Spatio-Temporal Patterns of Fish Assemblages and Influential Environmental Gradients in a West African Basin (Tai National Park, Côte D'ivoire (original) (raw)

Ichthyologic Diversity of Bandama River Basin (Côte D’Ivoire): An Update and Environmental Influences on Fish Distribution

European Scientific Journal, 2015

The inventory and distribution of fish assemblages of Bandama River were studied from October 2008 to September 2009. Fish samples were collected in three areas (upper, middle and lower catchment) using a back pack electrofisher and two batteries of gill-nets with mesh sizes between 8 and 80 mm. A total of 64 sites were visited and 83 fish species belonging to 11 orders, 30 families and 51 genera were identified. We counted 13 marine and/or brackish-water species and 70 freshwater species. Among them, two introduced species (Heterotis niloticus and Oreochromis niloticus) and one hybrid form (Tilapia zillii x T. guineensis) were found. Characiformes order, mainly represented by Alestidae family and Brycinus longipinnis species, are the most abundant. Studies comparing biodiversity of families used species richness and abundance, showed that families of Cichlidae and Cyprinidae (16% of species each), Mormyridae (11% of species) and Alestidae (10% of species) werethe most abundant. The influence of environmental parameters such us width, dissolved oxygen, turbidity, depth, canopy closure, mixed sand-gravel and aquatic plants on the distribution of fish population has been highlighted by a redundancy analysis (RDA) coupled with Monte Carlo test 499 permutations.

Fish diversity and assemblages according to distance from source along a coastal river gradient (Ehania River; southeast of Ivory Coast)

Iranian Journal of Fisheries Sciences

Fish assemblage was investigated during the study of longitudinal profile of the Ehania River Basin in southeastern Côte d'Ivoire. This area is subjected to intense human activities with many plantations (palm tree, banana, pineapple, coffee, rubber and cocoa). Samples were collected, with gillnets of different mesh sizes, through 6 sampling surveys during dry and rainy seasons from February 2010 to December 2010 at 6 sampling sites. A total of 70 fish species belonging to 48 genera, 28 families and 10 orders were recorded. The temporal variation of diversity index is less marked than spatial variation. The upstream, with 35 species, was less rich in species than the medium area and downstream areas (respectively 46 and 68). The upstream and downstream areas gathered 35 species. Thirty three species were common to the upper and middle areas and 46 species appeared both in the lower courses and the middle area. The 21 species restricted to the lower part of the river are mainly estuarine/marine origin. The beta diversity value revealed low similarity between the lower and upper course of Ehania River. The lowest values of Shannon's diversity index and equitability index were observed in the middle part of the River which characterized by high population density and intense agricultural activity with many plantations.

Environmental Influences on Fish Species Distribution in the Musolo River System, Congo River Basin (Democratic Republic of the Congo, Central Africa)

Ichthyofaunal distribution was studied in the Musolo River system, a small affluent tributary of the Congo River flowing into Pool Malebo (Democratic Republic of the Congo). Twelve ecological stations were sampled, of which eight were located in the Musolo main-channel and four in the Fushi River, a principal tributary of the Musolo. Each station was sampled four times over a two-year period, with fishing techniques following standardized methods utilizing dip and cast nets, and nine environment variables were measured at each station. Fifty-three fish species belonging to 36 genera and 16 families were collected with the Alestidae, Distichodontidae, Cichlidae, Cyprinidae, Mormyridae, and Mochokidae being the most diversified. Redundancy Analysis with forward selection coupled with Monte Carlo permutation tests (499 permutations) identified total dissolved solid (25.8%) and altitude (24.4%) as accounting for 50.2% of total variance (p < 0.05). The contribution of the two first axes was significant (F = 3.41; p = 0.004). Species richness increases from upstream to downstream. In general, the high value of Shannon's diversity (1.07-2.67) and Equitability (0.62-0.96) indices at all sites, indicates that the examined stretch of the Musolo River system is in good ecological health, despite its location adjacent to the megacity of Kinshasa.

Fish composition and structure along longitudinal gradient of a coastal river (Ehania River; south-east of Ivory Coast)

International Journal of Biosciences (IJB), 2013

Fish assemblage was examined during the study of longitudinal profile of the Ehania River Basin in southeastern Côte d'Ivoire. This region is subjected to strong human activities with numerous plantations (palm tree, banana, pineapple, coffee, rubber and cocoa). Samples were collected, with gillnets of different mesh sizes, through 6 sampling surveys during dry and rainy seasons from February 2010 to December 2010 at 6 sampling sites. A total of 70 fish species belonging to 48 genera, 28 families and 10 orders were recorded. The temporal variation of diversity index is less marked than spatial variation. The upstream, with 35 species, was less rich in species than the medium area and downstream areas (respectively 46 and 68). The upstream and downstream areas gathered 35 species. Thirty three (33) species were common to the upper and middle areas and 46 species appeared both in the lower courses and the middle area. The 21 species restricted to the lower part of the river are mainly estuarine/marine origin. The beta diversity value revealed low similarity between the lower and upper course of Ehania River. The lowest values of Shannon's diversity index and equitability index were observed in the middle part of the River which characterized by high population density and intense agricultural activity with many plantations.

First Data of the Ichthyological Fauna in the Bandama River at the Lamto Scientific Nature Reserve (Côte d'Ivoire, West Africa)

Fish species composition and organization of the Bandama River at the scientific nature reserve of Lamto have been investigated for the first time. The study was conducted from March 2021 to February 2022. Gillnets and traps were used to collect fish. A total of 41 species belonging to 35 genera, 13 families, and 5 orders were captured. The best-represented orders were the Siluriformes with 5 families and 11 species and the Perciformes with 3 families and 14 species of fish. The Cichlidae, Mormyridae, and Alestidae represented the best diversified family with 13, 5, and 5 species respectively. This study also showed a decrease in the average size of individuals of the main species retained, which could reflect overexploitation of the stocks. The Shannon index (2.21 bits/ind.) and equitability (0.58) values obtained reflect a more or less distribution of individuals by species. These results will make it possible to establish a database for the conservation of this fish population and its habitat.

Diversity and Relative Abundance of Fishes in Some Temporary and Perennial Water Bodies of the Baro Basin, Gambella, Ethiopia

Ethiopian Journal of Biological Sciences, 2012

The diversity and relative abundance of fish species of the Baro basin were studied using samples taken from seven sites. Fishes were sampled using seines, dip nets (mesh sizes 0.5 cm and 1 mm), hook and line, fish traps, cast net (local fishermen) and electro-fishing. Specimens were identified to species level using taxonomic keys found in the literature. Shannon diversity index (H') and Index of Relative Importance (IRI) were computed to evaluate diversity and relative abundance of fish species, respectively. A total of 51 species belonging to 38 genera, 20 families and 11 orders were identified. The number of species varied among sampling sites. Thus, the highest number of species was recorded from Alwero (H'=2.56) followed by Obela, Baro at Gambella and Gilo (H'=2.03 each), Itang (H'=1.91) and Tdha (H'=0.35). Mormyridae, which comprised 8 species, was the most dominant family in number of species followed by Mochokidae (7 species) and Cyprinidae (6 species). Barbus prince was found in six of the studied sites whereas Oreochromis niloticus was found in five sites, Brycinus macrolepidotus, Siluradon auritus, Clarias gariepinus, Barbus stigmatopygus and Polypterus senegalus were each found in four sites, and thus, were considered the most dominant. IRI showed that O. niloticus (IRI=37.2%) was the most abundant species followed by S. auritus (IRI=14.6%), B. macrolepidotus (IRI=13.1%), B. stigmatopygus (IRI=10.0%), B. prince (IRI=9.8%), and P. senegalus (IRI=7.4%). Further comprehensive assessment of the fish diversity of the basin and socioeconomic aspects for sustainable fish resource utilization is recommended.

Community dynamics of the fishes and some aspects of the limnology of two West African reservoirs A R T I C L E I N F O K E Y W O R D S Limnology Reservoir Potential fish yield Diversity

I S S N : 2 4 5 6-6 2 6 8 A B S T R A C T The ichthyofaunal diversity and limnology of Kpong and Oyun reservoirs located in Ghana and Nigeria respectively were studied with the main aim of gathering useful information to support the development, management and sustainable use of their respective fisheries to enhance the socioeconomic status of riparian communities. Experimental fishing with a battery of gill nets of various mesh sizes was used to sample for fishes monthly (September 2014 to August 2016) were individually identified, weighed and measured for standard and total lengths. Water samples were taken monthly and analyzed for physico-chemical parameters. Cichlidae and Mormyridae were the most abundant families in Kpong reservoir accounting for 77.7% and 8.7% respectively and Mochokidae was the least occurring with 2.0% while Oyun recorded Cichlidae, Claridae and Mormyridae as the most important families encountered with 45.99%, 25.41% and 12.2% respectively with Channidae (0.5%) the least occurring. In the Kpong Reservoir, 17 species belonging to 5 families were encountered with Oreochromis niloticus (28.94%) and Sarotherodon galilaeus (25.98) the most abundant and Gnathonemus cypriniodes (0.43%) the least. In the Oyun Reservoir, 18 species, representing 9 families, were obtained. Tilapia zilli (22.78%) and Oreochromis niloticus (14.14%) were the dominant species with Channa obscura (0.50%) the least. The fish diversity of the Kpong Reservoir was lower than that of the Oyun reservoir recording a species diversity (H') of 2.14 compared to 2.45 for Oyun. Herbivorous fishes were dominant in the two reservoirs while carnivorous ones were the least dominant. The Forage-Carnivore (F/C) ratios of 1.21 (by number) and 2.13 (by weight) for Oyun and 3.49 (by number) and 1.72 (by weight) for Kpong suggest a suitable ecological balance between carnivorous fishes and their prey populations. The estimated potential fish yield per year for the Oyun Reservoir (97.61kg/ha/yr) was higher than that of the Kpong Reservoir (60.69kg/ha/yr) possibly due to its shallower nature and higher productivity. Both reservoirs were well oxygenated all year-round with Oyun exhibiting a weakly acidic pH to Kpong's weakly basic trend. The key physico-chemical parameters in both reservoirs were within ranges for fish survival and production with Oyun being characterized by a comparatively higher ionic and nutrient content. Nutrients displayed greater impact on fish abundance hence the inference by the study that nutrient levels fluctuations are factors that play crucial roles in fish abundance in both reservoirs. Granted the adoption of appropriate management measures, both reservoirs are considered highly productive and possess the potential to optimize their fish production.

Fish assemblage structure in the Tropical Coastal Lagoon of Grand Lahou (Cte DIvoire, West Africa)

International Journal of Fisheries and Aquaculture, 2016

Fish assemblages and their relationship with hydrological variables were investigated in the coastal lagoon of Grand-Lahou (Côte-d’Ivoire) from November 2013 to October 2014. Samplings were carried out by means of artisanal fisheries, once a month, in three sites. A total of 8571 fish belonging to 47 fish species from 25 families were recorded. The most represented families were Cichlidae and Mugilidae with six species. Each environmental variable, notably, dissolved oxygen (DO), temperature and salinity according to the canonical correspondence analysis (CCA) allowed the distinction of two main sectors in the lagoon, associated with three fish assemblages. Sector 1 including sampling sites 2 and 3, characterized by high salinity fluctuations, functioned as a typical estuary. Two fish assemblages identified in this sector were Lutjanus dentatus, Mugil cephalus, Mugil bananensis, Tilapia guineensis and Tylochromis jentenki in station 2 and Sarotherodon melanotheron, Liza falcipinnis ...

Fish Diversity Along the Longitudinal Gradient in a Man–made Lake of West Africa, Taabo Hydroelectric Reservoir, Ivory …

Ribarstvo, 2010

Fish assemblage patterns in Taabo Reservoir, a hydroelectric lake of Ivory Coast, were studied and related to the longitudinal gradient (river-dam gradient) composed of riverine, transitional, and lacustrine zones. Data were collected at 5 stations and each one was sampled during 5 surveys. Fish community structure was analysed using alpha and beta diversity indices. In total, 53 fish species were obtained in the whole ecosystem. Total species richness recorded at each ecological zone was 42, 43 and 45 species respectively in the riverine, transitional and lacustrine zones. Alpha diversity did not differed significantly along the longitudinal gradient but reached the highest value (33 species) in the transitional zone and the lowest (18 species) occurred in both the riverine and lacustrine zones. Temporal variability of Alpha diversity according to the hydrological regime of the lake differed with the zone. Beta diversity showed that fish assemblages similarity was higher between the transitional and the riverine zones (â w = 0.43) and lower between the riverine and the lacustrine zones (â w = 0.79).

Community dynamics of the fishes and some aspects of the limnology of two West African reservoirs

2017

The ichthyofaunal diversity and limnology of Kpong and Oyun reservoirs located in Ghana and Nigeria respectively were studied with the main aim of gathering useful information to support the development, management and sustainable use of their respective fisheries to enhance the socio-economic status of riparian communities. Experimental fishing with a battery of gill nets of various mesh sizes was used to sample for fishes monthly (September 2014 to August 2016) were individually identified, weighed and measured for standard and total lengths. Water samples were taken monthly and analyzed for physico-chemical parameters. Cichlidae and Mormyridae were the most abundant families in Kpong reservoir accounting for 77.7% and 8.7% respectively and Mochokidae was the least occurring with 2.0% while Oyun recorded Cichlidae, Claridae and Mormyridae as the most important families encountered with 45.99%, 25.41% and 12.2% respectively with Channidae (0.5%) the least occurring. In the Kpong Re...