DOUMBIA Lassina et. al. /International Journal of Modern Sciences and Engineering Technology (IJMSET) ISSN 2349-3755; Available at https://www.ijmset.com Volume 1, Issue 8, 2014, pp.36-45

Feeding strategy of two taxonomically and morphologically similar mandibularis (Günther, 1867) and Rüppell, 1832 coexisting in Agnébi River (Côte d’Ivoire)

DOUMBIA Lassina1 BAMBA Yacouba2 Université Nangui Abrogoua Université Nangui Abrogoua UFR-Sciences et Gestion de l’Environnement UFR-Sciences et Gestion de l’Environnement Abidjan, République de Côte d’Ivoire Abidjan, République de Côte d’Ivoire [email protected] [email protected]

OUATTARA Allassane3 GOURENE Germain4 Université Nangui Abrogoua Université Nangui Abrogoua UFR-Sciences et Gestion de l’Environnement UFR-Sciences et Gestion de l’Environnement Abidjan, République de Côte d’Ivoire Abidjan, République de Côte d’Ivoire [email protected] [email protected]

Abstract: Feeding habits of Schilbe mandibularis and Schilbe intermedius in Agnébi River were studied during two years of sampling. The coefficient of emptiness, index of preponderance of Natarajan & Jhingran and that of Schoener helped to analyze and compare the diets of the two species of Schilbe. In terms of diet overall, both species have an omnivore tendency. Food preferences vary from station and also from one season to the other highlighting the opportunism of species studied. Regarding the size of individuals, juveniles and adults feeding behavior varies from one medium to another. The overall nutritional profile of both species indicates the general trend with an emphasis of piscivory in Schilbe intermedius for an eclectic tendency of Schilbe mandibularis.

Keywords: Côte d’Ivoire, Agnébi River, Feeding strategy, , Schilbe mandibularis, Schilbe intermedius.

1. INTRODUCTION: Knowledge of the natural environment fish food is an essential step to understanding their biology and ecology [1]. In addition, the Schilbeidae are one of the groups of freshwater and brackish water fish economically more important worldwide [2]. In Côte d'Ivoire, two species of the Schilbe were identified by Sangaré [3] and more recently by Gourène et al. [4]. This is Schilbe intermedius Rüppell, 1832 and Schilbe mandibularis (Günther, 1867) two sympatric species in the area of study that is the Agnébi River. Also, to Vanga [5], these fishes contribute appreciably to the production of inland fisheries landed in Côte d'Ivoire. Indeed, they are popular organoleptically by local residents of the study area [6]. Previous investigations on the diet of this type of fish [3]; [7]; [8]; [9], [10]; [11]; [12] are fragmentary. According to Doumbia [13], two species taxonomically and morphologically similar and occupying the same habitat can interfere with each other in relation to food. The purpose of this study is to verify the sharing of food resources between Schilbe mandibularis and S. intermedius from the general profile and dietary behaviors in different seasons and the various habitats are the three study sites and in the age classes. Two assumptions were made. Due to the opportunism of the species studied, there will be a difference in the composition of stomach contents. It is among the specimens of the juvenils as the most important diet similarity we must observe.

2. MATERIALS AND METHODS: Study site: Figure 1 shows the location of the Agnébi River and sampling stations selected (Gbessé, Pont-auto- route and Armébé).The Agnébi River is located between 5 and 7 degrees north and 4 and 5 ° West longitude latitude [14]. The Gbessé station to the upper is on the Kavi. This tributary of the Agnébi River been drying up during the long dry season. The station Pont auto-route (middle stream) at significant discounts during the long dry season. The water is summarizing a stream of water from a depth less than 30 cm. As for the © IJMSET-Advanced Scientific Research Forum (ASRF), All Rights Reserved “IJMSET promotes research nature, Research nature enriches the world’s future” 36 DOUMBIA Lassina et. al. /International Journal of Modern Sciences and Engineering Technology (IJMSET) ISSN 2349-3755; Available at https://www.ijmset.com Volume 1, Issue 8, 2014, pp.36-45 Armébé station (lower course) is characterized by the permanence of water that is certainly tied to the great depths (7 m on average). Note that the selection of study sites was preceded by a survey of six months.

N

Figure 1: Location of sampling stations on Agnébi River (based on [4]).

Sampling and stomach contents analysis

Test fisheries were conducted for 24 months stations deductions Agnébi River. During monthly outings, two batteries mesh nets: 10, 12, 15, 20, 30, 35, 40 and 50 were placed at 17h, visited the next day at 7h am for nights fisheries and re-visited before be raised to 13h for the days of fishing. During the various missions, fish caught were identified according to Lévêque et al. [15] and Gourène et al., [16]. Specimens randomly selected for the study of stomach contents were measured and dissected. Their stomachs were removed, weighed and stored in bottles containing a 5% formalin solution. Of a total of 921 analyzed stomachs, 211 from specimens Schilbe mandibularis and 710 individuals from S. intermedius. Regarding the analysis strictly stomach contents, each stomach was drained on absorbent paper, weighed and carefully opened under a dissecting microscope. After a first selection in this loop that eliminates the stomach contents too degraded by digestive juices, the different fractions of stomach contents deductions were identified, counted and weighed after spin on blotting paper.

The data were presented in the form of:

- Emptiness coefficient (ec): It allows to assess the feeding activity of the species and to identify their feeding behavior. Indeed, the emptiness ratio is the percentage of empty stomachs on the total number of stomachs examined [17]. Its formula is as follows: ec = number of empty stomachs x 100 © IJMSET-Advanced Scientific Research Forum (ASRF), All Rights Reserved “IJMSET promotes research nature, Research nature enriches the world’s future” 37 DOUMBIA Lassina et. al. /International Journal of Modern Sciences and Engineering Technology (IJMSET) ISSN 2349-3755; Available at https://www.ijmset.com Volume 1, Issue 8, 2014, pp.36-45 Number of stomachs analyzed

- Corrected occurrence percentage [17] and [18]: Fc = (Fi / ΣFi) x 100 with

Fi = (ni / NT) Fi is the frequency of prey i n is the number of stomachs containing prey i and NT is the total number of full stomachs examined;

- Weight percentage [19]: W = Wi / Wt x 100 Where Wi = total weight of prey i and Wt = total weight of all prey.

As blended index taking into account the two percentages described above, we chose the index of preponderance of Natarajan and Jhingran [20]. This index was used by Kouamélan et al. [21] in a study of the eating habits of three Mormyridae to Lake Ayame. Its formula is as follows:

According to Linton et al. [22], the index of Schoener [23] is the best estimator of food niche overlaps between 7 and 85%. Moreover, the use of this index is recommended by Hurlbert [24]. The degree of dietary overlap was determined using the index Schoener whose formula is as follows:

α= 1 – ½ ∑ │Pij - Pik│

Pij = proportion of taxa i in the stomach contents of the species j Pik = proportion of taxa i in the stomach contents of the species k

The higher the value of the index of Schoener [23] approach 1 plus the diet overlap is important. Size classes are defined based on the smallest size at first maturity determined by Ouattara [25]. He argues that people regarded as juvenils have a standard length of less than 123 mm (the smallest size at first sexual maturity). All specimens whose standard lengths greater than or equal to 123 mm are adults.

The chi-square test which according to Scherrer [26] applies to both frequencies than proportions (percentages) was used to compare the emptiness coefficients between the two species studied [27].

The Spearman rank correlation test (Statistica version 7.1 program) was used to compare the diets according to the variables considered.

3. RESULTS AND DISCUSSION:

For a total of 211 stomachs Schilbe mandibularis analyzed, 101 were empty. So the factor of emptiness is 47.87%. In Schilbe intermedius, we worked on 710 and 474 stomachs were empty. This corresponds to a coefficient of emptiness 66.76%. Worth X² = 3.11 to p = 0.05, the coefficients of emptiness do not present significant difference.

General diet

Table 1 shows the results of analysis of food containing stomachs expressed in index of dominance and classification propose by Rosecchi and Nouanze [17]. The general diet of the species studied has 11 major classes of prey and 11 orders of insects. The index of prey balance indicates the dominance of fish © IJMSET-Advanced Scientific Research Forum (ASRF), All Rights Reserved “IJMSET promotes research nature, Research nature enriches the world’s future” 38 DOUMBIA Lassina et. al. /International Journal of Modern Sciences and Engineering Technology (IJMSET) ISSN 2349-3755; Available at https://www.ijmset.com Volume 1, Issue 8, 2014, pp.36-45 (67.08%) in the diet of Schilbe intermedius. debris (25.17%) are secondary prey. In contrast, in Schilbe mandibularis, fruits (32.25%) and debris (28.71%) are the preferred prey. Fishes (24.62%) are secondary prey. As for insects, they occupy a rank of accidental prey with 13.38% in S. mandibularis to 5.88% in S. intermedius. Hymenoptera are the most abundant order as in the regime of S. mandibularis (4.70%) than in S. intermedius (1.78%). The Schoener index of 0.552, indicating a diet overlap between species studied. Similarly, the Spearman rank correlation coefficient reveals similarity of interspecific diet (N = 21; rs = 0.729, p = 0.0001).

Table 1: General Diet of Schilbe mandibularis and S. intermedius in Agnébi River expressed by the Index of preponderance (Ip) and prey classification according to Rosecchi and Nouanze [17]: n = number of stomachs containing food.

Schilbe intermedius Schilbe mandibularis Preys n=236 n=110 Ip Classification Ip Classification Insects 5.88 X 13.38 x Coleoptera 0.57 3.76 Diptera 1.37 0.16 Ephemeroptera 0.02 0.77 Hemiptera 0.04 0.03 Hymenoptera 1.78 4.70 Lepidoptera 0.46 0.67 Mantodea 0.01 0.00 Odonata 0.11 0.37 Orthoptera 1.47 2.88 Siphonatera 0.00 0.01 Tricoptera 0.04 0.05 Amphibians 0.33 0.13 Annelida 0.01 0.00 Arachnida 0.10 0.09 Crustacea 0.78 0.33 Molluscs 0.00 0.18 Myriapoda 0.07 0.04 Fishes 67.08 xxx 24.62 xx Fruits 0.18 32.25 xxx Animals debris 25.17 xx 28.71 xxx Vegetables debris 0.38 0.28

Schilbe mandibularis and S. intermedius are sympatric in Agnébi River [6]. Indeed, for both species taxonomically and morphologically similar and in addition occupy the same habitat, one should expect either a food niche overlap or a change of regime one of the species due to the presence competitor potential. Our results indicate that S. mandibularis has a diverse diet giving pride of place to fruits, animal and insect debris while S. intermedius have a tendency to piscivory and would have consumed large amounts of debris and animals insect. Diet overlap value based Schoener index and rank correlation coefficient Spearman attest to a diet of similarity between the two studied Schilbe. These findings coincide with those made by Paugy [28] and Kouamelan et al. [29]. Indeed, these authors classify species studied among omnivores. As for piscivory observed in S. intermedius, it corroborates the results of Doumbia [6] on Schilbeidae’s food strategy.

© IJMSET-Advanced Scientific Research Forum (ASRF), All Rights Reserved “IJMSET promotes research nature, Research nature enriches the world’s future” 39 DOUMBIA Lassina et. al. /International Journal of Modern Sciences and Engineering Technology (IJMSET) ISSN 2349-3755; Available at https://www.ijmset.com Volume 1, Issue 8, 2014, pp.36-45 Seasonal diet

In the rainy season, the diet of S. mandibularis to Gbessé station is dominated by animals debris (41.52%) and insects (33.51%). Fishes (16.24%) are secondary prey. While that of S. intermedius consists of insects (51.59%) and animal debris (37.63%). The Spearman correlation rank coefficient based on the index of preponderance of prey is not significant (n = 15; rs = 0.3177, p = 0.249). Schoener's index is equal to 0.502. In the dry season, insects (93.08%) make up the bulk of the diet of S. mandibularis. As for S. intermedius, it is ichtyophage (61.45%). During the same season, the Spearman correlation rank coefficient is negative (n = 14; rs = - 0.1463; p = 0.618). As the value of the index of Schoener we get 0.148.

The Pont auto-route, in the rainy season, S. mandibularis has a power dominated by fruits (39.77%) and animals debris (24.63%). Fishes (19.29%) are the secondary prey. However, the diet of S. intermedius essentially consists of fishes (60.98%) and fruits (31.39%) are secondary prey. The Spearman correlation rank coefficient is significant (n = 20 valid; rs = 0.739, p = 0.000198). Schoener's index is 0.490. In the dry season, the diets of both species are dominated by fish with 53.22% for S. mandibularis and 77.90% for S. intermedius. This gives a Spearman correlation rank coefficient not significant (n = 11 valid; rs = 0.173, p = 0.611) and the most important Schoener index (0.542).

At the Armébé station in lower stream, S. mandibularis diet was dominated by animals debris (87.72%) in the rainy season. As for S. intermedius, it remains ichtyophage (92.57%). The Spearman correlation rank is not significant (n = 8 valid; rs = 0.026, p = 0.952) and the index of Schoener (0.285) is low. In the dry season, S. mandibularis is frugivorous (84.29%) while S. intermedius is ichtyophage (83.28%). The Spearman correlation rank coefficient is not significant (n = 8 valid; rs = 0.266, p = 0.524) and the index of Schoener very low (0.136). As for the seasonal diet, Spearman correlation rank coefficient indicates the largest inter specific food similarity in the rainy season at Pont auto route. As for the index of Schoener, it has the highest values of overlapping regimes interspecif food in the dry season to Pont auto-route and rainy season in Gbessé. However, the data of the different species to the two hydrological seasons have clear preponderance of index variations highlighting strong regime similarity. This confirms the hypothesis of intense recovery food niches between species taxonomically and morphologically close as Doumbia [13] says.

Diet depending on the station

Table 2 shows the different values of the inter-specific dominance index at study on Agnébi River. At Gbessé, station on superior stream, the stomach contents of S. intermedius are dominated by animals debris (46.27%), insects (24.55%) and fishes (24.34%). However, those of S. mandibularis show significant proportions (59.19%) of insects and animals debris (30.70%). The Spearman correlation rank coefficient obtained was 0.5178 for n = 18 and p = 0.028. It was at this station that there is a high Schoener index (0.619).

Regarding changes in diets depending on the station, it was noted that Gbessé where there is a severe drying of the water, diet overlap is intense. This could be explained by the spatial restriction inducing power requirement from a limited amount of prey. Indeed, it becomes clear that the immediate consequence would be the significant overlap of feeding niche on this station.

© IJMSET-Advanced Scientific Research Forum (ASRF), All Rights Reserved “IJMSET promotes research nature, Research nature enriches the world’s future” 40 DOUMBIA Lassina et. al. /International Journal of Modern Sciences and Engineering Technology (IJMSET) ISSN 2349-3755; Available at https://www.ijmset.com Volume 1, Issue 8, 2014, pp.36-45 Table 2: General diet of Schilbe mandibularis and S. intermedius expressed by the Index of preponderance (Ip) at the three stations of sampling on Agnébi River. n=number of stomachs containing food.

Gbessé Pont auto-route Armébé Prey S. intermedius S. mandibularis S. intermedius S. mandibularis S. intermedius S. mandibularis n=58 n=22 n=118 n=73 n=60 n=15 Insects 24.55 59.19 5.32 9.83 0.83 0.48 Coleoptera 1.12 2.55 1.50 3.65 0.0001 0.11 Diptera 1.99 - 2.37 0.26 0.02 - Ephemeroptera 0.03 18.21 0.01 - 0.05 - Hemiptera - - 0.13 0.04 - - Hymenoptera 15.69 9.88 - 3.82 0.57 0.37 Lepidoptera 3.32 7.97 0.76 0.13 - - Mantodea 0.40 - - - - - Odonata 0.04 - 0.18 0.60 0.03 - Orthoptera 1.96 20.39 0.33 1.29 0.08 - Siphonatera - - - 0.01 - - Trichoptera - 0.19 0.04 0.03 0.068 - Amphibians - - 0.68 0.20 0.01 - Annelida - - - - 0.03 - Arachnida 0.04 - 0.21 0.14 - - Crustacea 3.46 2.97 0.02 0.04 1.83 0.63 Molluscs 0.20 - - 0.28 - - Myriapoda 0.75 - 0.03 0.06 - - Fishes 24.34 6.57 64.53 33.29 88.26 - Fruits - - - 33.87 1.63 47.46 Animals debris 46.27 30.70 29.01 22.10 7.13 50.89 Vegetals debris 0.38 0.56 0.20 0.17 0.30 0.55

Diet based on size classes

Different highest balance index values relate to insects, fishes, fruits and animals debris are presented on table 3. At Gbessé station, insects are the dominant prey for juvenils specimens (59.20%) and adults (59.90%) of Schilbe mandibularis. They are followed by animals debris with 30.70% and 32.54% respectively. Among the specimens of S. intermedius, this trend occurred in adults. As juvenils, they have a diet dominated by animals debris (39.53%) and insects (35.54%). Note that the fishes with 20.79% ranked third in the stomach contents of juvenils specimens for 11.67% in adults individuals.

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Size Schilbe mandibularis Schilbe intermedius Station class Insects Fishes Fruits Animals Insects Fishes Fruits Animals debris debris Juvenil 59.20 6.57 - 30.70 35.54 20.79 - 39.53 Gbéssé Adult 59.90 6.97 - 32.54 64.33 11.67 - 21.67 Pont Juvenil 9.83 33.29 33.87 22.10 5.32 64.53 - 29.01 Auto- Adult 8.82 37.63 39.16 13.47 3.17 82.86 - 12.65 route Juvenil 0.48 - 47.46 50.89 1.22 85.29 3.67 5.23 Armébé Adult 0.27 - 58.91 39.35 0.83 88.26 1.63 7.13

In Pont auto-route, S. mandibularis juvenils and adults expressed a preference for fruits which represent 33.87% and 39.16% of the stomach contents. Fishes, with 33.29% in juvenils to 37.63% in adults ranks second stomach contents. As for animals debris, they got 22.10% in juvenils to 13.47% in adults. At the same station, fishes make up the bulk of the diets of juvenils specimens (64.53%) and adults (82.86%) of S. intermedius. The animals debris are the side prey with 29.01% in juvenils against 12.65% in adults.

At Armébé station, Schilbe mandibularis juvenils have 50.89% of stomach contents made by animals debris and fruits represent 47.46%. As for the adults specimens, they have a diet dominated by fruits (58.91%) and animals debris (39.35%). In specimens of the two size classes of S. intermedius, have noted the piscivory with 85.29% of stomach contents in juvenils to 88.26% in adults.

Table 4 shows the values of Spearman correlation rank coefficients with those of the Schoener index. It was at the station Armébé where we noted no significant correlation coefficient we had both Schoener index values higher (0.984 and 0.923) and the lowest (0.266 and 0.264). At the Gbessé station, only the Spearman correlation rank coefficient comparing the stomach contents of juvenils and adults specimens of both species is not significant. At the same station index Schoener the lowest (0.672) was obtained between juvenils specimens of Schilbe mandibularis and those of S. intermedius. In Pont auto-route, the Spearman correlation rank coefficients were significant between juvenils and adults specimens of both species, between juvenils specimens of S. mandibularis and adults of S. intermedius. The index values of Schoener highest (0.975 and 0.912) are obtained at this station between the juvenils and adults of both species studied.

Compared to the size classes, the Schoener overlap index values highlight the diet of intraspecific similarities between specimens of the two size classes. Which invalidates the hypothesis intense diet overlap between juvenils specimens because of the limitations imposed by the size of the mouth such as evokes by Keast and Webb [30]. Indeed, in a study on food strategy based on the position and the size of the mouth as a factor influencing this author prey selection demonstrates that due to the narrowness of the mouth of juvenils, diet is limited to small prey. This would produce an intense competition effect between specimens of this category. Furthermore, it appeared that the Armébé station during lower is obtained low value of diet overlap index. This could be partly explained by the permanence of the water that would justify an abundance of prey. Thus, each of the studied specie manages to eat what it wants. This would reduce the food niche overlap. In contrast to Gbessé stations and the Pont auto-route where the significant change in water level is observed, the consequence would be the spatial restriction induces a high density would be the corollary of the intense food niche overlap.

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Table 4: Results of the Spearman correlation rank test comparing the trophic composition of specimens of Schilbe mandibularis, S. intermedius and different size groups at the three study sites on the river Agnébi River: n = number of stomachs containing food, S = Significant and NS = Not significant.

Study Stations Comparative size classes Correlation rank coeficient Schoener n valide rs P Observations index Smand juvenil n=22 X Smand adult n=21 11 0.909 0.000 S 0,883 Sinterme juvenil n=58 X Sinterm adult n=43 18 0.863 0.000 S 0,922 Smand juvenil n=22 X Sinterm juvenil n=58 18 0.567 0.014 S 0,672 Gbésse Smand juvenil n=22 X Sinterm adult n=43 15 0.609 0.016 S 0,683 Smand adult n=21 X Sinterm juvenil n=58 18 0.453 0.059 NS 0,690 Smand adult n=21 X Sinterm adult n=43 15 0.524 0.0451 S 0,695 Smand juvenil n=73 X Smand adult n=56 19 0.960 0.000 S 0,975 Sinterme juvenil n=118 X Sinterm adult n=58 17 0.748 0.0006 S 0,912 Pont Smand juvenil n=73 X Sinterm juvenil n=118 20 0.355 0.1240 NS 0,476 auto-route Smand juvenil n=73 X Sinterm adult n=58 20 0.478 0.0327 S 0,475 Smand adult n=56 X Sinterm juvenil n=118 20 0.345 0.1353 NS 0,457 Smand adult n=56 X Sinterm adult n=58 20 0.414 0.4568 NS 0,457 Smand juvenil n=15 X Smand adult n=11 6 0.886 0.984 NS 0,984 Sinterme juvenil n=60 X Sinterm adult n=31 14 0.001 0.923 NS 0,923 Smand juvenil n=15 X Sinterm juvenil n=60 14 0.048 0.266 NS 0,266 Armébé Smand juvenil n=31 X Sinterm adult n=31 11 0.100 0.289 NS 0,289 Smand adult n=11 X Sinterm juvenil n =60 14 0.048 0.264 NS 0,264 Smand adult n=11 X Sinterm adult n =31 11 0.203 0.287 NS 0,287

4. CONCLUSION

In view of the results, it is apparent opportunism of food species studied. Indeed, the coexistence of two species taxonomically and morphologically close was made possible by changes in diets inducing diversification of prey. However, there appeared a nutritional profile focusing on piscivory S. intermedius and S. mandibularis general trend. Dietary overlap both levels of the general diet as those in the different hydrological seasons, the longitudinal gradient and size classes, challenge us on experimentation utility in a semi-controlled system. Such study will observe the feeding behavior of two species while taking into account the allopatric and sympatric situations in cages in the wild. Which will benefit confirm or food intra- and interspecific interactions according to differents variables of density, sizes of the specimens and the availability of food resources.

5. ACKNOWLEDGEMENTS

This study was possible thanks to funding from the General Agency for Development Cooperation Bestuur voor Algemeen Ontwikkelingssamenwerking (AGCD-ABOS) of Belgium in the project VL.IR / K.U.L. (Flemish Interuniversity Raad) entitled "Evolution of fish diversity after the construction of a man- made lake: the case of the Bia River." Also, we thank the promoter Thys Van Den Audenaerde. Similarly, we salute the memory of the co-promoter Guy Teugels. May his soul rest in peace.

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AUTHOR’S BRIEF BIOGRAPHY

Dr. DOUMBIA Lassina: Teacher- researcher in the Republic of Côte d’Ivoire at Nangui Abrogoua University at the Training and Research Unit in Sciences and Environmental Management and member of Environment and Aquatic Biology Laboratory. Is interested in stand dynamics and feeding strategies of fishes. He holds a PhD in Sciences and Environmental Management option Ecology and Management of Aquatic Ecosystems of Abobo-Adjamé University in Côte d’Ivoire.

Dr BAMBA Yacouba: Teacher-researcher in the Republic of Côte d'Ivoire, at Nangui Abrogoua University. Is interested in booth feeding and nutrition of fishes in aquaculture. Is interested in fishes production in aquaculture with the use of alternative sources of protein in feed for cultured fishes for better management of natural stocks of aquatic environments

Prof. OUATTARA Allassane is full Professor at Nangui Abrogoua University. (Côte d’Ivoire). He is Côte d’Ivoire). He is a researcher at Environment and Aquatic Biology Laboratory. He focused mainly on algae diversity and fish diversity and their interactions with water quality. Most of his studies have been carried out in West Africa freshwaters (rivers, lake) and lagoon.

Prof. Gourène Germain is full Professor at Nangui Abrogoua University. He is the Director of the Environment and Aquatic Biology Laboratory; he is interested in Systematic, biodiversity and organization of communities in aquatic systems. He has 15 Ph Ds to his credit.

© IJMSET-Advanced Scientific Research Forum (ASRF), All Rights Reserved “IJMSET promotes research nature, Research nature enriches the world’s future” 45