Department of Marine and Fisheries Sciences

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    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 Sciences
    Artificial 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.
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    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 Sciences
    This 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.
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    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 Sciences
    A 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.
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    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 Sciences
    Genetic 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.
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    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 Sciences
    Little 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.
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    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.
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    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 Sciences
    Distribution 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.