Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Marine organisms are under threat globally from a suite of anthropogenic sources, but the current emphasis on global climate change has deflected the focus from local impacts. While the effect of increased sedimentation on the settlement of coral species is well studied, little is known about the impact on larval fish. Here, the effect of a laterite “red soil” sediment pollutant on settlement behaviour and post-settlement performance of reef fish was tested. In aquarium tests that isolated sensory cues, we found significant olfaction-based avoidance behaviour and disruption of visual cue use in settlement-stage larval fishat 50 mg L−1, a concentration regularly exceeded in situ during rain events. In situ light trap catches showed lower abundance and species richness in the presence of red soil, but were not significantly different due to high variance in the data. Prolonged exposure to red soil produced altered olfactory cue responses, whereby fish in red soil made a likely maladaptive choice for dead coral compared to controls where fish chose live coral. Other significant effects of prolonged exposure included decreased feeding rates and body condition. These effects on fish larvae reared over 5 days occurred in the presence of a minor drop in pH and may be due to the chemical influence of the sediment. Our results show that sediment pollution of coral reefs may have more complex effects on the ability of larval fish to successfully locate suitable habitat than previously thought, as well as impacting on their post-settlement performance and, ultimately, recruitment success.
ISSN: 0029-8549

hal-01346933
https://hal-uvsq.archives-ouvertes.fr/hal-01346933
https://hal-uvsq.archives-ouvertes.fr/hal-01346933/document
https://hal-uvsq.archives-ouvertes.fr/hal-01346933/file/ms%20O%27Connor%20et%20al%20%202014%20%28Oecologia%29.pdf
PUBMED : 26080759

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : In the present work, a biophysical dispersal model is used to understand the role of the physical environment in determining reef fish larval dispersal patterns in the South-West Lagoon of New Caledonia. We focus on a reef fish species, the humbug damselfish Dascyllus aruanus, to investigate seasonal variability of simulated larval retention at the scale of a reef patch and at the scale of the lagoon, and to explore links between larval retention and wind variability. The model shows that retention exhibits considerable temporal variability and periodically reaches values much larger than anticipated. Non-zero larval settlement occurs over a large part of the lagoon. Nevertheless, settlement values decrease quickly away from the natal reef and mean dispersal distances are of order 25-35 km. Cross-correlation analyses indicate that weather conditions characterized by strong south east trade winds lead to low retention rates at both local (reef) and regional (lagoon) scales. By contrast, subtropical weather conditions characterized by weak winds result in high retention rates. These results suggest that large-scale weather regimes can be used as proxies for larval retention of the humbug damselfish in the South-West Lagoon of New Caledonia. Nevertheless, relatively small mean dispersal distances suggest that meta-population dynamics occur on relatively small spatial scales.
Progress In Oceanography (0079-6611) (Pergamon-elsevier Science Ltd), 2014-03 , Vol. 122 , P. 105-115

Droits : 2013 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00170/28115/26326.pdf
DOI:10.1016/j.pocean.2013.12.006
http://archimer.ifremer.fr/doc/00170/28115/

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
When fish larvae recruit back to a reef, chemical cues are often used to find suitable habitat or to find juvenile or adult conspecifics. We tested if the chemical information used by larvae was intentionally produced by juvenile and adult conspecifics already on the reef (communication process) or whether the cues used result from normal biochemical processes with no active involvement by conspecifics (“spying” behavior by larvae). Conspecific chemical cues attracted the majority of larvae (four out of the seven species tested); although while some species were equally attracted to cues from adults and juveniles (Chromis viridis, Apogon novemfasciatus), two exhibited greater sensitivity to adult cues (Pomacentrus pavo, Dascyllus aruanus). Our results indicate also that spying cues are those most commonly used by settling fishes (C. viridis, P. pavo, A. novemfasciatus). Only one species (D. aruanus) preferred the odour of conspecifics that had had visual contact with larvae (communication).
ISSN: 1631-0691

hal-01212899
https://hal-univ-perp.archives-ouvertes.fr/hal-01212899
DOI : 10.1016/j.crvi.2015.05.004

Résumé : Le mérou géant, Epinephelus itajara, espèce en danger critique d’extinction au niveau mondial, est présent dans les eaux turbides et saumâtres de la Guyane française où l’espèce est exploitée par une pêcherie côtière. Dans la partie est du plateau continental guyanais, les mérous géants se localisent autour de tous les sites rocheux marins où ils se répartissent en fonction de la profondeur et du faciès (éboulis ou tombant). Les analyses des isotopes stables du carbone et de l’azote suggèrent qu’environ 30 % des mérous géants < 115 cm présents sur ces sites rocheux, proviendraient des mangroves alentours. Les analyses de contenus stomacaux révèlent un changement ontogénétique du régime alimentaire. Les petits individus (< 90 cm) s’alimentent principalement de Crustacés puis intègrent progressivement les poissons à leur alimentation jusqu’à devenir essentiellement piscivores au-delà de 140 cm. La population de Guyane est principalement composée d’individus juvéniles : seulement 8,5 % des individus capturés en Guyane a plus de 6 ans. Ces jeunes mérous sont très territoriaux durant les 4-5 premières années de leur vie puis ne sont plus retrouvés sur les sites rocheux. Le devenir de ces juvéniles est incertain, soit ils sont pêchés, soit ils migrent vers d’autres sites ou vers les agrégations de reproduction. Cependant, les mérous géants ne semblent pas se reproduire en Guyane. Il est possible que les conditions environnementales (forte turbidité et température) ne favorisent pas le développement gonadique, ce qui engendrerait une omission totale de reproduction. Le suivi par tags satellite suggère que les mérous géants migrent dans le sens des courants marins vers Trinidad-et-Tobago, potentiellement pour la reproduction. Aucun mouvement vers le Brésil n’a été mis en évidence bien que les stocks de mérous géants du Brésil et de Guyane semblent liés. En effet, ces deux stocks évoluent conjointement avec un déclin des populations au début des années 90. Le maintien de la population de mérou géant en Guyane se ferait grâce à l’apport de larves des sites d’agrégation du Brésil par le courant marin. La mortalité totale des mérous géants (0,65) est aussi élevée au sein de la réserve marine ainsi que sur les sites de pêche. Cela suggère que l’interdiction de pêche à la réserve n’est pas respectée et que les grands individus quittent la réserve pour des sites plus spacieux. En supposant que la population de mérous géants adultes a été réduite à cause de la pêche, une protection régionale des individus > 150 cm doit être instaurée afin de régénérer le stock d’individus matures. Il semble nécessaire de développer une politique de gestion internationale de l’espèce, surtout entre la Guyane et le Brésil, afin de conserver les populations de mérous géants d’Amérique du Sud.
The critically endangered Goliath Grouper, Epinephelus itajara, is found in the turbid and brackish waters of French Guiana, where the species is subject to a coastal fishery. Goliath Grouper populations inhabit all rocky habitats and exhibit increasing abundance with depth. Around 30% of individuals less than 115 cm may derive from the abundant mangrove habitat along the french Guiana coast. There is a ontogenetic shift of the diet, primarily crustacivorous, individuals >140 cm become piscivorous. The Goliath Grouper population in French Guiana is composed primarily og juvelines. The fate of the juvelines is unknonw, some may be caught in the fishery, others may move to other habitat. No evidence of spawning or gonadal readiness was found in french Guiana. it is possible that environmental conditions (high turbidity and temperature) are not conducive to reproductive activity. Goliath Grouper may migrate down current from French Guiana to Trinidad and Tobago or further. No movement of Goliath Grouper was found against the current toward Brazil. French Guiana juveniles may be derived from spawns occuring off Brazil. Calculated total mortality of Goliath Grouper off French Guiana is high (0.65) in both fished and protected areas suggesting that illegal fishing is occuring within the protected area, or that emigration rates are high. Assuming that the adult population of Goliath Grouper in French Guiana has been reduced due to fishing, protection of spawning-size adults (larger than about 150 cm TL) should be instated.

http://www.theses.fr/2014AGUY0721/document

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
The study of vertebrate ontogenies has the potential to inform us of shared developmental patterns and processes among organisms. However, fossilised ontogenies of early vertebrates are extremely rare during the Palaeozoic Era. A growth series of the Late Devonian ''acanthodian'' Triazeugacanthus affinis, from the Miguasha Fossil-Fish Lagerstätte, is identified as one of the best known early vertebrate fossilised ontogenies given the exceptional preservation, the large size range, and the abundance of specimens. Morphological, morphometric, histological and chemical data are gathered on a growth series of Triazeugacanthus ranging from 4 to 52 mm in total length. The developmental trajectory of this Devonian ''acanthodian'' is characteristic of fishes showing a direct development with alternating steps and thresholds. Larvae show no squamation but a progressive appearance of cartilaginous neurocranial and vertebral elements, and appendicular elements, whereas juveniles progress in terms of ossification and squamation. The presence of cartilaginous and bony tissues, discriminated on histological and chemical signatures, shows a progressive mineralisation of neurocranial and vertebral elements. Comparison among different body proportions for larvae, juveniles and adults suggest allometric growth in juveniles. Because of the phylogenetic position of ''acanthodians'', Triazeugacanthus ontogeny informs us about deep time developmental conditions in gnathostomes.
ISSN: 2167-8359

Droits : http://creativecommons.org/licenses/by/
hal-01633978
http://hal.upmc.fr/hal-01633978
http://hal.upmc.fr/hal-01633978/document
http://hal.upmc.fr/hal-01633978/file/peerj-3969.pdf
DOI : 10.7717/peerj.3969

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
As environmental sounds are used by larval fish and crustaceans to locate and orientate towards habitat during settlement, variations in the acoustic signature produced by habitats could provide valuable information about habitat quality, helping larvae to differentiate between potential settlement sites. However, very little is known about how acoustic signatures differ between proximate habitats. This study described within-and between-site differences in the sound spectra of five contiguous habitats at Moorea Island, French Polynesia: the inner reef crest, the barrier reef, the fringing reef, a pass and a coastal mangrove forest. Habitats with coral (inner, barrier and fringing reefs) were characterized by a similar sound spectrum with average intensities ranging from 70 to 78 dB re 1μPa.Hz-1. The
ISSN: 1932-6203

hal-01211705
https://hal-univ-perp.archives-ouvertes.fr/hal-01211705
https://hal-univ-perp.archives-ouvertes.fr/hal-01211705/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01211705/file/journal.pone.0135733.pdf
DOI : 10.1371/journal.pone.0135733

Éditeur(s) : Université de Montpellier II
Résumé : The sea bass, Dicentrarchus labrax, has been subjected to intensive aquaculture on the Mediterranean cost for ten years. Marine fish hatcheries are key factors in the aquaculture field, and face different pathologies, especially one of viral origin (nodavirus) that could challenge their feasibility. Consequently, we have tried to provide some data on larvae and spawning stocks. Firstly, we have studied the immunoglobulins, components of the specific humoral immunity, and their role as antibodies. On adult basses, these immunoglobulins are tetrameric molecules with high molecular weight (850 kD), made of heavy (H) - 80 kD and light (L) - 26 kD chains. In the eggs, simplest forms such as monomeric or dimeric are brought to the fore; they are located under the chorionic membrane. Secondly, we have studied the development of the immunity system on larvae, preparing IgM assays with ELISA method, the study on the organogenesis of the main lymphoid organs, and using flow cytometry for the ontogenesis of IgM producing cell. Based on this experience, we can propose a date for the immunocompetence onset of the bar, i.e. from the 54th day of the hatchery phase. Finally, we made the most of these different results to study a viral pathology (nodavirus) in spawners and larvae. We defined an experimental contamination model for larvae and eggs, and we highlighted that eggs born from vaccinated hen fishes were protected against the nodavirus.
Le bar, Dicentrarchus labrax, fait l'objet d'une aquaculture intensive sur le littoral Méditerranéen depuis une dizaine d'années. Les écloseries marines représentent un des maillons clefs de cette filière aquacole, et sont confrontées à différentes pathologies, dont une d'origine virale (nodavirus), pouvant remettre en cause leur faisabilité. Aussi, nous avons tenté d'apporter quelques données concernant la protection des larves et des géniteurs reproducteurs. Dans un premier temps, nous avons étudié les immunoglobulines, éléments de l'immunité spécifique humorale ainsi que leur rôle anticorps. Chez les bars adultes ces immunoglobulines sont des molécules tétramériques de haut poids moléculaire (850 kD), composées de chaînes lourdes (H) de 80 kD et légères (L) de 26 kD. Dans les oeufs, des formes plus simples, monomériques ou dimériques, sont mises en évidence et sont localisées sous la membrane chorionique. Dans un second temps, nous avons étudié la mise en place du système immunitaire spécifique chez les larves, en effectuant le dosage des IgM par ELISA, l'étude de l'organogenèse des principaux organes lymphoïdes, puis celle de l'ontogenèse des cellules productrices d'IgM par cytométrie de flux. L'ensemble de cette étude nous permet de proposer une date d'acquisition de l'immunocompétence à partir du 54ème jour d'élevage chez le bar. Enfin, ces différents résultats ont été mis à profit dans le cadre d'une pathologie virale (nodavirus) touchant les reproducteurs et les larves. Après avoir défini un modèle de contamination expérimental des larves et des oeufs, nous avons mis en évidence une protection des oeufs lorsque ceux-ci proviennent d'une femelle vaccinée (vaccin expérimental) contre le nodavirus.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1997/these-1265.pdf
http://archimer.ifremer.fr/doc/00000/1265/

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Microsatellite markers were developed for the coral reef fish Chaetodon vagabundus using shotgun pyrosequencing. As threats to coral reefs intensify, information on larval connectivity is of increasing value for efficient conservation planning. Here, 11 novel microsatellites were characterized for 192 individuals from Papua New Guinea. The number of alleles per locus ranged from 7 to 32, while observed and expected heterozygosity values varied from 0.214 to 0.903. These markers will be used to study population structure and larval connectivity of this iconic coral reef fish in coral reefs across the Indo-Pacific.
ISSN: 1877-7252

hal-01136139
https://hal.archives-ouvertes.fr/hal-01136139
DOI : 10.1007/s12686-015-0440-8

Éditeur(s) : HAL CCSD Royal Society, The
Résumé : International audience
Determining the conditions under which populations may persist requires accurate estimates of demographic parameters, including immigration, local reproductive success, and mortality rates. In marine populations, empirical estimates of these parameters are rare, due at least in part to the pelagic dispersal stage common to most marine organisms. Here, we evaluate population persistence and turnover for a population of orange clownfish, Amphiprion percula, at Kimbe Island in Papua New Guinea. All fish in the population were sampled and genotyped on five occasions at 2-year intervals spanning eight years. The genetic data enabled estimates of reproductive success retained in the same population (reproductive success to self-recruitment), reproductive success exported to other subpopulations (reproductive success to local connectivity), and immigration and mortality rates of sub-adults and adults. Approximately 50% of the recruits were assigned to parents from the Kimbe Island population and this was stable through the sampling period. Stability in the proportion of local and immigrant settlers is likely due to: low annual mortality rates and stable egg production rates, and the short larval stages and sensory capacities of reef fish larvae. Biannual mortality rates ranged from 0.09 to 0.55 and varied significantly spatially. We used these data to parametrize a model that estimated the probability of the Kimbe Island population persisting in the absence of immigration. The Kimbe Island population was found to persist without significant immigration. Model results suggest the island population persists because the largest of the subpopulations are maintained due to having low mortality and high self-recruitment rates. Our results enable managers to appropriately target and scale actions to maximize persistence likelihood as disturbance frequencies increase.
ISSN: 0962-8452

hal-01239322
https://hal-univ-perp.archives-ouvertes.fr/hal-01239322
DOI : 10.1098/rspb.2015.1311

Éditeur(s) : Interciencia
Résumé : Zooplankton abundance, biomass and composition were evaluated in various temporal scales in a seasonal coastal upwelling system at Margarita Island, Venezuela. Scales of temporal variation include weeks, months and seasons (relaxation, upwelling and transition). Seasons were delimitated by upwelling index and sea temperature. The sampling period comprise Sept/2002 - July/2003. Zooplankton samplings were made by horizontal trawls (1-10m depth), using 200,mu m nets, 2-6km from the coastal margin. Total abundance show important variation at week scales, with different patterns between locations, while seasonal differences of abundance are marginal. Biomass only shows seasonal variation due significant reduction in the transition season. Zooplankton assemblages show changes at scale of weeks, with different local patterns, and seasonal changes. Changes in assemblage between the relaxation and upwelling seasons include reduction (during upwelling) of abundance in copepods, cladocerans, salpidae, chaetognates, fish and crustacea larvae. Except by cirripedia larvae, those were important in the upwelling assemblages. Transition shows high variation, with reduction of biomass and assemblage composition similar to upwelling, except by an isolated event. Small scale variation in the zooplankton could be related to physical processes at small scales, eg. turbulence, local circulation, small eddies and filaments, and biological response. Additional sources of nutrient input, eg. riverine input and internal waves, could support local plankton productivity and abundance during relaxation. Detection of high variation in zooplankton abundance and composition at small scales, with local interaction, bring a new light over zooplankton estimation in time series in this system.
La abundancia, la biomasa y la composición del zooplancton costero fueron analizadas a varias escalas temporales en un área afectada por surgencia costera estacional (Isla de Margarita, Venezuela); considerando para ello escalas de semanas, meses y periodos, así como la variación local. La estimación del zooplancton fue realizada a partir de arrastres horizontales (1-10m de profundidad) utilizando redes de 200μ entre 2 y 6 km de la línea de costa, entre set/2002 y jul/2003. La abundancia total presentó alta variabilidad a escala de semanas, con patrones diferentes entre localidades, mientras que la diferencia entre periodos es marginal. La biomasa únicamente mostró variación a escala de periodos por una disminución durante el periodo de transición. La composición presentó fluctuaciones a escalas temporales pequeñas, con patrones de variación diferentes localmente, así como a escala de periodos. Los cambios en composición entre el periodo de relajación y el de surgencia incluyen disminución en la abundancia de copépodos, cladóceros, salpas, quetognatos, larvas de peces y crustáceos; excepto por las larvas de cirrípedos que forman un componente importante durante la surgencia. Se postula que procesos físicos a pequeña escala, como la turbulencia, la circulación local o la formación de pequeños giros o filamentos, y los procesos biológicos, condicionan esta elevada variabilidad a escalas pequeñas. La existencia de fuentes de enriquecimiento adicionales como aportes de ríos y ondas internas pudiera condicionar la presencia de elevada abundancia y biomasa, en especial durante periodos de relajación. Los cambios en composición resaltan la importancia del aporte de merozooplancton costero. Palabras clave / Biomasa / Escalas Temporales / Surgencia / Venezuela / Zooplancton Costero /
Interciencia (0378-1844) (Interciencia), 2014-02 , Vol. 39 , N. 2 , P. 122-128

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00187/29851/28297.pdf
http://archimer.ifremer.fr/doc/00187/29851/

Éditeur(s) : HAL CCSD National Academy of Sciences
Résumé : International audience
Natal philopatry, the return of individuals to their natal area for reproduction, has advantages and disadvantages for animal populations. Natal philopatry may generate local genetic adaptation, but it may also increase the probability of inbreeding that can compromise persistence. Although natal philopatry is well documented in anadromous fishes, marine fish may also return to their birth site to spawn. How philopatry shapes wild fish populations is, however, unclear because it requires constructing multigenerational pedigrees that are currently lacking for marine fishes. Here we present the first multigenerational pedigree for a marine fish population by repeatedly genotyping all individuals in a population of the orange clownfish (Amphiprion percula) at Kimbe Island (Papua New Guinea) during a 10-y period. Based on 2927 individuals, our pedigree analysis revealed that longitudinal philopatry was recurrent over five generations. Progeny tended to settle close to their parents, with related individuals often sharing the same colony. However, successful inbreeding was rare, and genetic diversity remained high, suggesting occasional inbreeding does not impair local population persistence. Local reproductive success was dependent on the habitat larvae settled into, rather than the habitat they came from. Our study suggests that longitudinal philopatry can influence both population replenishment and local adaptation of marine fishes. Resolving multigenerational pedigrees during a relatively short period, as we present here, provides a framework for assessing the ability of marine populations to persist and adapt to accelerating climate change.
ISSN: 0027-8424

hal-01417471
https://hal-univ-perp.archives-ouvertes.fr/hal-01417471
DOI : 10.1073/pnas.1611797113

Éditeur(s) : Elsevier
Résumé : Until recently, it was considered impossible to feed newly hatched marine fish species with a compound diet. Substituting a compound diet for live prey was performed several weeks after hatching, depending on the species. Compound diets were well ingested at the early stage but larvae died with a gut full of food, suggesting that larvae were unable to digest the compound diet. The hypothesis was that younger larvae have insufficient digestive enzymes to thrive on compound diets, and that exogenous enzymes, provided from live prey, are necessary for early stages.The organogenesis of marine fish larvae is not completely achieved at hatching and histological studies have revealed that the anatomy of the digestive tract undergoes developmental changes over some weeks. Nevertheless, biochemical studies over 20 years have shown that most of the digestive enzymes are present in young larvae. Recent studies have provided better understanding of digestion mechanisms in larvae and have led to proposed dietary compositions meeting larvae nutritional requirements. Pancreatic digestive enzymes are detected before mouth opening. Their synthesis is not induced by diet ingestion, but secretory mechanisms in the pancreas, and so enzymatic action, become efficient chronologically after those of synthesis. Inadequate diets can delay the onset of secretion mechanisms. The ratio of secreted enzymes to total enzymes indicates the nutritional value of the diet ingested by the larvae.At the intestinal level, cytosolic enzymes, which are peptidases, exhibit high activity in the early stages, suggesting a high capacity in larvae to digest protein hydrolysate. Indeed, larvae growth and survival is improved by the incorporation of a moderate concentration of peptide or hydrolysate in the diet. Peptidase activity abruptly decreases around day 25 in sea bass, concurrent with an increase in enzymes of the brush border membranes. This corresponds to a normal maturation process of enterocytes. Compound diets can slightly delay the onset of this maturation process, and inadequate diet can prevent it, leading to near death of the larvae. A proper onset of the maturation process has been associated with high larvae survival.The early developmental stage larvae exhibit high hydrolytic capacity, related to their weight. Enzyme activity pattern is age-dependent, but can be modulated by diet composition. Thus, larvae have the ability to digest and thrive on compound diet, if this diet is well adapted. Larvae have different specificities in digestion and nutritional requirements when compared to juveniles. Taking these specificities into consideration, recent research has led to the formulation of a compound diet that was well adapted for larvae from mouth opening, and could totally replace live prey.
Aquaculture (0044-8486) (Elsevier), 2001-08 , Vol. 200 , N. 1-2 , P. 161-180

Droits : 2001 Elsevier Science B.V. All rights reserved
http://archimer.ifremer.fr/doc/2001/publication-447.pdf
DOI:10.1016/S0044-8486(01)00699-8
http://archimer.ifremer.fr/doc/00000/447/

Éditeur(s) : Proceedings of the 59th Annual Gulf and Caribbean Fisheries Institute
Résumé : In most of marine fishes cultured, larvae in their early development are fed with live prey (rotifer and/or artemia). In hatcheries, culture of these preys is labour consuming, needs specific facilities and represent an important part of production cast. On the other hand, world artemia production is subjected to fluctuation of harvest in the wild which could Iimit fish farming industry in the near future. A dried formula adapted to marine fish larvae has been perfected by Ifremer's center of Brest (France) and is distributed by a feeding company since 1999. This artificial microbound diet has been successfully tested on several temperate fishes such as European seabass (Dicentrarchus labrax), Atlantic cod (Gadus morhua) or European seabream (Sparus aurata) in a co-feeding (i.e. artemia and dried diet) strategy. Experiments described here were carried out ta evaluate the performances obtained during total substitution of artemia by this diet in Red drum (Sciaenops ocellatus) larval culture. ln 2004 and 2005, four experiments were conducted on feed technology aspects (experimental or industrial manufacturing), weaning strategy (direct or co-feeding) and feed distribution method (prototypes or classical self feeder) in comparison to the standardized method using live preys. At the end of larval phase (day 15) and at day 30, end of nursery phase (0.6 g), survival relative to control (RTC) was respectively 96.9% and 111.0% in the best treatment. Concerning growth, the weight RTC reached at day 15 and day 30 was respectively 82.8% and 72.4%. However, it is important to note that rearing protocols have to be adapted ta the use of these micro pellets in order toprevent degradation of culture quality. These results show that this new product can be applied on industrial scale in private hatcheries. But further research is needed ta evaluate replacement of rotifers by this dried formula in order to completely eliminate live prey in larval culture of Red drum.
Dans la plupart des poisons marins élevés, les larves sont nourries avec des proies vivantes (rotifères et/ou artémia) au début de leur développement. Dans les écloseries, la culture de ces proies est consommatrice de main d'oeuvre, nécessite des installations spécifiques et entre pour une part importante dans le coût de production. Par ailleurs, la production mondiale d'artémia est dépendante de la fluctuation des récoltes dans le milieu naturel, ce qui pourrait gêner la filière piscicole marine dans un futur proche. Une formulation alimentaire inerte adaptée aux larves de poisson marin a été mise au point par le centre Ifremer de Brest (France) et est commercialisée par un provendier depuis 1999. Ces microparticules artificielles ont été testée avec succès sur plusieurs poissons tempérés comme le bar européen (Dicentrarchus labrax), la morue atlantique (Gadus morha) ou la daurade européenne (Sparus aurata) dans un contexte de co-feeding (i.e. artémia et aliment inerte). Les expériences décrites ici ont été menées afin d'évaluer les performances obtenues lors de la substitution totale des artémia par cet aliment dans l'élevage larvaire de l'ombrine (Sciaenops ocellatus). En 2004 et 2005, quatre expériences ont été menées sur l'aspect technologie alimentaire (fabrication expérimentale ou industrielle), la stratégie de sevrage (direct ou co-feeding) et le mode de distribution de l'aliment (distributeur classique ou prototypes) en comparaison au standard sur proies vivantes. En fin de phase larvaire (jour 15) et au jour 30 après une phase de prégrossissement (0.6g), la survie par rapport au témoin (RTC) était respectivement de 96.9% et 111 .1% dans le meilleur traitement. Concernant la croissance, les poids obtenus aux jours 15 et 30 atteignaient respectivement 82.8% et 72.4%. Cependant il est important de relever que les protocoles d'élevage doivent être adaptés à l'utilisation de ces microparticules afin de prévenir une dégradation de la qualité d'élevage. Ces résultats montrent que ce nouveau produit peut être appliqué à l'échelle industrielle dans les écloseries privées. Cependant, les recherches doivent être poursuivies pour évaluer les possibilités de remplacement des rotifères par ces aliments inertes afin de s'affranchir complètement de l'utilisation de proies vivantes dans l'élevage larvaire de l'ombrine.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/acte-6597.pdf
http://archimer.ifremer.fr/doc/00000/6597/

Éditeur(s) : Elsevier Science Bv
Résumé : The main goal of this work was to determine the effect of dietary live yeast Debaryomyces hansenii on the enzymatic antioxidative status of sea bass Dicentrarchus labrax larvae. Growth, activity and expression of the main antioxidative enzymes: catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD), and heat shock protein (HSP70) were measured in sea bass larvae at 23 and 48 days after hatching. Larvae were fed on two microdiets: group one, fed microdiet containing live yeast and the control group fed microdiet without yeast. Heat shock protein 70 showed the same expression levels in both fish larvae fed yeast and the control diet. The group fed D. hansenii showed highest growth and lower activity and expression levels of GPX and SOD compared to fish fed control diet. In our work the differences in activity and gene expression patterns could only be attributed to the presence of yeast, assuming a possible involvement of superoxide anion retention in fish larvae, which could represent importance to the host to increase cell or tissue responsiveness to growth- and/or differentiation-enhancing factors.
Aquaculture (0044-8486) (Elsevier Science Bv), 2010-02 , Vol. 300 , N. 1-4 , P. 142-147

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00002/11299/7881.pdf
DOI:10.1016/j.aquaculture.2009.12.015
http://archimer.ifremer.fr/doc/00002/11299/

Éditeur(s) : HAL CCSD
Résumé : International audience
The active selection of recent volcanic habitats by juvenile fish following a cyclone could explain the unusual mass-settlement of the Indian Ocean blacktip grouper Epinephelus oceanicus observed on 25 May 2006, few weeks after tropical storm Diwa on the latest lava flows of the Piton de la Fournaise volcano at Reunion Island. Following a cyclonic depression, shallow underwater habitats are devoid of resident fishes, including predators, favouring juvenile fish survival. Otherwise, the recent origin of the volcanic habitats, which vary in age, could facilitate the spatial segregation of adult and juvenile fish on the lava flows, reducing intraspecific competition and adult aggression toward juveniles. Regional characteristics of larval recruitment could also contribute to the infrequency of the described event; the isolated situation of the island would be expected to result in an average density of fish postlarvae 0.25 % to 1 % of that seen on some reefs in the Pacific. The supposed origin of juvenile groupers in the neighbouring island of Mauritius should encourage Reunionese managers to look beyond their own jurisdictions to adopt a collaborative approach to conservation of the entire connected network.
Environmental Biology of Fishes

hal-01306707
http://hal.univ-reunion.fr/hal-01306707
http://hal.univ-reunion.fr/hal-01306707/document
http://hal.univ-reunion.fr/hal-01306707/file/Mass-settlement%20of%20the%20Indian%20ocean%20black-tip%20grouper_hal.pdf
DOI : 10.1007/s10641-014-0303-2

Éditeur(s) : HAL CCSD
Résumé : International audience
The subterranean environment is often described as “extreme” and food poor. Laboratory experiments have shown that blind Mexican tetra Astyanax mexicanus (De Filippi, 1853) cavefish are better at finding food in the dark than surface fish. Several morphological and behavioural attributes that could foster this obvious adaptive response to cave environments have been described. Nonetheless, it is currently unknown what young cavefish actually eat in their natural cave environment. Our results from the Pachón cave in México during the dry and rainy season show that fry are efficient predators in their natural cave environment. Their primary food item is aquatic crustaceans. The guts of post-larval, pre-juvenile stage individuals (n=9) contained an average of 17.9 water fleas (Cladocera), copepods, ostracods, and isopods. Thus, the fry in this cave are well-fed. The Pachón cave environment does not appear to be “food poor” for juvenile cavefish. Food regimes change between post-larval and adult stages to become more dependent on partially decomposed material, guano, or detritus from the mud. We discuss the data with regards to our current developmental and genetic understanding of cavefish morphological and behavioural evolution, particularly regarding its enhanced Vibration Attraction Behaviour (VAB).
Subterranean Biology

hal-01432027
https://hal.archives-ouvertes.fr/hal-01432027
DOI : 10.3897/subtbiol.21.11046

Éditeur(s) : Elsevier Science Bv
Résumé : In this study, three microdiets were tested on weaning of Florida pompano larvae: Otohime, Gemma and a reference diet LR803. The experimental system was stocked with 11-day-old larvae, which were co-fed micro-diets and live food from 11 dph to 17 dph then micro-diets only until 28 dph. Survival from 11 dph to 28 dph was similar for all treatments, with an average of 33%. At the end of the trial, the Gemma larvae were significantly longer and heavier than larvae fed the other diets. Significant differences were observed in fatty acid composition of the diets and larvae between treatments. The Gemma larvae incorporated the lowest amount of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA). However, they had the highest DHA/EPA and ARA/EPA ratios, which is in agreement with the concept that the proportions of polyunsaturated fatty acids could be of greater importance than their absolute amount. Results from the enzyme analysis suggest that fishmeal is suitable as the main protein source for Florida pompano larvae compared to krill meal. This study gives new insights on Florida pompano early nutritional requirements and demonstrated the full functionality of the pancreas at 16 days post hatch, opening possibilities of an earlier weaning time.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-02 , Vol. 422 , P. 268-276

Droits : 2013 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/00169/28067/26282.pdf
DOI:10.1016/j.aquaculture.2013.12.006
http://archimer.ifremer.fr/doc/00169/28067/

Éditeur(s) : HAL CCSD University of South Bohemia in Ceske Budejovice ; Faculty of Fisheries and Protection of Waters
Résumé : CRISPR/Cas9 disturbance of the multiple vitellogenin (vtg) system: essential functions of different vtg types during zebrafish egg, embryo and larval development. 6. International Workshop on the Biology of Fish Gametes
6. International Workshop on the Biology of Fish Gametes
Vodnany, Czech Republic

hal-01595005
https://hal.archives-ouvertes.fr/hal-01595005
PRODINRA : 405326

Éditeur(s) : Springer
Résumé : The great fecundity and very high larval mortality of most marine invertebrates and fish make possible substantial variance in the number of offspring contributed by adults to subsequent generations. The reproductive success of such organisms may thus resemble a sweepstakes lottery, in which a minority of progenitors succeeds in replacing an entire population, while the majority fails to procreate. One specific prediction of this hypothesis, that genetic diversity of newly settled cohorts should be less than that of the adult population, is tested in the present study. Microsatellite DNA markers were examined in naturally spawned juvenile European flat oysters Ostrea edulis (L.), collected over a 12-day period in 1993 from the western Mediterranean Sea, near Sete, France (43 degrees 32'N, 3 degrees 56'E) and grown out for a period of up to 10 months. Variation in these juveniles was compared to that in a pooled sample of adults collected in 1994 from two locations (Thau Lagoon and Port St. Louis) that had statistically homogeneous allelic frequencies. Though nearly twice as large as the pooled adult sample, the juvenile sample had only 60% of the adult allelic diversity. Analyses of linkage disequilibrium and kinship, as well as estimation of the effective number of parents, suggested that 10-20 adults produced this juvenile cohort. This observation supports the hypothesis of sweepstakes reproductive success and suggests that partial inbreeding may occur even in species with large populations and dispersing planktonic larvae.
Marine Biology (0025-3162) (Springer), 2007-03 , Vol. 150 , N. 6 , P. 1173-1182

Droits : 2007 Springer
http://archimer.ifremer.fr/doc/2007/publication-2616.pdf
DOI:10.1007/s00227-006-0441-y
http://archimer.ifremer.fr/doc/00000/2616/

Résumé : Two batches of red drum larvae were air shipped from hatcheries in the U.S.A. and stocked in two intensive tank experiments at densities oc 7 :.nd 2-3 larvae per liter. Food items include live rotifers, copepods, brine shrimps. squid and commercial fish pellets. Growth rates were similar in both experiments up to day 20 (12-1" mm) but differences in feeding schedules and an infestation by the dinoflagelate Amyloodinium sp. affected the growth from day 20 to 43 in the second trial. Significant mortalities occurred in the tanks during the first feeding period (days 2 to 7) and again from days 17 to 20 as the result of cannibalism. Survival between day 2 and day 44 was 44% in the first trial. Abnormal inflation of the swim bladder and infection with Amyloodinium sp. reduced the survival to 6-19% in the second.
Deux lots de larves du tambour rouge ont été transportés par avion depuis des écloseries aux USA et stockés dans deux essais en bac intensif aux densités oc 7 : nd 2-3 larves le litre. L'alimentation comprend les rotifères vivants, les copépodes, les artémias, les encornets et les boulettes de poisson commerciales. Les taux de croissance étaient pareils dans les deux expériences jusqu'au jour 20 (12-1''mm) mais des différences dans les programmes d'alimentation et une infestation par le dinoflagellé Amyloodinium sp. ont modifié la croissance à partir du jour 20 jusqu'au jour 43 dans le deuxième essai. Des mortalités importantes se sont produites dans les bacs pendant la première période d'alimentation (jours 2 et 7) et encore du jour 17 jusqu'au 20 à la suite d'un cannibalisme. La survie entre le jour 2 et le jour 44 était de 44 % dans le premier essai. Un gonflement anormal de la vessie natatoire et une infection de l'Amyloodinium sp. ont réduit la survie de 6 ¿ 19 % dans le deuxième.

Droits : 1988 Ifremer, UAG, Orstom
http://archimer.ifremer.fr/doc/1998/rapport-1914.pdf
http://archimer.ifremer.fr/doc/00000/1914/