Mytilus Galloprovincialis Lmk Research Articles

Settlement and recruitment pattern variability of the mussel Mytilus galloprovincialis Lmk. from SE Bay of Biscay (Basque Country)

The annual settlement and recruitment patterns of Mytilus galloprovincialis Lmk. were assessed using collector ropes deployed at five sites along the Basque coast inhabited by wild mussel populations. The study was carried out over two periods of ten months each in three estuarine and two coastal sites, and enabled the discovery of a potential relationship between observed primary settlement and the spawning period of wild mussel populations, shedding light on the recruitment of these populations. Primary settlers were present throughout the year with highest abundances from early summer to fall. A spatial settlement pattern was also observed, with eastern estuaries showing higher settlement rates than western ones and coastal sites showing intermediate settlement rates. These spatial and temporal settlement variations could be partially explained by seasonal fluctuations in environmental factors, such as temperature and nutrients, as well as by spawning differences observed at these estuarine and coastal sites. Some inter-annual variability of settlement and recruitment was observed, with higher settlement rates in the second studied year. This inter-annual variability was consistent with the inter-annual variability of the environmental factors. The recruitment of juvenile mussels was shown to be more determined by post-settlement processes than by initial settlement abundance. Indeed, there was a substantial loss of post-larvae during fall and winter, which was due to these post-settlement processes. Thus, it is advised that ropes, which were deployed in spring and collected in winter, to be collected earlier to avoid such losses. Little space is available (i.e., due to user conflict) on the Basque Coast. Despite these limitations, these sites, particularly Bidasoa estuary, could be suitable for future seed gathering for the mussel aquaculture industry in the Basque Country.

Analysis of culture production and growth rate patterns of mussel (Mytilus galloprovincialis Lmk.) cultured in the open ocean of the SE Bay of Biscay for the commercial product development

Mytilus galloprovincialis Lmk. mussels were cultured at two culture depths in a submerged longline system, located in the SE Bay of Biscay, from June 2013 to August 2014. The Von Bertalanffy Seasonal Growth Function (VBSGF) of the original seeded batch, without newly settled seed, at each culture depth was assessed. Mussels maintained their reached size during the slow growing months and size increased thereafter. In addition, to test both culture depth scenarios for resource management, the production of commercial pieces (“small” and “large” mussels) in quantity (mussel classification) was assessed. VBSGF output proved that commercial mussels may well be harvested throughout the year in the studied site. The culture period required to produce mussels of a commercial size was 1 to 1.5 years, depending on seeding date.

Variability of the reproductive cycle in estuarine and coastal populations of the mussel Mytilus galloprovincialis Lmk. from the SE Bay of Biscay (Basque Country)

Mussel commercial production depends on wild populations to obtain the seed. Therefore, any new farming initiative needs deep knowledge on reproductive cycle of native mussel populations. The reproductive cycle of Mytilus galloprovincialis Lmk. from five sites, three estuarine and two coastal, along the coast of the Basque Country were assessed using gonad index and stereology over 2 consecutive years (2010 and 2011). Sex ratios, developmental stages of gonads, as well as reserve tissue cycle were analyzed. The onset of gametogenesis was observed from winter to spring, with spawning occurring from spring till summer. A resting phase followed with an increase in reserve tissues (adipogranular cells) was observed in fall. Mussels stayed ripe during winter until favorable environmental conditions were met in spring. Differences in reproductive cycles were found among populations, and also, year-to-year variability was observed within each population. In two of the studied sites asynchrony in the timing of spawning was observed between genders. These timing differences, however, did not prevent mussels at those sites from reproducing successfully. The Bidasoa estuary points to the potential of such studied sites for becoming the main source of wild mussel spats for future expected commercial mussel farming in the Basque Country. To ensure year-to-year maximum reproductive output, however, wild mussels harvest should be avoided from spring to the end of summer in this region.

Genetic Diversity Analysis of the Natural Populations of Mediterranean Mussels [Mytilus galloprovincialis (Lmk.)] in Agadir Bay: Assessment of the Molecular Polymorphism and Environmental Impact

Mediterranean mussel (Mytilus galloprovincialis Lmk) has a great environmental and economic importance for Morocco. This work studies the genetic structure and impact of chemical pollution on three different marine populations of Mytilus galloprovincialis that live within Agadir bay. Three collections were made at two clean sites (Cape Ghir and Cape Aglou) and at an impacted site exposed to intense boating and industrial activities (Anza). A 300-bp portion of the mitochondrial DNA coding-region Cytochrome C Oxidase subunit 1 (COI) was studied by polymerase chain reaction (PCR) and DNA sequencing reactions to assess and evaluate amounts of polymorphism in each site. Genetic analysis using COI for 64 individuals showed no significant differentiation between the three subpopulations. AMOVA demonstrated that only 2.83% of variation exists between populations. Besides the genetic evidence presented herein, mussel’s adaptation mechanisms and strategies to marine pollution are also discussed.

A sensory and nutritional validation of open ocean mussels (Mytilus galloprovincialis Lmk.) cultured in SE Bay of Biscay (Basque Country) compared to their commercial counterparts from Galician R\xedas (Spain)

Mussel shell biometry, nutritional quality as well as consumer sensory evaluation of experimental open ocean cultured mussel Mytilus galloprovincialis (Lamarck 1819) were analyzed and compared to that of commercial mussels from Galician Rías available in the local market. Both mussel products were of the same commercial size. In this study, open ocean mussels were significantly higher and wider than those of Galician Rías. In addition, with the exception of ash content, both mussel products showed similar biochemical composition. Regarding fatty acid profiles, however, statistical differences were detected. These differences were not fully reflected in the sensory assessment. In terms of consumer acceptability, both mussel products were considered equally satisfactory.

Growth, biochemical profile, and fatty acid composition of mussel (Mytilus galloprovincialis Lmk.) cultured in the open ocean of the Bay of Biscay (northern Spain)

Growth performance, allometry, condition index, and biochemistry of mussel (Mytilus galloprovincialis Lmk.) cultured in a submerged longline system were investigated from June 2013 to August 2014. Mussels grew faster from spring to autumn. Chlorophyll-a concentration along with sea current speed will represent major factors controlling mussel seasonal growth and survival success in the case-study region. The lowest condition indices and highest ash contents were respectively found within winter; so the most favorable conditions for mussel harvesting and commercialization operations would tentatively occur within autumn, spring and summer. The positive mussel growth and low chlorophyll-a concentrations found during summer may also indicate utilization of non-phytoplankton food sources. No clear evidence of local depth associated physiological effects on the mussel individuals was detected. This contribution represents the first available information on open ocean mussel aquaculture from the southeastern Bay of Biscay. Statement of relevance(1.)The present contribution fills a noticeable gap in the literature on mussel biology and aquaculture science in the Bay of Biscay.(2.)The present contribution reports the first technical and scientific success of open ocean mussel aquaculture practices in the Bay of Biscay.(3.)The present contribution offers scientific information for further data comparisons within the context of other case studies or hypothesis.(4.)The present contribution offers valuable information for decision-making processes on commercial open ocean aquaculture.

Biodeposit contribution to natural sedimentation in a suspended Mytilus galloprovincialis Lmk mussel farm in a Galician Ría (NW Iberian Peninsula)

Abstract This work aimed to study how mussel culture of Mytilus galloprovincialis Lmk modulates the natural sedimentation rates through the water column as key controlling factor of the potential organic load reaching the bottom sediments. To achieve this objective, seston, feces production and natural sedimentation dynamics were characterized during 4 seasonal campaigns at two mussel rafts and at a reference station not affected by the mussel culture in the Ria de Ares–Betanzos (NW Iberian Peninsula). Our results showed that seston content are below the pseudofeces threshold ( − 1 ) with inorganic contents ranging between maximum values of 76 ± 4% in winter and minimum values of 6 ± 4% in spring. These seasonal variations controlled the feces (biodeposits) production by mussels (11–221 mg ind − 1 d − 1 ) that increased with seston content, in particular under winter stormy conditions, when intense continental runoff and resuspension processes represented an important source of non-digestive inorganic particles for mussels. Natural sedimentation fluxes recorded by means of sediment traps under the rafts (84–536 g m − 2 d − 1 ) seasonally varied with mussel biodeposition being 6–7 folds the rates at the reference site. This fact corroborates that mussel feeding activity throughout the production of feces increased natural sedimentation rates in the Ria de Ares–Betanzos. However, the relatively energetic water column conditions and the potentially high degradation rates of feces in the culture area reduced up to 55–90% the biodeposits' organic carbon potentially arriving at the seafloor. This indicates that in highly hydrodynamic environments the impact derived from shellfish culture may be reduced, attenuating a possible impact on the benthic communities.

Feedback between physiological activity of Mytilus galloprovincialis and biogeochemistry of the water column

We investigated the filter-feeding behaviour of individual Mytilus galloprovincialis Lmk in the Ria de Vigo (Galicia, northwest Iberian Peninsula) in order to assess changes in water column biogeochemistry due to mussel culture and the effect of seston organic content on mussel physiological rates. The study was carried out during 1 yr under different oceanographic scenarios by comparing data from a station located in a raft area (RaS) and from a reference site (ReS) with no direct effects of rafting culture activities. Results showed differences between stations in water column nutrient contents, mainly in ammonium levels, with a mean annual excess of 40% at RaS due to mussel feeding activities. We also observed a pronounced deficit of particulate matter at RaS, both in terms of chlorophyll a (chl a, �33%) and microbial plankton carbon (�34%), reflecting preferential grazing of mussels on living plankton carbon. Our investigation of the seston organic compound revealed that feeding and digestion of M. galloprovincialis are highly dependent on the quality of the organic composition of the available food. Mussel organic ingestion rate and absorption efficiency were more strongly correlated with microbial plankton carbon contents than with particulate organic carbon and chl a, illustrating the importance of considering not only auto- trophic but also heterotrophic microbial plankton carbon as high-quality food for mussels in the Ria de Vigo.

Dietary Enhancement of Selected Fatty Acid Biosynthesis in the Digestive Gland of Mytilus galloprovincialis Lmk.

The fatty acid composition of the digestive gland from the mussel Mytilus galloprovincialis subjected to three different dietary regimens for 30 days was analyzed. Samples were collected at the beginning and end of the trial to obtain a comprehensive picture of fatty acid dynamics. Group A was unfed; group B received a diet consisting of 100% Thalassiosira weissflogii and, thus, similar to natural food; and group C received a diet consisting of 100% wheat germ conferring a 18:2ω-6 abundance. Results indicate that fatty acid composition of lipid and phospholipid classes was affected by dietary treatments. However, adult mussel homeostatic skills minimized effects, and thus, only wheat germ diet deeply modified the fatty acid composition. Furthermore, in group C, the occurrence of the non-methylene-interrupted trienoic fatty acids was indicative of de novo fatty acid synthesis presumably because of active fatty acid elongation and Δ5 desaturation system, also supported by the general ω-3 polyunsaturated fatty acid decrease.

Genetic Diversity Analysis of the Natural Populations of Mediterra­nean Mussels [Mytilus galloprovincialis (Lmk.)] in Agadir Bay: Assess­ment of the Molecular Polymorphism and Environmental Impact

Genetic Diversity Analysis of the Natural Populations of Mediterra­nean Mussels [Mytilus galloprovincialis (Lmk.)] in Agadir Bay: Assess­ment of the Molecular Polymorphism and Environmental Impact

Cytotoxic effect of palytoxin on mussel

Palytoxin is a large and complex polyhydroxylated molecule with potent neurotoxic activity. Dinoflagellates from the Ostreopsis genera were demonstrated to be producers of this compound and analogues. Even though initially palytoxin appearance was restricted to tropical areas, the recent occurrence of Ostreopsis outbreaks in Mediterranean Sea point to a worldwide dissemination probably related to climatic change. Those dinoflagellates can bioaccumulate in shellfish, especially in filter-feeding mollusks and have been involved in damaging effects in seafood or human toxic outbreaks. The present study describes palytoxins effect on metabolic activity of mantle and hepatopancreas cells from the mussel Mytilus galloprovincialis Lmk. Our results indicate that palytoxin is highly cytotoxic to mussel cells; unlike it happens with other toxins more common in European coasts such as okadaic acid and azaspiracid. These findings have a special significance for the marine environment and aquiculture since they are evidence for the ability of palytoxin to affect the integrity of bivalve mollusks that are not adapted to the presence of this toxin.

The Ca2+-independent PKC (p105) mediates the PMA-activation of marine mussel hemocytes and the Ca2+-dependent PKC (p60) does not intervene

Previous works revealed the presence of a Ca(2+)-dependent protein kinase (p60) and a Ca(2+)-independent protein kinase (p105) in the mantle tissue from the sea mussel Mytilus galloprovincialis Lmk. The expression of both isoforms shows a balance between cytosolic and membrane fractions in mantle, gills, and hepatopancreas, whereas, in hemocytes, their expression is mainly cytosolic, as happens in muscle tissues with p60 alone. Both enzymatic forms contain phosphorylated serines, and no phosphorylation was detected in tyrosines. Only the form p105 mediates the PMA-induced activation of the hemocytes of M. galloprovincialis, and it does so by a process of down-regulation. The form p60 does not respond to the presence of the phorbol ester, suggesting structural differences related to the binding sites of the diacylglycerol.

Purification and characterization of a new Ca2+-dependent protein kinase C in mussel (Mytilus galloprovincialis Lmk.) mantle

An enzyme that can be included into the so-called conventional PKCs has been purified to homogeneity from the mantle tissue of the sea mussel Mytilus galloprovincialis. This enzyme has a molecular weight of 60 kDa, which is DAG-dependent, PS-activated, and Ca2+-dependent. It was separated from a Ca2+-independent PKC (p105) (Mercado et al., Mol Cell Biochem 233:99-105, 2002) by means of an ionic exchange chromatography on DE-52 cellulose. The molecular weights and kinetic properties of both the enzymes are different. The protein p60 is broadly distributed among the tissues, which suggests that it may carry out specific functions, different from those performed by p105.

The impact of hangingcleaning husbandry practices on Mediterranean mussels, Mytilus galloprovincialis Lmk, cultivated in the Mar Piccolo (Taranto, Ionian Sea, Italy)

The impact of the stressful hanging-cleaning husbandry practices on the growth conditions of the cultured Mediterranean mussels, Mytilus galloprovincialis Lmk, cultivated in the Mar Piccolo (Ionian Sea) was investigated from November 2005 to June 2006. The experimental strings were randomly organized in four groups, with five replications, exposed to different time periods of hanging: Group A, none; Group B, once every 15 days; Group C, once every 30 days; Group D, once every 60 days.The study, carried out on a total of 2000 mussels, showed that the cleaning of the mussel strings using the hanging-cleaning practice exerted an adverse effect on mussel growth (SGR%=46.62 in Group A; 44.85 in Group D; 43.72 in Group C; 42.12 in Group B). In particular, the highest percentage of meat yield occurred in the mussels more frequently exposed to air (Group B, 4.2±0.43 g) in spite of their lower morphometric variable values. In order to evaluate mussel condition, three different indexes were calculated.The hanging practice in mussel cultivation, commonly used in the basin of Taranto and in many mussel farms all over the world, would provide an economic benefit to the mussel farmers allowing the greatest production and the highest specific growth rate (SGR%) of mussels, together with a more appreciable aesthetic for the consumer. Our findings suggest that the hanging practice every 60 days would provide an economic benefit allowing an increase of about 30% of total string weight compared to the 30-day hanging practice commonly in use.

Effects of storage temperature on oxygen depletion in intra-valve water and survival of the Mediterranean mussel Mytilus galloprovincialis Lmk

Summary Mussels are commonly air-stored during transportation and as a result suffer from anoxia. In this study, storage temperature effects on the viability and characteristics of the released intra-valve water of mussels were examined. Mussels kept at 20°C released all of their intra-valve water within approximately 60 h and died within 4 days; oxygen concentration in the intra-valve water dropped below the detectable level. In contrast, mussels kept at 0 and 5°C released 8.8% and 12% of their intra-valve water, respectively. The oxygen concentration in this water remained stable at about 3–4 mg L−1 until hour 72 of exposure to air and all mussels survived (5°C). Mussels immersed in seawater over-saturated with oxygen (35 mg L−1) did not show any uptake of the surplus oxygen into their intra-valve water.

In hemocytes from Mytilus galloprovincialis Lmk., treatment with corticotropin or growth factors conditions catecholamine release

The cells in charge of the innate immune response in the sea mussel Mytilus galloprovincialis Lmk. are the hemocytes, which have the capacity to release catecholamines when subjected to stressing conditions. Hemocytes were kept in culture before stimulation. That is, their behaviour was not studied immediately after extraction from the mollusc, as happens in most studies. This avoids the interference and variability caused by the conditions in which mussels may be when collected. This work describes the great variability found in the pattern of catecholamine release when the hemocytes are stimulated with either corticotropins or growth factors. Dopamine, adrenaline and noradrenaline release differs with each of the inducers assayed, with stimulation time and with the season of hemocyte collection. One of the results presented is particularly remarkable; such is the great amount of adrenaline and noradrenaline released to the medium when the hemocytes obtained in summer are stimulated with transforming growth factor-β1 (TGF-β1) for 60 min.

Effect of thermal stress on protein expression in the mussel Mytilus galloprovincialis Lmk

The exposure of organisms to stressing agents may affect the level and pattern of protein expression. Certain proteins with an important role in protein homeostasis and in the tolerance to stress, known as stress proteins, are especially affected. Different tissues and cells show a range of sensitivities to stress, depending on the habitat to which organisms have adapted. The response of different tissues and cells from the mussel Mytilus galloprovincialis Lmk. to heat shock has been studied in this work using different exposure times and temperatures. During the assays, protein expression was observed to vary depending on the tissue studied, the temperature or the exposure time used. But maybe the most prominent thing is the different response obtained from the cultured haemocytes and those freshly obtained from stressed mussels, which makes us think that the extraction procedure is the main cause of the response of non-cultured cells, although the haemolymph may contain components that modulate haemocyte response.

Fast, clean, low-cost screening of cadmium and lead in the mussel Mytilus galloprovincialis Lmk. by visible spectroscopy and partial least squares regression

The potential of visible (VIS) spectroscopy for screening cadmium and lead contents in the mussel Mytilus galloprovincialis Lmk. was assessed. The spectra of the samples were recorded (400–700 nm). The Cd and Pb contents were determined by graphite furnace atomic absorption spectroscopy, and were regressed against different spectral transformations by modified partial least square (PLSm) regression. Coefficients of determination in the cross-validation (Cd = 0.95; Pb = 0.77) were indicative of equations with excellent and good quantitative information, respectively. The standard deviation to standard error of cross-validation ratio (Cd = 4.43; Pb = 2.10) showed sufficient predictive accuracy for the equations to be used for screening purposes. PLSm loading plots corresponding to the first terms of the equations showed that chromophores influenced them significantly. This pioneering use of the VIS spectrum to predict Cd and Pb in mussels represents an important saving in time and cost of analysis in comparison to other methods.

Implication of PKC in the seasonal variation of the immune response of the hemocytes of Mytilus galloprovincialis Lmk. and its role in interleukin‐2‐induced nitric oxide synthesis

The hemocytes are the cells responsible for the immune response in marine mollusks. The role of NO in processes related to the activation of the hemocytes has turned out evident over the late years. In the case of the mussel Mytilus galloprovincialis Lmk., hemocyte NO basal production varies throughout the year, showing a maximum in summer and a minimum in winter. IL-2 reverts the low winter NO basal production through a process mediated by cAMP-dependent protein kinase and by an apparent side effect of protein kinase C. The seasonal variation of NO production in the presence of the PKC inhibitor bisindolylmaleimide (BSM) allows suggesting a model in which PKC would modulate the activity of the enzymes responsible for nitric oxide production.

Seasonal variations in haemocyte response in the mussel Mytilus galloprovincialis Lmk

In the marine mussel Mytilus galloprovincialis Lmk., the cells in charge of the immune response are the haemocytes. This work focused on the response capacity of these cells throughout the year, as significant differences between summer and winter months had been detected. The haemocytes were kept in culture for three days in order to obtain certain uniformity in cell state. Their response to inducers such as lipopolysaccharide (LPS) and interleukin-2 (IL-2) was then observed to differ significantly if collected either in summer or in winter. These differences appeared in nearly all the parameters assessed: expression of molecules binding monoclonal antibodies anti α chain of the receptor of IL-2 (anti-IL-2Rα MoAb), production of nitric oxide (NO) and catecholamines and expression of a novel protein kinase C (nPKC) purified from mussel and termed p105.