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Port-la-Nouvelle, France

Mercier L.,Montpellier University | Mouillot D.,Montpellier University | Bruguier O.,Montpellier University | Vigliola L.,Center Ird Of Noumea | Darnaude A.M.,Montpellier University
Marine Ecology Progress Series | Year: 2012

Precise knowledge of lifetime migrations is vital in exploited fish species, since all essential habitats must be protected to maintain sustainable stock levels. The present study used multi-element otolith fingerprints of the gilthead sea bream Sparus aurata (L.) to discriminate its main juvenile and adult habitats in the Languedoc-Roussillon region (Gulf of Lions, northwest Mediterranean) and infer the lifetime migrations of 12 individuals from the area (11 from the present day and 1 from the Roman era). This allowed for the first time the identification of key habitats for the successful completion of the species' life cycle in the Gulf of Lions, and the connectivity between them. Our results revealed that lagoon use by S. aurata is probably ancient (>2500 yr) and confirmed its current commonness. Yet, although most observed migration patterns were in accordance with the migratory behavior previously described for the species, strong inter-individual variations and new patterns in habitat use were detected. At the juvenile stage, a preference for shallow lagoons with low salinities was evidenced. Nevertheless, the first year of life can also be successfully completed in marine conditions. At the adult stage, lagoon use was shown to occur until at least age 4 yr, with periods of lagoon residency of up to 11 mo in a year, often including winter months. Because overwintering in the lagoons was previously thought to be impossible for S. aurata due to low temperatures, this finding has important implications for future stock management, especially since the species breeds in winter. © Inter-Research 2012.

Eyssartier G.,etangs de Beon | Ducousso M.,Center Ird Of Noumea | Buyck B.,CNRS Systematics, Biodiversity and Evolution Institute
Cryptogamie, Mycologie | Year: 2010

The authors describe and illustrate Entoloma pseudomurryai sp. nov., a new Entoloma with lemon yellow cap, from a mountain Nothofagus forest in New Caledonia. The species is suggested to belong to section Psittacina (Romagn.) Singer of subgenus Inocephalus Noordel., thereby emending the definition to include also species that are not blue. The discussion comments on close species and presents the typical features of this species group. © 2010 Adac.

Work T.M.,U.S. Geological Survey | Aeby G.S.,Hawaii Institute of Marine Biology | Lasne G.,Center Ird Of Noumea | Tribollet A.,French National Center for Scientific Research
Journal of Invertebrate Pathology | Year: 2014

We surveyed the reefs of Grande Terre, New Caledonia, for coral diseases in 2010 and 2013. Lesions encountered in hard and soft corals were systematically described at the gross and microscopic level. We sampled paired and normal tissues from 101 and 65 colonies in 2010 and 2013, respectively, comprising 51 species of corals from 27 genera. Tissue loss was the most common gross lesion sampled (40%) followed by discoloration (28%), growth anomalies (13%), bleaching (10%), and flatworm infestation (1%). When grouped by gross lesions, the diversity of microscopic lesions as measured by Shannon-Wiener index was highest for tissue loss, followed by discoloration, bleaching, and growth anomaly. Our findings document an extension of the range of certain diseases such as Porites trematodiasis and endolithic hypermycosis (dark spots) to the Western Pacific as well as the presence of a putative cnidarian endosymbiont. We also expand the range of species infected by cell-associated microbial aggregates, and confirm the trend that these aggregates predominate in dominant genera of corals in the Indo-Pacific. This study highlights the importance of including histopathology as an integral component of baseline coral disease surveys, because a given gross lesion might be associated with multiple potential causative agents. © 2014.

Cuypers Y.,University Pierre and Marie Curie | Bouruet-Aubertot P.,University Pierre and Marie Curie | Marec C.,Laval University | Marec C.,Center Ird Of Noumea
Biogeosciences | Year: 2012

One of the main purposes of the BOUM experiment was to find evidence of the possible impact of submesoscale dynamics on biogeochemical cycles. To this aim physical as well as biogeochemical data were collected along a zonal transect through the western and eastern basins of the Mediterranean Sea. Along this transect 3-day fixed point stations were performed within anticyclonic eddies during which microstructure measurements of the temperature gradient were collected over the top 100 m of the water column. We focus here on the characterization of turbulent mixing. The analysis of microstructure measurements revealed a high level of turbulent kinetic energy (TKE) dissipation rate in the seasonal pycnocline and a moderate level below with mean values of the order of 10 -6 W kg -1 and 10 -8 W kg -1, respectively. The Gregg Henyey (Gregg, 1989) fine-scale parameterization of TKE dissipation rate produced by internal wave breaking, and adapted here following Polzin et al. (1995) to take into account the strain to shear ratio, was first compared to these direct measurements with favorable results. The parameterization was then applied to the whole data set. Within the eddies, a significant increase of dissipation at the top and base of eddies associated with strong near-inertial waves is observed. Vertical turbulent diffusivity is increased both in these regions and in the weakly stratified eddy core. The stations collected along the East-West transect provide an overview of parameterized TKE dissipation rates and vertical turbulent diffusivity over a latitudinal section of the Mediterranean Sea. Strong TKE dissipation rates are found within the first 500 m and up to 1500 m above the bottom. Close to the bottom where the stratification is weak, the inferred vertical turbulent diffusivity can reach K z≃10 -3 m 2 s -1 and may therefore have a strong impact on the upward diffusive transport of deep waters masses. ©2012 Author(s).

Zarzoso-Lacoste D.,French National Center for Scientific Research | Ruffino L.,French National Center for Scientific Research | Vidal E.,French National Center for Scientific Research | Vidal E.,Center Ird Of Noumea
Journal of Zoology | Year: 2011

Invasive rats (Rattus spp.) are renowned bird predators and have been identified as a leading cause of island bird population declines and extinctions. Recently, new questions have been raised regarding the mechanisms and the severity of impact of invasive rat predation on bird populations. We investigated the predatory capacity of the invasive black rat Rattus rattus on bird eggs using captive trials on wild-trapped individuals. Five factors were specifically tested for their influence on egg predation success: egg size, egg state, rat body mass, gender and habitat. Our results showed that rats only managed to prey on intact eggs when these were small (canary) and that they had great difficulty preying on medium-sized (hen) and even small (quail)-sized intact eggs, regardless of the rat' body mass, gender and habitat. Conversely, rats preyed extensively on previously damaged eggs of all sizes. Our findings suggest that preying on intact bird eggs without specific learning skills, such as rolling an egg to break it, may be challenging for the black rats. Moreover, our findings strongly indicate that bird susceptibility to egg predation by rats varies with island contexts and may depend on a combination of multiple additive and synergic factors. Experiments that allow for testing the multiple evolutionary and ecological factors explaining between-island or between-population variation in rodent impacts are needed to promote a better overview of the processes involved in bird population declines. © 2011 The Authors. Journal of Zoology © 2011 The Zoological Society of London.

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