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Papers by samuel amponsah

Acta Aquatica, Nov 30, 2023

Sharks - Past, Present and Future

The main objective of the study was to assess the abundance and distribution of sharks in Ghana’s... more The main objective of the study was to assess the abundance and distribution of sharks in Ghana’s coastal area. Samples were collected daily from the three sampling sites from April – to December 2021. The data obtained from this study were assessed for species abundance and composition, ecological indices; species diversity, and exploitation status using PAST and Microsoft Excel. A total of eight species were recorded with Prionace glauca (68%) as the dominant species and Carcharhinus leucas (1%) as the least dominant species. The mean species richness index (SRI) of 0.9 indicated infinite diversity of the species. The mean species evenness index (SEI) of 0.5 showed an evenly distributed species. The mean species dominance index (SDI) of 0.4 implied that the habitat was not dominated by only one or two particular species. The mean Shannon Weiner index (SWI) was less than 3, which is suggestive of pollution and habitat degradation. The exploitation status indicated that the stock of...

Marine and Fishery Sciences (MAFIS)

Migration is a common feature of most small-scale fisheries (SSF) across the globe. To enhance fi... more Migration is a common feature of most small-scale fisheries (SSF) across the globe. To enhance fisheries resources sustainability and management, we examined the social issues in the SSF from the perspective of fishers, Chief Fishermen, and Fisheries Technical Officers who are actively involved in SSF migration and fisheries management along the coast of Ghana. We conducted in-depth interviews in six important migrant fishers’ communities and analysed documents on the socio-economic conditions of migrant fishers, conflicts among migrant fishers, rights of migrant fishers and the role of government in managing fishers’ migration. Findings showed that the successful integration of migrant fishers in the host communities resulted in minimal conflictual incidents that are resolved through dialogue. Furthermore, both the Fisheries Technical Officers and Chief Fishermen are involved in conflict resolution depending on the nature of the dispute. Also, most migrant fishers (over 50%) have t...

Greener Journal of Agricultural Sciences

European Journal of Biology and Biotechnology

Growth, mortality and exploitation rate of Selene dorsalis (Gill, 1863) from the continental shel... more Growth, mortality and exploitation rate of Selene dorsalis (Gill, 1863) from the continental shelf of Ghana (West Africa) were examined between July 2018 and June 2019. The study provided results on fishery dynamics parameters needed to estimate the stock status and characteristics of S. dorsalis in the coast of Ghana. Monthly length-frequency data were collected from 629 samples and analysed using fisheries models fitted in TropFishR package in R software. The von Bertalanffy growth parameters were utilised to analyse the population dynamics of the species using ELEFAN Simulating Annealing. Based on the estimates, the asymptotic total length (L∞) was 22.2 cm, the coefficient of growth (K) was 0.76 year-1, and the calculated growth performance index (phi) was 2.58 with Rn value of 0.55. The total mortality rate (Z) was 3.32 year-1 with a natural mortality rate (M) of 1.21 year-1 and fishing mortality rate (F) of 2.11 year-1. The exploitation rate (E) estimated for the species was ab...

Maritime Studies

In Ghana, the role of female informal traders (“market women”) in making low-cost smoked and drie... more In Ghana, the role of female informal traders (“market women”) in making low-cost smoked and dried fish available in urban and rural marketplaces is the key to explaining the high consumption of fish in the country. However, market women’s contribution to food security and nutrition (FSN), as well as to fish quality and safety is underrated and poorly understood. Fish marketing requires proficient distribution and preservation skills, economic and sociocultural competence, and a high degree of mobility. Fish traders face numerous constraints related to fish supplies, credit access, hygiene, storage facilities, transport, and market governance, all of which affect their incomes and may affect the quality and safety of fish. The article, which is based on semi-structured interviews with fish traders and fish consumers in coastal and inland markets in Ghana, documents how traders operate and exhibit agency to deal with constraints by activating a range of skills in their profit-making ...

International Journal of Aquatic Biology, 2021

The main objective of this study was to examine the growth, mortality, and exploitation rate of C... more The main objective of this study was to examine the growth, mortality, and exploitation rate of Chloroscombrus chrysurus from the continental shelf of Ghana, West Africa between July 2018 and June 2019. This study provided results on fishery dynamics parameters to contribute to estimating the stock assessment of these fish species. Monthly length-frequency data were collected from 697 samples and analyzed using fisheries models fitted in TropFish R. The von Bertalanffy growth parameters were utilized to analyze the population dynamics of these species using ELEFAN Simulating Annealing. The estimated asymptotic total length (L ∞ ), coefficient of growth (K), and growth performance index (Φ′) was 24.9 cm, 0.84 year -1, and 2.72, respectively, with a Response surface (Rn) value of 0.79. The total mortality (Z), natural mortality (M), and fishing mortality (F) rates C. chrysurus from the continental shelf of Ghana were 3.27 year -1 , 1.31 year -1 , and 1.96 year -1 , respectively. The e...

Egyptian Journal of Aquatic Biology and Fisheries, 2020

The present study was aimed to estimate population parameters including asymptotic length (L∞), g... more The present study was aimed to estimate population parameters including asymptotic length (L∞), growth rate (K), growth performance index (Φ′), natural mortality rate (M), fishing mortality rate (F), exploitation rate (E), and maximum exploitation rate (Emax) of Ilisha africana in coastal waters of Ghana for effective management measures and utilization using FiSAT. Of the total 804 specimens, asymptotic length, growth rate, and growth performance index were 23.6 cm, 0.48 per year, and 2.428, respectively. The total mortality rate (Z), natural mortality rate, and fishing mortality rate were 1.47 per year, 1.13 per year, and 0.34 per year, respectively. The exploitation rate (E) and maximum exploitation rate (Emax) were 0.23 and 0.56, respectively, indicating low exploitation rate of I. africana stocks in Ghanaian coastal waters. The induction of recruits into the stock of I. africana species was all year round, suggesting no recruitment for the assessed fish species. Although the ex...

International Journal of Fisheries and Aquatic Studies, 2016

Some vital population parameters of the bigeye grunt, Brachydeuterus auritus (Valenciennes, 1831)... more Some vital population parameters of the bigeye grunt, Brachydeuterus auritus (Valenciennes, 1831), within Ghana’s coastal waters were evaluated based on monthly pooled length-frequency data from June 2014 to January 2015 using the FiSAT Tool II. The estimated growth parameters from 1675 samples were: asymptotic length (L∞) = 16.28 cm standard length, growth rate (K) = 0.78 per year, growth performance index (ɸ) = 2.315, longevity (tmax) = 4 years, theoretical age (to) = -0.24 years and the ratio of Z/K = 1.26. The length at first capture (Lc50), length at first maturity (Lm50) and length at first recruitment (Lr) were estimated at 3.95 cm, 10.9 cm, and 3.5 cm respectively. The observed recruitment pattern portrayed an absence of recruitment overfishing while the ratio of Lc50/L∞ (0.24) showed the presence of growth overfishing. Total mortality rate (Z), natural mortality rate (M) and fishing mortality rate (F) were estimated at 3.21 per year, 1.73 per year and 1.48 per year, respect...

West African Journal of Applied Ecology, Aug 2, 2021

Academia Biology, Apr 28, 2023

Some life history aspects, including population parameters of Senegalese tongue sole (Cynoglossus... more Some life history aspects, including population parameters of Senegalese tongue sole (Cynoglossus senegalensis), in the coastal waters of Ghana, were studied between July 2018 and June 2019. The length data from a total of 528 specimens from the coastal waters of the Greater Accra region of Ghana was analysed for growth parameters, mortality parameters and biological reference points. The von Bertalanffy growth parameters were estimated at asymptotic length (L∞) = 57.2 cm TL, growth rate (K) = 0.40 per year, and growth performance index (Φ′) = 3.115. Mortality parameters were calculated as total mortality rate (Z) = 0.81 yr−1 , the natural mortality rate (M) = 0.56 yr-1 , and fishing mortality rate (F) 0.26 yr-1 . The exploitation rate (E) of 0.31 was lower than both the optimum level and the exploitation rate at MSY (Emax = 0.64), indicating that C. senegalensis fishery in Ghana is underexploited. However, for sustainable management of the species, there is the need for continuous monitoring of fishing efforts and improve data collection.

Research in Agriculture Livestock and Fisheries

Marine fishes are currently experiencing population decline which has severe repercussions on foo... more Marine fishes are currently experiencing population decline which has severe repercussions on food security, especially in fishing households. However, without assessing the distribution and abundance of these marine fishes, ensuring sustainable management will become impossible. Therefore, the study aimed at applying multivariate techniques to determine the biodiversity of fishes along the coast of Ahanta West, Ghana. Fish samples were collected daily through experimental fishing from November-December, 2011. Data obtained from the study were analyzed for ecological indices, species diversity, and community structure using PAST and PRIMER v6 software. From the results, Pteroscion peli (19.2%), Galeoides decadactylus (11.7%), and Brachydeuterus auritus (9.0%) were the dominant fishes. Multivariate analysis identified three main assemblages of fishes, at 18%. For the ecological indices, the species dominance index (SDI) ranged from 0.89 to 0.93, which indicated that the fish species ...

Journal of Fisheries and Coastal Management

Currently smoked Tilapia in Ghana enjoys high consumer acceptability and marketability with immen... more Currently smoked Tilapia in Ghana enjoys high consumer acceptability and marketability with immense profit margin for both wholesalers and retailers. However, considering the long and complex market channels in the distribution of smoked Tilapia, the study aimed at assessing the storability of smoked Tilapia based on pH and moisture content measurements. Two treated (fresh and aged) samples of Nile Tilapia, Oreochromis niloticus from the Volta Lake, Ghana were used. Both samples were subjected to the same processing procedure though aged Nile Tilapia (i.e. samples kept for 6 days without preservation) was cleaned in brine solution. Moisture content of smoked aged Tilapia (14.59 %, SE = 1.35) was significantly lower than that of smoked fresh Tilapia (19.54 %, SE = 0.54). The pH value of smoked fresh Tilapia (6.31, SE = 0.01) was significantly lower than recorded for smoked aged Tilapia (6.41, SE = 0.01), portraying lower water holding capacity and higher water absorption of the muscle in the smoked fresh Tilapia. From the results, storability of smoked aged Tilapia was relatively better, largely due to the presence of salt. Furthermore, pH values were within the range for quality fish (pH = 6.0 - 6.5), an indication that both smoked Tilapia samples are fresh products. Based on the outcome of the study, it is recommended that fish samples should be cleaned in salt water before smoking in order to reduce the moisture content of smoked fish and consequently increase its storability.

Acta Aquatica, Nov 30, 2023

Sharks - Past, Present and Future

Marine and Fishery Sciences (MAFIS)

Greener Journal of Agricultural Sciences

European Journal of Biology and Biotechnology

Maritime Studies

International Journal of Aquatic Biology, 2021

Egyptian Journal of Aquatic Biology and Fisheries, 2020

International Journal of Fisheries and Aquatic Studies, 2016

West African Journal of Applied Ecology, Aug 2, 2021

Academia Biology, Apr 28, 2023

Research in Agriculture Livestock and Fisheries

Journal of Fisheries and Coastal Management

In spite of the abundance of natural resources, constant exploitation has led to severe degradati... more In spite of the abundance of natural resources, constant exploitation has led to severe degradation of these resources in Ghana including fisheries resources. It was against this backdrop that the present study was conducted with the main objective, to assess the security of coastal fishing operations from the perspective of poverty. In all, four fish landing sites were chosen along the eastern coastline of Ghana with two each in both Greater Accra (Jamestown and Tema) and Volta (Denu and Vodzah) regions respectively. Qualitative data (through the use of questionnaires) obtained from 240 respondents and observational walks within the study areas indicated high poverty indices, low alternate livelihoods, marginalization and vulnerabilities. Overall, our results demonstrated that the security of coastal fishing operations is under relatively high risk. Management actions are urgently required to ensure that fisheries resources continue to contribute meaningfully to the actualization of SDGs 1 and 14 in Ghana.

Ocean acidification is an emerging environmental issue chained to climate change with numerous th... more Ocean acidification is an emerging environmental issue chained to climate change with numerous threats to benefits that marine resources provide humans and society. The main objective of the present study was to establish the impacts of ocean acidification within Ghana’s marine environment on fish diversity and abundance. Fish samples were collected from both artisanal and semi industrial fisheries sectors (situated in Teshie and Tema respectively) in Ghana for an extended period of two years; 2013 – 2014. Fish samples collected were subjected to Principal Coordinate and Canonical Correspondence analyses (PCA and CCA) using Primer 6 and PAST statistical tools respectively. Times series graph of ocean acidification parameters from the study indicated both increasing and decreasing trend – demonstrating the presence of ocean acidification or vice versa. Further, impact of ocean acidification parameters on fish abundance and diversity was found to be both direct and indirect. Overall, results from the present study revealed the occurrence of ocean acidification within Ghana’s coastal waters with impacts on fish diversity and abundance, requiring immediate implementation of effective management and scientific strategies – some of which are outlined in the present study.

Food security exists when all people meets their dietary needs and food preferences for an active... more Food security exists when all people meets their dietary needs and food preferences for an active and healthy life. The Volta delta for DECCMA covers about 3,301 sq km with total population of 863,810. Agriculture and fisheries are the largest economic activities. Home to several fish species such as tilapia, mudfish, oysters, shrimps and others. Accra, Keta, Aflao and other cities are economic centres for fisheries products. The objective of this study is to model economically the impact of climate change on fisheries as input into IO table for prediction under different climate scenarios for 2030, 2060 and 2100 (WP4).