fe content in larvae from F and FP groups was 1.4- and 1.7-fold higher than the control, respectively. Moreover, larvae from FP group showed the highest AA content throughout the whole experiment (p < 0.05). Larvae from FP group grew faster and completed metamorphosis earlier than the other groups (p < 0.05). Moreover, antioxidant enzymatic activities, lipid peroxidation and total antioxidant content (TAC) at the end of the experiment (p < 0.05) indicated a positive iron-vitamin C interaction with better antioxidant status in FP group. Similar skeletal typology and histological pattern in the development of tissues was observed at 28 dph for larvae under all feeding regimes assayed. Nevertheless, an increasing collagen fibre was evidenced in larvae of FP group The gene expression pattern during the experimental period revealed that different levels of iron and vitamin C modified the expression levels of genes involved in stress (crh, pomca2 and hsc70-4l), glycolytic pathway (pkm), antioxidative defence (slc23a1), osmoregulation (aqp3a, aqp12 and nppc1) and iron homeostasis (hamp1, fpn, tf). The present study is the first report about the potential effect of iron and vitamin C during the first stages of development in S. senegalensis larvae.

The aim of this study was to evaluate the short- and long-term effects of diets consisting in rotifers enriched with different oil emulsions (differing mainly in triacylglycerols levels) and provided during the first week of life. Survival, growth, metamorphosis progress, lipid profile and molecular regulatory pathways were evaluated. For comparison purposes, a diet used routinely in the aquaculture industry based on microalgae was also carried out. The present study shows that dietary triacylglycerols (TAG) levels and fatty acid composition modulate larval survival and growth when supplied during larval pelagic stages. Histological observation and gene expression pattern showed that early larvae regulated intestinal lipid transport, showing a coordinate activation of apolipo-proteins transcripts. Multivariate analyses identified the major contribution of apoEa to discriminate samples by dietary treatments, pointing out the importance of this apolipoprotein as key molecular marker for intestinal lipid mobilization. However, our data indicate that transport capacity is limited in early larvae, increasing in anterior intestine as intestine maturates with larval development, while the increase of fat deposits in the posterior intestine in older larvae supports the limited capacity of this gut section for lipid transport. The accumulation of TAG, phosphocholine (PC) and oleic acid (OA) along pre- and early metamorphosis indicates that these lipids influences positively daily mortality rate, eye-migration progress and growth. Moreover, larval TAG amounts correlate highly with apoA-NBa3 mRNA levels, indicating an active role of this apolipoprotein in endogenous lipid mobilization during development. These data provide new evidence that TAG, PC and OA dietary levels are important for larval development and complement the available information about energy management in sole larvae reinforcing the rotifer feeding period as critical to produce high-quality larvae.Statement of relevance: This paper provides new clues about the mechanisms involved in lipid management in larvae and their consequences during their life-cycle to produce high-quality fry and optimize husbandry procedures. (C) 2016 Elsevier B.V. All rights reserved.

The apolipoprotein E (ApoE) is a key component of several lipoproteins involved in lipid homeostasis. In this study, two cDNA sequences encoding ApoE (referred to as apoEa and apoEb) were characterized in the flatfish Solea senegalensis. The predicted peptides contained conserved structural blocks related with their capacity for lipid binding and lipoprotein receptor interaction. At genomic level, both genes contained five exons and four introns and they were organized into two tandem arrays with apoA-IV gene copies. The phylogenetic analysis clearly separated them into two well-supported clusters that matched with their organization in the genome of teleosts. Whole-mount in situ hybridization located the apoEa signal in the yolk syncytial layer (YSL) of lecitothrophic larval stages (0dph) and in the anterior intestine of exotrophic larvae and benthic fish. In the case of apoEb, hybridization signals were located in the YSL, tail bud, eyes and mouth at 0dph and in the otic vesicle, hindbrain, eyes, pharynx, mouth, heart and intestine at 1dph. In exotrophic larvae, apoEb was ubiquitously expressed in several tissues such as taste buds, brain, mouth, nostril, gills, intestine, liver and around the neuromasts and eyes. Quantification of mRNA levels in pools of whole larvae confirmed distinct expression patterns with a significant reduction of apoEa and an increase of apoEb mRNA levels throughout larval development. Moreover, only apoEa transcripts increased in response to food supply suggesting that this paralog mostly participates in the absorption and transport of dietary lipids and the apoEb in the redistribution of endogenous lipids as well as in neural tissue regeneration.

The apolipoprotein A-I (ApoA-I) is an essential component of the high density lipoproteins (HDL). In this study, the cDNA and genomic sequences of this apolipoprotein were characterized for first time in Solea senegalensis. The predicted polypeptide revealed conserved structural features including ten repeats in the lipid-binding domain and some residues involved in cholesterol interaction and binding. The gene structure analysis identified four exons and three introns. Moreover, the synteny analysis revealed that apoA-I did not localize with other apolipoproteins indicating a divergent evolution with respect to the apoA-IV and apoE cluster. The phylogenetic analyses identified two distinct apoA-I paralogs in Ostariophysi (referred to as Ia and Ib) and only one (Ib) in Acanthopterygii. Whole-mount in situ hybridization located the apoA-I signal mainly in the yolk syncytial layer in lecitotrophic larval stages. Later at mouth opening, the mRNA signals were detected mainly in liver and intestine compatible with its role in the HDL formation. Moreover, a clear signal was detected in some regions of the brain, retina and neural cord suggesting a role in local regulation of cholesterol homeostasis. After metamorphosis, apoA-I was also detected in other tissues such as gills, head kidney and spleen suggesting a putative role in immunity. Expression analyses in larvae fed two diets with different triacylglycerol levels indicated that apoA-I mRNA levels were more associated to larval size and development than dietary lipid levels. Finally, qPCR analyses of immature and mature transcripts revealed distinct expression profiles suggesting a posttranscriptional regulatory mechanism.

The apolipoprotein A-IV (ApoA-IV) plays a key role in lipid transport and feed intake regulation. In this work, four cDNA sequences encoding ApoA-IV paralogs were identified. Sequence analysis revealed conserved structural features including the common 33-codon block and nine repeated motifs. Gene structure analysis identified four exons and three introns except for apoA-IVAa1 (with only 3 exons). Synteny analysis showed that the four paralogs were structured into two clusters (cluster A containing apoA-IVAa1 and apoA-IVAa2 and cluster B with apoA-IVBa3 and apoA-IVBa4) linked to an apolipoprotein E. Phylogenetic analysis clearly separated the paralogs according to their cluster organization as well as revealed four subclades highly conserved in Acanthopterygii. Whole-mount analyses (WISH) in early larvae (0 and 1day post-hatch (dph)) showed that the four paralogs were mainly expressed in yolk syncytial layer surrounding the oil globules. Later, at 3 and 5dph, the four paralogs were mainly expressed in liver and intestine although with differences in their relative abundance and temporal expression patterns. Diet supply triggered the intensity of WISH signals in the intestine of the four paralogs. Quantification of mRNA abundance by qPCR using whole larvae only detected the induction by diet at 5dph. Moreover, transcript levels increased progressively with age except for apoA-IVAa2, which appeared as a low-expressed isoform. Expression analysis in juvenile tissues confirmed that the four paralogs were mainly expressed in liver and intestine and secondary in other tissues. The role of these ApoA-IV genes in lipid transport and the possible role of apoA-IVAa2 as a regulatory form are discussed.

The aim of this work was to assess the effects of a dietary supplement of vitamin C (as ascorbyl palmitate, AP) delivered through new and optimized alginate microcapsules (MA) on larval performance, antioxidant status and gene expression profiles. For this purpose, three MA (referred to as MA-1, MA-2 and MA-3) with increasing AP content ranging from 1700 to 5700μg AP g−1 DW were assayed. Sole larvae were fed the three MA from first feeding to 7days post-hatch (dph) and later replaced by Artemia from 7 to 28 dph. The experimental groups were performed in triplicate using a recirculation system. The efficiency of AP inclusion into MA was 55%. At 7 dph, larval ascorbic acid (AA) content was proportional to the AP concentration included in MA (p<0.05). Larval growth until 7 dph was low but significantly higher in larvae fed MA-2 and MA-3. After Artemia supplying, a compensatory growth was detected in the three experimental groups whereas a faster metamorphic process and a higher weight at 28 dph in larvae fed MA with a higher AP content (MA-2 and MA-3) was observed (p<0.05). Moreover, Artemia feeding substantially increased the larval AA content during development peaking at 18 dph and decreasing at the end of metamorphosis with significantly lower AA levels in larvae fed MA-3. This reduction coincided with a higher total antioxidant capacity and lipid peroxidation whereas no differences in catalase or total glutathione peroxidase were detected. Expression data revealed that MA diets significantly modified the transcript levels of 16 genes involved in antioxidant defence (gpx1), tissue structure (col1a1 col1a2 and col1a3), stress (hsc70-1, hsc70-2, hsc70-3, gr1, gr2, pomcb), glycolytic pathway (gapdh1 and pkm), osmoregulation (cftr, nkcc2 and nkcc1) and pigmentation (mc1r). All these data reveal novel new insights about role of vitamin C during early stages of S. senegalensis to modulate growth, stress and antioxidative status in later developmental stages.

In the present work, five genes encoding different Na(+),K(+) ATPase (NKA) α-isoforms in the teleost Solea senegalensis are described for the first time. Sequence analysis of predicted polypeptides revealed a high degree of conservation across teleosts and mammals. Phylogenetic analysis clustered the five genes into three main clades: α1 (designated atp1a1a and atp1a1b), α2 (designated atp1a2) and α3 (designated atp1a3a and atp1a3b) isoforms. Transcriptional analysis in larvae showed distinct expression profiles during development. In juvenile tissues, the atp1a1a gene was highly expressed in osmoregulatory organs, atp1a2 in skeletal muscle, atp1a1b in brain and heart and atp1a3a and atp1a3b mainly in brain. Quantification of mRNA abundance after a salinity challenge showed that atp1a1a transcript levels increased significantly in the gill of soles transferred to high salinity water (60 ppt). In contrast, atp1a3a transcripts increased at low salinity (5 ppt). In situ hybridization (ISH) analysis revealed that the number of ionocytes expressing atp1a1a transcripts in the primary gill filaments was higher at 35 and 60 ppt than at 5 ppt and remained undetectable or at very low levels in the lamellae at 5 and 35 ppt but increased at 60 ppt. Immunohistochemistry showed a higher number of positive cells in the lamellae. Whole-mount analysis of atp1a1a mRNA in young sole larvae revealed that it was localized in gut, pronephric tubule, gill, otic vesicle, yolk sac ionocytes and chordacentrum. Moreover, atp1a1a mRNAs increased at mouth opening (3 DPH) in larvae incubated at 36 ppt with a greater signal in gills.

To gain information concerning the optimal feeding conditions for meagre (Argyrosomus regius) culture at the juvenile stage (170g initial wt), four experimental feeding regimes were tested in duplicate lots. All fish were fed with a similar total weekly ration but distributed in 7, 6, or 5 days per week in the morning (lots 7M, 6M, and 5M, respectively) or 5 days per week in the afternoon (lots 5A). Over the 45 and 90-day experiment, some biometric, productive, and metabolic parameters were determined. Growth rates were very similar in all lots, the highest being in 6M fish, which exhibited the best food utilization. No major differences were detected either in body morphometry or body composition. Differences in liver and muscle activities in certain enzymes involved in the intermediary metabolism appear to reflect the impact of the intermittent food deprivation in 5M and 5A fish. In general, the feeding regime based on weekly one-day food deprivation appeared to be favourable for fish and thus could be profitable for fish farming. (C) 2014 Elsevier B.V. All rights reserved.

The aim of the present study was to evaluate the culture potential of meagre, Argyrosomus regius (Asso, 1801). Trials were conducted in two different facilities in Spain, the LIMIA research centre (Mallorca) and the IFAPA research centre “El Toruno” (El Puerto de Santa Maria). In May 2006, males with free milt and females with vitellogenic oocytes bigger than 500 μm were injected with salmon gonadotropin releasing hormone analogues (sGnRHa). Spawning occurred approximately 38 hours after induction. Fecundity was high with 1.207.000 eggs collected from a 13 kg female at LIMIA in a single spawn. The larval development, growth and morphological changes were described from 0 to 30 days post hatching (DPH). The mean length of the newly hatched larvae ranged from 2.20 ± 0.02 mm (LIMIA) to 3.19 ±0.09 mm (IFAPA). Feeding began on 3 DPH, initial swim bladder inflation was observed on 5 DPH, and metamorphosis was completed on 30 DPH. Growth was very fast and the post-larvae reached 15.11 ± 3.49 mm (LIMIA) and 11.66 ± 0.96 mm (IFAPA) in 30 days Cannibalism was observed from 15 DPH onwards. These preliminary results indicate the meagre as a priority species for the diversification in aquaculture.

The meagre (Argyrosomus regius) is a commercially important species for fisheries, and aquaculture production has been increasing in recent years. However, this growing importance has not been matched by increased genetic knowledge of the species. For this reason, an initial approach has been made to understanding the genetics of the meagre, using three particular multigene families (45S and 5S ribosomal DNA and U2 snRNA gene) as both molecular and cytogenetic markers. Only one type of 5S rDNA and only one ITS-1 (from 45S rDNA) were obtained, and these therefore could provide the basis for the development of genetic markers for this species. However, the U2 snRNA gene produced a multi-band electrophoretic pattern, and some of these bands were demonstrated to be linked with the U1 snRNA gene. This linkage could also provide a good species-specific marker which could be useful for tracing the evolutionary history of the Sciaenidae family. In this study, we have described for the first time the karyotype of the meagre: this is composed of 48 acrocentric chromosomes. Each of the three gene families were localized on different chromosome pairs, although the U2 snRNA gene probe was also located scattered throughout the genome of the meagre, as expected by the amplification pattern.

The reproductive cycle of Spisula solida (L., 1758) was investigated for the first time in the southwest of Spain, using specimens collected from Punta Umbria (Huelva), between April 2001 and May 2002. A total of 2805 individuals of shell lengths ranging from 9.1 to 38.4 mm were analysed. The gonad development was determined by means of histological methods and variations of dry weight. Five gametogenic stages were identified (I-Immature, II-Maturing, III-Ripe, IV-Spawning, V-Post-spawning). The sex-ratio obtained was 5:4 (chi(2)=6.12, df=1, p > 0.01), males being more abundant than females. Two hermaphrodite individuals were recorded. Development of the gonad began in November and spawning occurred between December and June, with maximum peaks in April (82% males) and May (87% females). The period of sexual rest took place from July to October. Gametogenesis in this species is a response to low seawater temperatures, and spawning occurs with low temperatures that increase progressively.

AbstractAssays carried out under laboratory‐controlled conditions revealed that eggs of Senegalese sole, Solea senegalensis Kaup 1858, incubated at 10, 18, 27 and 33 grams per litre (g L−1) reached their maximum hatching rates (above 80%) 48 h after incubation. In contrast, hatching was significantly delayed (24 h) and completely failed when the salinity was set at 5 and 0 g L−1, respectively. Newly hatched and early‐developing yolk sac larvae presented similar survival rates 3 days after hatching (DAH) when exposed to salinities of 10, 18, 27 and 33 g L−1. Larvae incubated at 5 g L−1 salinity died a few hours after hatching once they were released from their respective chorions. The notochord length was unmodified by salinity 5 DAH. Nevertheless, an overall lower myotomal height and a putative delay in the depletion of yolk sac were found in larvae reared at 10 g L−1. This anomaly in overall larval development became more pronounced with the occurrence (100% of analysed larvae) of mouth deformities and a lack of functionality under 10 g L−1 salinity. Transferring 2 DAH larvae from 33 g L−1 (exhibiting normal mouth development) to a medium with a salinity of 10 g L−1 had no effect on first feeding, weight and metamorphic index. Overall our results indicate the existence of a key time window (0–2 DAH) in which a salinity value higher than 10 g L−1 is required to achieve adequate mouth development and further functionality of larvae. The present work represents a valuable contribution to the sole industry, opening new possibilities in hatchery management practices.