1 page.-- Published in: Comptes-Rendus / Proceedings "8th International Symposium on Reproductive Physiology of Fish (ISRPF)", Saint-Malo, France, 3-8 juin 2007, Équipe "Reproduction des Poissons" de l’INRA (éd). To assess annual fecundity accurately it is necessary to identify the reproductive strategy of the fish species under consideration. The reproductive strategy of pouting was investigated and our results indicate that pouting has determinate fecundity. Peer reviewed
Brain aromatization of androgens is particularly important for the organization of sexually dimorphic structures in the brain, testosterone feedback on neuroendocrine circuits controlling the reproductive axis, and regulation of sexual behavior. The brain of teleost fish is characterized by a high aromatase activity corresponding to expression of Aromatase B (AroB) (cyp 19b), one of two cyp 19 duplicates. In teleost species, including the zebrafish, it was shown that Aromatase B (AroB) is expressed in radial glial cells. Given the well-known role of radial glial cells as progenitor cells during embryogenesis, we examined the possibility that Aromatase B radial cells are progenitor cells in the brain of adult fish using a combination of BrdU treatment and immunohistochemistry. We demonstrate for the first time, that aromatase-positive radial cells actively divide to generate newborn cells in many forebrain regions. These data provide new evidence for the mechanisms underlying adult neurogenesis in fish. Given that estrogens are known to affect proliferation, apoptosis, migration and differentiation, expression of Aromatase B (AroB) in progenitor cells is likely to affect adult neurogenesis under certain physiological conditions.
#Amphilius kakrimensis$ sp. n. est décrit d'après des exemplaires provenant d'un petit affluent du Kakrima en Guinée. L'espèce se distingue des autres Amphiliidés par un corps robuste et épais, un pédoncule caudal élevé et une nageoire caudale fortement échancrée. (Résumé d'auteur)
Kisspeptins and their G protein-coupled receptor, play a fundamental role in the control of reproductive function in mammals. here we show that the anterior brain and testis of the trout express a Gpr54-like transcript. trout at 3 stages of maturation were submitted to in vivo treatment with large amounts or repeated injections of mouse or human C terminal decapeptides (KiSS 10). Mammalian KiSS 10 did not increase lh or testosterone hormone concentrations in the trout blood and were not able to stimulate ovulation or spermiation. results even evoked a potential antagonistic effect of these peptides.
Kisspeptins and their G protein-coupled receptor, play a fundamental role in the control of reproductive function in mammals. Here we show that the anterior brain and testis of the trout express a GPR54-like transcript. Trout at 3 stages of maturation were submitted to in vivo treatment with large amounts or repeated injections of mouse or human C terminal decapeptides (KISS(10)). Mammalian KISS(10) did not increase LH or testosterone hormone concentrations in the trout blood and were not able to stimulate ovulation or spermiation. Results even evoked a potential antagonistic effect of these peptides.
Age, growth and diet of anchovy were studied for the first time from samples collected in the Bay of Benisaf (west Algerian coast) during summer (spawning period) and autumn (recruitment period) 2007. Age structure and growth parameters were determined by otolith (sagitta) analyses. The von Bertalanffy growth function fitted to age-length data showed that most of anchovy growth is achieved during the first year of life, suggesting that this stock is primarily supported by the smallest age groups and has a strong dependence on recruitment. There were no significant differences between males and females, and pooled mean parameters were: L infinity = 15.61 cm, k = 0.75 per year and to, -1.32 years. Whatever the age-class anchovy is strictly zooplanktivorous. Copepods constituted the dominant group (64% O; 81% N), while other crustaceans, mollusc larvae and fish larvae were less represented. The main species of copepods consumed were by order of abundance: Candacia longimana, Oncaea mediterranea and Pleuromamma abdominalis. The results indicated a diversification of the diet in the first age groups (0 to 2 years), and a relative specialization in the third age group. Environmental factors including sea surface temperature and chlorophyll-a concentrations were considered in order to explain differences in growth parameters and diet between different geographical areas. There was no significant relationship between the chlorophyll-a concentration and any growth parameter or L. The only significant relationship observed with chlorophyll-a was with the anchovy at age(-1). Concerning temperature, there was significant relationship only between SST and the anchovy size at age(-1).
Age, growth and feeding of anchovy were studied for the first time from samples collected in the Benisaf Bay (west Algerian coast) during summer (spawning period) and autumn (recruitment period) 2007. Age structure and growth parameters were determined by otolith (sagitta) analyses. The von Bertalanffy growth function fitted to age-length data showed that growth was almost achieved during the first year of life. Significant growth difference was recorded between males and females. Growth parameters were for females (L∞=17,46 cm, k=0,31 per year and t0= -3,46 years) and for male (L∞=16,67 cm, k= 0,35 per year and t0= -3,26 years). The parameters of the otoliths (surface, length, weight and width) were significantly correlated with age and fish length (LT) and seem to be a good indicator of somatic growth. The diet and ontogenetic variations in diet was studied on the same fish used for the study of growth. In all age-class anchovy was strictly zooplanctivorous. Copepods constituted the dominant group (64% O; 81% N), others crustaceans, molluscs larvae and fish larvae are less represented. The main species of Copepods were by order of decrease: C. longimana (89% O; 39% N), O. mediterranea ( 80% O; 8% N) and P. abdominalis (73% O; 6% N). 0-group anchovy fed mainly on small and medium size copepods (80% O; 93% N). Diet of others age groups (1 to 3) was more diversified and large preys were relatively well represented both in occurrence and number: (Copepods: 58% O; 76% N), (Amphipods: 16% O; 8% N) and (Decapods: 15% O; 10% N). The specific richness, the Shannon-Wiener diversity, Pielou index and the food niche width (B) increased from the 0-group to 2-group age and declined in the 3-group age. These results indicated a generalization of the diet in the first age group (0 to 2 years), and a relative specialization in the third age group.
#Acnodon senai$ n. sp., décrite du rio Jari (Brésil, Amapa), est une espèce proche de #A. normani$ Gosline, 1951 décrite du rio Tocantins. Ces deux espèces ont un museau pointu, une bouche terminale et deux séries de dents du prémaxillaire nettement séparées. Ces caractères les différencient de #A. oligacanthus$ (Müller et Troschel, 1844), décrit du Surinam, chez qui le museau est arrondi, la bouche infère et les séries prémaxillaires accolées. Les branchiospines, rigides et bordées d'une membrane simple chez #A. normani$, sont souples et bordées d'une membrane lobulée chez #A. senai$. (Résumé d'auteur)
Staghorn damselfish Amblyglyphidodon curacao were sampled underwater over 2 reproductive seasons from 4 reefs of differing coral cover on Australia's Great Barrier Reef. Plasma levels of estradiol (E2) [females], 11-ketostestosterone (11KT) [males], and testosterone (T) [both sexes] were correlated with reproductive development, and population density at each of the sites. In year 1, females from the site where population density was highest were smaller than fish from other sites, and fecundity was lowest. There were no site differences in plasma levels of T or 11KT in males, or T in females. Plasma E2 levels of females varied but not in relation to fish density. In year 2, fish densities were again highest at the same site as in year 1 and again females tended to be smaller than at other sites. Fecundity, plasma E2 and T of females, and plasma 11KT levels in males were highest in fish from the site of lowest population density. The results suggest that high-density sites are characterised by small fish, lower fecundity, and on occasion, reduced plasma levels of T and E2 in females. High density was not accompanied by elevated androgen levels in males. The effects may result from increased competition for planktonic food at high density, and are consistent with similar effects in the brooding damsel Acanthochromis polyacanthus. These results are at variance with studies on temperate damselfishes where increased population density results in elevated plasma levels of gonadal steroids in males, suggesting that food availability may be the prime driver of reproductive function in tropical systems. Yes Yes
The potential of wreckfish (Polyprion americanus) to breed in captivity was examined. Ovarian activity varied seasonally, with vitellogenesis beginning in November and ending in May. Slow-release implant with gonadotropin-releasing hormone agonist (GnRHa) prevented atresia, and both GnRHa injections or implants at the end of vitellogenesis triggered ovulation after 7 days. Spontaneous spawning was obtained only in one female, and the few eggs produced were of poor viability. Manual stripping and artificial fertilization produced viable gametes and embryos. Therefore, present captivity conditions inhibited final oocyte maturation (FOM) and spawning, but not vitellogenesis and spermatogenesis. GnRHa treatments stimulate FOM and ovulation of viable eggs.
Following the volcanic eruption of April 2007, nine specimens of Argyripnus (family Sternoptychidae, order Stomiiformes) were among the fish caught at the sea surface at Reunion Island (Indian Ocean). Seven species were described in this genus: A. ephippiatus Gilbert & Cramer, 1897 from Hawaii, A. iridescens McCulloch, 1926 from Australia. A. atlanticus Maul, 1952 from Madeira, A. brocki Struhsaker, 1973 from Hawaii, Argyripnus sp. Yamamoto in Okamura et al., 1982 from Japan, A. electronus Parin, 1992 from the South-east Pacific and A. pharos Harold & Lancaster, 2003 from the Indian Ocean and the central-west Pacific. The Argyripnus from Reunion Island is easily distinguished from the other species by the position of the anus just before the beginning of the anal fin (about half distance between the pelvic base and the beginning of the anal fin in the other species). The new Argyripnus from Reunion Island is described under the name A. hulleyi. Some indications are given on the bathymetric and geographical distributions of all the Argyripnus species. After a brief comparison of the characteristics of the seven species, an identification key is provided.
Première capture d'Erythrocles monodi (Poll & Cadenat, 1954) dans l'Atlantique nord-est. Les conditions de captures aux abords du Gouf de Capbreton et les caractéristiques biométriques de ce spécimen sont présentées. Première capture d'Erythrocles monodi (Poll & Cadenat, 1954) dans l'Atlantique nord-est. Les conditions de captures aux abords du Gouf de Capbreton et les caractéristiques biométriques de ce spécimen sont présentées.
First record of Ebinania costaecanariae (Scorpaeniformes: Psychrolutidae) in the North-eastern Atlantic and bathymetric distribution of Cottunculus thomsonii.The tropical Psychrolutidae, Ebinania costaecanariae (Cervigon, 1961), caught off northern coast of Spain is recorded for the first time from the North-eastern Atlantic. The bathymetric distribution of the psychrolutid, Cottunculus thomsonii, is discussed.
Age is a necessary parameter used in population dynamics to assess the state of exploited resources. This parameter is poorly known for most deep-sea species (depth > 400 m). This work focused on age estimation from otoliths of Alepocephalus bairdii (Alepocephalidae), Coryphaenoides rupestris (Macrouridae), Helicolenus dactylopterus (Sebastidae) and Hoplostethus atlanticus (Trachichthyidae), which French fishery exploitation, off the west coasts of the British Isles, began the late 1980's. Considering otolith growth zones as annual, the four species all show high longevity: 38, 54, 43 and 130 years, respectively, together with slow growth. The differences in growth between sex were estimated and difficulties in accurately estimating the age were highlighted and showed the need to standardise and validate age estimation. The ages currently estimated for deep-sea fish must be used with caution.
The eastern English Channel, which connects the Atlantic Ocean to the North Sea through the Dover Strait, is an area where numerous and often conflicting human activities take place. A cross-border multidisciplinary project called CHARM was initiated to provide knowledge and tools for planners and decision-makers to durably manage the shared marine living resources. One such tool was an atlas of fish spatial distributions and modelled habitats, which was used here to investigate ontogenic and seasonal shifts in fish spatial distribution and habitat through a case-study, the dab Limanda limanda. Survey data for several life-history stages (eggs, larvae, coastal nurseries, < and > 1 year old) and seasons were used to map spatial patterns (using geostatistics), and model potential habitats (using regression quantiles) based on environmental predictors. Habitat models were generally consistent with surveyed spatial patterns and helped explaining dab response to its environment. Dab response to hydrological parameters (e.g., temperature, salinity) was more variable (depending on the life stages and seasons considered) than response to physical parameters (e.g., depth, bed shear stress, seabed sediment type). The results of this work contribute to a better understanding of this species spatial ecology in the eastern English Channel.
The genus Pseudoscopelus Lutken, 1892 is easily distinguished from the other Chiasmodontidae by the presence of well-defined rows of photophores. Until 2005, eight species were known. Pseudoscopelus scriptus was the first described by Lutken in 1892, then P. sagamianus by Tanaka in 1908, P. stellatus by Beebe in 1932 and P. altipinnis by Parr in 1933. Later in 1934, Fowler described three new species: P. microps, P. cephalus, and P. obtusifrons. These three species, known from only one specimen each, have not been recorded since. Lastly, an easily distinguishable species, P. scutatus, was discovered by Krefft in 1971. In a recent review, Prokoviev and Kukuev (2005, 2006) confirmed the validity of all species and described a new one P. aphos, distinguishable by the absence of photophores. Our study proposes some different conclusion. A total of 58 specimens have been examined, four of them on photography. These fishes are deposited in the collections of the Museum d'histoire naturelle de La Rochelle (MHNLR), the Zoological Museum of the University of Copenhagen (ZMUC) or the National Museum of Natural History of Washingthon (USNM). We followed the standard method for counts and measurements. After examination, we describe a new species: P. pierbartus characterized by long pectoral fins extending beyond the 5(th) anal fin ray, teeth curved toward the front on the posterior part of the premaxilla and a photophore group on the caudal peduncle composed of three double rows forming an arrow in the direction of the head. We also propose to consider P. microps as a junior synonym of P. altipinnis and, similarly, P. cephalus with P. scriptus. P. scriptus, P. altipinnis and P. scutatus are three valid species and numerous specimens are available in museum collections. P. obtusifrons is also valid but few specimens seem to be available. The descriptions provided by Lutken, Parr, Krefft and Fowler allow their identification. According to Tanaka's original figure, the strong difference between P. sagamianus and P. scriptus is the position of the anus at a distance equal to the eye diameter of the anal fin. However, we didn't find a valid specimen. The types were lost and the 6 specimens from the examined materials identified as P. sagamianus were actually P. scriptus. Even Nakabo's illustrations of P. sagamianus (1993) show an anus close to the anal fin. So, to our knowledge, the validity of this species depends on the lost record of 1908. P. stellatus was not identified since its description by Beebe. The specimen is a juvenile and is too damaged for being re-examined. If the adult form is similar to that of the juvenile, this species will be valid. However, a study of juvenile forms of Pseudoscopelus is required. Finally, in the future, we recommend the group of photophores for identification and/or description of Pseudoscopelus spp.; a key is included to this study. Considering the numerous anatomical differences, like the presence of photophores and the form of the otoliths, between Pseudoscopelus and the other Chiasmodontidae, future study is required to determine whether the specimens currently included in the genus Pseudoscopehis should be placed in a new family. La plupart des espèces du genre P s e u d o s c o p e l u s n'ont été décrites qu'avec un nombre très restreint de spécimens. Malgré une révision récente (Prokoviev et Kukuev, 2005, 2006), la présente étude s'est attachée à vérifier la validité des espèces décrites jusqu'alors. Nos résultats diffèrent et nous conduisent à considérer P. micro p s F o w l e r, 1934 et P. c e p h a l u s F o w l e r, 1934 comme des synonymes junior de, respectivement, P. altipinnis P a r r, 1933 et P. scriptus L ü t k e n , 1892. La validité de deux espèces, P. sagamianus et P. stellatus, reste toujours à confirmer. Enfin, une nouvelle espèce découverte dans le golfe de Gascogne est décrite : P. pierbart u s n. sp. Nous recommandons de considérer à l'avenir les caractéristiques des groupes de photophores chez les spécimens du genre P s e u d o s c o p e l u s lors de toutes identifications ou descriptions ; une clé d'identification est proposée principalement dans ce sens.
Following the volcanic eruption of April 2007 at Reunion Island, 12 specimens of the pomacentrid genus Chromis were collected at sea surface. One of these fishes was a C. chrysura known from the reef Island fauna. The others have enlarged eyes. Among them were one C. axillaris (Bennett, 1831), new for the Island fauna, and ten specimens of a new Chromis species, described here under the name C. durvillei. This new species of deep dwelling Chromis is distinguishable by large sized eyes 1.9 to 2.4 in the head length, D. XIII, 12-13, 25 to 26 gill-rakers on the first gill arch, three spiniform procurrent caudal rays, without black or dark brown spot or band on the body, pectorals or caudal peduncle. C. axillaris, C. woodsi, C. unipa, C. okamurai, C. struhsakeri and generally C. mirationis have 14 spinous dorsal rays. C. abyssicola and rarely C. mirationis have 13 spinous dorsal rays but two spiniform procurrent caudal rays and a dark axillary spot on pectorals. Parmi les poissons récoltés en surface à l’île de la Réunion (océan Indien sud-ouest), après l’éruption volcanique d’avril 2007, se trouvaient 12 exemplaires du genre Chromis. Un C. chrysura connu de la faune récifale de l’île et 11 exemplaires présentant des yeux de grande taille : un C. axillaris (Bennett, 1831), nouveau pour la faune de l’île de La Réunion et 10 Chromis distinguables des autres espèces du genre par des yeux de grande taille (1,9 à 2,4 fois dans la longueur de la tête), D. XIII , 12-13, 25 à 26 branchicténies sur le premier arc branchial, trois rayons caudaux procurrents épineux et l’absence de tache ou de bande de couleur foncée sur le corps, les pectorales ou le pédoncule caudal. C. axillaris, C. woodsi, C. unipa, C. okamurai, C. struhsakeri et C. mirationis ont 14 rayons épineux à la dorsale, alors que C. abyssicola et rarement C. mirationis n’en ont que 13, mais deux rayons caudaux procurrents et une tache axillaire noire sur les pectorales. Cette espèce nouvelle de Chromis est décrite sous le nom de C. durvillei.
The ichtyofauna of Geyser and Zelee coral banks (north of Mozambique canal) was investigated in 1996, this work being the first quantitative study on this area. Quantitative data were collected on 11 stations (mean depth 18 m) by visual observations along 50 m transect, widened to 2 m for small sedentary species, and to 5 m for commercial species with a large action range. The main descriptors of the fish communities (species richness, abundance per species) and the trophic structure (omnivorous, herbivorous, carnivorous, browsers of sessile invertebrates) were described and analysed.A total of 294 fish species, belonging to 43 families were recorded. The species richness varied from 45 to 83 species / station, and the abundance, from 292 to 1322 individuals / 100 m(2), the lower values being recorded on the inner slope and the higher ones on the outer slope. In terms of number of individuals, diurnal planktivores were highly represented at all sites (mean 63.7%). Pomacentridae and Caesionidae were the most abundant families, damselfishes being mainly represented by Chromis ternatensis (mean 73 ind., max, 148 ind. 100 m(2)), C. dimidiata (mean 33 ind., max. 151 ind. / 100 m(2)) and Dascyllus carneus (mean 38 ind., max. 92 ind. 100 m(2)), and fusiliers by Pterocaesio chrysozona (mean 19 ind., max. 128 ind. / 100 m(2)), P. tile (mean 12 ind., max. 38 ind. / 100 m(2)) and Caesio teres (mean 6 ind., max. 32 ind. / 100 m(2)). The high values recorded showed that small and isolated coral banks can support relatively rich fish faunas and substantial populations of individuals. This result may be explained by different factors such as the oceanographic circulation favourable to a localised enrichment of nutrients from surface water, the low human impact, a good coral cover and a high degree of self-recruitment associated with regional recruitment. Nevertheless, the main commercial species such as Lutjanus bohar and Variola louti, observed at each station, were represented at a low density (mean 0.8 ind., max. 6 ind. / 100 m(2) and mean 0.2 ind., max. 0.8 ind. / 100 m(2) respectively). This result may be due to the exploitation of these coral banks between 1990 and 1992, which was interrupted following the fast decreasing output.Such an experience shows us the fragility of these small coral banks and the necessity to establish a rational management of the resource.
There is currently an increasing demand for the diversification of the production in fish aquaculture and the domestication of new species, which may display highly divergent strategy of reproduction. Yet, today, the domestication of a new species is still essentially realized by a long, costly, and usually empirical zootechnical process. Within this context, a research program has been launched to establish a functional typology, focusing on the function of reproduction, in order to cluster species displaying similar reproductive strategies, and thus apply or adapt rearing systems (zootechnical practices) already in use in species belonging to the same group. This research has been restricted to some temperate freshwater teleost species inhabiting Europe and North America. This objective has required the development of a new database, namely STOREFISH (acronym for STrategies Of REproduction in FISH), which currently comprises 50 reproductive traits for 80 species (distributed into 19 families). The 50 characters are classified into four main categories: 7 characters for egg, 7 for larvae, 21 for breeders and 15 for spawning conditions. Overall, 70 % of the character/species cells were successfully fulfilled, corresponding to 1000 biographical references. The potential applications of this database for the study of the domestication process in fish aquaculture are further discussed. [Il existe à l’heure actuelle une demande croissante pour une diversification de la production en pisciculture et la domestication de nouvelles espèces qui peuvent présenter des stratégies de reproduction très différentes. Or, à ce jour, la domestication d’une nouvelle espèce s’effectue essentiellement par une approche zootechnique souvent empirique, longue et coûteuse. Dans ce contexte, une recherche a été engagée dans le but d’établir une typologie fonctionnelle, en se concentrant sur la fonction de reproduction, afin de regrouper les espèces présentant des stratégies reproductives similaires, pour ensuite appliquer ou adapter des systèmes d’élevage (approches zootechniques) déjà éprouvés aux espèces appartenant au même groupe. Cette recherche a été limitée à quelques espèces de poissons téléostéens d’eaux douces tempérées d’Europe et d’Amérique du Nord. Cet objectif a nécessité le développement d’une nouvelle base de données, STOREFISH (acronyme de STrategies Of REproduction in FISH), qui comprend actuellement 50 caractères liés à la biologie de la reproduction pour 80 espèces (réparties en 19 familles). Ces 50 caractères sont regroupés en 4 grandes catégories : 7 caractères liés à l’oeuf, 7 à la larve, 21 aux géniteurs et 15 aux conditions de ponte. D’une manière générale, 70% des cellules caractère/espèce ont été remplies, ce qui correspond à 1000 références bibliographiques. Les applications potentielles de cette base de données pour l’étude du processus de domestication en pisciculture sont discutées.]
The aim of this study was to describe and determine the reproductive and spawning strategy of the sand flathead, Platycephalus bassensis Cuvier, 1829 based on histological analysis of ovary and testis. The presence of multiple group synchronous gamete development in both sexes within a reproductive season confirmed the hypothesis that sand flathead is a serial spawner and is reproductively active from October to March. Spawning frequency estimated from a combination of information acquired from field sampling and results from a laboratory experiment, indicated that sand flathead spawned on average once every 4-5.3 days during the spawning season. A clear pattern of diel periodicity in spawning was apparent in sand flathead with the peak of spawning activity during the day. Results of this study showed that estimating spawning periodicity from the presence, and age of postovulatory follicles is more reliable than using the presence of hydrated oocytes. This study highlights the details of reproductive biology of a serial spawner and its potential for variability, which can have implications for recruitment and adult population dynamics. Yes Yes
Very little is known on European hake's reproductive biology and especially on biological characteristics of its sperm despite a growing interest in its aquaculture potential. This study reports, for the first time some hake sperm characteristics. After activation, the swimming phase lasts 3 min (8 min when activated with 50% sea water (SW) but lower initial velocity). The initial flagellar beat frequency (BF), velocity and percentage of motile cells decreased after 100 s. After 2 days at 4 degrees C, the mean Adenylate Energy Charge (AEC) level was 0.71. Sperm stored at 4 degrees C still showed motility after 9 days for 2 individuals. When cryopreserved, the motility recovery index of thawed spermatozoa ranged from 11.8% to 29.6%.
Fish size and proximate composition were measured during the fattening process of two groups of bluefin tuna (Thunnus thynnus) kept in ocean cages in the southwestern Mediterranean Sea. The fish were first sampled just after capture in June 1998, and twice more over a month period at the two tuna farms located near Cabo Tiñoso in Murcia, Spain. Both groups were caught within 200 km of each other by purse seining during June. The results found that the mean of tuna fork lengths were significantly different among the three periods sampled, but not so between farms. Additionally, weight is significantly different over time. However, fat content was found to be significantly different between farms and increased from June to November at both locations. Variations in fat levels between both locations could be due to multiples reasons, such as different environmental conditions, feeding protocol or fish density.
Catch Per Unit Effort (CPUE) trends of the main target species of the deep-sea fishery were recorded for one sample trawler in two areas to the west of the British Isles, from 1993 to 1997. Considered species were the orange roughy (Hoplostethus atlanticus), the roundnose grenadier (Coryphaenoides rupestris), the black scabbard fish (Aphanopus carbo) and two squalid sharks: the Portuguese dogfish (Centroscymnus coelolepis) and the leafscale gulper shark (Centrophorus squamosus). Two sources of data have been used: the catch and effort database of IFREMER and the personal logbooks of the skipper from the sample trawler. The personal logbooks indicate the catch per haul, whereas the IFREMER database provides the catch and effort per day and statistical rectangle. From the personal logbooks, the time spent on deep-sea species can be known and CPUE corrected for the depth. These corrected CPUE allow to take into account the changes of the fishing strategy and the variations of the fish abundance according to depth. Both, the life strategies of the exploited species and the fishing strategy of the trawler are very important to consider the CPUE as abundance indices.
The effects of parasites on coral reef fishes are largely unexplored and unknown. In other fish-parasite systems, parasites may have far reaching effects upon their hosts, leaving few aspects of their host's biology unaffected. In French Polynesia, coral reef fishes are relatively well studied, but the effects of parasites upon the coral reef fish communities there are unevaluated. As a first step, we conducted a survey of the macroparasites of coral reef fishes in French Polynesia. We found a diverse array of parasites infecting fishes, including cestodes, copepods, digeneans, isopods, monogeneans, and nematodes. Diversity of digeneans, the most common parasite group, was lower in French Polynesia than on the Great Barrier Reef. The majority (69%) of fishes examined were infected with at least one species of parasite. Finally, we discuss the potential of parasites to influence coral reef fish communities by altering host life histories, interspecific interactions, community structure, and larval dynamics.
The ichthyofauna of Reunion Island, Southwestern Indian Ocean, was sampled during several ecological and artisanal fisheries studies. Information from these investigations and from other sources were included to compile the present checklist of the marine fishes of the island. A total of 885 species belonging to 150 families was recorded. Nine species are known only from Reunion, indicating endemism of about 1.0%. The most speciose families (Labridae, Gobiidae, Serranidae, and Pomacentridae) were also among the most speciose at the neighbouring Mauritius Island (except gobiids), and, generally, on other islands in the Indian Ocean area (Maldives, Chagos, Madagascar and Christmas Island). The Gobiidae only represented 5.4% of the ichthyofauna, which was similar to the ratio for Aqaba (Red Sea), contrasting with 8.0% recorded for the Maldives, 13.0% at Chagos or other higher percentages recorded in the Pacific Ocean. The Apogonidae and Scaridae are relatively poorly diversified at Reunion, also in contrast with the Maldives, Madagascar, Chagos, Aqaba (Red Sea) and certain Pacific areas. The recent geological origins of Reunion Island and the low diversity of its marine biotopes are probably the most significant factors explaining both the total species richness and species richness of some major families.
As in many marine fish, motility is triggered by osmotic pressure (OP) in cod and hake spermatozoa and motility ranges several minutes with a high velocity (above 50 mu m/s) period restricted to 100 s. A decrease in the flagellar beat frequency (BF) is partly responsible of this briefness. Detailed observations of the flagella during the motility period showed: 1) sea water provokes OP damages (blebs) which impair the correct wave propagation 2) waves become restricted to the proximal flagellum and tip becomes devoid of wave 3) the wave amplitude decreases. The combination of these factors drastically limits to the earliest period of motility the ability for spermatozoa to efficiently progress towards egg for fertilization.
Rivulus gaucheri, new species, is described on the basis of 11 specimens collected from small tributaries of the Litany river basin in the southwest highlands of French Guiana. R. gaucheri differs from all other congeners by the lack of the supracaudal spot at all ages in both sexes, a short base of dorsal fin, a yellow colour background of the body, a red colored sub-distal area on the anal fin in male, and a yellow one in female, and a dark margin of caudal fin. [Rivulus gaucheri, nouvelle espèce, est décrite à partir de 11 spécimens collectés dans des petits affluents du bassin de la rivière Litany, dans le sud-ouest montagneux de Guyane française. R. gaucheri diffère des autres espèces par l’absence de l’ocelle supracaudal à tous les âges et quel que soit le sexe, une nageoire dorsale à base courte, une coloration jaunâtre dominante du corps, une marge rouge sur la nageoire anale du mâle, une marge jaune sur celle de la femelle, et une marge noire sur la nageoire caudale.]
In order to improve Our understanding of factors determining egg quality in fish, seabass egg batches obtained from 34 females held under standard conditions, were assessed for biological performances and a fraction from each batch was subjected to proteomic analysis. Comparison of proteomic patterns from eggs of different quality revealed differential protein spots among which one was identified as Nucleoside Diphosphate Kinase, a highly conserved protein involved in cell proliferation. This study shows that molecular markers may help understand factors determining egg quality in fish.
Les poissons-chats du genre Harttia se répartissent principalement dans l'est du continent sud-américain : dans les fleuves côtiers du Sud-Est brésilien, dans la région amazonienne et sur le bouclier guyanais. Quatre espèces sont recensées en Guyane française : H. maculata, H. fowleri, H. surinamensis et H. guianensis. Cette dernière présente certaines incertitudes taxinomiques et n'est fondée que sur du matériel provenant de deux bassins (Approuague et Sinnamary). Afin de clarifier le statut taxinomique des différentes populations de l'Ouest du département et de préciser la répartition de chaque espèce, une étude morphologique de toutes les espèces et populations de Harttia présentes en Guyane française et de la série type de H. surinamensis du Surinam a été réalisée grâce à des analyses multivariées effectuées sur de nombreux caractères morphologiques. Il en résulte que H. surinamensis est absente de Guyane française et que sa répartition géographique pourrait être restreinte à la rivière Suriname. Les paratypes de H. surinamensis du haut Tapanahoni (bassin du Maroni, rive surinamienne) sont à rattacher à H. guianensis ainsi que toutes les autres populations du système fluvial du Maroni et de la Mana ; les paratypes de la rivière Coppename pourraient représenter une nouvelle espèce. Harttia fowleri est relativement proche morphologiquement de H. guianensis alors que H. maculata s'en distingue significativement. Quelques différences sont relevées entre les populations de H. guianensis. Les spécimens de la localité type de H. guianensis, l' Approuague, ont un corps plus haut que les spécimens de toutes les autres localités et les individus du Sinnamary présentent des caractéristiques méristiques particulières qui les distinguent de toutes les autres populations. Une clef de détermination pratique de toutes les espèces de Harttia de Guyane française et du Surinam étudiées dans ce travail est proposée. [The genus Harttia Steindachner, 1877 belongs to the family Loricariidae, the most diversified of all catfish families with 673 valid and around 300 undescribed species. Stream water fish of the genus Harttia are found in the upper course of rivers on rocky and sandy bottoms. This monophyletic genus comprises at present 22 species (Rapp Py-Daniel and Oliveira, 2001) mainly distributed on the Guiana shield, the South East of Brazil in coastal rivers, and in the Amazonian region. In French Guiana, Le Bail et al. (2000) list 5 species of Harttiini including 1 Harttia, H. surinamensis, and 2 other species now assigned to Harttia: Cteniloricaria fowleri from the Oyapock drainage and Cteniloricaria maculata from the Maroni and Sinnamary drainages. Morphological differences between populations of H. surinamensis were noted. French Guiana specimens differ from specimens of the type locality by the absence of abdominal scutes. Later, Rapp Py-Daniel and Oliveira (2001) put Cteniloricaria in the synonymy of Harttia and describe a new species from the Approuague and Sinnamary drainages in French Guiana without considering western populations. In the light of these recent works, a revision of the genus Harttia in French Guiana was clearly necessary in order to clarify the taxonomical position of all populations and species and to redefine their distribution. A morphological study was carried out on all Harttia species and populations from French Guiana and on the type material of H. surinamensis from Surinam. 28 continuous quantitative variables, 20 categorical quantitative variables, and 6 qualitative variables were noted for each specimen. After selection of the suitable variables, data were analysed with multivariate analysis. According to our results, the distribution of H. surinamensis may be restricted to the Suriname River drainage. Paratypes of H. surinamensis from the Maroni drainage (upper Tapanahoni, Surinam) are now assigned to H. guianensis, while those from the Coppename drainage may represent a new species. As noted by Le Bail et al., H. fowleri is morphologically close to the H. guianensis, whereas H. maculata is very different. Populations from the Maroni and Mana drainages are assigned to H. guianensis and differences between populations of H. guianensis are emphasized. Specimens from the type locality (Approuague drainage) are deeper than those of all other populations. Specimens from the Sinnamary drainage are different considering meristic data. A practical key to the species of Harttia from French Guiana and Surinam studied in this work is proposed.]
Presence of two populations of Norwegian topknot, Phrynorhombus norvegicus (Pleuronectiformes: Scophthalmidae), in western European seas.
The Norwegian topknot Phrynorhombus norvegicus (Gunther, 1862) is a little flatfish belonging to the scoplithalmid family. Generally, in the literature, the habitat of this species is mentioned to be rocky bottoms of the north-eastern European seas between 10 to 180 in depth, while few references noticed its presence in the same area and depth on muddy bottoms as well. A study of fisheries data conducted by the trawlers of ISTPM and IFREMER between 1976 to 2001 in Celtic sea and Bay of Biscaye shows that Norwegian Topknot is a rarely caught species with 423 specimens fished in 25 years. Moreover, this analysis leads to the conclusion that two groups of Norwegian topknot are present in western Europeans seas: one occurs on rocky substrates from the Celtic sea northwards, whereas another one is present more southwards on muddy substrates off the Bay of Biscay, the species being more abundant in the latter area. Gene flow exchange between these two groups could not be demonstrated yet. Only further studies based on meristic or molecular data could clarify the status of these local populations.
2 pages, 3 figures.-- Published in: Comptes-Rendus / Proceedings "8th International Symposium on Reproductive Physiology of Fish (ISRPF)", Saint-Malo, France, 3-8 juin 2007, Équipe "Reproduction des Poissons" de l’INRA (éd). Larger hake females have both higher batch fecundity and numbers of developing oocytes, however this is influenced by external energy availability and capacity to store energy in the short-term in the liver and muscle tissue. Peer reviewed
In fish, as in all poikilotherms, growth is strongly dependent on water temperature. Given that the GH/IGF system regulates growth, it could mediate the effects of temperature on fish growth. Indeed, before hatching, the higher embryonic growth rate in rainbow trout at high temperatures is associated with higher expression of the IGF2 gene in the whole embryo. Furthermore, post-natal growth fluctuations depend on water temperature and are associated with variations of plasma GH and IGF1. Although seasonal parameters such as photoperiod and nutritional status can also affect GH/IGF system activity, it has been shown that an increased temperature led to a specific increase of plasma GH. Moreover, this increase of plasma GH leads to higher plasma IGF1 levels in correlation with the growth rate. By contrast, plasma IGF2 levels as well as muscular levels of IGF1 and IGF2 mRNA are not specifically modified by temperature. Thus, seasonal fluctuations of water temperature affect growth rate through a direct action on plasma GH and IGF1 levels. The mechanisms of this effect are not yet elucidated, but could arise from modifications of metabolite levels (glucose, aminoacids, fatty acids, etc.), which regulate GH secretion directly or indirectly through somatostatin of pancreatic or hypothalamic origin.
From the 8(th) to the 11(th) April 2007 at Reunion Island (Indian Ocean) some fish were collected at sea surface after the eruption of the Piton de la Fournaise. Among these are two specimens of Symphysanodon (Perciformes: Symphysanodontidae). This family was recently reviewed (Anderson and Springer, 2005). Ten species have been described: three from the Atlantic Ocean S. berryi Anderson, 1970; S. octoactinus Anderson, 1970 and S. mona Anderson & Springer, 2005; four from the Pacific Ocean S. typus Bleeker, 1878; S. katayamai Anderson, 1970; S. maunaloae Anderson, 1970 and S. parini Anderson & Springer 2005; three from the Indian Ocean S. andersoni Kotthaus, 1974 from the entrance of the Gulf of Aden, S. rhax Anderson & Springer, 2005 from the Maldives Islands and S. disii Khalaf & Krupp, 2008 from Red Sea. An undescribed species with a lower number of gillrakers on the first arch was found partially digested in the stomach content of a coelacanth from the Comoros (McCosker, 1979). The two specimens found at Reunion Island are distinguishable from all Indopacific species of Symphysanodon by the following combination of characters: 19 caudal fin rays; 15 pectoral fin rays; 48-50 tubed lateral line scales; a total of 34-36 gillrakers on the first gill arch; a long depressed anal fin (33-38% SL); a long pectoral fin (length 30% SL) and comparatively large big eyes (10-11 % SL). These specimens are described as a new species named Symphysanodon pitondelafournaisei. A key to Indopacific species is given.
Using cDNA subtraction and differential screening, we identified 25 genes that were differentially expressed by 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (DHP) stimulation. Among these clones, eel trypsin and eel 11 beta-hydroxysteroid dehydrogenase short form (e11 beta-HSDsf) were analyzed. The results indicate that transcripts of eel trypsin and e11 beta-HSD in testis were induced by DHP stimulation. In vitro experiments revealed that trypsin induces initiation of meiosis and spermiogenesis. Moreover, cortisol enhanced the 11-ketotestesterone (11KT)-induced spermatogonial proliferation. From these results, we conclude that these two molecules are important for controlling spermatogenesis.
This study was conceived to investigate what are the main effects of an androgen masculinizing treatment on gonadal gene expression profiles in the rainbow trout during sex differentiation. Using microarrays we characterized a highly deregulated expression profile in female treated with androgens with a clear inhibition of the female specific gene expression patterns. This suggests that androgens may acts mainly through the inhibition of female development rather than through a direct stimulatory effect on testicular differentiation.
We have studied melatonin binding sites in the brain of the tropical catfish O. sifontesi using in vitro autoradiography and receptor binding assay. Specific binding was found in brain areas involved in the processing of visual information and in the pituitary. Binding was saturable around 150 pM. K D and Bmax were calculated.
Coastal marine zones located in front of large rivers are of major biological interest. The Danube is the second largest river in Europe after the Volga and represents 58% of the freshwater inputs to the Black Sea. Its delta, located between the North of Romania and the South of Ukraine, has a great impact on the sedimentation and marine ecosystems in the Black Sea. The objective of the present study was to estimate the impact of the seasonal fluctuations of the Danube particulate organic matter (POM) on the various marine trophic compartments (POM sea water, sediment, macro-invertebrates and fish) along the Romanian coasts. The ratios of the stable isotopes of carbon (C-13/C-12) and nitrogen ((15) N/N-14) allowed the identification of organic matter sources and the analysis of trophic webs. 670 analysis of stable isotopes of the particulate organic matter (POM) of the Danube water as well as marine POM, marine sediments and marine organisms (macrophytes, polychaetes, bivalves, gastropods, amphipods, macrurids, brachyurids and fishes) has been carried out on samples taken in 38 stations from the Northern, Central et Southern areas of the Romanian coasts in October 2004 and April-May 2005. The POM of the Danube presented average values of delta C-13 (-27.61 parts per thousand) and delta N-15 (4.39 parts per thousand), lower than those of the marine POM of the Black Sea (delta C-13 = -24.98 parts per thousand and delta N-15 = 7.08 parts per thousand). In the sea, the sediment presented average values decreasing from the North (delta C-13 = -20.02 parts per thousand and delta N-15 = 9.93 parts per thousand) to the South (delta C-13 = -23.59 parts per thousand, delta N-15 = 7.65 parts per thousand). Among invertebrates, stable isotope values depended on their trophic level and aptitude to consume the terrestrial POM brought by the river. The lowest values were found in polychaetes, copepods and amphipods, and the highest ones in macrurids, brachyurids and gastropods. Among the fish species studied, the lowest values of delta C-13 and delta N-15 were observed in starry sturgeon (Acipenser stellatus ponticus) and sprat (Sprattus sprattus), while the highest values was found in beluga sturgeon (Huso huso). These differences were explained mainly by differences in diet. Preliminary results showed a strong influence of the Danube particulate organic matter on the marine compartments of the Romanian coasts. The river influence decreased from the North to the South and was higher in spring when the river was flooding.
As early as 1666, Colbert asked the Royal Academy of Sciences to systematically complement its scientific work with drawings and engravings in order to make them more easily understandable and to achieve a better diffusion among the European scientific community. Some scientists therefore added illustrations to their observations or their accounts of their travels across the French provinces. That was the case of the astronomer P. de La Hire (1640-1718), who travelled along the coasts of Brittany in 1679-1680 with the anatomist J.-G. Du Verney (1648-1730). During this trip they dissected and drew fishes. Drawings by P. de La Hire are today preserved in the archives of the "Bibliothèque Centrale" of the "Museum national d'Histoire naturelle de Paris", under number MS 244. This collection is entitled Dissections de divers poissons faites sur les Costes de France pendant les années 1679 et 1680. It deals with about thirty species, 23 of which being fish species drawn in their entirety, with details of their dissected anatomical structures. Each drawing is accompanied by an accurate caption. For the history of ichthyological iconography, these drawings are innovative because they are realistic and accurate. They demonstrate that under the impulsion of the Royal Academy of Sciences, animals became true objects to study, the true anatomy of which had to be investigated, and no longer idealised as during the previous centuries.
Dusky grouper, Epinephelus marginatus, is an emblematic Mediterranean fish. Ten years ago, small populations induced by over-fishing seemed to increase by a low reproduction on the French coasts. At the beginning of the 1980 years, studies began, especially in the marine protected areas, to understand the population dynamics, maintenance, and the turnover of dusky grouper populations. In September 2001, an inventory of the dusky groupers (Epinephelus marginatus) of the marine reserve of Cerbère-Banyuls (France, Western Northern Mediterranean) was carried out by the GEM to quantify the density and the size distribution. The inventory was made in the marine reserve of Cerbère-Banyuls located in the Mediterranean Sea near Spain between the 2 and 8 September 2001 by visual census. The marine reserve is composed of a partially protected area (spear fishing forbidden and professional fishing controlled) and a totally protected area where all activity is forbidden. Along the coast, the depth zone between 0-25 m was sampled by 25 divers (15 scuba divers and 10 snorkel divers) covering all the reserve (including the totally protected area). Moreover, two off shore zones were sampled to represent a potential habitat for dusky grouper. Each diver noted the time, the size and the behaviour of each observed dusky grouper. On the whole, 193 dusky groupers were observed whereas only 7 and 50 individuals were counted in 1986 and 1998 respectively. These methods of census were compared and gave similar results. The size distribution showed a prevalence of medium size individuals corresponding to mature females (61%). The population comprised 10% large males (size exceeding 100 cm). The smallest dusky grouper measured 8 cm and corresponded to an individual born the year before. Regarding the spatial distribution, more than two thirds of the individuals were located in the totally protected area around Cape Rédéris. The protection effect contributes partly to the development of the population of dusky groupers in the marine reserve of Cerbère-Banyuls. However, the protection alone is insufficient to explain the recent appearance of the young individuals and mature females. Other hypotheses already proposed by several authors to explain this increase are discussed: migration of individuals from the South and reproductive success of individuals in the marine reserve. The latter hypothesis is supported by observations of reproductive behaviours in various French marine protected areas including the Cerbère-Banyuls reserve.
The objectives of this study were to determine the expression and the cellular localization of P450c17 in gonadal tissues in the zebrafish and to investigate the effect of (xeno)-hormones on its expression at both mRNA and protein levels. We showed that gonads are sites for cyp17 gene expression and we documented for the first time the cellular localization of the cyp17 protein expression within ovarian and testicular tissues in a cyprinid fish. Moreover, we demonstrated the down-regulating effect of (xeno)-estrogens on testicular cyp17 expression.
Estrogens are known to play an important role in the regulation of gonadotropin production, sexual differentiation and activation of sexual behaviour in vertebrates. In the present work, E2 and ER alpha abundance were studied in seven regions of sexually mature male and female Labeo rohita during the breeding period. Results indicate that the abundance of ER alpha, and the level of E2, were high in the fore and mid brain and increased during the breeding season. are discussed in the context of reproductive function and correlated to the annual gonadosomatic index (GSI) variation.
Recently, we have reported that ovulated female masu salmon excrete L-kynurenine (Kyn) as a releaser pheromone for conspecific spermiating males. In this study, we tested a primer effect of ovulated female urine and Kyn to males. Blood sample and the expressible milt were collected before exposure and 3 hours after exposure. All test groups showed no significant effect on volumes of expressible milt. However, exposures to ovulated female urine (OFU) and Kyn induced significant elevations in plasma 17,20β-dihydroxy-4-pregnene-3-one (17,20β-P) concentrations 3 hours after introducing odours. We suggest that the urine of ovulated female masu salmon and Kyn had a primer effect.
Information lacks about European eel (Anguilla Anguilla L.) infestation by the nematode Anguillicoloides crassus (Kuwahara, Niimi & Itagaki, 1974) in North African populations, and especially in Tunisia. In order to study the situation of this infestation in Tunisian hydrosystems, we: a) analysed the infestation rate and contamination evolution in the population of Ghar El Melh lagoon and "Ichkeul Lake-oued Tinja" system according to time (month, season, year) and we compared it with the Algerian, Moroccan and European eel populations; b) studied the parasite dynamics and contamination evolution by gender (undifferentiated, male, female) and development stage (elver, yellow, silver); c) and, finally, estimated the impact of this parasite on the vital functions of the eel (growth, condition, GSR, HSR, ISR) during its continental life. For comparison, we used samples of sub-adult eels from Bizerte lagoon and juveniles from Medjerda wadi. Our results showed that the infestation of eel populations in North Africa is relatively recent compared to European populations and that this parasite has evolved considerably since it appeared in Tunisia. However, the values of prevalence, mean intensity and abundance remain low compared to the values found for the eels in Algeria, Morocco and Europe. The infestation is more important in terms of prevalence, mean intensity and abundance in freshwater than in brackish or salt water. The levels of infestation appear to be strongly related to the salinity of the colonized water. We have also seen that the infection affects eels entering freshwater (stage VIA1 and VIA2). The infestation is higher in summer and/or in winter and the most parasitized eels are the undifferentiated and migrant specimens. Finally, we showed that Anguillicoloides crassus had neither influence on length and weight nor on the development of liver, gonads and intestines during continental eel life. The parasite seems to have a direct effect on swim bladder, which will probably affect the migration of eels towards the Sargasso Sea.