Variability of taurine concentrations in Mytilus galloprovincialis as a function of body size and specific tissue

7 páginas, 5 figurasVariability of taurine (2-aminoethane sulfonic acid) was studied as afunction of size in the mussel Mytilus galloprovincialis and tissue specificity. Isometric and/or allometric relationships were established with regard to total soft mass of the mussels between 20 and 60 mm shell length. Relative amounts of taurine dropped significantly with increasing mass of whole soft tissues with an allometric coefficient value of − 0.15. The inverse relationship between taurine and increasing size of mussels was confirmed for gill epithelium and labial palp (allometric coefficient values of − 0.16 and − 0.10, respectively), tissues that, in turn, represented isometric functions with regard to total soft mass. Although relative amounts of taurine were significantly different in digestive gland, mantle and foot, relationships with increasing size of mussels remained unchanged in these tissues. Gill area of mussels was related to soft mass with an allometric coefficient of 0.70 by 2D Image Analysis, but increased to 0.85 when introducing a third dimension, i.e. gill thickness. Results are discussed according to gill structure analysis and taurine functionality.This study was supported by the contract-project PROINSA, Code CSIC 2004448, Galicia PGDIT03RMA13E. JMFB acknowledges funding by the Program Ramón y Cajal 2003 from Ministry of Education and Science (Spain).Peer reviewe

Flexibility of physiological traits underlying inter-individual growth differences in intertidal and subtidal mussels Mytilus galloprovincialis

14 páginas, 5 figuras, 2 tablas.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedMussel seed (Mytilusgalloprovincialis) gathered from the intertidal and subtidal environments of a Galician embayment (NW, Spain) were maintained in the laboratory during five months to select fast (F) and slow (S) growing mussels. The physiological basis underlying inter-individual growth variations were compared for F and S mussels from both origins. Fast growing seemed to be a consequence of greater energy intake (20% higher clearance and ingestion rate) and higher food absorption rate coupled with low metabolic costs. The enhanced energy absorption (around 65% higher) resulted in 3 times higher Scope for Growth in F mussels (20.5±4.9 J h−1) than S individuals (7.3±1.1 J h−1). The higher clearance rate of F mussels appears to be linked with larger gill filtration surface compared to S mussels. Intertidal mussels showed higher food acquisition and absorption per mg of organic weight (i.e. mass-specific standardization) than subtidal mussels under the optimal feeding conditions of the laboratory. However, the enhanced feeding and digestive rates were not enough to compensate for the initial differences in tissue weight between mussels of similar shell length collected from the intertidal and subtidal environments. At the end of the experiment, subtidal individuals had higher gill efficiency, which probably lead to higher total feeding and absorption rates relative to intertidal individualsThis work was funded by the project Physiology and Genetic of Growth in Commercial Bivalves ‘FIGEBIV’ (AGL2013-49144-C3-2-R). Jade Irisarri was funded by JAE-Predoc CSIC-FSE 2012–2015.Peer reviewe

Lipid classes of mussel seeds Mytilus galloprovincialis of subtidal and rocky shore origin

15 páginas, 4 tablas, 1 figuraThe lipid class composition in juveniles of the mussel Mytilus galloprovincialis of rocky shore and subtidal origin were compared after transfer to a subtidal environment in the Ria de Arousa (northwest Spain). The experiment was conducted between November 27, 1995 and July 3, 1996. In addition to mussel origin, the influence of the different environmental parameters on the changes in lipid classes was studied. At the start of the experimental period, only the relative percentage of the triacylglycerols (energetic function) was significantly higher in the subtidal specimens. However, when the initial absolute contents were examined, the phospholipids and sterols were also significantly higher in this mussel group. Differences in the relative percentages of phospholipids and sterols were maintained until day 22 of the experiment. Our results show that during the first 36 days of the experimental period the mussel origin participated significantly in the model explaining the variance of triacylglycerols, phospholipids and sterols. These results suggest the initial differences in content and relative percentages of the lipid classes studied are possibly linked to the contrasting environmental conditions in which the two mussel groups had previously developed (subtidal and rocky shore habitats). In contrast, 50 days into the experiment the origin term did not participate in the model of variance of these lipid classes. These results in turn suggest that during the course of the investigation the mussel seeds of rocky shore origin were able to exploit the available food resources in the subtidal habitat. Based on these results, the influence of mussel origin and environmental parameters on the changes in lipid classes of both mussel groups is discussed.This study was financed by the project CICYT MAR97-0592.Peer reviewe

Effects of commercial enrichment diets on the nutritional value of the rotifer (Brachionus plicatilis)

12 páginas, 4 tablasThe rotifer, Brachionusplicatifis, pre-fed on baker’s yeast, was enriched for 6 h with three commercial products from Artemia Systems S.A., namely Protein Selco (microcapsules), Dry Selco (microparticles) and Super Selco (an emulsion containing high levels of n-3 HUFA). The biochemical composition (protein, carbohydrate, total lipid, lipid classes and fatty acids) and dry weight ofthe rotifers before and after the enrichment experiments were studied. Two of the enrichers, Dry Selco and Super Selco, are rich in lipid but poor in protein and carbohydrate. Protein Selco contains lipid as well as protein and carbohydrate. The biochemical composition and the dry weight of the rotifers were changed after 6 h of enrichment. The percentage of protein and lipid increased with all of the three enrichers and the percentage of carbohydrate decreased slightly. Rotifer dry weight increased in rotifers enriched on Protein Selco. Phospholipids, sterol esters+ waxes, triacylglycerols and free fatty acids increased after the enrichment with the three enrichers while sterols slightly decreased when the rotifers were fed on Protein Selco. The fatty acid content of the rotifers increased after the enrichment with all ofthe enrichers and this increase was particularly apparent in the case of n-3 HUFAs (20: Sn-3 and 22 : 6n-3).This work was supported by the contract-project “ Larval Nutrition of Turbot” with the fish farm Cultivo de Peces S.A. (CULTIPECSA).Peer reviewe

Anatomía funcional de moluscos bivalvos

1 pósterSe explica la anatomía de los moluscos bivalvos y las funciones de cada partePeer reviewe

The role of fish predation on recruitment of Mytilus galloprovincialis on different artificial mussel collectors

6 páginas, 3 figuras, 2 tablasFish predation interferes with mussel seed population dynamic and is an important limiting factor on seed supply in several areas of mussel farming production. In the present study we assessed the impact of fish predation in a mussel farm sited in the Rı´a de Ares-Betanzos (Galicia, NW Spain). To assess fish impact on recruitment, we have quantified mussel recruitment densities with or without excluding fish predation. The experiment was carried out using four different collector rope designs that could contribute to decrease the fish predation impact on the amount of mussel seed collected for cultivation. The unprotected long-line (fish exposed treatment) showed lower recruitment densities than the protected one (fish exclusion treatment) for every collector design tested (between 38 and 58%; ANOVA, p < 0.001) with the exception of non-filamentous loop complement ropes (NF-L), which showed similar density values (9104 316 and 7855 375 indiv/m in the protected and unprotected long-line, respectively; Tukey p > 0.05). In addition, in the protected long-line recruitment densities were homogeneous between collector designs (8820 635 indiv/m; ANOVA p > 0.05) whereas in the unprotected one statistically significant differences between collectors were observed. These results pointed out the influence of fish predation in the amount of mussel seed collected and its different effect between collector designs. The homogeneous density recorded in the protected long-line between collector designs would suggest the presence of another regulation factor of population size when fish predation is excluded. This regulation factor could be the intra-specific competition derived by space and food limitations of the studied area. With regard to the collector design, differences in recruitment density in the unprotected long-line would suggest different degree of protection from predators depending on collector texture and lacing complexity which could enhance the strength of seed attachment and create space refuges from fish.This study was supported by the contract-project CSIC-PROINSA, Code CSIC 20061089, Galicia PGIDIT06RMA018E.Peer reviewe

Free amino acid composition in juveniles of Mytilus galloprovincialis: spatial variability after Prestige oil spill

10 páginas, 5 figuras, 2 tablasComposition of free amino acids (FAA) in juveniles of Mytilus galloprovincialis was analysed along a large geographical coastline area in Galicia (NW Spain). Individuals were sampled in February 2003, three months after the Prestige oil spill. Pollution values at sampling time were reported as polycyclic aromatic hydrocarbons (PAHs) concentrations in soft tissues of individuals and varied between the highest amount observed in Carrumeiro mussels (502 ng/g dw) and the lowest in Pindo mussels (196 ng/g dw), both locations being close to each other in the centre of the geographical area under study. Pollution values in the other populations varied within the range of 241–347 ng/g dw. Total free amino acids (TFAA) were highest in Aguiño–Pindo–Carrumeiro juveniles at the centre of the Coastline area studied (420–462 μmol/g dw) as compared to the other populations at North and South of Galicia (312–347 μmol/g dw). TFAA results were based on the variability observed in protein free amino acids (PFAA μmol/g dw) among populations (214–249 μmol/g dw for Aguiño–Pindo–Carrumeiro mussels and 98–149 μmol/g dw for the other populations) whereas non-protein free amino acids (NPFAA) taurine and ornithine did not show any significant spatial pattern of variation. Glycine and alanine represented the most abundant PFAA (16–29% and 2.7–11.9% of TPFAA, respectively) and significant correlations between PFAA and both the protein content of soft tissues (r=−0.82) and the condition index of juveniles (r=0.86) were observed. No significant relationships were detected, however, between pollution values in soft tissues as PAHs and FAA profiles with the exception of alanine concentrations as percentage of TFAA (r=0.88; P<0.01). The latter seemed to be an “all or nothing” effect likely due to the influence of other abiotic factors at one of the sampling sites. Such relationship was found not significant when the outlier represented by Carrumeiro mussels was removed from the analysis. The most abundant free amino acid taurine (43.2–68.5%TFAA) followed an inverse variability of that of glycine and by extension of the group PFAA most likely as a compensatory decrease in mussel populations with low protein content (and high condition index). Accordingly, taurine:glycine (t:g) ratio varied between 1 and 2 in most mussel populations but increased up to 3.2–4.2 in Miranda and Bueu mussels at both ends of the geographical interval studied with a corresponding PAHs concentrations of 261 and 304 ng/g dw, respectively. These mussel populations with the highest t:g ratios were characterised by the lowest PFAA contents (below 40%) and condition index values (below 10%). Results of the present study established a significant link between energetic status of growing juveniles and FAA concentrations in environments with different pollution degrees. Variability of the free amino acids profiles in soft tissues were related to endogenous factors of juveniles (protein content, condition index) whereas no relationship with contamination values could be observed. The utility of t:g ratio as general condition factor for M. galloprovincialis is also corroborated for in situ growing juveniles.This study was supported by the contract-project PROINSA, Code CSIC 2004448, Galicia PGDIT03RMA13E. JMFB acknowledges funding by the Program Ramón y Cajal 2003 from Ministry of Education and Sciences (Spain).Peer reviewe

Solar irradiance dictates settlement timing and intensity of marine mussels

11 páginas, 4 figuras, 2 tablas.-- This work is licensed under a Creative Commons Attribution 4.0 International LicenseIdentifying the environmental factors driving larval settlement processes is crucial to understand the population dynamics of marine invertebrates. This work aims to go a step ahead and predict larval presence and intensity. For this purpose we consider the influence of solar irradiance, wind regime and continental runoff on the settlement processes. For the first time, we conducted a 5-years weekly monitoring of Mytilus galloprovincialis settlement on artificial suspended substrates, which allowed us to search for interannual variability in the settlement patterns. Comparison between the seasonal pattern of larval settlement and solar irradiance, as well as the well-known effect of solar irradiance on water temperature and food availability, suggest that solar irradiance indirectly influences the settlement process, and support the use of this meteorological variable to predict settlement occurrence. Our results show that solar irradiance allows predicting the beginning and end of the settlement cycle a month in advance: Particularly we have observed that solar irradiance during late winter indirectly drives the timing and intensity of the settlement onset, Finally, a functional generalise additive model, which considers the influence of solar irradiance and continental runoff on the settlement process, provides an accurate prediction of settlement intensity a fortnight in advanceThis study was funded by PROINSA-CSIC contract-project (CSIC0704101100001), CSIC- PIE project (CSIC 201540E107) and EU H2020 project ClimeFish (EU 677039).Peer reviewe

Water flows through mussel rafts and their relationship with wind speed in a coastal embayment (Ría de Ares-Betanzos, NW Spain)

14 páginas, 4 tablas, 8 figurasKnowledge of water flows through mussel rafts and their controlling factors is required for an ecosystem approach to the sustainable management of this culture in the Galician rías. With this aim, 4 acoustic 2D-ACM current meters were hung from the bow of 4 rafts located in the mussel cultivation areas of the Ría de Ares-Betanzos (NW Spain) during autumn 2007. Simultaneously, an Aanderaa DCM12 Doppler profiler was moored in an area free of rafts in the middle ría. There were differences in the subtidal and tidal dynamics of the middle channel and mussel farm areas. The tide explained 51.5% of the total variance of the surface current in the middle ría. The explained variance in the seed collection areas of Redes (inner ría) and Miranda (outer ría), where only 2–3 rafts are anchored, were 64.1% and 16.8%, respectively. In the cultivation areas of Arnela (inner ría) and Lorbé (middle ría), where 101 and 40 rafts are anchored, 14.3% and 53.4% of the total variance was explained by the tide. These disparities in the contribution of the tide are likely due to a combination of topographic and bathymetric differences among sites and distortions of the natural flow by the rafts and their hanging ropes. Furthermore, there was a marked influence of winds on the subtidal currents within the rafts; contrasting correlation coefficients and lag times between wind speed and currents were observed for the outer and inner sides of the embayment. The filtration rate of the growing mussels and the number of mussels per raft allow an efficient clearing of the particles transported across the hanging ropes by the measured subtidal currents of 2–3 cm s–1 characteristic of the cultivation areas of Arnela and LorbéPROINSA Mussel Farm, codes CSIC20061089 and 0704101100001Xunta de Galicia PGIDIT06RMA018E and PGIDIT09MMA038EESSMA project Spain–Canada Grant of MICINNPeer reviewe

Secretion of byssal threads in Mytilus galloprovincialis: quantitative and qualitative values after spawning stress

30 páginas, 2 tablas, 4 figuras.-- The final publication is available at www.springerlink.comThe effect of spawning events of the mussel Mytilus galloprovincialis on both quantitative and qualitative values of byssus secretion and its associated attachment force was investigated. Byssogenesis rates and absorption efficiency values were significantly reduced after spawning of individuals. However, the maintenance of individuals under sub-optimal conditions (lack of microalgae in the diet) for a week caused no effect on thread’s number. Surprisingly, the attachment force varied within a narrow range of values (1.7–1.9 N) with the exception of a significant drop in the experimental group spawned and kept unfed (1.0 N; P < 0.001), most likely due to a similar pattern of the thread’s thickness variability. Qualitative analysis concerned to the amino acid composition of the byssus highlighted a higher presence of the basic residues histidine and lysine in threads secreted by spawned individuals. The presence of both histidine and lysine residues in the byssal collagen is associated to the formation of cross-links and specifically histidine has a functionality with a pronounced effect on metal chelation to stabilise the integrity of the byssus. Results reported here evidence the necessity to integrate all components that eventually determines the attachment strength of the mussels to get more insight to the plasticity of such secretion. Morphology of the byssus (thickness) secreted under different endogenous conditions of mussels was the major parameter to explain variability in the attachment force. Moreover, aminoacidic composition as quality term of the byssus secreted may also contribute to understand the plasticity of this secretion and needs to be extended in further surveysThis study was funded by the Project AGL2006-06986/ACU (Ministerio de Educación y Ciencia, Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica 2004-2007)Peer reviewe