Department of Marine and Fisheries Sciences
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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.
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