Introduction à la végétation, à la flore et aux noms vernaculaires de l'île de Pentecôte (Vanuatu)

The authors bring here all the constituents of an ethnobotanical and ethnolinguistic study of the native and introduced plants of Pentecost Island (Vanuatu).Les auteurs apportent ici tous les éléments d'une étude ethnobotanique et ethnolin- guistique des plantes indigènes et introduites de l'île de Pentecôte (Vanuatu).Cabalion Pierre, Morat Ph. Introduction à la végétation, à la flore et aux noms vernaculaires de l'île de Pentecôte (Vanuatu). In: Journal d'agriculture traditionnelle et de botanique appliquée, 30ᵉ année, bulletin n°3-4, Juillet-décembre 1983. pp. 197-248

Les sécrétions internes et le système nerveux

Morat Jean-pierre. Les sécrétions internes et le système nerveux. In: Bulletin de la Société d'anthropologie de Lyon, tome 30, 1911. pp. 5-8

Evolution de la forme des otolithes de juvéniles de chevaines (Cyprinidae, Squalius cephalus)

L’analyse de la forme des otolithes est utilisée pour caractériser diverses populations locales, mais seulement quelques études s’intéressent à l’influence de l’âge sur la forme des otolithes. Le Chevaine Squalius cephalus (L.) est un poisson cyprinidé rhéophile très abondant et avec une large aire de répartition en Europe. Dans l’étude présentée, nous avons observé le lien entre l’âge et la forme des otolithes durant les premiers mois de la vie de Chevaines élevés en condition expérimentale. Les caractéristiques de forme des sagittae, asterisci, et des lapilli de chevaines éclos en laboratoire ont été étudiées jusqu’à l’âge de 180 jours post-éclosion. Nos observations montrent que les lapilli et les sagittae sont présents dès l’éclosion, alors que les asterisci sont formés entre 20 et 30 jours post-éclosion. A partir de 45 jours de vie post-éclosion, la forme des lapilli et des sagittae se complexifie. Les lapilli prennent une forme de haricots, tandis que les sagittae deviennent très fragiles avec le développement des rostres postérieur et antérieur. Ces observations nous confortent dans l’utilisation des lapilli, et non des autres paires d’otolithes, lorsqu’il s’agit d’études sur le chevaine s’appuyant sur de l’otolithométrie. A partir du jour 45 post-éclosion, les analyses de Fourier de la forme des lapilli montrent des différences significatives entre les classes d’âge. Cependant, au sein d’une même classe d’âge, la forme de l’otolithe n’est pas significativement différente, même entre des individus de longueur totale très différente. Ces résultats suggèrent que des taux différents de croissance individuelle n’influencent pas significativement la forme des otolithes. Pour des juvéniles de Chevaines, au regard du lien mis en évidence entre l’âge et la forme des otolithes, nous recommandons de prendre en compte ce paramètre dans le cas d’études ayant pour but de mettre en lumière l’effet de la génétique ou de l’environnement sur la forme des otolithes

Otolith shape development in young-of-the-year chub (Cyprinidae, Squalius cephalus)

Only a very few studies have focused on the influence of age on the otolith morphometry of cyprinids. Chub Squalius cephalus (L.) is an abundant and widespread European rheophilic cyprinid. Otolith shape analysis was used in many studies to characterize diverse local populations. In the present study we have evaluated the influence of age on the shape of otoliths during the early life of Chub when reared for experiment. Features of the sagittae, asterisci, and lapilli of laboratory-hatched larvae of the chub, were investigated until day 180 after hatching. Our observations showed that the lapilli and the sagittae were both present at hatching, whereas the asterisci were formed only between 20 and 30 days post-hatching. From day 45, the shape of the lapilli and the sagittae became more complex. The lapilli took the shape of a bean whereas the sagittae became far too fragile and inappropriate for study due to its developing very thin anterior and posterior rostra. From day 45, Fourier analysis of the shape of lapilli showed significant differences dependent on age group. However, the shape of the lapilli did not differ significantly between individuals of the same age group, even if their total length was different. This result suggested that differences in individual growth rate do not greatly influence the shape of the otolith. For young-of-the-year chub, according to the link between age and otolith shape, we recommend taking this parameter into account in any study aiming to highlight a genetic or environmental regulation of the otolith form

The Interannual Variability of the Fall Size of Young-of-The-Year Chub (Squalius cephalus): Influence of Phenology, Growth Patterns and Abiotic Factors

International audienceLong-term surveys confirm the rapidity of environmental and biological changes undergone by endangered species but that also concerned relatively “tolerant” species, especially common rheophilic species such as European chub ( Squalius cephalus , Linnaeus 1758). As many organisms, fish are highly vulnerable during their first life stages. Body size is a determinant factor for ecosystem functioning and for fish to survive to predators or to winter conditions. While numerous studies has already demonstrated the large variability of autumnal size of fish hatched during the year, few have focused on the factors explaining these interannual variations and on the growth patterns underlying these distributions. Using otoliths of young-of-the-year (YOY), we studied how the interannual variability in fall sizes of chub might be related to varying phenology, temperature, hydrology and growth patterns. YOY were sampled in three sections of the same reach of the Rhône River with contrasted hydrological regime: an artificial deep lotic channel (the tailrace of Bollène), a bypassed section with both lotic and lentic areas (former river channel before dam construction) and a reservoir with lentic deep waters. Sampling was performed on each sector during two thermally distinct years. Temperature had an important effect on both phenology and growth rate but it was not expressed similarly among river sections. Fish hatched earlier in the warmer year. Fish sizes were positively correlated with growing degree-days, but with distinct relationships between years and sections. The growth was faster in the warmer year, and in the warmer section, but differences in growth patterns varied between sections. In the bypassed section, the difference was slight, almost not significant, even if temperatures were very different between the 2 years considered. Autumnal variations in size could be explained either by an earlier phenology or by a faster growth due to higher temperatures occurring during the final part of the growing period. Our results were in accordance with general theory’s predictions relating individual growth to temperature, but they also showed that other factors might mitigate the influence of temperature on fish early life stages

A multitracer approach to assess the spatial contamination pattern of hake (Merluccius merluccius) in the French Mediterranean

International audienceChemical contamination levels and stable isotope ratios provide integrated information about contaminant exposure, trophic position and also biological and environmental influences on marine organisms. By combining these approaches with otolith shape analyses, the aim of the present study was to document the spatial variability of Hg and PCB contamination of the European hake (Merluccius merluccius) in the French Mediterranean, hypothesizing that local contaminant sources, environmental conditions and biological specificities lead to site-specific contamination patterns. High Hg concentrations discriminated Corsica (average: 1.36 ± 0.80 μg g(-1) dm) from the Gulf of Lions (average values<0.5 μg g(-1) dm), where Rhône River input caused high PCB burdens. CB 153 average concentrations ranged between 4.00 ± 0.64 and 18.39 ± 12.38 ng g(-1) dm in the Gulf of Lions, whatever the sex of the individuals, whereas the highest values in Corsica were 6.75 ± 4.22 ng g(-1) dm. Otolith shape discriminated juveniles and adults, due to their different habitats. The use of combined ecotracers was revealed as a powerful tool to discriminate between fish populations at large and small spatial scale, and to enable understanding of the environmental and biological influences on contamination patterns

Spawning areas and migration patterns in the early life history of Squalius cephalus (Linnaeus, 1758): Use of otolith microchemistry for conservation and sustainable management

International audience1. In the context of the River Rhône restoration programme, the objective of this study was to assess the dispersal and population connectivity of the European chub, Squalius cephalus (Linnaeus, 1758) in a section of the natural, free-flowing part of the lower River Rhône. 2. The elemental water signatures for Sr:Ca and Ba:Ca were measured at seven stations within the river section, including its tributaries and backwaters, to determine whether they could be differentiated by microchemistry. From Augus