Éditeur(s) : Elsevier Science Bv
Résumé : The ontogeny of osmoregulationwas investigated in Litopenaeus stylirostris by studying salinity tolerance and osmoregulatory capacity. Shrimp at different larval and postlarval stages were exposed to various salinities and survival was monitored for 24 h. Survival rates exceeded 80% at salinity over 25 ppt (750 mOsm.kg(-1)) at all the stages. At salinities below to 25 ppt, salinity tolerance was higher in nauplii and zoeae than in mysis larvae. Postlarval stages were able to withstand lower salinities, e.g. 6.0 ppt (176 mOsm.kg(-1)) at PL9 stage, but they were more sensitive than larvae to salinities over 35 ppt (1035 mOsm.kg(-1)). Zoea and mysis larvae slightly hyper-regulated at all tested salinities. After metamorphosis, postlarvae progressively acquired the adult pattern of hyper-hypo-osmoregulation: At PL9, the estimated isosmotic salinity was 24.5 ppt (720 mOsm.kg(-1)); below and over this salinity, animals hyper-regulated and hypo-regulated, respectively. Finally, we determine the effects of lowering salinity at different animal development stages. We conclude that seawater salinity (35 ppt) is optimum during larval stages; but for postlarval stages, lowering salinity at 27 ppt leads to a better growth in 19 days compared to those maintained at 35 ppt (1.07 mg vs 0.47 mg). These results are in agreement with penaeid natural life cycle during which larvae are released in oceanic water while juveniles live in coastal areas where salinity is more fluctuant. (c) 2012 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier Science Bv), 2012-09 , Vol. 362-363 , P. 10-17

Droits : 2012 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/00107/21843/20058.pdf
DOI:10.1016/j.aquaculture.2012.07.026
http://archimer.ifremer.fr/doc/00107/21843/

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) : Université de la Polynésie Française
Résumé : The ontogeny of osmoregulation was studied in the blue shrimp Litopenaeus stylirostris in New Caledonia. The implication of branchial organs in ionic regulation was first demonstrated in juveniles by immunolocalization of three ion transporting proteins ( namely NKA, co-transporter NKCC1 and CFTR ) and ionocyte detection was done by means of electron microscopy. The role of the main ion transporting enzyme, NKA, was subsequently investigated during post-embryonic development using an integrative approach associating physiological, histological, immunological and biomolecular studies. Results obtained allowed us to propose a model of the osmoregulatory pattern in L. stylirostris based on weak regulation in the early stages, then progressively this species acquires the adult pattern of hyper-hypo-regulation after metamorphosis with the concurrent development of epipodites and gills. Strong NKA immunofluorescence and abundance of NKA transcripts in these two tissues compared to others organs suggest their functional implication in osmoregulatory processes. The results of this study allow us to increase our knowledge of the penaeid shrimp osmoregulation and to propose zootechnical measures to improve the animal physiological comfort. These propositions have been already tested during larval rearing trials, leading a two-fold-growth in 19 days-old postlarvae.
L’étude de l’ontogenèse de l’osmorégulation a été entreprise chez la crevette bleue Litopenaeus stylirostris en Nouvelle-Calédonie. L’implication des tissus de la cavité branchiale dans la régulation ionique a été déterminée au préalable chez des juvéniles par immunolocalisation de trois transporteurs protéiques d’ions, ( la NKA, le co-transporteur NKCC1 et le CFTR ) et par la détection de ionocytes en microscopie électronique. Le rôle de la NKA a été particulièrement étudié et son implication a été examinée au cours du développement post-embryonnaire par une approche intégrative associant des études physiologiques, histologiques, immunologiques et moléculaires. Cette démarche nous a permis de proposer un modèle d’osmorégulation chez L. stylirostris: de faible régulatrice dans les premiers jours de sa vie, cette espèce évolue vers l’hyper-hypo-régulation après la métamorphose avec le développement progressif des épipodites et des branchies. L’immunofluorescence prononcée de la NKA ainsi que l’abondance des transcrits du gène codant la NKA dans les tissus de ces deux organes suggèrent leur implication fonctionnelle dans l’ionorégulation. Les résultats de ce travail nous ont permis d’accroître nos connaissances sur l’osmorégulation chez les pénéidés et de proposer des améliorations zootechniques visant à augmenter leur confort physiologique. Ces préconisations ont fait l’objet de premiers essais en conditions d’élevage et se sont traduites par un doublement de la croissance des post-larves de 19 jours.

Droits : 2011 The author, Univ. Polynésie Française
http://archimer.ifremer.fr/doc/00052/16314/13816.pdf
http://archimer.ifremer.fr/doc/00052/16314/

Éditeur(s) : Université de Nantes
Résumé : The reproductive cycle of Megathura crenulata was documented and quantification of oocyte lipid reserves with lipo-specific stains was explored in both this species and in Crassostrea gigas. The necessity of providing food to female broodstock C. gigas in spring was re-evaluated, because subsequent larval and post-larval rearing performance was not affected by broodstock starvation during conditioning. Developmental study of the organs responsible of particle processing in C. gigas allowed the identification of critical stages related to the ontogenesis of each organ, as well as a better understanding of the evolution of these organs, highly-modified in the Ostreidae. Ciliary type identification and mucocyte mapping from post-larval to adult stage showed that the heterorhabdic specialization precedes the anatomic formation of gill plicae specific to this condition.
Le cycle reproducteur de Megathura crenulata a été documenté et la quantification des réserves ovocytaires par des colorants lipospécifiques a été tentée, sans résultats concluants pour cette espèce, ni pour Crassostrea gigas. L'intérêt d'une alimentation des géniteurs femelles C. gigas au printemps est re-évalué, car la performance ultérieure des élevages larvaires et post-larvaires n'a pas été affectée par le jeûne imposé lors du conditionnement. L'étude du développement des organes impliqués dans le traitement des particules chez C. gigas a permis d'identifier des stades critiques associés à l'ontogenèse de chaque organe, ainsi qu'une meilleure compréhension de l'évolution de ces organes si particuliers chez les Ostreidae. L'examen des types ciliaires et la cartographie des mucocytes de la post-larve à l'adulte ont montré que la spécialisation hétérorhabdique précède même la formation anatomique des plis branchiaux caractéristiques de cette condition.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2005/these-1371.pdf
http://archimer.ifremer.fr/doc/00000/1371/

Éditeur(s) : 3e Rencontres Scientifiques Internationales du contrat de baie de la rade de Brest. Brest 14-16 mars 1995
Résumé : Aquaculture production of scallop has been identified by a series of technical operations during the past ten years programme under a partnership involving the fishermen organizations with regional and national grants. 3 million juveniles have been produced annually, giving a potential recapture by fishing of 100 to 120 tonnes 3 years later. Results in terms of technical and economical approach have pointed out the principal unknown factors responsable for high costs. 7he pilot programme aims to increase the production to reach a level of 5 million juveniles to support the fishery of the rade de Brest and induce new management of the resources. Two priorities were selected, control of the reproduction in the hatchery to obtain reliable larval and postlarval rearing during a larger period of the year, mainly during summer, and improvement of survival rate of the juveniles by minimizing stress when manipulating the animals. But biological and ecological mechanisms are still poorly understoodfor scallop and generally bibvalves and the last two years have shown unchanged results. The technical pathways shows interactions between the different steps of the production of juveniles where different teams operate separately. Management of the livestock has to be developed to increase the survival rate by better breeding but also to reduce the loss by adapted and coordinated practices. Recapture results indicate that fishery strategies depend also on the production of juvenile, and could orientate the management of the hatchery.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00044/15494/12860.pdf
http://archimer.ifremer.fr/doc/00044/15494/

Éditeur(s) : Elsevier Science Bv
Résumé : The euryhaline white shrimp Litopenaeus vannamei lives in both coastal and oceanic areas through ontogeny. Its osmoregulation pattern and variations in its tolerance to salinity are partially known from several studies under different experimental conditions (developmental stages, salinities and acclimation procedures). Although L. vannamei is recognized as one of the most euryhaline penaeid species, with adults and juveniles exhibiting an hyper-hypo-osmoregulatory pattern and being able to tolerate a wide salinity range, little is known on larval and early postlarval strategies to cope with salinity fluctuations. In order to establish their euryhalinity range and to fully understand the ontogenetic changes in L. vannamei osmoregulatory pattern, we evaluated the effect of six salinities (5, 10, 20, 32, 45 and 60 psu) on 17 developmental stages by directly exposing them to experimental salinities and conducting observations during the next 48 hours. At 5 hours post osmotic shock (hps), all developmental stages survived (> 20%) in 20, 32 and 45 psu. The euryhalinity and osmoregulation pattern changed at some developmental stages of L. vannamei. The hyper-hypo osmoregulatory pattern exhibited by Juvenile and Adult appears to be established early in the first post-larval stage PL1 (ontogenetic osmoregulation pattern type 3), with higher tolerance to salinity variations observed in PL2, PL4 and PL22 suggesting that L. vannamei shows a progressive increase in the efficiency of osmoregulatory mechanism following last metamorphosis.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-02 , Vol. 422 , P. 261-267

Droits : 2013 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00169/28068/26283.pdf
DOI:10.1016/j.aquaculture.2013.11.034
http://archimer.ifremer.fr/doc/00169/28068/

Éditeur(s) : Elsevier
Résumé : Vibriosis is a major disease problem in shrimp aquaculture, affecting all developmental stages, from larvae in hatchery tanks to juveniles and broodstock in growout ponds. However, bacterial strains responsible for vibriosis in the successive stages are usually considered to be different, and virulence specificity has been reported both at the species and at the stage levels. The so-called « Syndrome 93 » is a seasonal juvenile vibriosis caused by Vibrio penaeicida which affects Penaeus stylirostris in growout ponds and broodstock tanks in New Caledonia. This pathology does not cause any mortality in hatchery or nursery phases. An experimental infection design using balneation of postlarvae and early juveniles in V. penaeicida suspensions was used to evaluate the developmental stage at which shrimp become sensitive to this vibriosis. We demonstrated that the acquisition of susceptibility to this pathogen is very sudden and correlated with the acquisition of the definitive rostral formula, and from this draw conclusions regarding virulence mechanisms of V. penaeicida in P. stylirostris.
Aquaculture (Elsevier), 1998-12 , Vol. 169 , N. 3-4 , P. 291-296

Droits : 1998 Elsevier Science B.V. All rights reserved
http://archimer.ifremer.fr/doc/1998/publication-383.pdf
DOI:10.1016/S0044-8486(98)00380-9
http://archimer.ifremer.fr/doc/00000/383/