Influence des apports rhodaniens sur les traits d'histoires de vie de la sole commune (Solea Solea) (apports de l'analyse structurale et minéralogique des otolithes.)

La sole commune présente au cours de son cycle de vie un changement ontogénétique d habitat. Les larves sont marines et pélagiques, les juvéniles sont benthiques et vivent dans les nourriceries côtières (lagunes et estuaires) alors que les adultes sont benthiques et marins en zones plus profondes. Les otolithes sont des concrétions minéralisées de carbonate de calcium de l oreille interne des téléostéens qui ne subissent ni dissolution ni résorption. Ils enregistrent les caractéristiques chimiques et isotopiques des milieux traversés.L étude de la croissance, de la composition chimique et isotopique des otolithes des soles des nourriceries a confirmé l existence de deux stocks de soles dans le golfe du Lion, un à l Est et l autre à l Ouest. Les faibles valeurs de 13C et les fortes valeurs de Ba/Ca des otolithes des soles de l Est du golfe ont été associées à une forte influence des apports rhodaniens sur la phase de vie larvaire lors des années où le débit du Rhône est normal. En période de crue, une forte influence du fleuve est visible sur les otolithes des soles des nourriceries de l ensemble du golfe. La croissance des otolithes des juvéniles a été plus élevée lorsque la salinité a été proche de 20 et la température comprise entre 20 et 25C (période estivale). Les signatures des otolithes de Mauguio et Berre ont présenté des 13C et Sr/Ca plus faibles que ceux de Thau (influences plus marines sur les proies et les masses d eau). La spécificité des signatures chimiques et isotopiques des otolithes a permis d élaborer des profils qui ont été retrouvés chez les populations de soles adultes du golfe, mais aussi vers Marseille et Bandol. Ces soles ont montré une influence du Rhône durant la phase de vie larvaire à 53%. Elles ont également montré une forte similarité avec les profils chimiques de type lagune de Thau (10-56%) et Rhône (19-30%) durant leur vie juvénile. Toutefois, une proportion non négligeable de soles originaires de nourriceries non caractérisées (26-50%) a été observée.The life cycle of the common sole shows an ontogenetic shift of habitats. The larvae are marine and pelagic, the juveniles are benthic in coastal nurseries (lagoons and estuaries) whereas adults are benthic and live in marine deeper areas. Otoliths are paired calcified structures from the inner ear of teletost fish. They are metabolically inert (neither resorption nor dissolution) and they record, both the age (daily and annual increments) and the chemical and isotopic characteristics of the environment inhabited. Otoliths study provides information on the life history traits of individuals.The study of growth, chemical and isotopic otolith composition of soles from nurseries confirmed the existence of two sole stocks in the Gulf of Lions, one in the Eastern part and the other in the Western part. Low values in 13C and higher values in Ba/Ca ratio measured in Eastern sole otoliths during the larval life were associated to a high influence of the Rhône River discharge during a normal flow rate periods. Conversely, the one hundred return flood of the 2nd of December 2003 was very high and visible on otoliths from all nurseries in the Gulf of Lions. Juvenile otolith growth was higher in nurseries with low salinity (~20) and temperatures between 20 and 25C than in more marine nurseries. 13C and Sr/Ca ratios of otoliths from Berre and Mauguio coastal lagoons were lower than those observed in Thau coastal lagoon (more marine influences on preys and water masses). These specificities of otolith compositions were used for the elaboration of reference profiles, which have been identified in adult populations of the Gulf of Lions, Marseilles and Bandol. Adult have shown an influence of the Rhône River during their larval life at 53%. They have shown a similarity with Thau chemical profile (10-56%) and Rhône profile (19-30%) during their juvenile life. However, 26-50% of fish from uncharacterised nurseries have been observed.AIX-MARSEILLE2-Bib.electronique (130559901) / SudocSudocFranceF

Indicios preliminares de variaciones ontogenéticas y espaciales en las señales isotópicas y elementales de otolitos de Solea solea del Golfo de León (Mediterráneo noroccidental)

Knowledge of fish life cycles is important for exploited species. In the Mediterranean Sea, catches of common sole (Solea solea) have fluctuated widely since the 1970s. Solea solea displays an ontogenetic shift in habitat: sole larvae are marine, juveniles inhabit shallow marine waters and coastal lagoons and adults inhabit deeper marine waters. Although the results of this study were obtained using only a small set of individuals, the otolith elemental composition and isotopic ratios were investigated for the three life stages (post-larval, juvenile and adult) in order to acquire a better knowledge of the variability in environmental conditions experienced by the common sole at each life stage in the NW Mediterranean. Moreover, this study provides the first evaluation of the potential of whole otolith microchemistry for investigating habitat connectivity in sole populations from the Gulf of Lions. The elemental and isotopic signatures of otoliths of post-larvae captured in various environments appear to show variations related to the River Rhône inputs (high Ba/Ca and low Sr/Ca ratios). Juveniles appear to show significant variations in otolith elemental and isotopic compositions depending not only on the physico-chemical properties of water in the nurseries they inhabit (Rhône River, Thau or Mauguio lagoons), but also as a result of variations in the chemical composition of their surrounding sediments and in their benthic prey. Adults exhibit otolith differences for isotopic ratios only, which is probably linked to the River Rhône inputs. Finally, several significant relationships were observed between otolith elemental composition and fish size in specimens captured at the River Rhône mouth. However, these variations seem to be an indication of the composition acquired in each environment rather than a sign of ontogeny.El conocimiento del ciclo de vida es importante para las especies comerciales de peces. En el mar Mediterráneo, las capturas de lenguado común (Solea solea) han fluctuado ampliamente desde la década de los 70. Solea solea presenta un cambio de hábitat ontogenético, las larvas son marinas, los juveniles viven en aguas marinas y en lagunas costeras, y los adultos viven en aguas marinas más profundas. Aunque los resultados de este estudio fueron obtenidos usando sólo un número pequeño de individuos, la composición de elemental los otolitos y las relaciones isotópicas fueron investigados en las tres etapas de vida (post-larval, juveniles y adultos) con el fin de adquirir un mejor conocimiento de la variabilidad en las condiciones ambientales que experimenta el lenguado común en cada etapa de la vida en el mediterráneo noroccidental. Por otra parte, este trabajo permite una primera evaluación del potencial de toda la microquímica de otolitos para la investigación de la conectividad del hábitat en las poblaciones de lenguado en el Golfo de León. Las señales elementales e isotópicos de los otolitos de las post-larvas capturadas en diferentes entornos muestran variaciones en relación a los materiales aportados por del río Ródano (alta relación Ba/Ca y baja relación Sr/Ca). Los juveniles parecen mostrar variaciones significativas en la composición elemental e isotópica de los otolitos dependiendo no sólo de las propiedades físico-químicas del agua en los viveros que habitan (Thau, Mauguio o el río Ródano), sino también como resultado de las variaciones en la composición química de los sedimentos circundantes y de su presa béntica. Los adultos presentan únicamente diferencias en las relaciones isotópicas de los otolitos, que está probablemente vinculado a por materiales aportados por el río Ródano. Por último, se observaron varias relaciones significativas entre la composición elemental de los otolitos y el tamaño de los peces en las muestras capturadas en la desembocadura del río Ródano. Sin embargo, estas variaciones parecen ser una indicación de la composición adquirida en cada entorno, más que ser debidas a la ontogenia

Nutrient limitation, bioenergetics and stoichiometry: A new model to predict elemental fluxes mediated by fishes

Energy flow and nutrient cycling dictate the functional role of organisms in ecosystems. Fishes are key vectors of carbon (C), nitrogen (N) and phosphorus (P) in aquatic systems, and the quantification of elemental fluxes is often achieved by coupling bioenergetics and stoichiometry. While nutrient limitation has been accounted for in several stoichiometric models, there is no current implementation that permits its incorporation into a bioenergetics approach to predict ingestion rates. This may lead to biased estimates of elemental fluxes.Here, we introduce a theoretical framework that combines stoichiometry and bioenergetics with explicit consideration of elemental limitations. We examine varying elemental limitations across different trophic groups and life stages through a case study of three trophically distinct reef fishes. Further, we empirically validate our model using an independent database of measured excretion rates.Our model adequately predicts elemental fluxes in the examined species and reveals species‐ and size‐specific limitations of C, N and P. In line with theoretical predictions, we demonstrate that the herbivore Zebrasoma scopas is limited by N and P, and all three fish species are limited by P in early life stages. Further, we show that failing to account for nutrient limitation can result in a greater than twofold underestimation of ingestion rates, which leads to severely biased excretion rates.Our model improved predictions of ingestion, excretion and egestion rates across all life stages, especially for fishes with diets low in N and/or P. Due to its broad applicability, its reliance on many parameters that are well‐defined and widely accessible, and its straightforward implementation via the accompanying r‐package fishflux, our model provides a user‐friendly path towards a better understanding of ecosystem‐wide nutrient cycling in the aquatic biome.A free Plain Language Summary can be found within the Supporting Information of this article.A free Plain Language Summary can be found within the Supporting Information of this article.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162691/5/fec13618_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162691/4/fec13618-sup-0002-AppendixS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162691/3/fec13618-sup-0001-Summary.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162691/2/fec13618-sup-0003-AppendixS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162691/1/fec13618.pd

The great melting pot. Common sole population connectivity assessed by otolith and water fingerprints

Quantifying the scale and importance of individual dispersion between populations and life stages is a key challenge in marine ecology. The common sole (Solea solea), an important commercial flatfish in the North Sea, Atlantic Ocean and the Mediterranean Sea, has a marine pelagic larval stage, a benthic juvenile stage in coastal nurseries (lagoons, estuaries or shallow marine areas) and a benthic adult stage in deeper marine waters on the continental shelf. To date, the ecological connectivity among these life stages has been little assessed in the Mediterranean. Here, such an assessment is provided for the first time for the Gulf of Lions, NW Mediterranean, based on a dataset on otolith microchemistry and stable isotopic composition as indicators of the water masses inhabited by individual fish. Specifically, otolith Ba/Ca and Sr/Ca profiles, and delta C-13 and delta O-18 values of adults collected in four areas of the Gulf of Lions were compared with those of young-of-the-year collected in different coastal nurseries. Results showed that a high proportion of adults (>46%) were influenced by river inputs during their larval stage. Furthermore Sr/Ca ratios and the otolith length at one year of age revealed that most adults (similar to 70%) spent their juvenile stage in nurseries with high salinity, whereas the remainder used brackish environments. In total, data were consistent with the use of six nursery types, three with high salinity (marine areas and two types of highly saline lagoons) and three brackish (coastal areas near river mouths, and two types of brackish environments), all of which contributed to the replenishment of adult populations. These finding implicated panmixia in sole population in the Gulf of Lions and claimed for a habitat integrated management of fisherie

Influence des apports rhodaniens sur les traits d'histoires de vie de la sole commune (Solea Solea) : apports de l'analyse structurale et minéralogique des otolithes.

La sole commune présente au cours de son cycle de vie un changement ontogénétique d’habitat. Les larves sont marines et pélagiques, les juvéniles sont benthiques et vivent dans les nourriceries côtières (lagunes et estuaires) alors que les adultes sont benthiques et marins en zones plus profondes. Les otolithes sont des concrétions minéralisées de carbonate de calcium de l’oreille interne des téléostéens qui ne subissent ni dissolution ni résorption. Ils enregistrent les caractéristiques chimiques et isotopiques des milieux traversés.L’étude de la croissance, de la composition chimique et isotopique des otolithes des soles des nourriceries a confirmé l’existence de deux stocks de soles dans le golfe du Lion, un à l’Est et l’autre à l’Ouest. Les faibles valeurs de 13C et les fortes valeurs de Ba/Ca des otolithes des soles de l’Est du golfe ont été associées à une forte influence des apports rhodaniens sur la phase de vie larvaire lors des années où le débit du Rhône est normal. En période de crue, une forte influence du fleuve est visible sur les otolithes des soles des nourriceries de l’ensemble du golfe. La croissance des otolithes des juvéniles a été plus élevée lorsque la salinité a été proche de 20 et la température comprise entre 20 et 25°C (période estivale). Les signatures des otolithes de Mauguio et Berre ont présenté des 13C et Sr/Ca plus faibles que ceux de Thau (influences plus marines sur les proies et les masses d’eau). La spécificité des signatures chimiques et isotopiques des otolithes a permis d’élaborer des profils qui ont été retrouvés chez les populations de soles adultes du golfe, mais aussi vers Marseille et Bandol. Ces soles ont montré une influence du Rhône durant la phase de vie larvaire à 53%. Elles ont également montré une forte similarité avec les profils chimiques de type lagune de Thau (10-56%) et Rhône (19-30%) durant leur vie juvénile. Toutefois, une proportion non négligeable de soles originaires de nourriceries non caractérisées (26-50%) a été observée.The life cycle of the common sole shows an ontogenetic shift of habitats. The larvae are marine and pelagic, the juveniles are benthic in coastal nurseries (lagoons and estuaries) whereas adults are benthic and live in marine deeper areas. Otoliths are paired calcified structures from the inner ear of teletost fish. They are metabolically inert (neither resorption nor dissolution) and they record, both the age (daily and annual increments) and the chemical and isotopic characteristics of the environment inhabited. Otoliths study provides information on the life history traits of individuals.The study of growth, chemical and isotopic otolith composition of soles from nurseries confirmed the existence of two sole stocks in the Gulf of Lions, one in the Eastern part and the other in the Western part. Low values in 13C and higher values in Ba/Ca ratio measured in Eastern sole otoliths during the larval life were associated to a high influence of the Rhône River discharge during a normal flow rate periods. Conversely, the one hundred return flood of the 2nd of December 2003 was very high and visible on otoliths from all nurseries in the Gulf of Lions. Juvenile otolith growth was higher in nurseries with low salinity (~20) and temperatures between 20 and 25°C than in more marine nurseries. 13C and Sr/Ca ratios of otoliths from Berre and Mauguio coastal lagoons were lower than those observed in Thau coastal lagoon (more marine influences on preys and water masses). These specificities of otolith compositions were used for the elaboration of reference profiles, which have been identified in adult populations of the Gulf of Lions, Marseilles and Bandol. Adult have shown an influence of the Rhône River during their larval life at 53%. They have shown a similarity with Thau chemical profile (10-56%) and Rhône profile (19-30%) during their juvenile life. However, 26-50% of fish from uncharacterised nurseries have been observed

Environmental and genetic determinant of otolith shape revealed by a non-indigenous tropical fish

International audienc

Otolith shape analysis of three gobiid species of the Northwestern Black Sea and characterization of local populations of Neogobius melanostomus

International audienceThe present study describes the otolith shape and age of three species of Gobiidae: Neogobius melanostomus (Pallas, 1814), Ponticola eurycephalus (Kessler, 1974) and Mesogobius batrachocephalus (Pallas, 1814) from the Western part of the Black Sea. These phylogenetically close species showed otolith shape differences. The round goby, Neogobius melanostomus, showed differences in otolith shape between local populations, probably related to differences in diet and environmental variability influenced by the Danube River inputs in the North of the study area. The age of these commercially exploited species was estimated by otolith microstructural analysis and the results were linked to sex, size and weight. This information is valuable for fishery management purposes

Differential uses of coral reef habitats by a poorly‐known cryptic fish predator

International audienceThis study used otolith microchemistry to evaluate whether the moray eel Gymnothorax chilospilus uses different habitats throughout its life (mainly juvenile and adult phases). Of the most informative trace elements within otoliths (the twelve isotopes 23Na, 25Mg, 43Ca, 55Mn, 59Co, 60Ni, 63Cu, 66Zn, 86Sr, 111Cd, 138Ba and 208Pb) only three ratios of Ca (Na:Ca, Sr:Ca and Ba:Ca) were informative and therefore used in a multivariate regression-tree analysis. Using a multivariate partitioning, three main phases were described from profiles, including the larval life phase (leptocephali), the intermediate phase (longest section between the larval life phase and the terminal phase) and the terminal phase (final section i.e., the most recent months preceding the death of fish). According to concentrations of the three ratios to Ca, G. chilospilus can be separated into three groups during their larval life stage (very different in Sr and Na), four groups during the intermediate phase (few differences in Sr and Na) and three groups during the terminal phase (differences in Sr), illustrating that G. chilospilus inhabit different habitats during these three phases. Our results showed that the leptocephali encountered different oceanic water masses with fluctuating Sr:Ca ratios during the early larval phase. During the intermediate phase (main part of their life-span), they lived in lagoonal waters such as fringing reefs or reef flats of lagoonal islets, characterized by a lower Sr:Ca ratio. During the latter part of their life, approximately one third of G. chilospilus encountered more oceanic waters close to or at barrier reefs, suggesting possible movements of these fish along a coast-to-ocean gradient

Fingerprints of lagoonal life: Migration of the marine flatfish Solea solea assessed by stable isotopes and otolith microchemistry

The commercially important marine flatfish common sole (Solea solea) facultatively uses NW Mediterranean lagoons as nurseries. To assess the imprint left by the lagoonal passage, muscle carbon (C) and nitrogen (N) isotope values of S. solea juveniles caught in Mauguio lagoon in spring (shortly after arrival from the sea) and in autumn (before the return to the sea) were compared with values of juveniles from adjacent coastal marine nurseries. In addition, in the lagoon, sole otolith stable isotope (C and oxygen (O)) and elemental (11 elements) composition in spring and autumn, and the stable isotope composition (C and N) of organic matter sources in autumn, were determined. Overall, our data indicate that a distinct lagoonal signature existed. Specifically, lagoon soles showed a strong enrichment in muscle tissue 15N (>6‰) compared to their coastal relatives, likely linked to sewage inputs (see below), and a depletion in 13C (1–2‰), indicative of higher importance of 13C depleted terrestrial POM in the lagoon compared to coastal nurseries. In addition, over the time spent in the lagoon, sole otolith δ13C and δ18O values and otolith elemental composition changed significantly. Analysis of the lagoon sole foodweb based on C and N isotopes placed sediment particulate organic matter (POM) at the base. Seagrasses, formerly common but in decline in Mauguio lagoon, played a minor role in the detritus cycle. The very strong 15N enrichment of the entire foodweb (+7 to +11‰) compared to little impacted lagoons and coastal areas testified of important human sewage inputs. Regarding the S. solea migration, the analysis of higher turnover and fast growth muscle tissue and metabolically inert and slower growth otoliths indicated that soles arrived at least several weeks prior to capture in spring, and that no migrations took place in summer. In the autumn, the high muscle δ15N value acquired in Mauguio lagoon would be a good marker of recent return to the sea, whereas altered otolith δ18O values and elemental ratios hold promise as long-term markers. The combination of several complementary tracers from muscle and otoliths may present the chance to distinguish between fish from specific lagoons and coastal nurseries in the future

A 31-year-old brown meagre female poached inthe Scandola marine reserve in Corsica, France

International audienceLe corb, Sciaena umbra, est une espèce longévive à croissancelente très convoitée par les chasseurs sous-marins. Cette pressionde chasse a contribué à la diminution des effectifs et à une raréfactiondes individus de grande taille hors des réserves marines. En2014, en réponse à ce déclin, un moratoire de cinq ans a été mis enplace pour protéger cette espèce sur les côtes françaises. Dans cetteétude, l’âge d’une grande femelle braconnée dans la réserve marinede Scandola a été estimé à 31 ans, ce qui est l’âge le plus élevétrouvé à ce jour dans la bibliographie pour cette espèce