Papers by Philippe LALEYE
The Management of IMARES is not responsible for resulting damage, as well as for damage resulting... more The Management of IMARES is not responsible for resulting damage, as well as for damage resulting from the application of results or research obtained by IMARES, its clients or any claims related to the application of information found within its research. This report has been made on the request of the client and is wholly the client's property. This report may not be reproduced and/or published partially or in its entirety without the express written consent of the client.
International Journal of Biological and Chemical Sciences, Jul 16, 2008
L'étude de l'âge et de la croissance chez Clarias gariepinus a été réalisée dans le delta de l'Ou... more L'étude de l'âge et de la croissance chez Clarias gariepinus a été réalisée dans le delta de l'Ouémé par l'analyse des structures par tailles et l'examen de coupes minces dans l'épine de la nageoire pectorale droite. Les tailles obtenues par retrocalcul aux différents âges ont été comparées à celles des structures par tailles. La taille moyenne modale chez C. gariepinus se situe entre 25 et 30 cm Lt à la fin de la première année de vie. Les résultats obtenus, couplés à une analyse des caractéristiques physico-chimiques et biologiques du milieu, nous révèlent l'apparition de marques d'arrêt et/ou de ralentissement de croissance sur les pièces osseuses de l'espèce aux mois de juillet-août. Les facteurs responsables de l'inscription des marques sur les pièces sont la diminution du niveau de l'eau dans le fleuve à l'étiage (février, mars, avril), le confinement des poissons dans un petit volume d'eau et la rareté des ressources alimentaires dans le milieu.
Knowledge and Management of Aquatic Ecosystems, 2010
Ganvié et Zogbo) du lac Nokoué à l'intérieur et à l'extérieur des acadjas à l'aide des pêcheurs a... more Ganvié et Zogbo) du lac Nokoué à l'intérieur et à l'extérieur des acadjas à l'aide des pêcheurs artisanaux. Les paramètres physico-chimiques ont été également mesurés à l'intérieur et à l'extérieur des acadjas expérimentaux des mêmes stations. Au total, 25 espèces de poissons appartenant à 17 familles ont été identifiées à l'intérieur des acadjas sur un total de 51 espèces de poissons réparties en 34 familles inventoriées en 2001 au lac Nokoué. Cette richesse spécifique des acadjas représente ainsi 49 % de la richesse spécifique de l'ensemble du lac Nokoué. Cinquante-six pourcent (56 %) des espèces de poissons capturés dans les acadjas sont des formes estuariennes et représentent 78 % de l'ensemble des formes estuariennes recensées au lac Nokoué en 2001. L'analyse de la variance a montré que la richesse spécifique des acadjas variait de façon significative avec les stations (p < 0,05), avec une grande richesse spécifique dans la station de Zogbo où les acadjas sont moins abondants. Les acadjas sont ainsi sélectifs pour certaines espèces de poissons telles que les cichlidés, qui représentent près de 95 % de l'abondance numérique totale et contribuent à près de 90 % de la biomasse totale des poissons capturés dans les acadjas. Ainsi la densité élevée des acadjas pourrait contribuer à la réduction de la richesse spécifique des poissons. La gestion rationnelle consisterait en la réorganisation de la superficie du lac Nokoué tout en préservant des zones du lac où les acadjas seraient interdits pour les espèces de poissons ne colonisant pas les acadjas.
Inventaire et caractéristiques faunistiques des macroinvertébrés de la rivière Alibori dans le ba... more Inventaire et caractéristiques faunistiques des macroinvertébrés de la rivière Alibori dans le bassin cotonnier du Bénin [ Inventory and faunistic characteristics of the macroinvertebrates of the Alibori River in the cotton basin of Benin ]
Cybium, 2012
Le développement postembryonnaire de la morphologie externe et du squelette céphalique chez Labeo... more Le développement postembryonnaire de la morphologie externe et du squelette céphalique chez Labeo parvus a été étudié de la fin de l'éclosion à 29 jours (j) post-éclosion. Pendant cette période, la croissance moyenne est de 1,7 mm/ jour. La bouche s'ouvre à 18 h et le sac vitellin est résorbé à 36 h. A l'éclosion aucune structure cartilagineuse n'est observée. À 18 h, les trabécules, les plaques paracordales, le plancher des capsules otiques, les cartilages de Meckel, les hyosymplectiques, les cératohyaux et les trois premiers cératobranchiaux sont visibles. À 24 h, les quatrième et cinquième cérato-branchiaux sont formés. À 36 h, les capsules otiques, les taeniae marginales, la plaque ethmoïdienne, les palatocarrés, les hypohyaux, le basibranchial, les 4 paires d'hypobranchiaux et la ceinture scapulaire se mettent en place. Entre 36 h et 4 j, le chondocrâne se développe. À 10 j, toutes les structures importantes sont formées et le chondocrâne entre en régression. Les premières structures osseuses comme les operculaires, les mâchoires pharyngiennes et leurs dents apparaissent à 4 j. Les operculaires sont bien développés à 6 j et la larve est capable déjà de créer un courant d'eau d'avant en arrière. À 8 j, la mandibule, les prémaxillaires, les maxillaires et une paire de rayons branchiostèges apparaissent. À 10 j, le parasphénoïde et le basioccipital apparaissent pour former le plancher de la boîte crânienne et empêcher tout impact de prise de nourriture exogène sur la base du cerveau. De 14 à 29 j, de nouvelles structures osseuses apparaissent et rendent la boîte crânienne plus performante.
Journal of Fisheries International, 2011
Archives Of Physiology And Biochemistry, 1994
This paper shows the usefulness of polyacrylamide gel electrophoresis (PAGE) separation of a few ... more This paper shows the usefulness of polyacrylamide gel electrophoresis (PAGE) separation of a few well-characterized muscle proteins, the parvalbumins, in the systematic study of 13 cichlid species. The separation of the isoforms of these abundant, quite species-specific fish parvalbumins is fast, easy, and requires but small quantities of muscle material. Used alone, this technique suggests hypotheses for species classification. In conjunction with morphological analysis, it makes it possible to confirm or invalidate doubts about the determination.
Aquaculture Research, Jul 28, 2011
This study aimed at (1) evaluating the efficacy of live food organisms (Artemia and natural zoopl... more This study aimed at (1) evaluating the efficacy of live food organisms (Artemia and natural zooplankton) and an artificial diet in the larval rearing of African carp Labeo parvus and (2) determining appropriate rearing conditions. After yolk sac resorption, the larvae were separated into five different feeding trials with two replicates. At the end of the larval rearing period (28 days post-hatching), the highest (94.6%) and the lowest (53.7%) cumulative survival rates were found when larvae were fed with natural zooplankton for 7 days followed by Nippai food for 21 days, and when larvae were fed from the beginning of exogenous feeding with Nippai food only respectively. The significant highest body weight (351.6 mg), total length (34.4 mm) and specific growth rates (15.5%day À1) were recorded when the larvae were fed with Artemia nauplii for 14 days followed by Nippai food for 14 days. The lowest growth performance (body weight and specific growth rates) were obtained when larvae were fed exclusively Nippai food. These results indicate that L. parvus can be successfully cultured in indoor nursery systems from hatching to the early juvenile stage.
Afin de determiner les avantages du jeune chez Oreochromis niloticus et Clarias gariepinus dans l... more Afin de determiner les avantages du jeune chez Oreochromis niloticus et Clarias gariepinus dans l’optimisation de la productivite, une experience a ete conduite durant 56 jours dans les trous a poissons (whedos) du delta de l’Oueme au Benin. Les juveniles de poids moyen 8,06 ± 0,23 g et 7,02 ± 0,10 g respectivement pour O. niloticus et C. gariepinus ont ete soumis a quatre (4) traitements testes chacun en triplicat. Il s’agit des traitements T0 (poissons nourris normalement 3 fois par jour), T1 (12 H de jeune), T2 (24 H de jeune), T3 (48 H de jeune). Au total, 12 happas (1m3 de volume chacun) disposes tous dans un whedo (10 m × 14 m × 1m de volume) ont ete utilises pour chaque espece. Les juveniles de O. niloticus ont ete nourris au Skretting 35% de proteines et ceux de C. gariepinus au Skretting 45%. Au terme de l’etude, il ressort que chez les deux especes, les T1 et T2 engendrent une croissance compensatrice complete. Par contre, le T3 n’a pas permis une recuperation totale du retard de croissance chez les deux especes. Dans la presente etude le jeune n’a pas veritablement influence les parametres d’utilisation alimentaire chez les deux especes. Cela serait du aux larges variations entre individus ou aux faibles periodes de jeune utilisees dans l’etude. La determination de la composition corporelle des poissons a la fin de l’experience a revele chez C. gariepinus que les proteines deposees semblent etre utilisees preferentiellement comme source d’energie aux reactions metaboliques alors que chez O. niloticus c’est les lipides qui semblent jouer ce role. En privilegiant la reduction des couts de production et l’embonpoint des poissons, le jeune de 24 H serait ideal pour l’amelioration de la pisciculture extensive au Benin.
Journal of the Indian Society of Coastal Agricultural Research, Dec 31, 2021
International Journal of Fisheries and Aquatic Studies, May 1, 2022
Etheria elliptica (Bivalvia, Etheriidae) is the only freshwater oyster occurring widely in tropic... more Etheria elliptica (Bivalvia, Etheriidae) is the only freshwater oyster occurring widely in tropical Africa and Madagascar. The distribution and ecology of E. elliptica were investigated in Pendjari River, a tributary of Volta basin. Correspondence Analysis and corrected frequencies were performed on bivalve presence/absence data and abiotic factors. Mean density and mean biomass ranged from 0 to 40 ind./m 2 and 0 to 3.8 kg/m 2 , respectively. E. elliptica exhibited a patchy distribution in Pendjari River (Morisita index Iδ =14.8) occurring mostly in middle and downstream sites. Conversely, species was absent in river upstream. Oyster showed a preference for sections of river with hard substrates used for cementation. However, the oyster was encountered also in silty and sandy habitats forming large size colonies. Total Dissolved Solids (TDS) and altitude appeared to be the significant factors affecting oyster distribution in Pendjari River. Oyster was observed both in calm and turbulent sections of the River. Range of water parameters corresponded to ecological requirements for oyster survival and development. E. elliptica showed plasticity for a large range of habitats suggesting its potential for culture in the River. Management strategies based on oyster ecology could ensure its conservation in Pendjari River.
HAL (Le Centre pour la Communication Scientifique Directe), 2009
A study on the relationships between the physicochemical parameters and of the macroinvertebrates... more A study on the relationships between the physicochemical parameters and of the macroinvertebrates of the Lake Nokoué was carried out for the purpose of developing a biotic index of pollution. A total of 96 stations were prospected twice during the flooding and the dry seasons from September 2004 to February 2006. At each station, seven physicochemical parameters were measured and macroinvertebrates were collected. Canonical analyses of correspondence were used to show the relations between the parameters of the environment and the macroinvertebrates. A self-organizing map (SOM) of Kohonen allows the categorization of the studied stations into four groups according to different degrees of pollution. Rough scores were allotted to each taxon according to its abundance in the various groups of stations determined by the SOM for each campaign. A synthesis of the data obtained from the four field surveys allows the assignment of a score to each taxon according to its abundance in the different groups of stations. A biotic index was developed and used for the evaluation of the level of pollution of the stations studied. It then emerged that the borders of the lake present a «poor quality» of water; however, during the dry season there is slight improvement.
Zootaxa, Apr 2, 2019
The Indo-Pacific portunid, Charybdis hellerii (A. Milne-Edwards, 1867), is a crab species native ... more The Indo-Pacific portunid, Charybdis hellerii (A. Milne-Edwards, 1867), is a crab species native to the Indian and Western Pacific Oceans and has previously colonized the Eastern Mediterranean and the Western Atlantic. It is now recorded in the Eastern Atlantic, on the coast of Benin, where a thriving population has established. This invasive and widely distributed species exhibits morphological variations within and between populations, which are discussed in detail. Its current distribution is presented, and its future expansion along the West African coast and future impact on coastal ecosystems and local fisheries are the object of tentative forecasts. Illustrations of sexually mature specimens from different sizes and regions are presented, and their allometric, individual and geographical variations are discussed. A new synonymy and a new account on the taxonomy and the biology of the species are presented. Illustrations of the lectotype and the paralectotype of C. hellerii are also provided for the first time. Charybdis spinifera (Miers, 1884), C. merguiensis (De Man, 1887) and C. vannamei Ward, 1941 are here treated as subjective junior synonyms of C. hellerii. The holotype of C. spinifera and two syntypes of C. merguiensis are illustrated.
International Journal of Fisheries and Aquatic Studies, Jul 1, 2022
The objective of this work was to study the survival and growth of juveniles of the oyster Crasso... more The objective of this work was to study the survival and growth of juveniles of the oyster Crassostrea gasar reared in ponds at different depths. Rearing trials were carried out for 42 days (6 weeks) in two ponds (12 m 2 x 1.10 m deep), one of which was fertilized with poultry droppings and the other with no fertilization. For each pond, 03 depths (30 cm, 60 cm and 90 cm) were tested in duplicate. At each depth, two iron mesh bags (40 cm x 20 cm x 10 cm) were used. Oysters with an average size of 40.50 mm and average weight of 15.36 g were cultivated at a density of 30 individuals per bag. Phytoplankton density, pH, temperature, transparency and salinity of the water were daily measured between 7:00 and 8:00 am. Oysters were counted weekly. Individual length and weight were measured to evaluate their survival and growth. The values of physico-chemical parameters measured during this study met the requirements of tropical water oysters. After 6 weeks of rearing, the best survival rates were observed at 60 cm in the ponds (86.67% and 81.67% in the fertilized and unfertilized ponds, respectively) while the lowest survival (46.67% and 41.67 in the fertilized and unfertilized ponds, respectively) was recorded at 90 cm depth. The highest mean final sizes (40.584 mm and 40.568 mm in the fertilized and unfertilized ponds respectively) were recorded at 60 cm depth while the lowest values (40.557 mm and 40.553 mm in the same order) were recorded at 90 cm depth. The average final weight ranged from1 5.32 g (at 90 cm depth) to 15.38 g (at 60 cm) while it overlapped between 15.3 g (90 cm depth) to 15.35 g (30 cm depth) in the unfertilized pond. The average daily gain was 0.0004 g/day and 0.0005 g/day respectively for the 30 cm and 60 cm depths of the fertilized pond. The best zootechnical performance was recorded between 30 cm and 60 cm depth in the fertilized pond. Fertilized pond culture highlight future prospects for the promotion of Crassostrea gasar oyster culture in controlled environment.
Journal of entomology and zoology studies, May 1, 2019
Disturbances in aquatic ecosystems are studied with several methods based on macroinvertebrates. ... more Disturbances in aquatic ecosystems are studied with several methods based on macroinvertebrates. This study aims to characterize the ecological status of the Alibori River through the use of macroinvertebrates using multivariate statistical analyzes. The data collection was conducted from June 2015 to May 2016. Measures of physico-chemical parameters were carried out in situ and the nutrients analysed by the ICS 1000 chromatographic method. Macroinvertebrate sampling was conducted monthly using an Eckman grab. Multivariate analyzes were used to illustrate the distribution patterns of organisms and to identify environmental factors determining the community distribution. The results show a clustering of taxa according to their susceptibility to pollution and upstream-downstream and seasonal distribution. Mineralization parameters were the main variables that governed the distribution of benthic macrofauna. The mineralization parameters were the main variables that governed the distribution of benthic macrofauna. The differences in structure and community organization indicated by multivariate analysis are related to the environmental conditions of stations appearing less stable downstream and highlighting a stress gradient on macroinvertebrates.
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Papers by Philippe LALEYE