Department of Marine and Fisheries Sciences
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Item Evaluating The Performance Of CMRI For Estimating The Spatial Distribution Of Mangroves At The Keta Lagoon Complex In The Volta Region Of Ghana(University of Ghana, 2020-10) Sackey-Addo, S.Data obtained from remote sensing is useful for evaluating and mapping infrastructure and natural resources including vegetation. Over the past years, a number of vegetation indices have been developed to detect vegetation with the use of satellite imageries to monitor the distribution and phenology of mangroves. Forest managers and environmental scientists have developed a wide range of indices for delineating and assessing the health of different vegetation and forest cover. This study will evaluate the performance of Combined Mangrove Recognition Index (CMRI) for estimating and distinguishing mangroves in the Keta Lagoon Complex. The CMRI was compared to the Normalized Vegetation Index (NDVI), a widely used vegetation index and supervised classification (maximum likelihood) which were selected based on their classification accuracies of about 80% in the estimation of vegetation. Sentinel-2 imagery was used to generate vegetation maps for the NDVI and CMRI indices and a land cover map generated using the supervised classification (maximum likelihood) technique. The threshold value method was used to extract the values of mangrove areas for each index and used to delineate areas of mangrove and non-mangrove using binary data with the use of UAV imagery for validation. Random points with their coordinates were generated as reference points on the UAV imagery and overlaid on the other maps. Areas of mangroves were denoted “1” and areas with non-mangroves were denoted “0”. The Cochran’s Q test, used for statistical analysis of binary data was used to derive the p-value after which the area coverage of mangroves in the study area was estimated. From the study, the threshold values used to mask out mangroves were observed to be between 0.27 and 0.37, and between 0.51 and 0.70 for NDVI and CMRI respectively. UAV imagery was used to validate the area coverage due to its high resolution. The imagery covered an area of 1.8 km2 and was used as a subset for the mangrove area coverage comparison. Mangrove area coverage was estimated to be 0.32km2, 0.30km2, and 0.25km2 for NDVI, supervised classification and CMRI respectively. All techniques used in classification showed no statistical significance (>0.05) when compared to ground truth data. The CMRI was observed to have performed better and hence confirmed its sensitivity in estimating mangroves and that other satellite missions with optical sensors and multiple bands can be used to generate the index with high accuracy.Item The Ecological Statusof The Keta Lagoon Using Physicochemical And Biological Indicators Of Water Quality(University Of Ghana, 2021-09) Danso, P.The Keta Lagoon and its catchment areas are under the influence of intensive agriculture which depend heavily on agrochemical usage. It is necessary that, the quality of water in the lagoon is assessed to broaden our understanding of how the lagoon and its associated biota are responding to agro-related activities in its watershed. This study carried out a comprehensive assessment of the ecological status of the lagoon using physicochemical parameters (temperature, DO, turbidity, pH, nitrate, phosphate, silicate, ammonia), Trophic State Index and diversities of benthic macroinvertebrates and phytoplankton communities. The lagoon was partitioned into five zones (A to E) to depict the intensity of human impact as reflected through farming along the bank of the lagoon. Zone A is the area in close proximity to Anloga, Zone B, covers the mid-section of the lagoon and falls between Anloga and Woe, Zone C is main Woe area, Zone D represents the area between Woe and Afedome and finally Zone E which represents the area beyond Afedome extending towards Keta. The average physicochemical parameters reported during the study showed that Zones A and B recorded the highest levels of pH, 9.6 0.16 which was above the acceptable range levels by Ghana’s EPA and USEPA (6.0 to 9.0). The least pH level was recorded for Zone C at 8.5 0.03 which was within the acceptable range of pH. Dissolved oxygen levels measured was highest in Zone D (8.1 0.26 mg/l) and least in Zone A (6.5 0.13 mg/l), all within Ghana EPA and USEPA as well as the World Health Organization tolerable limits. Zones A recorded the higest nitrate values of 3.4 0.03mg/l and least in Zone E, 1.9 0.02 mg/l. All zones recorded nitrate levels that were above the Ghana and US EPA permissible ranges. Ammonia was highest in Zone A (0.12 0.02 mg/l) and least in Zone E (0.03 0.02 mg/l), and Phosphate levels was highest in Zone A (0.26 0.01mg/l) and least in Zone E (0.13 0.01 mg/l). Both phosphate and ammonia measured were within the permissible limits. The Trophic State Index based on Chlorophyll-a estimation indicated that the lagoon was hypereutrophic (61.3-64.9). However, Zone A recorded the highest TSI value (64.9) and the least TSI was recorded by Zone E (61.3). Zones A, B and C (4.9-6.5) were in poor ecological conditions. D (3.0-3.8) was in fair ecological conditions. Zone E was in good ecological conditions. The mean Plankton Index of Biotic Integrity (P-IBI) for the entire lagoon, however, was 3.96 and that shows a mesotrophic lagoon with diverse populations of phytoplankton.The total number of macrobenthic species counted in the Keta lagoon was 1018 which consisted of 83% mollusks and 17% polychaetes as the major taxa. Generally, Macrobenthic assemblage richness, evenness and diversity were 1.2, 0.8 and 1.7 respectively for the lagoon. The trends of physicochemical parameters (temperature, DO, turbidity, pH, nitrate, phosphate, silicate, ammonia), Trophic State Index, diversities of benthic macroinvertebrates and phytoplankton communities showed that the lagoon is in the state of deterioration with time.Item Evaluating The Performance Of CMIR For Estimating The Spatial Distribution Of Mangroves At The Keta Lagoon Complex In The Volta Region Of Ghana(University of Ghana, 2020-10) Samuel, S-A.Data obtained from remote sensing is useful for evaluating and mapping infrastructure and natural resources including vegetation. Over the past years, a number of vegetation indices have been developed to detect vegetation with the use of satellite imageries to monitor the distribution and phenology of mangroves. Forest managers and environmental scientists have developed a wide range of indices for delineating and assessing the health of different vegetation and forest cover. This study will evaluate the performance of Combined Mangrove Recognition Index (CMRI) for estimating and distinguishing mangroves in the Keta Lagoon Complex. The CMRI was compared to the Normalized Vegetation Index (NDVI), a widely used vegetation index and supervised classification (maximum likelihood) which were selected based on their classification accuracies of about 80% in the estimation of vegetation. Sentinel 2 imagery was used to generate vegetation maps for the NDVI and CMRI indices and a land cover map generated using the supervised classification (maximum likelihood) technique. The threshold value method was used to extract the values of mangrove areas for each index and used to delineate areas of mangrove and non-mangrove using binary data with the use of UAV imagery for validation. Random points with their coordinates were generated as reference points on the UAV imagery and overlaid on the other maps. Areas of mangroves were denoted “1” and areas with non-mangroves were denoted “0”. The Cochran’s Q test, used for statistical analysis of binary data was used to derive the p-value after which the area coverage of mangroves in the study area was estimated. From the study, the threshold values used to mask out mangroves were observed to be between 0.27 and 0.37, and between 0.51 and 0.70 for NDVI and CMRI respectively. UAV imagery was used to validate the area coverage due to its high resolution. The imagery covered an area of 1.8 km2 and was used as a subset for the mangrove area coverage comparison. Mangrove area coverage was estimated to be 0.32km2 , University of Ghana http://ugspace.ug.edu.gh iv 0.30km2 , and 0.25km2 for NDVI, supervised classification and CMRI respectively. All techniques used in classification showed no statistical significance (>0.05) when compared to ground truth data. The CMRI was observed to have performed better and hence confirmed its sensitivity in estimating mangroves and that other satellite missions with optical sensors and multiple bands can be used to generate the index with high accuracy.Item Food and Feeding Habits of Three Tuna Species Landed in Ghana(2020-08) Tuga, A.Food and feeding habits of the three tuna species landed in Ghana were investigated for a period of six (6) months from October 2019 to March 2020. The species are Thunnus albacares, Katsuwonus pelamis, and Thunnus obesus. The study sampled a total of 210 individuals of the three tuna species, out of which 90 individuals were Katsuwonus pelamis, 60 individuals of Thunnus albacares, and 60 individuals of Thunnus obesus. The study sampled 90 specimens for Katsuwonus pelamis because they are of high abundance and very common in Ghanaian waters than Thunnus albacares and Thunnus obesus. These tuna species were sampled for stomach content analysis, to determine which type of prey item is most important and preferred as food for these three tuna species. The samples were transported to the Fisheries Scientific Survey Division (FSSD) laboratory in Tema, under the Ministry of Fisheries and Aquaculture Development for analysis. At the laboratory, some morphometric measurements of the samples were taken. The fish samples were dissected and their guts were removed for examination. Gut content analysis was conducted on each of the fish sampled. The gut fullness was determined on a scale of 0/4 to 4/4 by visual inspection. The commonest prey items discovered in the stomachs during the studies were Engraulis encrasicolus, Exocoetus spp, Penaeus kerathurus, Sepia hierredda, Loligo spp, and Metapenaeus monoceros. Engraulis encrasicolus was found to be the most preferred food item accounting for 58% occurrence by number, with Diplodus spp being the least preferred food item accounting for 2% for Thunnus albacares. For Katsuwonus pelamis, Penaeus kerathurus was found to be the most preferred food item accounting for 57% occurrence by number, with Sepia hierredda being the least preferred food item accounting for 10% of total prey items found. Exocoetus spp was also found to be the most preferred food item accounting for 86% occurrence by number, with Metapenaeus monoceros being the least preferred food item accounting for 12% for Thunnus obesus. Similarly, the most important food items identified using Index of relative importance were Engraulis encrasicolus, Penaeus kerathurus and Exocoetus spp with Diplodus spp, Sepia hierredda and Metapenaeus monoceros recording the least important for Thunnus albacares, Katsuwonus pelamis and Thunnus obesus respectively. There was a significant difference among these three tuna species with respect to Engraulis encrasicolus, Penaeus kerathurus Exocoetus spp, Sardinella aurita, Caranx crysos, Sepia hierredda, Loligo spp, and Brachyuran spp. Continuous research on food and feeding habits of these Tuna species to cover all the yearly seasons was recommended owing to their commercial importance to Ghana and the international community.Item Assessment of Beach Litter at the Sakumono and La Pleasure Beaches(University of Ghana, 2019-07) Adjei, O.Ghana faces a major challenge when it comes to waste management, especially in the urban areas. Population growth even makes the situation more exacerbated in the coastal urban areas. Most of the waste that is generated and lost inland end up in the coastal and marine environment when the rains fall and wash the solid wastes downstream. Some of the waste is also produced on the beaches by revelers when they use the beaches for tourist and entertainment purposes. This study was carried out on two beaches in the Greater Accra Region, namely Sakumono and La Pleasure beaches. The main objective of this study was to assess the amount of beach litter at the two beaches. A transect of 1000 m2 was used in the study. A total of 2,697 litter items were collected from the two beaches. The total weight of the litter throughout the survey was 50.07 kg from both sites. Weight of litter collected from Sakumono beach was 31.79 kg accounting for 63.49% of the total weight of litter surveyed whereas the weight of litter collected from La was 18.28 kg, also accounting for 36.51% of total litter surveyed. Plastics were found to be the most abundant both by number as well as weight. For both beaches, plastics made up 72.56% composition by number or quantity at 1975 items and 65.53% by weight at 32.81 kg. Sakumono beach was found to be more littered than La Pleasure beach. This was significant at an alpha value of 0.05 (p value = 0.02). Continuous monitoring, intensive education, and the enforcement of appropriate policy initiatives remain crucial to addressing the beach litter menace along the coasts of Ghana.Item Investigating Pathological Agents Associated With the Rusty-Brown Spots on Farmed Nile Tilapia (Oreochromis Niloticus Linnaeus, 1758) in Ghana(University of Ghana, 2019-07) Deho, R.E.A.The outbreak of disease in fish farming has become a worldwide problem. The aquaculture industry in Ghana has seen a major rise in the rate of fish mortality in recent times with significant economic losses. New and emerging diseases maybe associated with these mortalities including the rusty brown spot recorded on cultured Oreochromis niloticus (Nile tilapia). However, there is no much information on the pathological agents associated with the condition. The rusty brown spots have been observed in tilapia cultured in earthen ponds and concrete ponds. This work looks at isolating and identifying the possible organisms that are likely to be the cause of the rusty brown spots. Preliminary culture of the fish skin on Tryptone soy agar (TSA) and Tryptic Yeast Extract salt agar (TYES) recorded the following bacteria species Psuedomonas aureginosa, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus chonii and Flavobactrium. Data obtained shown that Aspergillus niger and Flavobacterium spp. were the primary pathogens associated with the rusty brown spots. However, molecular identification is yet to be done to determine the exact strain of Flavobacterium and Aspergillus niger and to confirm their virulence in a challenge infection experiment.Item Effects of Broodstock Sex Pairing Ratios and Resting Periods of the Nile Tilapia Oreochromis Niloticus (Linnaeus, 1758) on Fry Production(University of Ghana, 2019-07) Oblie, E.N.A.The Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) forms about 80% of farmed fish in Ghana. However, the unavailability of its seed all year round for culture is a major constraint. This study evaluated the effects of varying male to female broodstock pairing ratios of 1:1, 1:2 and 1:3 with resting intervals of 0, 3 and 7 days on fry production performance of the Akosombo strain of the Nile tilapia at the Ashaiman Aquaculture Demonstration Centre, Ghana. Nine (9) treatments were arranged according to a 2 x 3 factorial design with three replicates giving a total of 27 spawning hapas (1 m3). Male and female brooders of mean body weight (200±50 g and 171±23.7 g respectively) were paired according to the three different sex ratios. Water quality parameters for temperature and DO were taken daily while’s pH, salinity and ammonia were measured weekly. The total mean fry output for the sex pairing ratios (1:1, 1:2, 1:3) were 716±344, 973±325 and 723±577 respectively. The total fry output for 0, 3 and 7 days of resting were 1503±868, 2030±637 and 3051±1054 respectively with an observed 35% (3 days rest) and 103% (7 days rest) fry production increment over the 0 resting treatment. With respect to the combined effect of varying sex ratios and resting periods, the highest mean fry production (701±405) was attained under the 7 days resting period at a pairing ratio of 1:2. Although results subjected to ANOVA showed no significant differences (p>0.05) among the treatments, the relatively high reproductive performance observed for broodstock pairing ratio 1:2 and resting period of 7 days under this study confirms that it is a more efficient broodstock management technique for an increased Nile tilapia fry production.Item Studies on Abundance of Jellyfish in Beach Seine Landings along the Coast of Greater Accra Region of Ghana(University of Ghana, 2019-07) Adongo, P.A.The study was conducted in three landing villages along the coast of Greater Accra Region of Ghana, namely; Ada, La and Bortianor from November 2018 to April 2019. The purpose of the study was to assess the abundance of jellyfish in beach seine landings. Biological data was obtained primarily from local fishermen who deployed beach seine net. The jellyfish families that were encountered were four in number and a total of 2,676 individuals from 72 beach seine hauls. These were; Catostylidae (35%), Chirodropidae (31%), Rhizostomatidae (30%) and Pelagiidae (4%). Ada had 37% of jellyfish, La 49% and Bortianor 14% of the total jellyfish landings. Rhizostomatidae was the most abundant at Ada, whereas Chirodropidae and Catostylidae were the most abundant at La and Bortianor respectively. The fish families that were encountered together with the jellyfish were thirteen and consisted of 352,228 individuals. They were; Carangidae > Portunidae > Penaeidae > Dasyatidae > Sciaenidae > Haemulidae > Cynoglossidae > Sphyraenidae > Sparidae > Stromateidae > Lutjanidae > Trichiuridae > Sepiidae; in order of decreasing abundance. Physico-chemical parameters at each site where fishing was carried out were collected. Five water quality parameters (DO, Conductivity, TDS, Phosphate and Chlorophyll-a) out of the eleven water parameters measured were identified to contribute significantly to the biological variations observed. A Canonical Correspondence Analysis (CCA) was used to identify which of the principal water quality parameters influenced abundance of both jellyfish and fish at each site. Decreasing DO, Conductivity and Chlorophyll-a levels influenced a decrease of jellyfish at Ada while increasing DO, Conductivity and Chlorophyll-a influenced an increase of jellyfish at La. Conversely, decreasing levels of TDS and Phosphate led to a decrease in Bortianor.Item Predicting Nutrient Distribution Patterns in Some Coastal Lagoons in Ghana Using Mike 3 Model(University of Ghana, 2019-07) Kwame-Biney, M.The study assesses the levels of phosphate, nitrate and ammonia in water and sediments from the Mukwe, Sakumono II, Gao and Laloi lagoons situated within the central coast of Ghana alongside other physicochemical parameters (pH, Dissolved Oxygen, Total Dissolved Solids and Temperature). Data collected over a six-month period was used in calibrating and predicting nutrient concentrations in the Sakumono II and Gao lagoons using the MIKE 3 model. High pH measurements beyond USEPA and Ghana’s EPA permissible limits of 6.5 to 8.5 and 6.0 to 9.0, respectively, were recorded in the Sakumono II and Mukwe lagoons whiles Gao and Laloi recorded pH values within these permissible limits. With the exception of the Laloi lagoon which had an average dissolved oxygen value of 5.1mg/l, dissolved oxygen concentration in all the other lagoons were lower than the EPA and WHO permissible limits of 5.0mg/l to 6.5mg/l and 5.0mg/l to 6.0mg/l, respectively. Total Dissolved Solid measurements in all the lagoons were above the EPA permissible limit of 500mg/l. Phosphate, nitrate and ammonia concentrations in all the four lagoons were generally above Ghana’s EPA and USEPA permissible limits. Discharge rates measured were highest for the Laloi lagoon and lowest for the Gao lagoon, which may be linked to the width and depth of the lagoons. Sediment nutrient concentrations were used together with the instantaneous sediment discharge formula to calculate the rate of discharge of sediment nutrient for the four lagoons. The results indicated that sediment nutrient concentration has a positive correlation with sediment discharge rate. Apart from few discrepancies in the results which was caused by poor rainfall data and non-point discharges, the correlation analysis indicated that MIKE 3 model was able to generally predict nutrient concentrations and show the distribution patterns in the Sakumono II and Gao lagoons. Average sediment nutrient concentrations recorded for phosphate during the dry and rainy season for Sakumono II, Mukwe, Gao and Laloi lagoons were (0.121 and 0.128mg/kg), (0.146 and 0.113mg/kg), (1.42 and 1.22mg/kg) and (0.112 and 0.103mg/kg) respectively. The average sediment nutrient concentrations recorded for ammonia during the dry and rainy season for Sakumono II, Mukwe, Gao and Laloi lagoons were (37.18 and 25.85 mg/kg), (41.49 and 37.46mg/kg), (4.58 and 4.31mg/kg) and (41.74 and 40.93mg/kg) respectively. The average sediment nutrient concentrations recorded for nitrate during the dry and rainy season for Sakumono II, Mukwe, Gao and Laloi lagoons were (14.54 and 11.55mg/kg), (15.15 and 15.41mg/kg), (3.83 and 3.46mg/kg) and (13.22 and 11.77mg/kg) respectively. Average sediment discharge rates recorded in the Sakumono II, Mukwe, Gao and Laloi lagoons for ammonia, nitrate and phosphate were (0.00000399 m3/s, 0.00000133m3/s and 0.0000000143m3/s), (0.0000377m3/s, 0.0000126m3/s and 0.00000131m3/s), (0.000021m3/s, 0.0000073m3/s and 0.0000000746m3/s) and (0.00001624m3/s, 0.0000537m3/s and 0.0000000465m3/s) respectively.Item Induced Breeding of the African Catfish (Clarias Gariepinus Burchell, 1822) Under Varying Brood Stock Ratios Using Ovaprim(University of Ghana, 2019-06) Ameti, S.K.Modern methods of producing African catfish (Clarias gariepinus) fingerlings require that the male brooder is sacrificed to obtain milt for artificial fertilization of the eggs stripped from the female under hormonal induction. The objective of this research was to study the semi artificial technique of producing catfish larvae with different brood stock ratios using Ovaprim. The experiment was made up of three (3) treatment groups and each treatment had three (3) replicates each. The treatments were T1 (artificial spawning with 1:1 female: male ratio), T2 (semi artificial spawning with 1:1 female: male ratio) and T3 (semi artificial spawning with 2:1 female: male ratio). The relative fecundity of female brooders in T1, T2 and T3 were 68 ± 6.31, 78 ± 12.29 and 65 ± 8.18 respectively and they were not significantly different (p>0.05). Percentage fertilization for T1 (81±1.52%), T2 (75 ± 2.51%) and T3 (62 ± 2.50%) were significantly different (p<0.05). The observed percent hatchability (85 ± 2.51%, 83 ± 3.21% and 82 ± 2.50%) in respect of T1, T2 and T3 were not statistically different. Differences in total egg weight (96 ± 3.30 g, 72 ± 10.53 g and 59 ± 0.50 g), and total larval production (57,700 ± 3672; 42,423 ± 6972 and 34,078 ± 762) for T1, T2 and T3 respectively were statistically significant (p<0.05) between artificial spawning and semi artificial spawning. Larval survival was statistically (p<0.05) different between T1 (84 ± 2.31) and T3 (92 ± 2.50) but both did not differ significantly from T2 (87 ± 2.51). In conclusion, semi artificial spawning of C. gariepinus with Ovaprim could be beneficial to fish farmers if done at a brood stock sex pairing ratio of 1:1.Item Changes in Fishing Gears and Implications for the Marine Fisheries Industry at Elmina, Ghana(University of Ghana, 2019-07) Damoah, N.K.The marine fisheries industry of Ghana is widely noted for its importance in income and employment generation for most economies and therefore major efforts by various Governments are geared towards sustainable growth of the industry. To this end, any practice that seems to undermine this growth will threaten livelihoods. The primary objective of the study examines changes in fishing gears on development of the marine fishing industry at Elmina, Ghana. The study describes major gears used by local fishers at Elmina, their effects and management implications. The data used was mainly primary, taken from landing of fishers and secondary was taken from the Fisheries Scientific Survey Division of the Fisheries Commission, Ghana. Collected data was coded and input into a Statistical Package for Social Sciences (SPSS) for analysis. The study employed techniques such as the pair-wise correlation, chi-square and logistic regression for the analysis. Monofilament nets and Ali were found as key gears that impact on the future development of the marine industry. Fish landed by both gears were below the recommended 25mm lateral stretch and this may have dire consequences on stock levels. The use of explosives, chemical and small mesh size nets also pose threat to the development of the marine fisheries industry. The implications include depletion of fish stock and increase unemployment levels in Elmina. The study attributes this scenario to low level of law enforcement, the desire to increase catch and make enough profit, the influx of cheap fishing gears of smaller mesh sizes and inadequate knowledge on best practices among others, motivates the use of these fishing gears and practices. It is recommended that, The marine fisheries industry of Ghana is widely noted for its importance in income and employment generation for most economies and therefore major efforts by various Governments are geared towards sustainable growth of the industry. To this end, any practice that seems to undermine this growth will threaten livelihoods. The primary objective of the study examines changes in fishing gears on development of the marine fishing industry at Elmina, Ghana. The study describes major gears used by local fishers at Elmina, their effects and management implications. The data used was mainly primary, taken from landing of fishers and secondary was taken from the Fisheries Scientific Survey Division of the Fisheries Commission, Ghana. Collected data was coded and input into a Statistical Package for Social Sciences (SPSS) for analysis. The study employed techniques such as the pair-wise correlation, chi-square and logistic regression for the analysis. Monofilament nets and Ali were found as key gears that impact on the future development of the marine industry. Fish landed by both gears were below the recommended 25mm lateral stretch and this may have dire consequences on stock levels. The use of explosives, chemical and small mesh size nets also pose threat to the development of the marine fisheries industry. The implications include depletion of fish stock and increase unemployment levels in Elmina. The study attributes this scenario to low level of law enforcement, the desire to increase catch and make enough profit, the influx of cheap fishing gears of smaller mesh sizes and inadequate knowledge on best practices among others, motivates the use of these fishing gears and practices. It is recommended that, regulatory agencies should be proactive in the monitoring and surveillance of the sea in order to crack the whips on the negative fishing practices. Co-management should be embedded in the Fisheries Act 625, Civil society Groups and other authorities to help the Fisheries Commission which is unfortunately understaffed to educate fishermen on the best practices.Item Distribution of Macroalgae in the Intertidal Zone of Ghana(University of Ghana, 2019-07) Amamoo, P.A.Marine macroalgae or seaweeds, as they are generally referred to, are primary producers which play a central role in the productivity of coastal habitats and also serve as a source of ecosystem goods and services. They are used directly or indirectly in the production of food products, fertilizer, animal feed additives, bioenergy, nutraceutical, confectionary, textiles, paper, paint, and varnish among others. How far this can be exploited depends on the knowledge of available species. In Ghana, there have been sporadic studies of seaweeds or macroalgae since the 1950s, when inventory of the species began, until recent investigation which considered community structure analysis. Following from what is known about this biological community, this study was designed to comprehensively evaluate macroalgal distribution across the coast of Ghana. The key objectives of the research were to: (1) assess of species diversity within the intertidal zone of Ghana; (2) characterize the distribution and community structure of the macroalgae in the intertidal zone of Ghana; and (3) determine the effect of nutrients on observed distributional patterns. Ten sampling locations were selected in a manner that allowed the entire Ghana coast to be covered – i.e. Dixcove, Takoradi, Aminano, Mumford, Kokrobite, Christianborg Castle, Teshie (Next Door), Tema, Prampram and Old Ningo. The macroalgae were purposively sampled using a 1m x 1m quadrat constructed from polyvinyl chloride pipes. Species abundance were estimated as percentage cover within each quadrat, from the high to the low water mark on selected days where the tidal height was lowest. Water quality at each location was analysed for five nutrients (i.e. phosphate, nitrate, ammonia, silicate and sulphate). The sampling period was from 11th October, 2018 to 5th January, 2019. The data was subjected to various statistical analyses using Plymouth Routines in Multivariate Ecological Research (PRIMER version 6). Altogether, forty-one species belonging to 25 families were identified. Of these, ten species played an important role in influencing the spatial community structure, i.e. Ulva fasciata, Ulva flexuosa, Ulva lactuca, Hydropuntia dentata, Hypnea musciformis, Ralfsia expansa, Lithothamnion bisporum, Centroceras clavulatum, Chaetomorpha linum and Caulerpa taxifolia. This study identified these species as keystone species in terms of their dominance and contribution to observed spatio-temporal patterns in community structure, and zonation within the intertidal region; from the supra-littoral across the mid-littoral to sublittoral zones. This study did not find any evidence of the role of nutrients on the observed macroalgal distributional pattern, and attributed it possibly to the short-term temporal nature of the study. Therefore, it is recommended that long-term investigation, in relation to the effect of nutrients on macroalgae community characterization, be undertaken in future studies. Furthermore, adoption of molecular techniques to assist taxonomic characterization of macroalgae and use of unmanned aerial vehicle in field assessment should be explored towards a more comprehensive assessment.Item Evaluation of Nile Tilapia (Oreochromis Niloticus, Linnaeus 1758) Fingerling Production at the Aquaculture Demonstration Centre - Ashaiman, Ghana.(University of Ghana, 2018-07) Lutterodt, J.B.The Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) fingerling production is important for continual expansion of the global tilapia aquaculture. This study evaluated the Akosombo Strain Nile tilapia fingerling production at the Aquaculture Demonstration Centre- Ashaiman, Ghana. A total of 1350 female brooders of mean weight 150.7±41.8 g and 450 males of mean weight 218.6±63.1 g were stocked into nine outdoor concrete tanks of size 50 m2 each in a sex ratio of 3:1 respectively for 14 days. From the estimated 675,000 eggs produced by the females, a total of 138,631 fry were harvested resulting in 20.5% hatching success. The survival rate of the fry after hormonal treatment was 79.5% with estimated FCR of 1.46 and SGR of 6.05±0.35%day-1. For growth to the fingerling stage, the fry were stocked into an earthen pond of size 1200 m2 for 24 days at an initial weight of 0.23±0.04 g. The final mean weight of fingerlings harvested was 2.47±0.55 g with FCR of 1.09, SGR (3.26±0.18%day-1) and a survival rate of 75.3%. The estimated final standing crop was 1708.4 kg ha-1. Results from statistical analysis indicated that there were no significant differences among fry produced in the breeding tanks (p=0.73).Water quality measurements in the breeding tanks, fry tanks and fingerlings pond were respectively 29.03±0.51oC, 28.07±1.79oC and 27.07±1.68oC for temperature; 3.56±0.04 mgL-1, 3.62±0.18 mgL-1 and 3.74±0.21 mgL-1 for DO; 7.38±0.19, 7.35±0.18 and 7.56±0.25 for pH; salinity were 0.23±0.01‰, 0.24±0.02‰ and 0.29±0.02‰, and ammonia levels of 0.12±0.06 mgL-1, 0.01±0.002 mgL-1 and 0.04 ± 0.01 mgL-1 respectively. The study concludes that the Centre can increase production of fingerlings if the current management practice at the breeding stage of production is improved.Item Quality of the European Anchovy, Engraulis Encrasicolus (Linnaeus, 1758) Processed from Open Sun Drying and Solar Tent Drying Methods in Ghana.(University of Ghana, 2018-06) Sabo, M.Traditional open sun drying method is still the predominant drying method especially for anchovy in Ghana. In this study solar tent dryer (STD) and open sun drying (OSD) methods were used to determine the flesh quality of Engraulis encrasicolus. Fresh fish samples (FFS) were dried using the two methods and the quality of dried anchovy was compared with two different traditional open sun dried samples from Tema (TOSDT) and Accra (TOSDA). It was observed that STD and OSD methods had similar drying rates of 76.39% and 76.77% respectively after twenty hours of drying. After proximate analysis, moisture contents of 17.30 ± 0.11%, 17.61 ± 0.31%, 17.68 ± 0.04%, 18.15 ± 0.02% and 75.99 ± 0.31% were obtained for OSD, STD, TOSDA, TOSDT and FFS respectively. The protein values were 40.96 ± 0.01%, 53.08 ± 0.36%, 33.95 ± 0.01%, 12.19 ± 0.00% and 8.63 ± 0.00% for OSD, STD, TOSDA, TOSDT and FFS respectively. The fat contents were 5.60 ± 0.03%, 4.46 ± 0.40%, 3.67 ± 0.319%, 2.56 ± 0.00% and 1.62 ± 0.00% for OSD, STD, TOSDA, TOSDT and FFS respectively. Ash values under OSD, STD, TOSDA, TOSDT and FFS were 14.02 ± 0.78%, 12.41 ± 0.17%, 14.99 ± 0.74%, 15.29 ± 0.12% and 3.67± 0.14% respectively. Microbiological quality showed total viable counts of 5.0 ± 0.00×103 cfu/g, 9. 5 ± 0.02×101 cfu/g, 2.5 ± 0.00×102 cfu/g, 21.0 ± 0.01×102cfu/g and 6.5 ± 0.01×101 cfu/g for FFS, OSD, TSD, TOSDA and TOSDT respectively. Faecal coliform counts of 7. 0 ± 0. 00 ×101 cfu/g were only found in FFS. Staphylococcus aureus counts of 7.5 ± 0.02×101 cfu/g, 6.0 ± 0.00×101 cfu/g, 3.3 ± 0.01×103 cfu/g and 1.8 ± 0.00×102 cfu/g were observed for FFS, OSD, TOSDA and TOSDT respectively but no S. aureus was present in STD samples. Escherichia coli was also not reported for STD but the following counts were made 2. 5 ± 0. 00 × 01 cfu/g, 1. 5 ± 0.04 ×101 cfu/g, 2. 5 ± 0.01×101 cfu/g and 2.0 ± 0.0×101 cfu/g in respect of FFS, OSD, TOSDA and TOSDT. The study established that STD provided improved and hygienic drying option to the traditional sun drying methods. These finding would therefore lead to better ways of improving the storage processing and marketing anchovies in Ghana.Item Nutritional Composition, Bacterial Load and Organoleptic Quality of Farm-Raised Catfish (Clarias Gariepinus, Burchell, 1822) From the Dormaa Municipality, Ghana.(University of Ghana, 2018-07) Issifu, K.The aim of this study was to evaluate the nutritional composition, bacterial load and organoleptic quality of farm-raised African catfish (Clarias gariepinus; Burchell, 1822) in the Dormaa Municipality. Thirty (30) specimen of freshly harvested fish Clarias gariepinus of average weight 912.78 ± 16.43 g obtained from a fish farm and an equal number of smoked farm-raised fish of average weight 769.19 ± 6.48 g were used for the study. Proximate analysis, bacterial and organoleptic quality assessments yielded the following results: The mean percent moisture, ash, fat, protein and total carbohydrate contents for fresh farmed fish were 77.4 ± 1.94%, 1.34 ± 0.26%, 0.57 ± 0.17%, 17.58±0.23% and 4.45 ± 1.55% respectively. The corresponding levels in smoked farmraised fish were 11.63 ± 0.43%, 7.06 ± 0.66%, 9.31 ± 1.80%, 25.72 ± 1.51% and 53.34 ± 0.15% respectively. The mean total viable counts, total coliform counts, Staphylococcus aureus and E. coli for the fresh fish were respectively 2.2x105 cfu/g, 8.7x102 cfu/g, 5.5x103 cfu/g and 2.3x103 cfu/g. For the smoked fish, mean total viable counts, total coliform counts, S. aureus and E. coli were 4.2x105 cfu/g, 0.0 cfu/g, 2.8x103 cfu/g and 2.5x103 cfu/g respectively. The overall acceptability of fresh and smoked farm-raised catfish ranged from 3.2 to 4.6 and 3.0 to 3.8 respectively. There were significant differences (P < 0.05) in the nutritional, bacterial and organoleptic qualities between the fresh and smoked catfish. Results from the study revealed higher nutritional composition in smoked catfish and lower bacterial loads in both fresh and smoked fish except E. coli, which must be of concern for consumer safety.Item Evaluation of Larval Meal Diet of Black Soldier Fly (Hermetia Illucens: L. 175) On Fingerlings Culture of Nile Tilapia( Oreochromis Niloticus: L.)(2017-07) Teye-Gaga, C.The decreasing availability and increasing cost of fishmeal have called for efforts in evaluating wide varieties of relatively lower cost ingredients that could partially or wholly replace fishmeal. The Black Soldier Fly (BSF), Hermetian illucens larvae hold potential in this regard due to their high protein and fat contents. This study was conducted at the BSF Centre of the Ghana Atomic Energy Commission, Accra, and Aquaculture Research and Development Centre at Akosombo, to evaluate the growth performance of fingerlings of Oreochromis niloticus (Akosombo strain) using diets with BSF larval meal as an alternative source of protein to fishmeal and to determine the apparent digestibility of nutrients of BSF larval meal in comparison to those of traditional sources of protein, such as fishmeal and soybean meal. The BSF larvae were reared on fruit and vegetable wastes and then solar dried. The BSF larval meal was used to replace fishmeal at 25, 50 and 75% inclusion levels in formulated diets for O. niloticus fingerlings. Two other tilapia diets, an on-farm type (ARDEC) and a commercial one (RAANAN), containing 0% BSF larval meal served as controls. In all, five isonitrogenous (380 gkg-1 crude protein) and isoenergetic (18 kJg-1 gross energy) diets were used in culturing O. niloticus fingerlings (initial mean weight 1.3±0.23 g) for 10 weeks. Apparent digestibility coefficients (ADCs) were determined using chromic oxide as inert marker. The reference diet was formulated to contain 380 gkg-1 crude protein and 18 kJg-1 gross energy. The reference diet was replaced with test ingredients at 70:30 ratios. Proximate analysis on the whole BSF larvae was found to contain crude protein (37.83%) and crude fat (22.7%) (dry matter basis). All diets were readily accepted by fish. Growth and nutrient utilisation parameters of the cultured O. niloticus fingerlings indicated no significant differences (p > 0.05) among the various dietary treatments. BSF 25 had the highest final mean weight gain (33.82±2.53 g) and the least was BSF 75 (30.53±3.95 g). Whole-body observation of harvested fingerlings showed no abnormalities on the external and internal body. This suggests that BSF larval meal does not exert a negative effect on fish health. Analysis on the cost effectiveness of the various diets used in culturing O. niloticus fingerlings showed that producing a kilogram of fish using BSF 75 diet was more cost effective than other diets. Nutrient digestibility of BSF meal compared favourably with those of fishmeal and soybean meal. The apparent digestibility coefficients (ADCs) of nutrients of BSF meal, fishmeal and soybean meal were high (> 52%), implying good utilization of feed for tissue synthesis and metabolic activities. On the basis of final mean weight gained, feed conversion ratio and the cost-effectiveness of diets, it suggests that BSF larval meal may partially replace fishmeal at best 50% inclusion level without affecting fish growth, health and carcass quality.Item Assessing Heavy Metal Load of Fish and Shorebirds in The Densu Delta Ramsar Site, Ghana(University of Ghana, 2017-06) Addo, A.A.The study aimed at assessing the impact of pollution on shorebirds at Densu Delta in Ghana. In view of this study, data on trace metals in water, sediment and biotic factors (fish and shorebirds) were collected and analyzed from August 2016 to February 2017 in four sampling stations within the Densu Delta. The trace metals assessed from the study were copper, zinc, cadmium, arsenic and mercury. From the study, the dominant trace metals assessed in water, sediment, fish and shorebirds were copper and zinc. From the wet season, the average concentration of copper and zinc in sediments was 6.68 ± 0.24 mg/kg and 28.99 ± 0.95 mg/kg respectively. For the dry season, the average concentration of copper and zinc in sediments was 6.01 ± 0.21 mg/kg and 30.02 ± 0.99 mg/kg respectively. Regarding water samples, the average concentration of copper and zinc was 1.54 ± 0.11 mg/kg and 2.98 ± 0.38 mg/kg respectively during the wet season while in the dry season, the mean concentration of copper and zinc was 1.11 ± 0.07 mg/kg and 13.04 ± 0.4 mg/kg correspondingly. Mean concentrations of these dominant trace metals between the dry and wet seasons were significantly different (p < 0.05). Concerning fish samples, the mean concentration of copper and zinc was 0.14 ± 0.17 mg/kg and 5.35 ± 0.81 mg/kg correspondingly for Sarotherodon melanotheron (Blackchin tilapia) while for Coptodon zillii (formerly known as Tilapia zillii) (Red belly tilapia) the mean concentration of copper and zinc was 0.11 ± 0.09 mg/kg and 4.20 ± 0.56 mg/kg correspondingly. However, the variation in dominant trace metals for both fish species was not significantly different (p > 0.05). Regarding shorebirds, the study focused on three main species including Cerylerudis (Piedkinfisher), Phalacrocorax africanus (Longtail Cormorant) and Egretta ardesiaca (Black Heron). The mean concentration of copper was 1.57 ± 0.24 mg/kg, 6.16 ± 0.55 mg/kg and 11.89 ± 0.15 mg/kg correspondingly for Cerylerudis (Piedkinfisher), Phalacrocorax africanus (Longtail Cormorant) and Egretta ardesiaca (Black Heron) while for zinc, the respective concentrations were 4.36 ± 0.75 mg/kg, 12.41 ± 0.01 mg/kg and 17.58 ± 0.16 mg/kg. The variation in concentration of the trace metals for the shorebirds was significant (p < 0.05). Correlation analysis in terms of trace metals revealed a strong association (R2 = 0.81 – 0.93) with fish (prey items). From the results, the concentration of the dominant trace metals in the shorebirds was below the threshold limit, indicating that these shorebirds within the Densu Delta of Ghana are not polluted. To ensure that these bird species are protected from pollution, some recommendations have been provided including consistent environmental monitoring of the Densu Delta by appropriate authoritiesItem Macrobenthic Infaunal Assemblage Structure in Nearshore and Offshore Seabeds of Ghana(University Of Ghana, 2017-06) Commey, N.A.The increased need for energy self-sufficiency has caused an extensive search for various sources of energy (especially, oil and gas) in the marine environment. Globally, the magnitude of impacts of the activities on the marine environment is increasing over the years and most felt on the seafloor. The study of seafloor (benthic) organisms therefore, are vital determinants of impacts on the seafloor. This thesis sought to determine the community structure of nearshore and offshore benthic macrofaunal assemblages and sediment characteristics of the two environments. It further provides a baseline of benthic macrofaunal assemblages prior to the proposed coal-powered facility at Ekumfi Aboano (nearshore), as well as, determine the current (2015) state of benthic macrofaunal assemblages in the Jubilee Fields (deep-sea). The study was carried out within the nearshore Ekumfi Aboano (av. depth–15 meters) and offshore regions (av. depth–1250 meters) of the Jubilee Fields. Sediment samples were obtained using a Van Veen grab and box corer for the nearshore and deep-sea environments respectively. Benthic macrofaunal distribution was investigated using PRIMER. Using GRADISTAT, nearshore sediment (mean grain size of 99.80 μm) was characterized as moderately sorted with very fine sand. Conversely, offshore sediment (mean grain size of 109.79 μm) was characterized as poorly sorted with very coarse silty fine sand. From the macrobenthic infauna analyses, 1113 individuals with an average density of 38 individuals/m2 were found at the nearshore environment and 2205 individuals with an average density of 47 individuals/m2 were found in the deep-sea environment. Numerical abundance showed polychaetes were 194 and 983, crustaceans were 827 and 696, molluscs were 35 and 229, echinoderms were 14 and 37 and “others” (foraminiferans, nematodes, nemerteans, sipunculids) were 43 and 260, for iv the nearshore and offshore environments respectively. The order of dominant taxa was; crustaceans > polychaetes > molluscans > others > echinoderms–for shallow Ekumfi seabed and; polychaetes > crustaceans > molluscans > others > echinoderms–for the offshore Jubilee seabed. Species identified nearshore were 116, whereas 188 species were identified within the deep-sea environment. Both sites were evenly spread (J’ > 0.8) and showed high diversity (H’ > 4; 1-D > 0.9). Polychaetes dominated (44.58 %) offshore as arthropods dominated nearshore (74.30 %). Macrobenthic infauna abundance was higher deep-sea than nearshore and were 75 % dissimilar, possibly due to varied anthropogenic influence within the two environments.Item Aspects of the Structure and Sustainability of the Fisheries in the Cross River Estuary of Nigeria-the Role of Community-Based Management(University of Ghana, 2015-07) Antigha, A.A.; Armah, A. K.; Nyarko, E.; University of Ghana,College of Basic and Applied Sciences School of Biological Sciences Department of Marine and Fisheries SciencesThis study focused on aspects of the structure and sustainability of the fisheries in the Cross River estuary with a view to addressing the unsustainable fishing activities in the Cross River estuary. The physicochemical characteristics of water were analyzed in order to determine the quality of water and health status of fishes in the study area. These included surface temperature, pH, DO, turbidity, salinity, alkalinity, phosphate and nitrates. The catch rates and catch composition of the multispecies gillnet fishery in the estuary, exploitation rates, sizes of fishes and socioeconomic factors were also investigated in order to determine their vulnerability to human and environmental factors. The water quality of the area showed a significant variation in turbidity at the locations of study, 52.2 NTU at Esuk Anansa, 30.3 NTU at Esuk Okon, and 21.8 NTU at Esuk Anantigha, with a range of 21.8 - 52.2. However, the general water quality was within the tolerable limit of fish during the study period. The mean weight of monthly catches sampled averaged 21.2 kg (range 15.3 kg to 27.0 kg).The mean CPUE was 7.1 kg/boat/trip. The catch composition revealed that Pseudotolithus elongatus accounted for 56.69%, by weight, Ethmalosa fimbriata was 30.28% by weight, while Chrysicthys nigrodigitatus was 7.53% by weight. The results of the study showed that these species are being threatened as a result of unsustainable fishing methods leading to harvesting of small fishes mostly between 10 and 15cm of length. The socioeconomic status of artisanal fishermen, traders and mangrove loggers in the estuary was determined with the view of updating knowledge on the socioeconomic indices, fishing gears, prime catches of the fishes in the area, in order to suggest management measures for the fishery and ecosystem of the area. The study recommends the introduction of community-based coastal resource management approach for the sustainability of the fisheries and the ecosystem of the area.Item Assessment of the Security of Coastal Fishing Operations in Ghana from the Perspectives of Safety Poverty and Catches(University of Ghana, 2015) Amponsah, S.K.KThe study was conducted in four fish landing sampling stations along the southern coastline of Ghana, namely: Vodzah and Denu (both in the Volta Region) as well as Jamestown and Tema (both in the Greater Accra Region) from June, 2014 to January, 2015. The purpose of the study was to assess the security of coastal fishing operations in Ghana from three main perspectives, namely safety, poverty and fish catches. Data was obtained from both primary sources (field data) and grey literature by courtesy of FSSD and MCSD. A number of factors were found to impact the security of coastal fishing from the perspective of safety. These included total fines and the number of IUU infractions recorded in Ghana’s coastal waters; awareness of fisheries regulation measures, compliance with fisheries regulations and the absence of government officials as the prominent enforcement agent of fisheries regulation measures. From the perspective of poverty, the security of coastal fishing was found to be under high risk with respect to high poverty head count, vulnerabilities and marginalization indicators. Similarly, the security of coastal fishing operations from the perspective of catches was also under high risk. This was because the calculated fishing mortality rates (F) (ranging from F=1.48 yr-1 to F= 2.92 yr-1, compared to Fopt = 0.4M) were beyond the limit for sustainable fishing. Consequently, the estimated exploitation rates (E) for majority of the assessed fish species ranging from 0.53 to 0.76 were greater than the optimum level of 0.5, implying heavy exploitation. Further, the calculated lengths at first capture (Lc) (3.71 cm – 13.19 cm) were less than the calculated lengths at first maturity (Lm) (7.4 cm – 17.9 cm) indicating the presence of growth overfishing. It was concluded that the overall security of coastal fishing operations was under very high risk requiring urgent management attention. Some recommendations for effective management have been provided including initiating community sensitization programmes and partition of marine patrols between Ghana Navy and Ghana Marine Police.