Pub Date : 2010-06-25DOI: 10.4314/WAJAE.V16I1.55872
J. Owusu-Sekyere, E. Bekoe
A mathematical model was used to examine the interactions of NH4 + transport to rice roots, as well as to calculate root length densities required to relate N uptake to concentrations of NH4 + in solution around the rooting medium for three water treatments: water table 30 cm below the surface, 15 cm below the surface and a flooded system. Measured uptake was greatest for the plants under the 30 cm treatment, followed by the 15 cm treatment, then the flooded treatment. Solution concentrations were highest under the flooded treatment followed by the 30 cm treatment, then the 15 cm treatment. Calculated root length densities were greatest for the plants under the 30 cm water table treatment, followed by those under the 15 cm treatment, then the flooded treatment. Measured root length densities were similarly greatest for the plants under the 30 cm water table treatment, followed by those under the 15 cm water table depth treatment, then the flooded treatment. However, differences between measured and calculated root length densities became significant for all treatments after 30 days of treatment imposition. Transport rates varied with treatments but uptake rates did not reflect these differences in transport rates, thus, transport through the growth medium did not limit uptake of nitrogen by the plants.
{"title":"Nitrogen Uptake in Soils under Different Water Table Depths","authors":"J. Owusu-Sekyere, E. Bekoe","doi":"10.4314/WAJAE.V16I1.55872","DOIUrl":"https://doi.org/10.4314/WAJAE.V16I1.55872","url":null,"abstract":"A mathematical model was used to examine the interactions of NH4 + transport to rice roots, as well as to calculate root length densities required to relate N uptake to concentrations of NH4 + in solution around the rooting medium for three water treatments: water table 30 cm below the surface, 15 cm below the surface and a flooded system. Measured uptake was greatest for the plants under the 30 cm treatment, followed by the 15 cm treatment, then the flooded treatment. Solution concentrations were highest under the flooded treatment followed by the 30 cm treatment, then the 15 cm treatment. Calculated root length densities were greatest for the plants under the 30 cm water table treatment, followed by those under the 15 cm treatment, then the flooded treatment. Measured root length densities were similarly greatest for the plants under the 30 cm water table treatment, followed by those under the 15 cm water table depth treatment, then the flooded treatment. However, differences between measured and calculated root length densities became significant for all treatments after 30 days of treatment imposition. Transport rates varied with treatments but uptake rates did not reflect these differences in transport rates, thus, transport through the growth medium did not limit uptake of nitrogen by the plants.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"16 1","pages":"107-115"},"PeriodicalIF":0.0,"publicationDate":"2010-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V16I1.55872","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-06-25DOI: 10.4314/WAJAE.V16I1.55871
E. Glover, A. Faanur, J. Fianko
Experiments measuring the dissolution rates of stilbite (NaCa [Al Si O ].14H O) in pH-buffered solutions were 2 5 13 36 2 performed in batch reactors at 4, 25, 40 and 60 oC. The pH conditions of the buffer solutions ranged from 8.5 to 12.5. The dissolution rates calculated from silicon concentration of the reacting fluid increased with increasing temperature (4–60 oC) and pH. The dissolution rates ranged from 3.45 x 10-15 (mol cm-2 s-1) at pH 10.7 and 4oC to 1.93 x 10-9 (mol cm-2 s-1) at pH 12 and 60oC and were pH dependent. The rate law was established as R = k (a -)n , where k is OH the rate constant, a is the activity of the OH- species and n the reaction order. The n values obtained were, 0.32 at 4 oC, 0.35 at 25 oC, 0.38 at 40 oC and 0.38 at 60 oC. Activation energy determined using Arrhenius plot was 48.45 kJ/mol at pH 9 and 30.88 kJ/mol at pH 12.
测定静止物(NaCa [Al Si O])溶解速率的实验。在4、25、40和60℃的间歇反应器中进行。缓冲液的pH值为8.5 ~ 12.5。根据反应液硅浓度计算的溶解速率随温度(4 ~ 60℃)和pH的增加而增加。溶解速率在pH 10.7和4℃时为3.45 × 10-15 (mol cm-2 s-1)，在pH 12和60℃时为1.93 × 10-9 (mol cm-2 s-1)，且与pH有关。建立反应速率规律为R = k (a -)n，其中k为OH的速率常数，a为OH-的活度，n为反应级数。得到的n值分别为:4℃0.32,25℃0.35,40℃0.38,60℃0.38。用阿伦尼乌斯图测定的活化能在pH为9时为48.45 kJ/mol，在pH为12时为30.88 kJ/mol。
{"title":"Dissolution Kinetics of Stilbite at Various Temperatures under Alkaline Conditions","authors":"E. Glover, A. Faanur, J. Fianko","doi":"10.4314/WAJAE.V16I1.55871","DOIUrl":"https://doi.org/10.4314/WAJAE.V16I1.55871","url":null,"abstract":"Experiments measuring the dissolution rates of stilbite (NaCa [Al Si O ].14H O) in pH-buffered solutions were 2 5 13 36 2 performed in batch reactors at 4, 25, 40 and 60 oC. The pH conditions of the buffer solutions ranged from 8.5 to 12.5. The dissolution rates calculated from silicon concentration of the reacting fluid increased with increasing temperature (4–60 oC) and pH. The dissolution rates ranged from 3.45 x 10-15 (mol cm-2 s-1) at pH 10.7 and 4oC to 1.93 x 10-9 (mol cm-2 s-1) at pH 12 and 60oC and were pH dependent. The rate law was established as R = k (a -)n , where k is OH the rate constant, a is the activity of the OH- species and n the reaction order. The n values obtained were, 0.32 at 4 oC, 0.35 at 25 oC, 0.38 at 40 oC and 0.38 at 60 oC. Activation energy determined using Arrhenius plot was 48.45 kJ/mol at pH 9 and 30.88 kJ/mol at pH 12.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V16I1.55871","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-06-25DOI: 10.4314/WAJAE.V16I1.55867
T. Ewemoje, A. Sangodoyin
The study determined subsurface flow processes of 92.3 ha catchment area in order to examine functional relationship among the surface and subsurface flow variables from the water balance components data. Days without rainfall had zero infiltration while peak values of infiltrated water corresponded with peak rainfall. However, the Crawford and Linsley infiltration model was deficient by its inability to distinguish between days of zero rainfall and days when rainfall was less than 1.0 mm. Interflow occurred continuously even when there was no rainfall. This was shown to be responsible for the stream flows on dry days. Hence, total subsurface flows, a combination of interflow and groundwater flow, had the two components contributing to stream flow on days with rainfall. On days without rainfall, the interflow component was the only contributor to subsurface flows.
{"title":"Modelling Interconnectedness of Subsurface Flow Processes from a Simple Conceptual Infiltration Model","authors":"T. Ewemoje, A. Sangodoyin","doi":"10.4314/WAJAE.V16I1.55867","DOIUrl":"https://doi.org/10.4314/WAJAE.V16I1.55867","url":null,"abstract":"The study determined subsurface flow processes of 92.3 ha catchment area in order to examine functional relationship among the surface and subsurface flow variables from the water balance components data. Days without rainfall had zero infiltration while peak values of infiltrated water corresponded with peak rainfall. However, the Crawford and Linsley infiltration model was deficient by its inability to distinguish between days of zero rainfall and days when rainfall was less than 1.0 mm. Interflow occurred continuously even when there was no rainfall. This was shown to be responsible for the stream flows on dry days. Hence, total subsurface flows, a combination of interflow and groundwater flow, had the two components contributing to stream flow on days with rainfall. On days without rainfall, the interflow component was the only contributor to subsurface flows.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"16 1","pages":"33-49"},"PeriodicalIF":0.0,"publicationDate":"2010-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V16I1.55867","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-06-25DOI: 10.4314/WAJAE.V16I1.55863
K. Nyalemegbe, E. Darkwa, M. Yangyuoru, F. Mawunya, D. Acquah, Jw Oteng, P. Terry, T. Willcocks
The Vertisols of the Accra Plains of Ghana are water logged after significant rainfall due to the low-lying topography (0.1-1 %). Camber bed (Cb) drainage landforms have been developed at the Agricultural Research Centre, Kpong, for draining off excess water. Field experiments were conducted to verify if maize growth and yield gradient from the trough to the crest were the result of nutrient gradient or some other factors. Four 5 m and two 10 m Cbs and a 20-m flatland were prepared in a split-split plot design, with landform as main plot, nutrient levels as sub plot and crop row as sub-sub plot. A pot experiment was also carried out for detailed studies. Soil movement brought about a nutrient gradient from the trough of the camber bed to the crest, and also made the soil profile homogeneous. The trough was low in nutrients, compact and prone to water logging, but nutrient levels increased through the middle slope to the crest. The flatland did not have a nutrient gradient but was prone to water logging due to its low-lying nature. Total dry matter (TDM) of maize and grain yield similarly increased from the trough to the crest. Grain yield of maize on the flatland ranged from 2.5–2.6 t ha- 1, while yields on the 5-m Cb were 3.6, 4.2 and 4.8 t ha-1 on the trough, middle slope and crest, respectively. Excess application of 15-15-15 NPK and sulphate of ammonia fertilizers (150% of recommended levels) did not appreciably increase biomass and grain yield in the troughs. However, the maize crop in pots, with soil from the trough, responded positively to fertilizer application, thus confirming that low yield in the trough was the result of both low nutrient availability and the compact subsoil.
由于地势低洼(0.1% - 1%)，加纳阿克拉平原的高原在大量降雨后积水。Kpong农业研究中心开发了弯床(Cb)排水地貌，以排出多余的水。通过田间试验，验证玉米从谷到峰的生长和产量梯度是养分梯度还是其他因素的结果。设置4个5 m和2个10 m的农田和1个20 m的平地，以地形为主地块，营养水平为次地块，作物行为次次地块。还进行了盆栽试验进行了详细研究。土壤的运动使土壤的养分梯度从拱床的槽向垄顶形成，并使土壤剖面均匀化。槽内养分含量低，紧凑，容易淹水，但养分水平从中坡到坡顶逐渐增加。该平原没有营养梯度，但由于地势低洼，容易发生内涝。玉米总干物质(TDM)和籽粒产量由谷向峰呈相似的递增趋势。平原区玉米产量在2.5 ~ 2.6 t ha-1之间，而5米垄槽、中坡和坡顶的产量分别为3.6、4.2和4.8 t ha-1。过量施用15-15-15氮磷钾和硫酸盐氨肥(推荐用量的150%)没有显著提高槽内生物量和粮食产量。然而，盆栽玉米作物与槽内土壤对施肥反应积极，从而证实槽内低产量是营养有效性低和底土致密的结果。
{"title":"The Effect of Camber Bed Drainage Landforms on Soil Nutrient Distribution and Grain Yield of Maize on the Vertisols of the Accra Plains of Ghana","authors":"K. Nyalemegbe, E. Darkwa, M. Yangyuoru, F. Mawunya, D. Acquah, Jw Oteng, P. Terry, T. Willcocks","doi":"10.4314/WAJAE.V16I1.55863","DOIUrl":"https://doi.org/10.4314/WAJAE.V16I1.55863","url":null,"abstract":"The Vertisols of the Accra Plains of Ghana are water logged after significant rainfall due to the low-lying topography (0.1-1 %). Camber bed (Cb) drainage landforms have been developed at the Agricultural Research Centre, Kpong, for draining off excess water. Field experiments were conducted to verify if maize growth and yield gradient from the trough to the crest were the result of nutrient gradient or some other factors. Four 5 m and two 10 m Cbs and a 20-m flatland were prepared in a split-split plot design, with landform as main plot, nutrient levels as sub plot and crop row as sub-sub plot. A pot experiment was also carried out for detailed studies. Soil movement brought about a nutrient gradient from the trough of the camber bed to the crest, and also made the soil profile homogeneous. The trough was low in nutrients, compact and prone to water logging, but nutrient levels increased through the middle slope to the crest. The flatland did not have a nutrient gradient but was prone to water logging due to its low-lying nature. Total dry matter (TDM) of maize and grain yield similarly increased from the trough to the crest. Grain yield of maize on the flatland ranged from 2.5–2.6 t ha- 1, while yields on the 5-m Cb were 3.6, 4.2 and 4.8 t ha-1 on the trough, middle slope and crest, respectively. Excess application of 15-15-15 NPK and sulphate of ammonia fertilizers (150% of recommended levels) did not appreciably increase biomass and grain yield in the troughs. However, the maize crop in pots, with soil from the trough, responded positively to fertilizer application, thus confirming that low yield in the trough was the result of both low nutrient availability and the compact subsoil.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"16 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2010-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V16I1.55863","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-06-25DOI: 10.4314/WAJAE.V16I1.55869
O. Olusoji, O. Anifowose, M. Y. Sodamola
The length-weight relationships, condition factor and fecundity of the West-African freshwater crab, Sudanonautes africanus, was studied from different freshwater bodies within south-western Nigeria. The crabs were separated into males (151) and females (112). The length-weight relationship, condition factors, and fecundity of the crabs were determined. Growth parameters a and b of the length-weight relationship, (LWR) w = aLb, for S. africanus was 0.889, 5.029 and 0.713 for males, females and entire population, respectively. The values of b estimated were 2.475, 3.185 and 2.567 for males, females and whole population, respectively. The regression equation for the LWR are W= - 0.046 + 2.475L for males, W= 0.717+3.185L for females and W= - 0. 147 + 2.567L for the total crab population. The coefficient of determination of males, females and entire population were 0.716, 1.049 and 0.699, respectively, showing a strong correlation between the variables. There was a strong relationship (r2 = 0.81) between length and weight of males and females and the entire crab population. The LWR was allometric for all crabs. Results also show that there is a weak correlation (r2 = 0.36) between fecundity and total body weight (BW)/carapace length (CL) of the crabs. The length-weight distribution pattern did not show remarkable differences between species, sexes, and populations. Length-weight relationships have no influence on the fecundity. Mean (± SE) fecundity (292.8 ± 76.07 eggs) was positively related (r2 = 0.75) to CL. Fecundity ranged between 120 and 449 eggs with a mean diameter of 1.66 mm ± 0.068 mm. No relationship between egg size and carapace length was found. There was no significant difference (P > 0.01) in condition factors between the sexes.
{"title":"Length-Weight Relationships, Condition Factor and Fecundity of the West Africa Freshwater Crab, Sudanonautes africanus (Milne-Edwards 1883), in Western Nigeria","authors":"O. Olusoji, O. Anifowose, M. Y. Sodamola","doi":"10.4314/WAJAE.V16I1.55869","DOIUrl":"https://doi.org/10.4314/WAJAE.V16I1.55869","url":null,"abstract":"The length-weight relationships, condition factor and fecundity of the West-African freshwater crab, Sudanonautes africanus, was studied from different freshwater bodies within south-western Nigeria. The crabs were separated into males (151) and females (112). The length-weight relationship, condition factors, and fecundity of the crabs were determined. Growth parameters a and b of the length-weight relationship, (LWR) w = aLb, for S. africanus was 0.889, 5.029 and 0.713 for males, females and entire population, respectively. The values of b estimated were 2.475, 3.185 and 2.567 for males, females and whole population, respectively. The regression equation for the LWR are W= - 0.046 + 2.475L for males, W= 0.717+3.185L for females and W= - 0. 147 + 2.567L for the total crab population. The coefficient of determination of males, females and entire population were 0.716, 1.049 and 0.699, respectively, showing a strong correlation between the variables. There was a strong relationship (r2 = 0.81) between length and weight of males and females and the entire crab population. The LWR was allometric for all crabs. Results also show that there is a weak correlation (r2 = 0.36) between fecundity and total body weight (BW)/carapace length (CL) of the crabs. The length-weight distribution pattern did not show remarkable differences between species, sexes, and populations. Length-weight relationships have no influence on the fecundity. Mean (± SE) fecundity (292.8 ± 76.07 eggs) was positively related (r2 = 0.75) to CL. Fecundity ranged between 120 and 449 eggs with a mean diameter of 1.66 mm ± 0.068 mm. No relationship between egg size and carapace length was found. There was no significant difference (P > 0.01) in condition factors between the sexes.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"16 1","pages":"65-74"},"PeriodicalIF":0.0,"publicationDate":"2010-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V16I1.55869","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-01-13DOI: 10.4314/WAJAE.V15I1.49424
S. A. Ennin, E. Otoo, F. Tetteh
A cassava seedbed preparation field study was established at Fumesua in the forest and Ejura in the forest-savanna transition agroecologies of Ghana in 2004/2005. The experimental design was split plot with three seed bed preparation methods as the main plots and three nitrogen rates as sub plots, with basal application of 45-90 kg ha-1 P205 - K20 on the fertilized plots. A similar study was conducted on yam seedbed preparation in 2003/2004, with a 23 factorial design. Cassava and yams on ridges resulted in highest root and tuber yields, on both Lixisols in the coastal and forest-savanna transition and Acrisols in the forest agro-ecologies. However, yam tuber yield on mounds was not statistically different from yields on ridges. Number of roots per plant was identified as a major contributory factor to the yield increase of cassava on ridges. Seed bed preparation method was, however, not an important determinant of cassava root yield at high rates of fertilizer application of 90-45-90 kg ha-1 N-P205-K20. Planting on mounds resulted in slender, cylindrically shaped cassava roots and yam tubers, while ridging produced oblong shaped roots and tubers. Weeding and fertilizer application were easier on manual ridging than on manual mounds. The study points to ridging as a potential option to mounding for cassava and yam production, with the feasibility of mechanization of ridges to reduce drudgery associated with roots and tuber crop production in the West African sub-region.
2004/2005年，在加纳森林的Fumesua和森林-热带草原过渡农业生态的Ejura开展了木薯苗床制备实地研究。试验设计采用三种苗床整备方式为主区、三种施氮方式为副区的分割小区设计，施肥地块基肥45 ~ 90 kg hm -1 P205 - K20。2003/2004年进行了类似的山药苗床制剂研究，采用23因子设计。在沿海和森林-热带草原过渡的Lixisols和森林农业生态的Acrisols上，木薯和山药的根和块茎产量最高。然而，山药块茎在土墩上的产量与在山脊上的产量无统计学差异。单株根数是木薯垄上产量增加的主要因素。然而，在高施肥量90-45-90 kg hm -1 N-P205-K20条件下，种床整理方式不是木薯根产量的重要决定因素。在土墩上种植会产生细长的、圆柱形的木薯根和山药块茎，而在山脊上种植会产生椭圆形的根和块茎。在人工垄上除草和施肥比在人工丘上更容易。该研究指出，在木薯和山药的生产中，垄作是一种潜在的选择，而且在西非分区域，垄作机械化可以减少与块根和块茎作物生产相关的繁重劳动。
{"title":"Ridging, a Mechanized Alternative to Mounding for Yam and Cassava Production","authors":"S. A. Ennin, E. Otoo, F. Tetteh","doi":"10.4314/WAJAE.V15I1.49424","DOIUrl":"https://doi.org/10.4314/WAJAE.V15I1.49424","url":null,"abstract":"A cassava seedbed preparation field study was established at Fumesua in the forest and Ejura in the forest-savanna transition agroecologies of Ghana in 2004/2005. The experimental design was split plot with three seed bed preparation methods as the main plots and three nitrogen rates as sub plots, with basal application of 45-90 kg ha-1 P205 - K20 on the fertilized plots. A similar study was conducted on yam seedbed preparation in 2003/2004, with a 23 factorial design. Cassava and yams on ridges resulted in highest root and tuber yields, on both Lixisols in the coastal and forest-savanna transition and Acrisols in the forest agro-ecologies. However, yam tuber yield on mounds was not statistically different from yields on ridges. Number of roots per plant was identified as a major contributory factor to the yield increase of cassava on ridges. Seed bed preparation method was, however, not an important determinant of cassava root yield at high rates of fertilizer application of 90-45-90 kg ha-1 N-P205-K20. Planting on mounds resulted in slender, cylindrically shaped cassava roots and yam tubers, while ridging produced oblong shaped roots and tubers. Weeding and fertilizer application were easier on manual ridging than on manual mounds. The study points to ridging as a potential option to mounding for cassava and yam production, with the feasibility of mechanization of ridges to reduce drudgery associated with roots and tuber crop production in the West African sub-region.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"15 1","pages":"19-26"},"PeriodicalIF":0.0,"publicationDate":"2010-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V15I1.49424","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-01-13DOI: 10.4314/WAJAE.V15I1.49428
K. Van Waerebeek, P. Ofori-Danson, J. Debrah
The cetaceans of Ghana and the Gulf of Guinea have, until recently, remained unstudied. Periodical monitoring of artisanal fisheries for bycatches in seven Ghanaian artisanal fishing ports and landing sites over 1996-2004 has provided photographic and specimen evidence to validate occurrence of 18 species (17 odontocetes, 1 mysticete) in a tropical, predominantly pelagic cetacean fauna. At least nine species and subspecies had not previously been documented for Ghana (with asterisk), and four species are authenticated for the first time in the Gulf of Guinea (double asterisk), i.e. Tursiops truncatus, Stenella clymene, S. longirostris longirostris*, S. attenuata, S. frontalis, Delphinus capensis capensis*, Lagenodelphis hosei, Steno bredanensis, Grampus griseus, Peponocephala electra*, Feresa attenuata**, Globicephala macrorhynchus, Orcinus orca*, Pseudorca crassidens*, Kogia sima**, Physetermacrocephalus*, Ziphius cavirostris** and Megaptera novaeangliae . Also, the limited published information on distribution, natural history and conservation status is critically reviewed for each taxon. Indications are that most species encountered off Ghana may be widely distributed in the Gulf of Guinea, most notably the long-beaked common dolphin. The vulnerable Atlantic humpback dolphin, Sousa teuszii , remains unrecorded in Ghana and neighbouring nations despite apparently suitable coastal habitat. It is suggested that localized extinction may be blamed, possibly the result of accumulative bycatches and disturbance. A number of other cetacean species not yet encountered could occasionally occur in Ghana’s waters, e.g. Balaenoptera brydei, Mesoplodon densirostris, Kogia breviceps, Stenella coeruleoalba and Delphinus delphis
{"title":"The Cetaceans of Ghana, a Validated Faunal Checklist","authors":"K. Van Waerebeek, P. Ofori-Danson, J. Debrah","doi":"10.4314/WAJAE.V15I1.49428","DOIUrl":"https://doi.org/10.4314/WAJAE.V15I1.49428","url":null,"abstract":"The cetaceans of Ghana and the Gulf of Guinea have, until recently, remained unstudied. Periodical monitoring of artisanal fisheries for bycatches in seven Ghanaian artisanal fishing ports and landing sites over 1996-2004 has provided photographic and specimen evidence to validate occurrence of 18 species (17 odontocetes, 1 mysticete) in a tropical, predominantly pelagic cetacean fauna. At least nine species and subspecies had not previously been documented for Ghana (with asterisk), and four species are authenticated for the first time in the Gulf of Guinea (double asterisk), i.e. Tursiops truncatus, Stenella clymene, S. longirostris longirostris*, S. attenuata, S. frontalis, Delphinus capensis capensis*, Lagenodelphis hosei, Steno bredanensis, Grampus griseus, Peponocephala electra*, Feresa attenuata**, Globicephala macrorhynchus, Orcinus orca*, Pseudorca crassidens*, Kogia sima**, Physetermacrocephalus*, Ziphius cavirostris** and Megaptera novaeangliae . Also, the limited published information on distribution, natural history and conservation status is critically reviewed for each taxon. Indications are that most species encountered off Ghana may be widely distributed in the Gulf of Guinea, most notably the long-beaked common dolphin. The vulnerable Atlantic humpback dolphin, Sousa teuszii , remains unrecorded in Ghana and neighbouring nations despite apparently suitable coastal habitat. It is suggested that localized extinction may be blamed, possibly the result of accumulative bycatches and disturbance. A number of other cetacean species not yet encountered could occasionally occur in Ghana’s waters, e.g. Balaenoptera brydei, Mesoplodon densirostris, Kogia breviceps, Stenella coeruleoalba and Delphinus delphis","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"15 1","pages":"61-90"},"PeriodicalIF":0.0,"publicationDate":"2010-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V15I1.49428","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70685134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-01-13DOI: 10.4314/WAJAE.V15I1.49421
J. Aggrey-Fynn
The grey triggerfish, Balistes capriscus, resource had declined for nearly two decades in West African waters; its distribution and growth remain to be reported after late 1980s. In order to fill this gap, specimens were collected during small pelagic fish stock assessment surveys in 2005 in coastal waters of Benin, Togo, Ghana and La Cote d’Ivoire (Western Gulf of Guinea) from 17 out of 165 swept-area hauls in depths range of 23–60 m. The modal size classes were 27.0–31.9 cm and 32.0–36.9 cm. The age classes were determined by interpreting growth rings on sections of first dorsal spines. Estimates of theoretical growth in length were obtained by fitting the observed length-at-age data to the standard form of von Bertalanffy growth equation. The estimated L∞ for B. capriscus was 45.1 ± 1.4 cm and the growth rate, K, was 0.21 yr-1. The phi prime (O’) growth performance obtained was 2.63, which is comparable to that obtained in the 1980s on the same fish species in waters of Senegal, La Cote d’Ivoire and Ghana. The results suggest that the growth and distribution of grey triggerfish in the Western Gulf of Guinea had not changed, in spite of the apparent disappearance of the fish species in many areas of the West African coastal waters for nearly two decades.
{"title":"Distribution and Growth of Grey Triggerfish, Balistes capriscus (Family: Balistidae), in Western Gulf of Guinea","authors":"J. Aggrey-Fynn","doi":"10.4314/WAJAE.V15I1.49421","DOIUrl":"https://doi.org/10.4314/WAJAE.V15I1.49421","url":null,"abstract":"The grey triggerfish, Balistes capriscus, resource had declined for nearly two decades in West African waters; its distribution and growth remain to be reported after late 1980s. In order to fill this gap, specimens were collected during small pelagic fish stock assessment surveys in 2005 in coastal waters of Benin, Togo, Ghana and La Cote d’Ivoire (Western Gulf of Guinea) from 17 out of 165 swept-area hauls in depths range of 23–60 m. The modal size classes were 27.0–31.9 cm and 32.0–36.9 cm. The age classes were determined by interpreting growth rings on sections of first dorsal spines. Estimates of theoretical growth in length were obtained by fitting the observed length-at-age data to the standard form of von Bertalanffy growth equation. The estimated L∞ for B. capriscus was 45.1 ± 1.4 cm and the growth rate, K, was 0.21 yr-1. The phi prime (O’) growth performance obtained was 2.63, which is comparable to that obtained in the 1980s on the same fish species in waters of Senegal, La Cote d’Ivoire and Ghana. The results suggest that the growth and distribution of grey triggerfish in the Western Gulf of Guinea had not changed, in spite of the apparent disappearance of the fish species in many areas of the West African coastal waters for nearly two decades.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"38 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2010-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V15I1.49421","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-01-13DOI: 10.4314/WAJAE.V15I1.49426
IF Aboagye, D. Edoh
Urinary schistosomiasis is of great public health importance in developing countries. It has adverse economic and health implications on residents living in endemic areas. Various factors including human behaviour are known to play key role in the transmission of the disease. The knowledge of the levels of risk of infection of urinary schistosomiasis and people’s perception will be an important tool in its control. The study determined the prevalence of urinary schistosomiasis and the risk of infection in some communities near the Weija lake in the Ga District. It assessed the knowledge base of the subjects on the disease and its impact on transmission. Data were collected on demographic variables, some behavioural activities in water bodies, knowledge base on the disease and sanitary facilities. Urine samples were analysed using the centrifugation technique. The percentage prevalence for Mahem and Galilea were 58% and 49%, respectively. The difference in prevalence was insignificant; 0.09 (-0.04, 0.21; P < 0.426). Bloody urine was associated with high risk of infection; OR of 4.55 (2.82, 7.36); P < 0.001. Subjects with primary level of education and invariably below 26 years of age had about two times the risk of infection; OR of 2.12 (1.13, 3.97); P < 0.02. The communities had 52% prevalence of urinary schistosomiasis. Frequent contacts and use of the infested lake were associated with infection. Educational intervention alone may not be effective in the control of the disease. The use of an integrated approach should be given favourable consideration.
{"title":"Investigation of the risk of infection of urinary schistosomiasis at Mahem and Galilea communities in the Greater Accra Region of Ghana.","authors":"IF Aboagye, D. Edoh","doi":"10.4314/WAJAE.V15I1.49426","DOIUrl":"https://doi.org/10.4314/WAJAE.V15I1.49426","url":null,"abstract":"Urinary schistosomiasis is of great public health importance in developing countries. It has adverse economic and health implications on residents living in endemic areas. Various factors including human behaviour are known to play key role in the transmission of the disease. The knowledge of the levels of risk of infection of urinary schistosomiasis and people’s perception will be an important tool in its control. The study determined the prevalence of urinary schistosomiasis and the risk of infection in some communities near the Weija lake in the Ga District. It assessed the knowledge base of the subjects on the disease and its impact on transmission. Data were collected on demographic variables, some behavioural activities in water bodies, knowledge base on the disease and sanitary facilities. Urine samples were analysed using the centrifugation technique. The percentage prevalence for Mahem and Galilea were 58% and 49%, respectively. The difference in prevalence was insignificant; 0.09 (-0.04, 0.21; P < 0.426). Bloody urine was associated with high risk of infection; OR of 4.55 (2.82, 7.36); P < 0.001. Subjects with primary level of education and invariably below 26 years of age had about two times the risk of infection; OR of 2.12 (1.13, 3.97); P < 0.02. The communities had 52% prevalence of urinary schistosomiasis. Frequent contacts and use of the infested lake were associated with infection. Educational intervention alone may not be effective in the control of the disease. The use of an integrated approach should be given favourable consideration.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"15 1","pages":"27-32"},"PeriodicalIF":0.0,"publicationDate":"2010-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V15I1.49426","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-01-13DOI: 10.4314/WAJAE.V15I1.49423
S. Tsagbey, A. Mensah, F. Nunoo
Beach litter accumulation and reduced water quality are important aspects of beach degradation which have adverse effects on the users of the beach and marine life. The study aims at determining how the degree of human pressure at the La and Korle Beach resorts in Accra, Ghana, which serve different social communities, contributes to beach degradation. A weekly collection of fresh and accumulated litter from a belt transect of 500 m2 and samples of seawater from each beach were obtained during a 3-week festive period (Dec. 26, 2005–Jan. 9, 2006) and a 3-week non-festive period (Jan. 23, 2006–Feb. 6, 2006). Thirty-two types of litter were identified and the total number and weight of litter collected from La were 2261 and 72695 g, and that of Korle were 2691 and 43239 g, respectively. Plastic material dominated the total litter at 66% for Korle and 53% for La, respectively. The numbers of litter increased with increasing visitor pressure during the festive season for Korle, although the type and diversity of the beach litter was location specific irrespective of the season for both sites. Microbial values for coliforms were higher for Korle than La, with significant increase in Korle during the festive season. The implications for leisure activity like swimming at both sites has minimal health risks since the mean levels of the indicators are within the WHO international permissible range.
{"title":"Influence of tourist pressure on beach litter and microbial quality - case study of two beach resorts in Ghana.","authors":"S. Tsagbey, A. Mensah, F. Nunoo","doi":"10.4314/WAJAE.V15I1.49423","DOIUrl":"https://doi.org/10.4314/WAJAE.V15I1.49423","url":null,"abstract":"Beach litter accumulation and reduced water quality are important aspects of beach degradation which have adverse effects on the users of the beach and marine life. The study aims at determining how the degree of human pressure at the La and Korle Beach resorts in Accra, Ghana, which serve different social communities, contributes to beach degradation. A weekly collection of fresh and accumulated litter from a belt transect of 500 m2 and samples of seawater from each beach were obtained during a 3-week festive period (Dec. 26, 2005–Jan. 9, 2006) and a 3-week non-festive period (Jan. 23, 2006–Feb. 6, 2006). Thirty-two types of litter were identified and the total number and weight of litter collected from La were 2261 and 72695 g, and that of Korle were 2691 and 43239 g, respectively. Plastic material dominated the total litter at 66% for Korle and 53% for La, respectively. The numbers of litter increased with increasing visitor pressure during the festive season for Korle, although the type and diversity of the beach litter was location specific irrespective of the season for both sites. Microbial values for coliforms were higher for Korle than La, with significant increase in Korle during the festive season. The implications for leisure activity like swimming at both sites has minimal health risks since the mean levels of the indicators are within the WHO international permissible range.","PeriodicalId":39286,"journal":{"name":"West African Journal of Applied Ecology","volume":"15 1","pages":"11-18"},"PeriodicalIF":0.0,"publicationDate":"2010-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/WAJAE.V15I1.49423","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70684851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：