The trophic ecology of European hake (Merluccius merluccius) larvae and early-juveniles from the Iberian shelf off Galicia (NW Spain) are assessed by means of stable isotopes (SIA) and nutritional condition in conjunction with hydrobiological variations observed during the winter and summer season of 2012. Hake early-juveniles (18-47 mm SL) showed higher delta N-15 than larvae (3-11 mm SL) together with the microzooplankton (55-200 mu m) and mesozooplankton (>200 mu m) during both seasons. Low delta N-15 values and high variability in both zooplankton and hake larvae were found during winter coinciding with an unusually strong upwelling event. Inversely, high delta N-15 content in zooplankton in summer suggests strong nitrogen reutilization. However, hake larvae sampled in summer had a higher RNA:DNA ratio in line with higher Fulton condition factors than those sampled in winter. Higher delta C-13 values for microzooplankton and mesozooplankton and hake larvae in summer compared to late winter point to prey availability differences. The relationship between nitrogen and carbon stable isotopes versus size or weight suggests an ontogenetic shift in the diet of hake larvae. Early-juveniles had a lower isotopic niche width compared to larvae in both late winter and summer, indicating a trophic specialization related to changes following settlement process from planktonic life to demersal habitat. Higher trophic specialization was observed in summer, which recorded a narrower isotopic niche and higher trophic position estimations.

The objective of this study was to determine how preservation methods affect the standard length (SL, mm) of European hake larvae. We used five fixative methods: (i) freezing in seawater at -20 degrees C; (ii) RNAlater at -80 degrees C; (iii) 4% borax-buffered formalin; (iv) freezing with liquid nitrogen and (v) 95% ethanol. Standard length hake larvae were initially measured and individually fixed in each of the five fixatives. To evaluate the effect of the time preserved in each one, we obtained the SL of larvae for a second time after three different preservation periods: 15, 44 and 91 days. To assess the effect of initial size on final shrinkage, we analysed two groups of larvae born in captivity, 15 and 24 days post hatching respectively. Most shrinkage occurred within the first period of preservation in all fixatives, the preservation time having no effect on the percentage of shrinkage for any preservative. However, initial SL affects the percentage of shrinkage depending on the fixative used. We suggest five correlation equations to convert an initial SL into a final contracted size of hake larvae for each fixative.

This review presents some applications of proteomics and selected spectroscopic methods to validate certain aspects of seafood traceability. After a general introduction to traceability and the initial applications of proteomics to authenticate traceability information, it addresses the application of proteomics to trace seafood exposure to some increasingly abundant emergent health hazards with the potential to indicate the geographic/environmental origin, such as microplastics, triclosan and human medicinal and recreational drugs. Thereafter, it shows the application of vibrational spectroscopy (Fourier-Transform Infrared Spectroscopy (FTIR) and Fourier-Transform Raman Spectroscopy (FT Raman)) and Low Field Nuclear Magnetic Resonance (LF-NMR) relaxometry to discriminate frozen fish from thawed fish and to estimate the time and temperature history of frozen fillets by monitoring protein modifications induced by processing and storage. The review concludes indicating near future trends in the application of these techniques to ensure seafood safety and traceability.

This review presents the primary applications of various proteomic strategies to evaluate the impact of farming conditions on food quality and safety in aquaculture products. Aquaculture is a quickly growing sector that represents 47% of total fish production. Food quality, dietary management, fish welfare, the stress response, food safety, and antibiotic resistance, which are covered by this review, are among the primary topics in which proteomic techniques and strategies are being successfully applied. The review concludes by outlining future directions and potential perspectives.

Event Abstract Back to Event Trophic ecology of European hake (Merlucius merlucius) larvae by stable isotopes analysis influenced by seasonal variability of oceanographic conditions off NW Galician waters. Raul L. Carrion1, Agueda C. Rodriguez2, Jos M. Q. Ervas1, Alma H. De Rojas3, Jose Maria R. Lopez3, Piñeiro A. Carmen2* and Alberto G. Garcia1 1 Oceanographic Center of Málaga, Spanish Institute of Oceanography (IEO), Spain 2 Oceanographic Center of Vigo, Spanish Institute of Oceanography, Spain 3 Instituto Español de Oceanografía (IEO), Spain A combined study of environmental variables, and stable isotope analysis (SIA) was performed to compare the trophic ecology of European hake (Merlucius merlucius) larvae from northwestern Iberian shelf off Galicia (NW Spain) during the two main contrasting spawning seasons, spring and summer 2012. Distinct oceanographic conditions of each seasons influenced nutrient uptake from the pelagic food web according to the differences observed in nitrogen isotopic signatures not only in larvae but also in micro- and meso-zooplankton fraction analyzed. Isotopic niche widths were estimated using SIBER package (Stable isotope Bayesian ellipses in R) from 39 and 130 larvae form spring and summer respectively. Estimated Standard Ellipses Areas (SEAc) were discussed based on contrasting spawning scenarios with different isotopic baselines. Higher isotopic niche width was estimated in the spring hake larvae according to higher productivity and food availability, suggesting a more euriphagous diet in spring condition comparing to summer season. Lower values together with high variability of 15N in both plankton and larvae were found during spring coinciding with unusually strong upwelling. Inversely, higher nitrogen isotopic signatures were observed during summer suggesting strong nitrogen limitation for primary producers during this season. Distinct carbon isotopic signature reveals differences in the origin of food sources in spring and summer. Both nitrogen and carbon stable isotopes values vs size or weight relationships observed in spring and summer suggest an ontogenetic diet shift in hake larvae. Acknowledgements This study was funded by CRAMER-MICINN. Keywords: trophic ecology, European hake (Merluccius merluccius), Larvae, seaonal variability, NW Galician waters, Isotopes analysis 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: Carrion RL, Rodriguez AC, Ervas JQ, De Rojas AH, Lopez JR, Carmen PA and Garcia AG (2019). Trophic ecology of European hake (Merlucius merlucius) larvae by stable isotopes analysis influenced by seasonal variability of oceanographic conditions off NW Galician waters.. Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00143 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: 14 May 2019; Published Online: 27 Sep 2019. * Correspondence: Dr. Piñeiro A Carmen, Oceanographic Center of Vigo, Spanish Institute of Oceanography, Vigo, 36390, Spain, carmen.pineiro@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 Raul L Carrion Agueda C Rodriguez Jos M. Q Ervas Alma H De Rojas Jose Maria R Lopez Piñeiro A Carmen Alberto G Garcia Google Raul L Carrion Agueda C Rodriguez Jos M. Q Ervas Alma H De Rojas Jose Maria R Lopez Piñeiro A Carmen Alberto G Garcia Google Scholar Raul L Carrion Agueda C Rodriguez Jos M. Q Ervas Alma H De Rojas Jose Maria R Lopez Piñeiro A Carmen Alberto G Garcia PubMed Raul L Carrion Agueda C Rodriguez Jos M. Q Ervas Alma H De Rojas Jose Maria R Lopez Piñeiro A Carmen Alberto G Garcia 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 Seasonal growth variability of young of the year European hake (Merluccius merluccius) off NW Spanish waters Piñeiro A. Carmen1*, Lorena R. Fernandez1*, Jose Q. Hervas2, Agueda C. Rodriguez1 and Alberto G. Garcia2 1 Oceanographic Center of Vigo, Spanish Institute of Oceanography, Spain 2 Oceanographic Center of Málaga, Spanish Institute of Oceanography (IEO), Spain Daily growth of Atlantic juvenile hake (Merluccius merluccius) from Northwest Spanish Iberian coasts was estimated by counting daily increments of the transversal and sagital sections of otoliths. The microstructural analysis of otoliths enabled to relate variations of growth rates with the seasonal variability of the upwelling regime. Juveniles were sampled in one of the most important recruitment areas of the species of NW Atlantic Iberia in surveys that were carried out during March and July, 2012. A total of 125 otoliths (sagittae) of individuals ranging from 2 and 25 cm total length was successfully aged between 59 to 443 days. Overall, the growth rates of individuals from March and July were not significantly different (ANCOVA F (1, 98) =2.3591; p>0,05). However, otolith microstructure analysis revealed that juvenile growth show increased growth pulses of varying intensity throughout the year related with variation of hydro-climatic conditions linked to the upwelling regime of the Galician coasts. This hypothesis is supported by the variability of increment widths, used as growth proxies. These show a declining trend from 7.2 to 5.7 µm from June 2011 to January 2012 which is temporally coincident with a similar declining upwelling index pattern (Fig. 1). Furthermore, hatch dates of juveniles were back-calculated from otolith readings and the results indicated that spawning takes place all year round with spawning peaks mainly occurring in winter and summer (Fig. 2). Figure 1 Figure 2 Acknowledgements This study was made possible by the financial support of project CRAMER-MICINN and ECOPREGA-Xunta de Galicia. Keywords: Hake (Merluccius merluccius), age estimaion, Daily growth, Juveniles, NW Iberian waters 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: Carmen PA, Fernandez LR, Hervas JQ, Rodriguez AC and Garcia AG (2019). Seasonal growth variability of young of the year European hake (Merluccius merluccius) off NW Spanish waters. Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00101 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: 14 May 2019; Published Online: 27 Sep 2019. * Correspondence: Mx. Piñeiro A Carmen, Oceanographic Center of Vigo, Spanish Institute of Oceanography, Vigo, 36390, Spain, carmen.pineiro@ieo.es Mrs. Lorena R Fernandez, Oceanographic Center of Vigo, Spanish Institute of Oceanography, Vigo, 36390, Spain, Lorena.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 Piñeiro A Carmen Lorena R Fernandez Jose Q Hervas Agueda C Rodriguez Alberto G Garcia Google Piñeiro A Carmen Lorena R Fernandez Jose Q Hervas Agueda C Rodriguez Alberto G Garcia Google Scholar Piñeiro A Carmen Lorena R Fernandez Jose Q Hervas Agueda C Rodriguez Alberto G Garcia PubMed Piñeiro A Carmen Lorena R Fernandez Jose Q Hervas Agueda C Rodriguez Alberto G Garcia 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.

Age estimation based on fish otolith microstructure analysis is a very repetitive and time-consuming task. The lack of appropriate image analysis software, capable of both overlaying a number of images automatically and recording a high number of daily increments, has been a significant limitation in counting and measuring daily growth increments in large otoliths from juvenile and adult fish individuals. This paper presents a new software to assist marine biologists with faster, more efficient, and more reliable microstructure readings of fish otoliths. Open source code is preferred so that software packages can be updated with new image processing algorithms developed by the scientific community. The approach consists of three steps: 1) a single grayscale digital image combining images of different parts of the same fish otolith is obtained using the blind image registration technique fast normalized cross correlation; 2) the growth rings of the image are enhanced for age estimation purposes, using the adaptive histogram equalization technique; and 3) a semiautomatic interactive tool draws a simple polygonal chain along which the microstructures are easily identifiable and the points of interest can be marked, whose data will be saved automatically. This new tool opens up the opportunity of aging juvenile and adult fish individuals at regular intervals by counting growth rings in the otolith microstructure and facilitates working with other calcified pieces of marine species that exhibit a daily ring pattern, such as cephalopod beaks and mollusk shells.

This is the first study to provide age estimations of the two black hake species living in Mauritanian waters. Here we propose a new interpretation of microstructural growth increments that are assumed to be deposited daily. Our approach to age-reading combining the counts in both sagittal and transverse planes proved successful with black hake otoliths, including adults'. A newly developed image analysis software tool (OTOLab) was used to help in identifying and marking daily growth increments throughout the otoliths. Larval growth was analyzed from otolith sagittal sections and showed wider mean daily increments in Merluccius polli (3.32 mu) than in Merluccius senegalensis (2.85 mu). Conversely, once recruited to demersal life after metamorphosis, juvenile and adult growth was analyzed from otolith transverse sections, where the widest mean daily increments were found in M. senegalensis (4.19 mu) (M. polli, 3.19 mu). Although the growth models of both species were not statistically different, the two black hakes probably have alternate growth strategies and, like the European hake, belong to the group of fast-growing hakes. When both species were considered together, the mean length of one-year-old black hakes was 36.7 cm, while the averaged individual growth rate was 1.12 mm day(-1). These growth values are the highest found for any hake species and are probably explained by the influence of one of the world's most important upwelling systems, off northwest Africa. Although environmental factors may influence individual growth, ontogeny is the main factor determining growth rates at any life stage. Our results support otolith microstructural analysis as a realistic choice to regularly age hakes. (C) 2016 Elsevier B.V. All rights reserved.

Once the metapopulation structure of the European hake (Merluccius merluccius) has been outlined, temporal stability of its stock units and their connectivity pattern are key factors to understand its population dynamics and design appropriate management policies. Using five microsatellite markers from the European hake and an extensive sampling coverage within stocks, we have tested the connectivity pattern between the two managed fish stocks of this species, the Northern stock and the Southern stock, over the last decade. On the spatial domain, the non-significant genetic variance between stocks (F-CT = 0.001, k=1 gene pools) as opposed to the low but significant divergence within stocks (F-SC = 0.008) suggests that demographic exchange occurs between stocks. On the temporal domain, the non-significant variation among years (F-CT < 0.001) suggests that the genetic background within the Atlantic hake metapopulation did not change significantly over the last decade. The pattern of connectivity observed fits a classic Wright continuum model and the negative correlation between restriction to gene flow (F-ST) and migration rate (m) responds closely to theoretical expectations. No evidence of stable differences in gene diversity was observed between stocks, what is consistent with an intermittent and variable intensity of bi-directionally exchange between them. The current pattern of connectivity indicates that uncoupling exists between actual management areas and the genetic commonality within this metapopulation. Nevertheless, the geographic segregation and the relative demographic independence of both stocks advocate for considering two sub-management units. A subsidiary stock assessment capable of modelling fishing effort upon stock interdependence would add up for their sustainability. Indeed, actual EU subsidiary management of both stocks matches social, economic and cultural needs as well as fishing capacity and fishing tradition of local fleets. (C) 2016 Elsevier B.V. All rights reserved.

This article introduces the application of proteomics to food and nutrition studies. It contains a brief description of what proteomics is and the main laboratory requirements to perform the analyses followed by a technical part that includes the main applications of proteomics (protein identification and characterization, differential proteomics, and functional proteomics), the proteomic workflow, and mass spectrometric analysis. Then, proteomic studies applied to food groups are illustrated using cereals and fruits, dairy products, eggs, meat, seafood, and bioactive compounds as examples. Finally, the concept of systems biology and its application to nutritional studies is introduced to the reader.

The composition and structure of the larval fish community (LFC) in the NW Iberian upwelling system in late winter 2012 were examined, and the influence of abiotic and biotic factors on the horizontal distribution of fish larvae and on the horizontal structure of the LFC was investigated. The LFC, composed of 62 taxa (59 species and 3 genera) in 28 families, was dominated by Micromesistius poutassou followed by Scomber scombrus, Merluccius merluccius and Maurolicus muelleri. Multivariate analyses identified depth, sea surface temperature, geostrophic velocity and mesozooplankton biomass as the environmental factors involved in explaining variability in the LFC parameters (larval fish abundance, species richness and diversity) and revealed that the LFC was structured into coastal and slope larval fish assemblages. The main factor defining these assemblages was depth. However, the unusual coastal downwelling that occurred during the study would have participated in creating them and in maintaining assemblage boundaries, so that the importance of depth to the cross-shelf structuring of the LFC may have been overestimated. Our results suggest that larval fish assemblages in regions of coastal upwelling are driven by coastal downwelling during the winter mixing period and support the idea that fish larvae act as short-term (similar to 10 d) biological tracers of the hydrography of the region during that period.

This work investigates the production of hyaluronic acid (H) by Streptococcus equi subsp. zooepidemicus in complex media formulated with peptones obtained from Scyliorhinus canicula viscera by-products. Initially, in batch cultures, the greatest productions were achieved using commercial media (3.03 g/L) followed by peptones from alcalase hydrolyzed viscera (2.32 g/L) and peptones from non-hydrolyzed viscera (2.26 g/L). An increase of between 12% and 15% was found in subsequent fed-batch cultures performed on waste peptones. Such organic nitrogen sources were shown to be an excellent low-cost substrate for microbial H, saving more than 50% of the nutrient costs.

The vertical distribution and vertical migrations of fish larvae and implications for their cross-shelf distribution were investigated in the northern limit of the NE Atlantic upwelling region during the late winter mixing period of 2012. The average positive values of the upwelling index for February and March of this year were far from normal, although the average hydrographic conditions during the period of study were of downwelling and the water column was completely mixed. Fish larvae, most in the preflexion stage, were concentrated in the upper layers of the water column and their distribution was depth stratified, both day and night. However, the larval fish community was not structured in the vertical plane and fish larvae did not show significant diel vertical migration (DVM), although five species showed ontogenetic vertical migration. In regions of coastal upwelling and in the absence of DVM, the location of fish larvae in the water column is crucial for their cross-shelf distribution. Thus, the cross-shelf distribution of the six most abundant species collected in this study can be explained by the surface onshore flow associated with coastal downwelling, retaining larvae of the coastal spawning species with a relatively shallow distribution in the shelf region and transporting larvae of slope spawning species onto the shelf. The wide vertical distribution shown by larvae of the offshore spawning species could be an adaptation of these species to ensure that some larvae reach the inshore nursery areas.

In this communication, the research multidisciplinary team of researchers from the research fields of fisheries and engineering plans to develop a new tool designed to add efficiency in the weighty task of estimating the age of fishes based on DGI analysis. The technique is based on new computer algorithms that interpret DGI patterns, whether it be in a semi-automatic way or in such a manner that otolith readers are allowed to interact with the system or run automatically when the technique finds determined types of otolith structural patterns considered consistent and reliable. The technique, when registered, will be made available freely to the international scientific community in the open access mode. Although some image analysis software is available in the market nowadays, including some centered in otolith image processing, they all show at least two main restrictions: they do not manage ‘live’ images which allow to specifically focus determined microstructures at great magnification, and moreover, the high costs of the software. We present here the first results on the development of this forthcoming software which is expected to resolve the before mentioned limitations.

Mounting evidence now shows that fishing activity modifies both heritable life-history traits and ecological processes in harvested populations. However, ecological and evolutionary changes are intimately linked and can occur on the same time scale, and few studies have investigated their combined effect on fish population dynamics. Here, we contrast two population subunits of a harvested fish species in the Northeast Atlantic, the European hake (Merluccius merluccius), in the light of the emerging field of evolutionary demography, which considers the interacting processes between ecology and evolution. The two subunits experienced similar age/size truncation due to size-selective fishing, but displayed differences in key ecological processes (recruitment success) and phenotypic characteristics (maturation schedule). We investigate how temporal variation in maturation and recruitment success interactively shape the population dynamics of the two subunits. We document that the two subunits of European hake displayed different responses to fishing in maturation schedules, possibly because of the different level of adaptive phenotypic plasticity. Our results also suggest that high phenotypic plasticity can dampen the effects of fisheries-induced demographic truncation on population dynamics, whereas a population subunit characterized by low phenotypic plasticity may suffer from additive effects of ecological and life-history responses. Similar fishing pressure may thus trigger contrasting interactions between life history variation and ecological processes within the same population. The presented findings improve our understanding of how fishing impacts eco-evolutionary dynamics, which is a keystone for a more comprehensive management of harvested species.

The aim of this work was the purification and identification of the major angiotensin converting enzyme (ACE) inhibitory peptides produced by enzymatic hydrolysis of a protein concentrate recovered from a cuttlefish industrial manufacturing effluent. This process consisted on the ultrafiltration of cuttlefish softening wastewater, with a 10 kDa cut-off membrane, followed by the hydrolysis with alcalase of the retained fraction. Alcalase produced ACE inhibitors reaching the highest activity (IC50 = 76.8 ± 15.2 μg mL−1) after 8 h of proteolysis. Sequential ultrafiltration of the 8 h hydrolysate with molecular weight cut-off (MWCO) membranes of 10 and 1 kDa resulted in the increased activity of each permeate, with a final IC50 value of 58.4 ± 4.6 μg mL−1. Permeate containing peptides lower than 1 kDa was separated by reversed-phase high performance liquid chromatography (RP-HPLC). Four fractions (A–D) with potent ACE inhibitory activity were isolated and their main peptides identified using high performance liquid chromatography coupled to an electrospray ion trap Fourier transform ion cyclotron resonance-mass spectrometer (HPLC-ESI-IT-FTICR) followed by comparison with databases and de novo sequencing. The amino acid sequences of the identified peptides contained at least one hydrophobic and/or a proline together with positively charged residues in at least one of the three C-terminal positions. The IC50 values of the fractions ranged from 1.92 to 8.83 μg mL−1, however this study fails to identify which of these peptides are ultimately responsible for the potent antihypertensive activity of these fractions.

Spawning stock biomass (SSB) is one of the most common measures of stock status. However recent research on reproductive potential has shown that alternative variables may be an improvement over SSB. In the case of European hake (Merluccius merluccius), it is known that large individuals produce more eggs by unit of body weight, and their quality is better than those of small individuals. Under these circumstances, application of reproductive potential may be pertinent in the implementation of the Johannesburg agreement, since it is not only the spawning biomass but also its age or length structure that defines stock productivity and its ability to achieve maximum sustainable yield (MSY). In this contribution we used an age-length structured population model to assess the impact of different reproductive indices (total spawning biomass, female spawning biomass and egg production) on MSY reference points. First, we analyzed how these different indices alter our perception about per recruit productivity. Second, we analyzed the quality of these alternative reproductive indices to explain and predict recruitment using different model structures (Ricker and Beverton–Holt) and Bayesian inference. Third, we combined per recruit models and stochastic stock–recruitment relationships to estimate the probability distributions of MSY biological reference points (MSY, Fmsy, Stockmsy, and Fcrash). Our results show that, for hake stocks where larger fish have a strong contribution to stock reproductive potential, use of alternative reproductive indices will affect estimations of stock sustainability. The change in perception of relative contribution of each length class is exhibited in two opposite ways: reproductive potential per recruit and the shape of the stock–recruitment relationship defined with steepness. In our case, the change from SSB to egg production, resulted in an increase in steepness which counteracted the depletion per recruit resulting in a larger Fmsy.