West African Journal of Applied Ecology

Small Mammals Distribution and Composition in the Agumatsa Range, Volta Region, Ghana

F. A. Boahene — 2024-06-25

The diversity and abundance of flora and fauna are declining alarmingly. Loss of original habitat has been documented as the most prevalent cause of species extinction globally. We assessed the present status of the small mammal species in the Agumatsa range, specifically in the Gbledi Gborgame, Gbledi Chebi, Fodome Ahor, and Wli Afegame settlements, which are located at the foot of the Agumatsa Range with similar habitat structure and complexity. Fifteen Sherman live collapsible traps (8 x 9 x 23 cm) were placed in 15- eter transects (n=60) separated 10 meters apart in the four communities and monitored for six months in 2019 and 2020. Traps were activated for five consecutive nights at each site for every sample session, making 14,400 trap nights of sampling. All traps were baited with peanut butter mixed with cornbread and set at ground level at the sampling sites. Seven hundred eighty-seven individual species were recorded, with an overall trap success rate of 5.5%. Species and frequencies recorded in the entire survey were Praomys tullbergi (238), Mastomys erythroleucus (200), lemniscomys striatus (139), Crocidura crossei (92), Mus musculus (75), Tatera kempi (21), Dasymys incomtus (14) and Oenomys ornatus (8). Specifically, 279 individual species were recorded in the rainy season, and 264 and 246 individuals were recorded in the dry and minor rainy seasons, respectively. The Gbledi Gborgame community had the most individual species (n=237). Praomys tullbergi (n=87) was the most numerous species during the dry season, whereas Mastomys erythroleculus (n=69) was the most abundant during the minor wet season. Praomys tullbergi was detected at all altitudes where the traps were deployed. Dasymys incomtus and Oenomys ornatus were species discovered in the Fodome Ahor community only, whereas Lemniscomy straitus was the only species not discovered in Gbledi Gborgame. The results of this study indicate that the forest along the Agumatsa range is under pressure from increased demand for natural products, thereby reducing the size and quality of small mammal habitats. The fast rate of deforestation of the Agumatsa range urgently requires an update of current records on the status of the different small mammal communities.

Relative condition factor and parasites of the Bigeye grunt, Brachydeuterus auritus (Valenciennes, 1831) inhabiting the coastal waters off Tema, Ghana

B. Kwansa-Bentum — 2024-06-26

The marine ray-fined Brachydeuterus auritus is one of the most exploited and heavily consumed fishes of the tropical and sub-tropical waters of the eastern-central Atlantic. Fish microbial studies have raised awareness of parasites that can impact fish health, growth, survival, reproduction, and the possible transmission of fish-to-humans situations. The study assessed the well-being of this economically important fish and the prevalence of parasites that they harbour which potentially is of public health interest.. This cross- ectional study involved sampling of fish from June to December, 2016. A total of 424 B. auritus were collected of which 228 were males, 157 females and 39 being hermaphrodites. Data on their length and weight were taken and condition factors determined. Ectoparasites were isolated for identification using a compound light microscope by direct smear of mucous scraped from the skin, fins and mouth, whereas endoparasites were isolated from the gut. The length of B. auritus ranged from 9.70 to 22.20 cm, and weighed between 13.51 to 149.92 g. The correlation coefficient (r) between the log of total length and body depth of the sexes ranged from 0.960 - 0.970. Brachydeuterus auritus in this part of the coastal waters of Ghana showed negative allometric growth for both sexes. Most of the parasites isolated were parasitic crustaceans, such as Achtheres sp., Clinostomum sp., Cymothoa sp., Ergasilus sp., and Rhabdochona sp. which were recovered from the gills and mouth. Parasite density was higher in males than in females. Samples of intermediate sizes had the highest parasite prevalence, and also had the least parasite intensity. This study has contributed to the knowledge on the parasitic infestations associated with this economically important fish species and their potential roles and dangers in the fish-to-human transmissions. More education on proper handling and cooking of fish be given to farmers, traders and consumers, as well as control of piscivorous birds is to maximize profitability in fish farming.

Exogenous Inoculation of Seed with Plant Growth-promoting Rhizobacteria Effectively Enhanced Growth of Cucumber in a Greenhouse

A. R. Oloyede — 2024-06-26

Cucumber (Cucumis sativus L.) production in most countries remains unprofitable due to poor growth and low yields resulting from low soil fertility. Concern over environmental contamination and human health hazards posed by increased use of chemical fertilizers requires the development of an alternative strategy to increase food production. The study was conducted to assess the effectiveness, and consistency, of plant growth-promoting rhizobacteria (PGPR) strains in enhancing growth promotion of cucumber plants in a greenhouse. The in-vitro germination bioassay was conducted on eight potential PGPR strains. The effectiveness of the two most efficacious PGPR strains (Pseudomonas aeruginosa OG04 and Bacillus subtilis MO07) on cucumber plants was repeatedly evaluated in the greenhouse for three trials using seed bacterization and soil inoculation methods. Data on plant heights, leaf lengths, leaf numbers, number of branches, root weights and shoot weights were collected and analysed. The seed germination bioassay showed that cucumber seeds inoculated with potential PGPR strains had significantly higher percentage germination rate (16.20% - 53.30%) and vigour index (18.30% - 114.70%) than un-inoculated seeds. Inoculation of cucumber with P. aeruginosa and B. subtilis significantly (p ≤ 0.05) increased the plant heights (4.40 – 28.70%), leaf numbers (9.10 – 33.30%), leaf lengths (5.60 – 42.50%), fresh root weights (20.90 – 62.40%), dry root weights (29.50 – 113.30%), fresh shoot weights (13.20 – 54.30%) and dry shoot weights (46.40 – 100.0%) over un- noculated plants in all trials. Pseudomonas aeruginosa OG04 and Bacillus subtillis MO07 could be exogenously applied as microbial inoculants to promote growth of cucumber under greenhouse conditions.

Preliminary analysis of spatio-temporal fish assemblage variations of Gandoule Marine Protected Area in Senegal

O. Diankha — 2024-06-26

The study investigated the spatial and temporal fish assemblage structure in relation to the abiotic factors in the Gandoule Marine Protected Area (GMPA) in Sine-Saloum Estuary. Samples were collected in four seasons (cold season, transition from cold to warm season, warm season and transition from warm to cold) from seven stations with a beach seine in 2017. Environmental parameters such as temperature, salinity and pH were measured during each season at all stations. Overall, the fish assemblage of GMPA consisted of 35 species belonging to 20 families. The most abundant species were Ethmalosa fimbriata, Gerres nigri, Mugil curema, Neochelon falcipinnis and Mugil bananensis, accounting for 63.58% of the total abundance. In terms of ecological and trophic guilds, the fish assemblage was dominated by species with estuarine affinity and herbivorous species. The results of similarity analysis showed a significant difference between sampling seasons and stations. The similarity percentage analysis revealed that similarity among seasons was between 7.65% and 13.27%, whilst similarity between stations ranged from 9.51% to 15.24%. The canonical correspondence analysis indicated that temperature and salinity were the main drivers influencing the distribution of species such as Chelon dumerili, Mugil bananensis, Mugil curema, Coptodon guineensis, Neochelon falcipinnis and Ethmalosa fimbriata.

Assessing the trophic structure and functioning of a large tropical lagoon. Case study: Keta Lagoon, Ghana

S. M. Abobi — 2024-06-26

A model of trophic interactions in the Keta Lagoon was developed to assess the current state and the energy flow within the food web structure of the system components using an ECOPATH with ECOSIM modelling approach. Seventeen (17) functional groups were identified for the Keta Lagoon model construction. Ecosystem health and maturity parameters were derived using the ecological network analysis. The functional groups identified in the food web were of varied trophic levels ranging from primary producers (trophic level (TL) = 1) to top predators (TL = 3.216). Most fish groups had higher eco-trophic efficiencies (EE > 0.9), indicating their high utilisation within the system. The total system throughput was estimated at 10,287.920 t/km²/year, with the system depending on the consumption of primary producers. The mean trophic level of the catch (2.762) indicated that the fisheries target fish groups with higher trophic levels. Ecological indices such as the net system production (1,480.452 t/km²/year), total primary production/total biomass (7.207), total biomass/total system throughput (0.054 t/km²/year), Finn’s cycling index (4.933%), system omnivory index (0.155), ascendency (26.29%) and system overhead (73.71%) indicated that the ecosystem is in its developing stage and prone to environmental disturbance hence, the need for management. The mixed trophic impact routine indicated that the lower trophic level groups positively impacted most of the higher trophic level groups. Also, predatory birds and macro-invertebrates were the most influential functional groups structuring the lagoon. Management strategies that could be implemented include habitat protection, stock enhancement, alternative livelihoods (aquaculture), closed seasons, and enforcement of fisheries regulations.

Effects of supplementation of sole and combined browse leaves on in vitro digestibility of rice straw

E. D. Yeboah — 2024-06-26

The utilization of browse leaves as quality livestock feeds during the late dry season can alleviate nutritional deficiencies and maintain livestock production. This study investigated the nutritional value in terms of dry matter (DM), crude protein (CP), ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) of both sole and combined browse leaves in Southern Ghana. Browse leaves used were Cajanus cajan (CC), Spondias mombin (SM) and Leuceana leucocephala (LL). Untreated Rice Straw (URS) was used as the basal diet which was harvested during the late dry season (September and October) from an irrigated rice field. The proportion of rice straw to browse leaves was 75 to 25 percent. Rumen liquor for the in vitro study was obtained from two forest type fistulated wethers of average weight 23 kg. The values for DM, CP, NDF, ADF and ash of the experimental diets ranges between 909.5 to 919.7 g/kg, 87.3 to 211.3 g/kg DM, 591.5 to 700.3 g/kg DM, 202.6 to 235.4 g/kg DM and 129.5 to 145.7 g/kg DM respectively. The combination of the three browse leaves (LLSMCC) had the lowest (p<0.05) ADF and NDF values whilst URS was the highest (p<0.05). All browses used improved the IVDMD of URS significantly from 388.7 g/kg DM to between 441 and 472.1 g/kg DM. The highest (p<0.05) IVDMD was obtained by the combination of Spondias mombin and Cajanus cajan (SMCC). Also, IVOMD of URS was improved from 346.4 g/kg DM to between 446.3 g/kg DM and 483.4 g/kg DM. Results obtained from this study showed that browse leaves were high in CP and moderately low in crude fibre and ash hence, can be recommended as supplements for ruminants most especially in the dry season when feed is scarce.