Department of Marine and Fisheries Sciences
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Item Some Aspects of The Biology and Dynamics of the Blue- Spotted Sea Bream, Sparus Caeruleostictus in Ghanaian Waters(University of Ghana, 1994-05) Owusu-Boateng, K.; Vanderpuye, C.J.; Koranteng, K.A.; Armah, A.K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesThis study, undertaken during the period March, 1992 - March, 1993, investigated the distribution, growth, population parameters, dynamics, food habits and reproduction of Sparus caeruleostictus in Ghanaian coastal waters - S.caeruleostictus show a distinctive size distribution by depth; bigger fish are found in deeper waters - There are two spawning periods in a year and new recruits come into the exploited population in their first year of life. S.caeruleostictus mature in their second year of life. Crustaceans are the main diet for the species. Growth and mortality parameters, as estimated with the Electronic Length Frequency Analysis (ELEFAN) methods are: LCTO = 44.3 cm (fork length), K = 0.48/yr., Z = 2.480/yr., M= 0.856 and F= 1.621/yr. The mean length at first capture, LC50 was estimated to be 10.75 cm (fork length) and the rate of exploitation E, 0.65. The lengths at first maturity for the males and females, were 18.4cm and 17.2cm (fork length) respective1y. Fecundity ranged from 4 0,000 — 400,000 (size range: 17.5 - 24.8cm fork length). Length and fecundity relationship was exponential and described by the equation: Log F = 1.3671 + 2.9479 Log L. Analysis of the relative yield per recruit (Y/R)’ showed that to achieve the maximum sustainable yield (MSY) it will be necessary to reduce the level of the present fishing effort.Item Studies on the Mycoflora and some Physical characteristics of Ghanaian Maize (Zea Mays L) Varieties and the Effect of Extracts of Zanthoxylum Xanthoxyloides Lam and Kigelia Africana Benth on some of the Contaminant Fungi(University of Ghana, 1995-12) Hackman, D.K.; Odamtten, G.T.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries Sciences.Mycoflora of mixed maize grains and the newly developed Abeleehi and Obaatanpa varieties and airspora in the Warehouse of the Ghana Food Distribution, GFDC, at Balduzzi, Kumasi have been studied under normal and simulated ambient Environmental Relative Humidities (ERH’s) representative of the Ghanaian conditions. Some important physical and processing characteristics of £. and normal stackbumed white and yellow maize (seed water absorption, swelling index, 1000-seed weight, fermentation parameters) and gemination capacity of grains were also examined. To ascertain the ability of Abeleehi and Obaatanpa varieties to absorb and desorb moisture in relation to the development of attendant resident fungi, the moisture sorption isotherm at ERH’s 55-95% were determined in simulated humidity chambers. Finally results of the use of aqueous, acetone and methanolic extracts of the dry leaves of Zanthoxylum xanthoxyloides and the dry leaves and dry fruit of Kigelia africana as biofungicides to control vegetative growth and sporulation of important potential pathogenic fungi (Paecilomyces carneus, P.puntoni, P.varioti, Curvularia lunata, Fusarium moniliforme and Penicillium digitatum) resident in Abeleehi and Obaatanpa varieties are reported. Fifteen different fungal species (Aspergillus flavus, A.niger, A.sulphureus, A.tamarii, Penicillium brevicompactum, P.chrysogenum, P.citrinum, P.cyclopium, P. digitatum, P.glabrum, P.oxalicum, Cladosporium herbarum, Fusarium moniliforme, F.roseum andMucor haemalis) were isolated from maize grains obtained from the GFDC Warehouse at Balduzzi, Kumasi. Aspergillus species (A.flavus, A.niger, A. sulphur e-US', A.tamarii) and Penicillium species (Penicillium brevicompactum, P.chiysogenum, P.citrinum, P.cyclopium, P.digitatum) predominated. The initial fungal population in the mixed grain variety was 4.8 - 5.4 log |0 CFU/g but this decreased by 0.4 -1.3 log cycle after 2 months. There was no statistical difference (P< 0.05) between the population of fungi isolated from grains sampled from the top, middle and bottom of the bagstacks. Aspergillus flavus was Hie most predominant fungi encountered constituting 41.7- 44.0% of the species followed by Mucor haemalis (4.0 - 20.5%). Both A.flavus and M. haemalis occurred at all positions sampled. Twenty four different airspora of fungi (Aspergillus flavus, A.clavalus, A.fiumigatus, A.niger, A.ochraceus, A.parasiticus, A.sulphureus, A.tamarii, Penicillium chrysogemim, P.citrinum, P.cyclopium, P.digitatum, P. expansum, P.italicum, P.oxalicum Paecilomyces carneus, Ppuntonii, P.varioti, Cladosporium herbarum, Curvularia lunata, Fusarium moniliforme, Mucor haemalis, Neurospora sitophila, Rhizopus oryzae) were isolated from the Balduzzi Warehouse. Species of airspora that were not foundinthe grains wereA.clavatus, A.ochraceus, Aparasiticus, A.fumigatus, P.expansum, Paecilomyces carneus, Ppuntonij P.varioti, Curvularia lunata and Rhizopus oryzae. Generally mycological media used and the method used in isolation influenced the profile o f fungal species encountered. Thirty and 28 fungal species belonging to 13 genera were isolated from Abeleehi and Obaatanpa varieties respectively, and they are being recorded for the first time in Abeleehi and Obaatanpa varieties. The species diversity was influenced by grain variety, method of isolation, mycological media used, storage humidity and whether the grains were exposed in petri dishes or in woven polypropylene sachets. A.flavus was ubiquitous and was isolated from both Abeleehi and Obaatanpa stored at 55-95% ERH in both open Petri dishes and in woven polypropylene sachets; Fusarium moniliforme was encountered atERH’s 65-95% in open Petri dishes but not at 65 and 75 ERH in woven polypropylene sachets. Xerophilic species, like Aspergillus giganteus, P. carneus, P.puntoni and P.varioti were isolated at 55-65% ERH in both grain varieties. There was no statistical difference (analysis of variance P.< 0.05) between germination capacity of Abeleehi grains stored in woven polypropylene sachets at ERH 55- 85%; seed germination was drastically reduced at 90 and 95% ERH after 2 months storage period. Data on grains kept exposed in Petri dishes to the same ERH’s were similar. The same trend as above was observed for Obaatanpa grains. The storage ERH influenced the length of the emerging radicles of the germinating grains such that the higher the incubating ERH, the shorter the length of the emerging radicle. At ERH 95% radicle length was reduced by 39-69% (depending on the maize variety used). There was however a significant (P< 0.05) difference between the higher radicle length recorded in grains of both varieties stored in woven polypropylene sachets than same grains exposed in Petri dishes under the same ERH conditions. Abeleehi and Obaatanpa vai-ieties showed the characteristic sigmoid water absorption patterns o f macromolecules. The equilibration period of grains stored at 65-85% ERH was 8-12 days; those stored at 90-95% ERH continued rising while there was decrease in moisture content of grains incubated at 55% ERH for both grain varieties. Analysis of variance to ascertain the influence of ERH, Packaging material (P), incubation period (I) and maize variety (V) on moisture sorption as well as the interaction o f these factors showed that P, I and V significantly (P< 0.05) influenced moisture sorption. Moisture sorption by Obaatanpa was significantly higher than that of Abeleehi under the same environmental conditions. Obaatanpa variety had a higher density (1000 - seed weight o f273,9g) than Abeleehi (268.9g); stackbumed yellow (329.3 } 5.4g) and white grains (275.3 } 2. lg). The moisture content of stackbumed grains (13.0 -13.5 } 0.1 %) did not differ significantly (P< 0.05) from the normal grains of the same type (12.0-13.5 } 0.1). Seed length of normal white maize soaked for 48h. was 2-3% greater than that o f stackbumed white maize. Swelling of normal yellow maize initially lagged behind that of stackbumed samples but this was reversed after 24h. soaking resulting in 1 -2% increase in seed length over that o f the stackbumed yellow maize. Similar trends were observed for seed width and seed thickness. pH profile o f wet and dry-milled maize (normal and stackbumed) undergoing spontaneous fermentation was generally similar at least during the first 24-48 h. attended by a drop in pH from initial 5.0 - 6.5 to final pH 4.2 - 4.6. Steepwater of normal white maize was more acidic (pH 4.2 -4.3) than stackbumed grains (pH 5.1 - 5.2) of the same grain variety. Aqueous, acetone and methanolic leaf extract o f Zanthoxylum xanthoxyloides and leaf and fruit extracts of Kigelia africana obtained with the same solvents variably prevented or depressed vegetative growth and sporulation by pathogenic fungi (Paecilomyces carneus, P.puntonii, P. varioti, Fusarium moniliforme, Curvularia lunata, Penicillium digitatum) in maize meal media amended with the extracts. The efficacy of the extracts in depressing vegetative growth of the test fungi can be .. ng order: Methanol > acetone > aqueous (water) Extracts of leaf of Kqfricana was more potent at higher concentrations than extracts obtained from its own fruit or the leaf of Z.xanthoxyloides. P. puntonii appeared to be the most resistant fungus (among the other test fungi) to the biofungicides. Analysis of variance showed that the effectiveness of the plant extracts of Z.xanthoxyloides and K. africana in suppressing spomlation of the test fungi at high concentration differed significantly and can be ranked as follows in descending order: Leaves o f Z.xanthoxyloides > leaves o f K. africana > fruit of K. africana. Although each test fungus responded and behaved differently in vitro, a fortuitous condition is created in which especially the methanolic extract not only prevent vegetative growth at higher concentration but also prevent sporulation. The possible methods of application of the results from this thesis are discussed and further studies suggested.Item Morphometric and Allozymic Characterisation and Genetic Variation in Three Species of Chrysichthys in Ghana(University of Ghana, 1996-08) Dade, M.K.; Vanderpuye, C.J.; Abban, E.K.; Addy, M.E.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesChrysichthys species have been characterised by previous investigators. Most often, characterisation has been based on morphological and meristic characters. These characters may be modified by environmental factors, thus making them difficult to use in characterising species. There is the need therefore to refine or supplement taxonomy based on morphological and meristic characteristics. In the present study, variation in meristic counts and twelve body proportion variables in three species of the Catfish, Chrysichthys from two river basins (Volta and Densu) in Ghana were evaluated for their reliability in separating the species. Position of the longest dorsal soft fin ray and the number of branched pectoral fin rays were found to be stable and dependable in the identification of the three species. Body proportion values showed wide ranges which overlap so much that they do not give precise identification of species. In addition to the moiphometric study, variation at 15 loci involving eleven proteins were studied by allozyme electrophoresis in each of the species to (i) identify loci that discriminate between species, (ii) estimate levels of genetic variation among C. auratus, C. nigrodigitatus and C. maurus, (iii) estimate phonetic relationships among populations and species, and (iv) indicate whether there are any significant differences in the genotypic frequencies of populations. Seven discriminating loci were found between C. auratus and either C. nigrodigitatus or C. maurus. At the loci investigated, genetic variation was generally low in all the species. It was highest in C. auratus and least in C. nigrodigitatus [Polymorphism, P, (l% criterion) = 0.178 in C. auratus, 0.133 in C. maurus and 0.089 in C. nigrodigitatus-, Heterozygosity, He, = 0.029 in C. auratus, 0.016 in C. maurus and 0.009 in C. nigrodigitatus]. There were no significant genetic differences between populations within C. auratus and C. nigrodigitatus (average gene diversity between populations, Dst, = 0.001 in both species). Again based on lod screened, the closest species genetically were C. nigrodigitatus and C. maurus (Genetic identity, I, = 0.999) while the most distant species were C. auratus and C. maurus (I = 0.525). There were no significant changes in the genotypic frequencies of the populations (X205 ranges from 0.020 to 2.292 for polymorphic loci).Item Traditional Fermentation and the Quality of Balancotta Variety of Black Pepper {Piper Nigrum)(University of Ghana, 1999-06) Esiape, J; Sefa-Dedeh, S; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesA study was made of the effect on pepper quality of the traditional method of processing the "Balancotta" variety of Piper nigrum (black pepper). The study comparatively considered the microbiological quality, drying method, drying rate, colour and appearance, washing or cleaning method, prior to fermentation or heaping as well as an alternative method - heat treatment processing of the commodity. Using a solar dryer as a drying apparatus resulted in 9.8% moisture content of the sample as opposed to 12.5% obtained for the traditional method of sun/open air-drying. The drying was more effective using a solar dryer and hence provided a better-dried product giving an assurance of better keeping/storage qualities. Air-drying and solar drying were carried out in the same area/locality with solar drying yielding a more hygienic product, giving 1.2 x 10zcfu/g of microorganisms compared to 8.0 x 104cfu/g enumerated in the sample dried by the traditional open air method. Chlorine disinfection prior to drying was, comparatively, a potent cleaning mechanism, yielding samples with microbial counts in the region of 0.1 x lOcfu/g immediately after its application. Sanitation of the processing/drying environment had a significant bearing on the microbiological quality of the dried products after the chlorine washing hence the 1.2 xlOzcfu/g and 8.0 x 104cfu/g microbial counts obtained for the solar and air-dried samples respectively. Product Colour and appearance were studied by comparing traditionally heaped/fermented samples with samples, which were given some heat treatment by immersion in hot water prior to drying, and that, which was not given any treatment at all. The heat-treated sample tended to be more brightly coloured (black), followed by the untreated, but solar dried sample and then the traditionally fermented sample, which had a brownish (dull) black colour. The highest L values for colour intensity for both the heattreated and traditionally fermented samples were 54.8 and 51.7 respectively.Item Taxonomy, Exploitation and Conservation of Dolphins in the Marine Waters of Ghana(University of Ghana, 2000-09) Debrah, J.S.; Vanderpuye, C.J.; Ofori-Danson, P.K.; Abban, E.K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesLittle is known about dolphins present in Ghanaian coastal waters. Taxonomic status, catch rate, and impact of the fishery on these animals, are areas, which have remained virtually untouched by previous workers. The present study attempts to fill-in these gaps in knowledge. Studies conducted during 1998 -2000 revealed the presence of the following eight species in Ghanaian waters: Stenella clymene, Stenella attenuata, Steno bredanensis, Tursiops truncatus, Grampus griseus, Lagenodelphis hosei, Globicephala macrorhynchus, and Delphinus capensis. S. Chlymene emerged as the most abundant species. Dolphin catches were low with peak period in August and September. Demand for dolphin meat for human consumption and bait for the shark fishery increased during the period of study. Though laws designed to protect and conserve dolphins exist on the Ghanaian statutes, little effort is made to enforce them. An educational programme, which would sensitize fisher folk on the issue of conservation, is also absent. Morphological taxonomy proved very useful in discriminating between species of dolphins encountered but no single character was found to be suitable. A combination of morphological characters, however, proved most effective. It was difficult to use biochemical characters possibly because the Delphinidae family, exists as polymorphic form of the same species.Item Growth Response of Pink Shrimp Penaeus notialis (Perez Far Fante) to Protein enhanced Diets(University of Ghana, 2001-08) Akorlor, F. H. K.; Vanderpuye, C. J.; Darpaah, G. A.; Entsua-Mensah, R. E. M.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesArtificial feeds of different protein levels (20%, 30% and 40%) were formulated and prepared using locally available Agro Industrial By-Products (AIBPs) such as wheat bran, soybean meal, groundnut cake, fish meal, premix and cassava starch. Prepared feeds were fed to three populations of Penaeus notialis Post Larval Shrimps (PLs) under semi-intensive pond conditions for a 24 week culture period. PLs were fed a daily ration administered six hourly at the rate of 10%, 8%, 6%, 4%, and 2%, biomass/body weight. These rates were changed monthly in that order. There was regular water exchange and environmental monitoring. At the end of the culture period of 24 weeks the final average body weights gained under the three different feed types, were: 12.72 g, 7.697 g and 6.982 g respectively for the 20%, 30% and 40% treatment. The respective growth rates were 12.7 g, 7.7 g and 7.0 g for the 24 week growth period. Analysis of variance using F-test showed that only 20% crude-protein feed gave a significantly different result at the 95% confidence level. With this growth rate of 12.7 g/24 week culture period and also with a recorded survival rate of 49%, two culture cycles could be undertaken in a year. For two croppings, a projected yield estimated at 1.29 mt/ha/yr could be obtained.Item The Population Parameters, Food Habits and Physicochemical Environment of Three Cichlid Species in The Southwestern Sector Of The Keta Lagoon(University of Ghana, 2001-12) Ababio, S.D.; Vanderpuye, C. J.; Armah, A.K.; University of Ghana,College of Basic and Applied Sciences,School of Biological Sciences,Department of Marine and Fisheries Sciences.The study was carried out in the southwestern sector of the Keta lagoon, a closed coastal lagoon located in the southeastern part of Ghana. The study was aimed at studying the population parameters and the feeding habits of the major fish species (in terms of catch) in the lagoon in relation to the prevailing physiochemical parameters and the benthic macro fauna of the area. The water physiochemical parameters studied included the electrochemical and the optical properties of the water as well as the nutrients available for production. Macro benthic fauna studies were also carried out, in relation to sediment grain size distribution and organic matter content, as an index of the ecological state of the area. The findings from the study indicate that the seasonal precipitation pattern of the area was mainly responsible for fluctuations in the lagoon water physiochemical regime during the period of the study. The benthic fauna diversity did not indicate any effect of any external perturbation on the lagoonal environment, except salinity changes. The study on the fishery resource of the lagoon indicated that even though there source is highly exploited, it is able to maintain itself by rapid reproduction at an early age. However, if exploitation is maintained at or above the current rate, its effect, coupled with that of the stressful environment could result in diminishing catches, with catches comprising mainly of small-bodied fishes.Item Distribution and Ecology of Nesting Sea Turtles in Ghana(University of Ghana, 2002-10) Amiteye, B.T.; Armah, A.K.; Darpaah, G.A.; Ofori-Danson, P.K.; University of Ghana,College of Basic and Applied Sciences,School of Biological Sciences,Department of Marine and Fisheries SciencesDistribution and Ecology of Nesting Sea Turtles in Ghana. Information on the occurrence and reproductive biology of sea turtles in Ghana is very scanty, therefore there is a need for detailed scientific studies on which their conservation and protection could be based. The present study has shown that the Olive ridley, Leatherback and Green turtles are the three main species that continue to nest on the beaches along the coast of Ghana. The Olive ridley having the highest relative abundance of 91% at the intensive study area followed by the Leatherback turtle with 6% and the Green turtle 3%.The nesting season begins in August and extends to March, sometimes early April. It peaks in October for the Olive ridley and between December and January for the Green and Leatherback turtles. The Olive ridley turtles arrive first, followed by the green and Leatherback turtles. The nesting period of the Green and Leatherback turtles overlaps that of the Olive ridley. Sea turtles nest in a wide range of beach sediment type along the coast of Ghana. Beach sand with median grain size between 0.2-0.4 mm (medium to coarse sand) and sorting coefficient between 0.4-0.7 (well-sorted to moderately well sorted) are those preferred by nesting turtles along the coast of Ghana. Based on the above grain characteristics, the potential sea turtle nesting sites in Ghana may include beaches along Princess Town to Busua, Senya Bereku to Accra, Prampram to Old Ningo and Anloga to Denu. Estimated average clutch size for Olive ridley, Green and Leatherback turtles were 86, 83 and 81 respectively. However, those counted for the Olive ridley and Leatherback were 100 (SD=6.64) and 85 (SD=10) respectively. Emergence period for the Olive ridley was 52 days, Green turtle 56 days and Leatherback 63 days. Percentage hatching success was very high among all the three nesting species with Olive ridley recording the highest with 92.40%.The percentage hatching success for the other two, Green turtle and leatherback were respectively 89.38 and 88.32. Destruction of sea turtle eggs by dogs at the intensive study area was very high, but this problem was not widespread along the entire coast of Ghana. Percentage false crawls where found to be higher within zones closer to human habitation.Item Seasonal Dynamics of Benthic Macrofauna in the Keta Lagoon(University of Ghana, 2003-05) Lamptey, E.; Armah, A.K.; Wiafe, G.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesThis study was therefore, undertaken to investigate the seasonal dynamics of benthic macrofauna distribution and abundance in relation to environmental variables of the Keta lagoon. The studyl provides an understanding into benthic ecology in the Keta lagoon. The study also will provide an important baseline information on the likely long-term impacts of constructional activities of Keta Sea Defence Work Project and anthropogenic impacts of the settlements around the lagoon especially from the growing populations on the coastal belt.Item Studies on the Growth Pattern of the Penaeid Shrimp Penaeus Notialis (Perez-Farfante) in Ponds Manured with Chicken Droppings(University of Ghana, 2003-06) Dzidzornu, K.E.A.; Darpaah, G.A.; Dfori-Danso, P.K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesA study was conducted on the growth pattern of the penaeid shrimp, Penaeus notialis, in earthen ponds at the Volta Estuary of Ghana. The ponds were treated with chicken manure at the rate of 0 kg/ha (control), 100 kg/ha, 200 kg/ha, and 300 kg/ha respectively. The culture period was divided into two phases; the first phase covered a period of 90 days and the second phase took 180 days. Growth rates established at the end of the 90 days of culture were 0.04 - 0.13 g/day that resulted in the yield of 128.03 kg/ha, 138.00 kg/ha, 168.88 kg/ha and 243.60 kg/ha in the 0 kg/ha, 100 kg/ha, 200 kg/ha and 300 kg/ha manure treatments respectively. The growth rates at the end of 180 days of culture were 0.04 - 0.07 g/day that resulted in yield of 258.72 kg/ha, 261.05 kg/ha, and 327.18 kg/ha in the 0 kg/ha, 100 kg/ha and 200kg/ha treatments respectively. Analysis of Length-weight relationship showed isometric growth during the second half (91 to 180 days) of culture whilst the growth during the first 90 days was not isometric in all the treatments. Regression of total length on Carapace length; Body weight on Carapace length and Body weight on Total length showed strong correlation for both 90 and 180 days of culture periods. Productivity test showed nearly uniform primary production in all the ponds with 100 kg/ha treatments registering the highest value of 3.53 mg/l and 300 kg/ha treatments the lowest value at 1.45 mg/l The results indicated that P. notialis would not be ready for harvest during the first 90 days of growth; at least 5 months of growth is required to attain marketable size. Chicken manure could be used at 200 kg/ha and 300 kg/ha rates, an illustration that shrimp culture development and production in Ghana has a great potential.Item Genetic Characterization and Early Life Culture Performance Evaluation of Four Ghanaian Populations of Tilapia Guineensis (Pisces; Cichlidae)(University of Ghana, 2004-07) Agyakwah, S.K.; Abban, E.K.; Koranteng, K.A.; Ofori-Danson, P.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesGenetic characteristics of four populations of the cichlid Tilapia guineensis were studied using allozyme (starch gel) electrophoresis and early life culture performance characterization to generate information on genetic structure and characteristics of major culture performance traits during early life of the species. Samples of the fish populations were collected from three freshwater reservoirs: (i) the Volta reservoir at Kpong, (ii) the Okye-Aminsa reservoir at Akotogua and (iii) the Ayensu reservoir at Okyereko; and a coastal open lagoon of the Volta system at Aglorkpovie. Observed heterozygosity (Ho) and polymorphism (P) of allozymes as indices of genetic diversity were relatively low in Akotogua (Ho = 0.077; P = 0.077) and Aglorkpovie (Ho = 0.077; P = 0.077) populations compared to those of Kpong (Ho = 0.308; P = 0.089) and Okyereko (Ho = 0.462; P = 0.087) populations. Early life culture performance characteristics of populations evaluated over 84 days showed significantly higher final mean length, weight gain and condition factor in Akotogua populations compared to growth characteristics of Aglorkpovie and Kpong populations. Results suggest that heterozygosity and polymorphism might be important in determining culture performance traits. Additionally, high genetic diversity did not confer high culture performance characteristics on the early life of the fish. The biochemical genetic structure and growth characteristics observed in Akotogua population identify it as a population with a potentially better early life culture performance that could be used by culturists for improvement of T. guineensis in aquaculture.Item Comparative Study of the Reproductive and Early Life Growth Performance of Three Stocks of the African Catfish, Clarias Gariepinus, (Burchell, 1822) In Ghana.(University of Ghana, 2011-03) Teye, C.; Ofori-Danson P. K.; Atsu, D. K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesA comparative study was carried out into the reproductive and early life growth performance of three stocks of the African catfish, Clarias gariepinus (Burchell 1822) in Ghana under pond culture system at Aquaculture Research and Development Center (ARDEC) in Akosombo in the Eastern Region from January, 2009 to October, 2009. Broodstocks of C. gariepinus were collected from Kumah Farms in Kumasi (Ashanti Region), the Pacific Farms in Ashaiman (Greater Accra Region) and ARDEC at Akosombo (Eastern Region). The broodstocks were used for artificial propagation under more controlled conditions including; stripping of eggs, collection of the sperm, followed by fertilization and incubation of eggs. The fries were stocked at 2000 fries per 200 m2 pond (10 fries per lm2) in six fenced experimental ponds at an average weight of 0.003 g and harvested at an average weight of 3.304 g after six weeks pond culture for five consecutive times. Differences in fecundity (P = 0.592) and gonado-somatic index (P = 0.114) as well as specific growth rate (P = 0.163), condition factor (P = 0.345) and survival rates (P = 0.601) among the three stocks were all not statistically significant. Temperature, Dissolved Oxygen and pH ranges from 30.88.0.75 to 31.15.0.87, 4.28.2.34 to 4.99.2.45 and 6.18.0.15 to 6.98.0.61 respectively. These water quality parameters taken were all within the conducive ranges for the culture of the fish species. No statistical difference was found among the mean weight of ARDEC stock (3.496 g). Pacific farms stock (3.304 g) and Kumah farms stock (3.256 g) indicating that C. gariepinus grows at approximately the same rate regardless of its geographical location. This implies that fish farmers can reduce cost and save time and resources as they rely on the nearest fish seed (fingerlings) for stocking.Item Impact of Wave Dynamics on the Coast Of Ghana(University of Ghana, 2013-06) Xorse, T. M.; Addo, K .A.; Wiafe, G.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesWave and wind dynamics are important in the estimation of beach erosion rates and sediment transport modelling. They are also important in modelling sea fatigue, oil spill transport and planning of coastal and marine activities. This work sought to quantify the magnitude of wave and wind parameters along the coast of Ghana as well as identify how these parameters varied across the year. A nine years wave and wind data from the National Oceanic and Atmospheric Administration (NOAA) global wave model and data from a Wave Rider Buoy were analysed for this purpose. Wave data analyses were based on long term and short term methods. Potential sediment transport rates were also calculated using the Soulsby-Van Rijn sediment transport equation. From the results, mean significant wave height was 1.39 m, mean period was 10.91 s and mean wind speed was 4.65 ms-1. The results also revealed monthly trend of wave heights where wave heights increased gradually from January (1.00 m), the beginning of the year to a peak in August (1.73 m) and then began to decrease to a low in December (1.10 m). Wave periods also exhibited an almost similar trend but the highest wave period occurred in May (11.85 s). Wind speeds showed similar monthly variability and had the highest in July (5.61 ms-1). Wave directions were mainly in the South (S) and South-South-West (SSW) direction with those in the SSW direction forming majority. Sediment volume transport were also determined where crosshore transports, 2.25E+08 m3y-1, were found to be higher than longshore transports1.82E+08 m3y-1 (E+08= ×10^8; m3y-1 = metre cube per year). The outcomes of this study are very relevant as it will aid in policy making for the monitoring and protection of the coastal environment and; serve as a guide for the construction of coastal and offshore structures.Item Effects of Stocking Density on the Production of Nile Tilapia (Oreochromis niloticus) in Floating Net Cages on the Volta Lake(University of Ghana, 2013-07) Asase, A.; Nunoo, F.K.E.; Attipoe, F.Y.K.Stocking density is an important factor affecting fish production in cages. However, information related to its impact on the growth performance of Nile tilapia Oreochromis niloticus fingerlings during cage culture under the ecological conditions of the Volta Lake in Ghana is limited. Hence, healthy Oreochromis niloticus fingerlings (2.12 ± 0.02 g) were randomly stocked in triplicate 8 m 3 cages at densities of 50 fish/m 3 , 100 fish/m 3 and 150 fish/m 3 and fed a commercially extruded diet (30% Crude Protein) to evaluate their growth and economic feasibility. After 177 days of culture, differences in growth (weight gain and final weights) at these densities were significant (p < 0.05). Fish stocked at 50 fish /m 3 exhibited the highest average weight gain (271.98 ± 0.39 g) while fish stocked at 150 fish/ m 3 had the lowest (169.15 ± 0.49 g). There were significant effects (p < 0.05) of stocking density on daily weight gain, specific growth rate and survival rates. Moreover, the feed conversion ratio and protein efficiency ratio were significantly affected by stocking densities (p < 0.05). However, differences in daily weight gain, specific growth rates, condition factor and profit index were not significant (p > 0.05) between the 100 fish/m 3 and 150 fish/m 3 treatments. The production (10.697 - 22.48 kg/m 3 ), net yield (84.55 – 177.25 kg/cage) and gross profits (GH₵ 63.73 – 229.8) showed significant (p < 0.05) increase with higher stocking densities. Apart from dissolved oxygen which declined below optimal concentrations in February 2012, the levels of water quality parameters measured remained within suitable ranges for Nile tilapia growth throughout the experiment. The study demonstrated that cage farmers can utilize stocking densities of 50 fish/m 3 and 150 fish/m 3 effectively for larger size demand over a six months period and augmented production respectively.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.Item Assessment of the Maximum Sustainable Yield (MSY) of the Tuna Fishery in Ghana and its Application in Management(University of Ghana, 2015) Mawuko, A.GThe Ghanaian tuna fishery is a thriving industry employing more than 15,000 people. Three major tuna species, Skipjack (Katsuwonus pelamis), Yellowfin (Thunnus albacares) and the Bigeye (Thunnus obesus) form the base of the fishery. High fishing effort, use of modern technologies, fish aggregating devices and increased number of vessels have increased total landings, largely composed of juveniles. This study assessed the catch trends and sustainability of the fishery in Ghana. The results indicated that total tuna landings declined from 94,180 MT in 2010 to 79,447 MT in 2013. K. pelamis dominated the landings from 1987 to 2013 with an average component of 71 % of current landings. T. obesus contributed least of the three species, with 12.13 % composition of current landings. Catch per unit effort, (CPUE), of the fishery declined from 29.49 MT/fishermanday in 2001 to 17.12 MT/fishermanday in 2013, symptomatic of overfishing. Using the equilibrium assumptions of the Schaefer’s Surplus Production Model, 187.38 MT, 20,091.59 MT, 60,274.38 MT and 2,091.56 MT were the MSY estimates for T. obesus, T. albacares. K. pelamis and the artisanal fishery, respectively, making a total of 82,644.91 MT with average FMSY of 3,076 fishermandays. The total MSY for the tuna fishery, 82,644.91 MT, compared favourably with the range of sustainable yield of the resource estimated to be in the Ghanaian waters. The current average total landings, 86,477.2 MT, is in excess of the estimated MSY. Current landings of both T. obesus and K. pelamis are also in excess of the MSY estimated. The CPUE and MSY coupled with information on size composition of landings of the fishery provided evidence that the tunas in the Ghanaian waters are fully exploited and being overfished. With the stocks of K. pelamis viscous, local management actions would be very useful in managing the stock. The MSY and average FMSY estimated can be useful in setting catch quotas and implementing input controls for the Ghanaian tuna fishery. Although regulations by the International Commission for the Conservation of Atlantic Tunas (ICCAT) have been helpful, national management actions are needed to keep the tuna stocks at sustainable levels to save the highly profitable tuna fishery and industry in Ghana from collapse in the near future. To this end, the cooperation of all stakeholders in the Ghanaian fisheries is needed to plan and enforce practical precautionary management actions including setting restrictive quotas and regulation of inputs of the fishery to moderate Fcurrent and regulate landings. This would not only ensure the sustainability of the fishery but increase its profitability too.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 Shoreline Morphological Changes in Brass (Niger-Delta, Nigeria)(University of Ghana, 2015-07) Olali, O.A.; Appeaning- Addo, K.; Ababio, S.D.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Marine and Fisheries SciencesAssessment of shoreline morphological changes provides information about the historical, present and future shoreline positions. Such information is essential to coastal planning and managing natural coastal environments and human communities. Oil exporting facilities which are vital to the economy of Nigeria are located on the Okpoama- Brass shoreline in the Niger delta. The shoreline experiences morphological changes caused by natural and anthropogenic factors. Recent studies on shoreline morphological change in some parts of the Niger delta indicate that shoreline erosion is dominant over accretion. However, they did not provide information for the entire coastline of the Niger Delta. Approximately 551 transects were cast along the entire shoreline at 50m interval and rates of change statistics were calculated using the End Point Rate, Linear Regression, and Weighted Linear Regression methods. The estimate of shoreline position error for the extracted shorelines was 1m. The study reveals that in the long term, accretion is the dominant trend with overall mean shoreline change rate of + 0.1 m/yr ± 1m (meso accretion). However in the short term, the study revealed that erosion was dominant with overall mean shoreline change rate of - 0.42 m/yr ± 1m (meso erosion). Some transects revealed erosion rate as high as 7.03 m/yr ± 1m (extreme erosion). The study also forecasted the future shoreline position in fifty (50) years, which reveals erosion and minimal accretion. This study will serve as a guide in the planning and management of the natural environment and communities in the study area. The methodology used for this study can also be replicated in other selected areas along the coastline of the Niger Delta in NigeriaItem Preliminary Studies on Impacts of Ocean Acidification on Diversity of Fish Species Landed by Artisanal and Semi-Industrial Fisheries and Coastal Community Livelihoods in Ghana(2015-12-01) Quansah, E. E. K.; Nunoo, F.K.E.; Ofori-Danson,P.K; Onumah,E.E.; University of Ghana, College of Basic and Applied Sciences , School of Biological Sciences , Department of Marine and Fisheries SciencesIncreased absorbance of carbon dioxide from the atmosphere has led to the changing of the chemistry of the oceans. In addition to already existing stressors, the resultant ocean acidification poses multiple threats to marine species biodiversity and goods and services and livelihoods that depend on them. The study set out to determine possible impacts of this phenomenon on the abundance and diversity of fin and shellfish species and ichthyoplankton in the artisanal and semi-industrial fisheries of Ghana, and the degree of reliance of the local fisher folks on these two fisheries. Physico-chemical parameters in the sites where fishing by artisanal and semi-industrial vessels were carried out were collected in the lean and peak seasons. Fish samples were collected, species identified, counted and diversity indices calculated for each fishery and season. A Canonical Correspondence Analysis (CCA) was used to identify which of the principal factors influenced the fish species. Fisher folks were randomly interviewed using structured interview guides on their reliance on the fishery and analysed using the Tobit Regression Model (TRM). Four ocean acidification parameters (pH, carbonate ion concentration, total alkalinity, Revelle factor) out of six principal components were identified to contribute significantly (RELATE, r = 0.955, P < 0.05) to biological variations observed in the two fisheries. A decreasing trend in ocean acidification indicators was observed for both fisheries and variations observed in species abundance between seasons and fisheries, which indicate the possible occurrence of ocean acidification in Ghanaian waters and likelihood of impacts on fish diversity. The Tobit model revealed a significant reliance (P < 0.01) of fisher folks on the two fisheries and implies that livelihoods would be impacted with occurring ocean acidification. Education and provision of alternative livelihoods for fisher folks is thus necessary in ensuring upkeep of livelihoods in the face of ongoing ocean acidification of Ghanaian coastal waters.Item 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.