The Mankessim Reservoir supports a thriving cichlid fishery that provides both financial gain and nutritional value to the people. Fish samples of Hemichromis fasciatus, Tilapia zillii and Sarotherodon melanotheron were obtained from artisanal fishermen by gill nets (10 m long and 1.5 m deep, 3, 6 and 12 mm mesh) and cast nets (25 mm mesh and 2.5 m radius) in the reservoir (5018''52.08'''N 1001''45.08'''W) from September 2011 to August 2012. Physicochemical parameters were measured in situ and nutrients level determined by the spectrophotometric method. Stomach contents were analyzed using the frequency of occurrence and “points” method and condition was evaluated by means of Fulton condition index. As a result, food resources exploited by T. zillii and S. melanotheron were highly similar. T. zillii fed more on plant material and benthic invertebrates with diatoms (Navicula spp., Pinnularia nobilis, Frustulia rohomboides, Stephanodiscus cymbella, Melosira spp., Gyrosigma spp., Tabellaria sp. and Diatoma sp.) blue green (mainly Ulothrix sp. Oscillatoria spp., Anabaena spp., and Microspora sp.) and desmids being the most preferred algae. S. melanotheron ingested more of debris, and fed on considerable amount of algae and benthic invertebrates mainly chironomid larvae and oligochaetes showing a high level of trophic flexibility. The three cichlids showed very good condition (1.75 ± 0.11 - 1.98 ± 0.40). This could probably be as a result of the observed favourable environmental conditions as all physicochemical parameters were within acceptable limits for their sustenance except for phosphates (1.68 ± 0.04 mg/L to 5.37 ± 0.02 mg/L). Key words: Hemichromis fasciatus, Tilapia zillii, Sarotherodon melanotheron, Cichlids, Physicochemical parameters, Condition factor
{"title":"Investigation on Food Ecology of three Cichlid Species in the Mankessim Reservoir, Central Region of Ghana","authors":"S. Atindana, J. Blay, K. Yankson","doi":"10.5897/IJFA2015.0535","DOIUrl":"https://doi.org/10.5897/IJFA2015.0535","url":null,"abstract":"The Mankessim Reservoir supports a thriving cichlid fishery that provides both financial gain and nutritional value to the people. Fish samples of Hemichromis fasciatus, Tilapia zillii and Sarotherodon melanotheron were obtained from artisanal fishermen by gill nets (10 m long and 1.5 m deep, 3, 6 and 12 mm mesh) and cast nets (25 mm mesh and 2.5 m radius) in the reservoir (5018''52.08'''N 1001''45.08'''W) from September 2011 to August 2012. Physicochemical parameters were measured in situ and nutrients level determined by the spectrophotometric method. Stomach contents were analyzed using the frequency of occurrence and “points” method and condition was evaluated by means of Fulton condition index. As a result, food resources exploited by T. zillii and S. melanotheron were highly similar. T. zillii fed more on plant material and benthic invertebrates with diatoms (Navicula spp., Pinnularia nobilis, Frustulia rohomboides, Stephanodiscus cymbella, Melosira spp., Gyrosigma spp., Tabellaria sp. and Diatoma sp.) blue green (mainly Ulothrix sp. Oscillatoria spp., Anabaena spp., and Microspora sp.) and desmids being the most preferred algae. S. melanotheron ingested more of debris, and fed on considerable amount of algae and benthic invertebrates mainly chironomid larvae and oligochaetes showing a high level of trophic flexibility. The three cichlids showed very good condition (1.75 ± 0.11 - 1.98 ± 0.40). This could probably be as a result of the observed favourable environmental conditions as all physicochemical parameters were within acceptable limits for their sustenance except for phosphates (1.68 ± 0.04 mg/L to 5.37 ± 0.02 mg/L). \u0000 \u0000 \u0000 \u0000 Key words: Hemichromis fasciatus, Tilapia zillii, Sarotherodon melanotheron, Cichlids, Physicochemical parameters, Condition factor","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133825120","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}
This study described some aspects of the reproductive biology of Blackchin tilapia (Sarotherodon melanotheron, Cichlidae) from Brimsu reservoir. A total of 457 specimens were sampled using a monofilament gill net of mesh size 25 mm from September, 2009 to September, 2010. Standard length for the species ranged between 7.5 and 17.6 cm, with both males and females having a unimodal modal length of 10.0 to 10.9 cm. The length at sexual maturity (L50) was 11.26 and 11.34 cm for males and females, respectively. The pattern of fluctuation in gonadosomatic index indicates that the species had an extended spawning season starting from February to August. Key words: Sarotherodon melanotheron, reproductive biology, sexual maturity.
{"title":"Reproductive biology of Blackchin tilapia, Sarotherodon melanotheron (Pisces: Cichlidae) from Brimsu Reservoir, Cape Coast, Ghana","authors":"K. K. Mireku, J. Blay, K. Yankson","doi":"10.5897/IJFA2015.0511","DOIUrl":"https://doi.org/10.5897/IJFA2015.0511","url":null,"abstract":"This study described some aspects of the reproductive biology of Blackchin tilapia (Sarotherodon melanotheron, Cichlidae) from Brimsu reservoir. A total of 457 specimens were sampled using a monofilament gill net of mesh size 25 mm from September, 2009 to September, 2010. Standard length for the species ranged between 7.5 and 17.6 cm, with both males and females having a unimodal modal length of 10.0 to 10.9 cm. The length at sexual maturity (L50) was 11.26 and 11.34 cm for males and females, respectively. The pattern of fluctuation in gonadosomatic index indicates that the species had an extended spawning season starting from February to August. \u0000 \u0000 Key words: Sarotherodon melanotheron, reproductive biology, sexual maturity.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115764421","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}
Thomas Severine, Thyer Sascha, Cooper Ross, Emily S. Hope, R. Laming
Reef HQ Aquarium (Townsville, Australia) pumps its new exhibit seawater from a tidal inlet. This study presents the in-house calibration of a bioassay based on juvenile mysids to do a rapid assessment (presence or absence) of toxicity in the new seawater. Calibration tests were carried out for several substances: copper, sodium lauryl sulphate (SLS or SDS), ammonia, antifouling paint, bilge oil from a yacht, oil from a dive compressor, seawater cooling effluent from a commercial ferry vessel, and aquarium tank water. Results were compared with two other bioassays already in use at Reef HQ Aquarium, based on (a) artemia hatched from aquaculture cysts and (b) Vibrio fischeri bacteria (Microtox®). This study determined (a) that the juvenile mysids bioassay yielded meaningful results and was viable operationally, (b) its sensitivity with respect to likely local pollutants, and (c) how it compares in terms of sensitivity with the artemia and the Microtox® bioassays. Key words: ARTOX, bioassay, mysid, Microtox®, Reef HQ Aquarium, seawater, toxicity.
{"title":"Bioassay using juvenile mysids for rapid assessment of seawater: A case study from Reef HQ Aquarium (Townsville, Australia)","authors":"Thomas Severine, Thyer Sascha, Cooper Ross, Emily S. Hope, R. Laming","doi":"10.5897/IJFA2015.0501","DOIUrl":"https://doi.org/10.5897/IJFA2015.0501","url":null,"abstract":"Reef HQ Aquarium (Townsville, Australia) pumps its new exhibit seawater from a tidal inlet. This study presents the in-house calibration of a bioassay based on juvenile mysids to do a rapid assessment (presence or absence) of toxicity in the new seawater. Calibration tests were carried out for several substances: copper, sodium lauryl sulphate (SLS or SDS), ammonia, antifouling paint, bilge oil from a yacht, oil from a dive compressor, seawater cooling effluent from a commercial ferry vessel, and aquarium tank water. Results were compared with two other bioassays already in use at Reef HQ Aquarium, based on (a) artemia hatched from aquaculture cysts and (b) Vibrio fischeri bacteria (Microtox®). This study determined (a) that the juvenile mysids bioassay yielded meaningful results and was viable operationally, (b) its sensitivity with respect to likely local pollutants, and (c) how it compares in terms of sensitivity with the artemia and the Microtox® bioassays. \u0000 \u0000 \u0000 \u0000 Key words: ARTOX, bioassay, mysid, Microtox®, Reef HQ Aquarium, seawater, toxicity.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125485879","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}
Botanical piscicides over the years have been used singly in fishing efforts. This research investigated the joint action of binary mixtures of Carica papaya + Nicotiana tabacum, Anacardium occidentale + Senna occidentalis, and A. occidentale + Luffa cylindrica. Relative toxic units (RTU) estimations and synergistic ratio (SR) models were used in the joint action evaluation. The 96 h LC50 (95% confidence limit [CL]) results revealed that the mixture of C. papaya and N. tabacum showed antagonism (reduction in toxicity) in both predetermined mixture ratio 1:1 and equitoxic mixture ratio 1:2. The RTU value for mixture ratio 1:1 was 0.298, while SR was 0.221. The mixture ratio 1:2 had RTU of 0.421 and SR of 0.384. The mixture of A. occidentale and S. occidentalis also followed the antagonistic model with mixture ratio 1:1, having RTU of 0.927 and SR of 0.577, while the mixture ratio 1:2 had RTU of 0.489 and SR of 0.360. The mixture ratio 1:1 of A. occidentale and L. cylindrica was synergistic with RTU of 2.145 and SR of 1.442. Most of the binary mixtures of the botanical piscicides were antagonistic. Key words: Joint action, binary mixtures, botanical piscicides, Clarias gariepinus.
多年来，植物杀虫剂一直被单独用于捕鱼工作。本研究考察了番木瓜+烟草、西洋木犀草+西洋番泻草、西洋木犀草+丝瓜的二元组合的联合作用。联合作用评价采用相对毒性单位(RTU)估计和协同比(SR)模型。96 h LC50(95%置信限[CL])结果显示，在预定混合比1:1和等毒混合比1:2条件下，番木瓜与烟草的混合物均表现出拮抗作用(毒性降低)。混合比为1:1时，RTU值为0.298,SR值为0.221。混合比1:2的RTU为0.421,SR为0.384。西花楸与西花楸的混合也符合配比为1:1的拮抗模式，RTU为0.927,SR为0.577，配比为1:2的混合RTU为0.489,SR为0.360。西白茅与白茅的混合比例为1:1,RTU为2.145,SR为1.442。多数植物性杀鱼剂二元混合剂具有拮抗作用。关键词:联合作用;二元混合物;植物性杀菌剂;
{"title":"The joint action effects of the binary mixtures of some botanical piscicides on post juvenile Clarias gariepinus","authors":"E. Ekpendu, J. Saliu, A. Otitoloju","doi":"10.5897/IJFA2015.0513","DOIUrl":"https://doi.org/10.5897/IJFA2015.0513","url":null,"abstract":"Botanical piscicides over the years have been used singly in fishing efforts. This research investigated the joint action of binary mixtures of Carica papaya + Nicotiana tabacum, Anacardium occidentale + Senna occidentalis, and A. occidentale + Luffa cylindrica. Relative toxic units (RTU) estimations and synergistic ratio (SR) models were used in the joint action evaluation. The 96 h LC50 (95% confidence limit [CL]) results revealed that the mixture of C. papaya and N. tabacum showed antagonism (reduction in toxicity) in both predetermined mixture ratio 1:1 and equitoxic mixture ratio 1:2. The RTU value for mixture ratio 1:1 was 0.298, while SR was 0.221. The mixture ratio 1:2 had RTU of 0.421 and SR of 0.384. The mixture of A. occidentale and S. occidentalis also followed the antagonistic model with mixture ratio 1:1, having RTU of 0.927 and SR of 0.577, while the mixture ratio 1:2 had RTU of 0.489 and SR of 0.360. The mixture ratio 1:1 of A. occidentale and L. cylindrica was synergistic with RTU of 2.145 and SR of 1.442. Most of the binary mixtures of the botanical piscicides were antagonistic. \u0000 \u0000 \u0000 \u0000 Key words: Joint action, binary mixtures, botanical piscicides, Clarias gariepinus.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128901671","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}
This study was intended to report the disastrous mass mortality of Nile tilapia (Oreochromis niloticus) and common carp (Cyprinus carpio) in Lake Hashenge, Tigray occurred in June, 12 to 15th, 2014 and to investigate the possible causes of this phenomenon. The dissolved oxygen (DO) of the water of the lake was 2.20 mg/L in the north part and 2.09 mg/L in the south west part of the lake with an average of 2.15 mg/L. The temperature was not out of the permeable range (18.05 to 24.30°C) which was 22.19°C and pH value was 7.67. Mass kills as well as respiratory distressed fish were seen along the lake. The disaster zone was so serious in the south western part of the lake when compared with the other parts of the lake, which were estimated at several thousands of Nile tilapia and common carp were dead. Clinically, the affected fish showed asphyxia with mouth wide opened and flared gills. Respiratory stressed fishes were smaller in size, while most of the mortalities were limited to large sized fishes. Previous record indicates that similar cases of mass kills have occurred 14 years ago in 2000, but the losses were much less. Laboratory analysis of water quality indicated that the low level of DO was the primary cause for the mass mortality of the fishes. The physico-chemical characteristics of water revealed the presence of abnormal water color, low level of DO (2.39 mg/L), low secchi disk reading, and slightly alkaline pH. So it was concluded that the turnover of the lake due to the mixing of the thermally layered water was the reason for the low DO, which causes mass kills of the fishes. The mass mortality was more severe in Nile tilapia as compared to mortality of common carp.
{"title":"Report of fish mass mortality from Lake Hashenge, Tigray, Northern Ethiopia and investigation of the possible causes of this event","authors":"T. Teame, P. Natarajan, H. Zebib, G. Abay","doi":"10.5897/IJFA2015.0498","DOIUrl":"https://doi.org/10.5897/IJFA2015.0498","url":null,"abstract":"This study was intended to report the disastrous mass mortality of Nile tilapia (Oreochromis niloticus) and common carp (Cyprinus carpio) in Lake Hashenge, Tigray occurred in June, 12 to 15th, 2014 and to investigate the possible causes of this phenomenon. The dissolved oxygen (DO) of the water of the lake was 2.20 mg/L in the north part and 2.09 mg/L in the south west part of the lake with an average of 2.15 mg/L. The temperature was not out of the permeable range (18.05 to 24.30°C) which was 22.19°C and pH value was 7.67. Mass kills as well as respiratory distressed fish were seen along the lake. The disaster zone was so serious in the south western part of the lake when compared with the other parts of the lake, which were estimated at several thousands of Nile tilapia and common carp were dead. Clinically, the affected fish showed asphyxia with mouth wide opened and flared gills. Respiratory stressed fishes were smaller in size, while most of the mortalities were limited to large sized fishes. Previous record indicates that similar cases of mass kills have occurred 14 years ago in 2000, but the losses were much less. Laboratory analysis of water quality indicated that the low level of DO was the primary cause for the mass mortality of the fishes. The physico-chemical characteristics of water revealed the presence of abnormal water color, low level of DO (2.39 mg/L), low secchi disk reading, and slightly alkaline pH. So it was concluded that the turnover of the lake due to the mixing of the thermally layered water was the reason for the low DO, which causes mass kills of the fishes. The mass mortality was more severe in Nile tilapia as compared to mortality of common carp.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"309 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122313579","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}
B. Coulibaly, L. Tah, Gnahor eacute Toussaint Joanny Tape, T. Koné, K. Essetchi
Fish assemblages and their relationship with hydrological variables were investigated in the coastal lagoon of Grand-Lahou (Côte-d’Ivoire) from November 2013 to October 2014. Samplings were carried out by means of artisanal fisheries, once a month, in three sites. A total of 8571 fish belonging to 47 fish species from 25 families were recorded. The most represented families were Cichlidae and Mugilidae with six species. Each environmental variable, notably, dissolved oxygen (DO), temperature and salinity according to the canonical correspondence analysis (CCA) allowed the distinction of two main sectors in the lagoon, associated with three fish assemblages. Sector 1 including sampling sites 2 and 3, characterized by high salinity fluctuations, functioned as a typical estuary. Two fish assemblages identified in this sector were Lutjanus dentatus, Mugil cephalus, Mugil bananensis, Tilapia guineensis and Tylochromis jentenki in station 2 and Sarotherodon melanotheron, Liza falcipinnis and Pomadasys jubelini in station 3. Sector 2 comprising the sampling site 1, characterized by low salinity fluctuation is associated with 11 fish species, notably, Ethmalosa fimbriata and Elops lacerta. The fish assemblage in this sector depends on season, temperature and DO.
{"title":"Fish assemblage structure in the Tropical Coastal Lagoon of Grand Lahou (Cte DIvoire, West Africa)","authors":"B. Coulibaly, L. Tah, Gnahor eacute Toussaint Joanny Tape, T. Koné, K. Essetchi","doi":"10.5897/IJFA15.0537","DOIUrl":"https://doi.org/10.5897/IJFA15.0537","url":null,"abstract":"Fish assemblages and their relationship with hydrological variables were investigated in the coastal lagoon of Grand-Lahou (Côte-d’Ivoire) from November 2013 to October 2014. Samplings were carried out by means of artisanal fisheries, once a month, in three sites. A total of 8571 fish belonging to 47 fish species from 25 families were recorded. The most represented families were Cichlidae and Mugilidae with six species. Each environmental variable, notably, dissolved oxygen (DO), temperature and salinity according to the canonical correspondence analysis (CCA) allowed the distinction of two main sectors in the lagoon, associated with three fish assemblages. Sector 1 including sampling sites 2 and 3, characterized by high salinity fluctuations, functioned as a typical estuary. Two fish assemblages identified in this sector were Lutjanus dentatus, Mugil cephalus, Mugil bananensis, Tilapia guineensis and Tylochromis jentenki in station 2 and Sarotherodon melanotheron, Liza falcipinnis and Pomadasys jubelini in station 3. Sector 2 comprising the sampling site 1, characterized by low salinity fluctuation is associated with 11 fish species, notably, Ethmalosa fimbriata and Elops lacerta. The fish assemblage in this sector depends on season, temperature and DO.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127942448","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}
Tilapia rendalli juveniles (±9.5 g) were cultured in concrete tanks to determine the effect of four dietary protein levels (30, 35, 40 and 45% crude protein (CP) in feed on ammonia concentration and growth performance of the fish, stocked at 15 fish per tank. Fish were monitored for a period of 90 days. Fish that were fed on 40% CP diet had significantly (P<0.05) higher weight gain, growth, and feed conversion ratio (FCR). Ammonia concentration was significantly higher (P<0.05) in tanks where the 45% CP diet was administered, and where also poor growth and survival rate was observed. Poor growth performance of the fish at inadequate (below 30% CP) and oversupply (above 40% CP) protein diet is evidence of the importance of taking precautions on the levels of protein inclusion in diet in tank culture. Higher dietary protein diet precipitates ammonia accumulation, thus compromising growth performance. Based on findings in this study, optimal protein level of 40% CP is recommended for tank culture. Key words: Ammonia concentration, dietary protein, growth performance, Tilapia rendalli.
{"title":"Effect of dietary protein levels on ammonia concentration and growth of Tilapia rendalli (Boulenger, 1896), raised in concrete tanks","authors":"R. Makwinja, F. Kapute, W. Singini, H. Zidana","doi":"10.5897/IJFA15.0505","DOIUrl":"https://doi.org/10.5897/IJFA15.0505","url":null,"abstract":"Tilapia rendalli juveniles (±9.5 g) were cultured in concrete tanks to determine the effect of four dietary protein levels (30, 35, 40 and 45% crude protein (CP) in feed on ammonia concentration and growth performance of the fish, stocked at 15 fish per tank. Fish were monitored for a period of 90 days. Fish that were fed on 40% CP diet had significantly (P<0.05) higher weight gain, growth, and feed conversion ratio (FCR). Ammonia concentration was significantly higher (P<0.05) in tanks where the 45% CP diet was administered, and where also poor growth and survival rate was observed. Poor growth performance of the fish at inadequate (below 30% CP) and oversupply (above 40% CP) protein diet is evidence of the importance of taking precautions on the levels of protein inclusion in diet in tank culture. Higher dietary protein diet precipitates ammonia accumulation, thus compromising growth performance. Based on findings in this study, optimal protein level of 40% CP is recommended for tank culture. \u0000 \u0000 \u0000 \u0000 Key words: Ammonia concentration, dietary protein, growth performance, Tilapia rendalli.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132097181","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}
Dogbeda Mawulolo Yao Azumah, G. Wiafe, P. Ofori-Danson, R. Makwinja, F. Kapute, W. Singini, H. Zidana
A geographic information system (GIS)-modeling of fish production in the Stratum VII of the Volta Lake was undertaken with the objective of investigating temporal changes and modeling fish production into the future. Parameters used included number of canoes, number of fishers, and water level. Stratum VII of the Volta Lake is currently one of the areas with the highest fishing activities, the largest fish market at Yeji and relatively a research center. Nevertheless, the lake has faced many setbacks due to poor management and monitoring. In order to combat these challenges, this study was conducted to investigate the temporal changes and forecasting production of Stratum VII of the Volta Lake using Geographic Information System. Long term field data from 1970 to 1998 on fisheries were acquired and analyzed for modeling fish production from 1970 to 2060, using ArcGIS management tools and model builder. A hind cast was first performed to validate the model. The model, “CPUE model” predicted a depletion of the fish of Stratum VII by 2055 with a maximum of 22,779 tonnes at a fishing effort of 9,826 canoes and a CPUE of 10.76 kg/canoe/day in the year 2005. Long and short term data were also compared in the Stratum VII. The R2 values of the correlation of the number of fishermen, number of canoes and the water level over the years are high (89.9%, 78.21%) and moderate (50.71%). These correlations showed a continuous increase in the fishing effort and decrease in the water level; trends that impact negatively on the fish production over the years. This study has established appropriate mechanism for incorporating field data into a GIS database to support fishery management in the Volta Lake. Key words: Geographic information system (GIS) modeling, CPUE model, temporal changes, fish production, fishing effort.
{"title":"Application of geographic information system for inland fisheries management: A case study of Stratum VII (Yeji Sector), Volta Lake, Ghana","authors":"Dogbeda Mawulolo Yao Azumah, G. Wiafe, P. Ofori-Danson, R. Makwinja, F. Kapute, W. Singini, H. Zidana","doi":"10.5897/IJFA15.","DOIUrl":"https://doi.org/10.5897/IJFA15.","url":null,"abstract":"A geographic information system (GIS)-modeling of fish production in the Stratum VII of the Volta Lake was undertaken with the objective of investigating temporal changes and modeling fish production into the future. Parameters used included number of canoes, number of fishers, and water level. Stratum VII of the Volta Lake is currently one of the areas with the highest fishing activities, the largest fish market at Yeji and relatively a research center. Nevertheless, the lake has faced many setbacks due to poor management and monitoring. In order to combat these challenges, this study was conducted to investigate the temporal changes and forecasting production of Stratum VII of the Volta Lake using Geographic Information System. Long term field data from 1970 to 1998 on fisheries were acquired and analyzed for modeling fish production from 1970 to 2060, using ArcGIS management tools and model builder. A hind cast was first performed to validate the model. The model, “CPUE model” predicted a depletion of the fish of Stratum VII by 2055 with a maximum of 22,779 tonnes at a fishing effort of 9,826 canoes and a CPUE of 10.76 kg/canoe/day in the year 2005. Long and short term data were also compared in the Stratum VII. The R2 values of the correlation of the number of fishermen, number of canoes and the water level over the years are high (89.9%, 78.21%) and moderate (50.71%). These correlations showed a continuous increase in the fishing effort and decrease in the water level; trends that impact negatively on the fish production over the years. This study has established appropriate mechanism for incorporating field data into a GIS database to support fishery management in the Volta Lake. \u0000 \u0000 \u0000 \u0000 Key words: Geographic information system (GIS) modeling, CPUE model, temporal changes, fish production, fishing effort.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121585297","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}
Brush parks consist of branches of trees or shrubs stuck into muddy bottoms of lagoons, lakes or rivers at a depth of 1 to 1.5 m. The branches are placed in water to form aggregations, which are removed after a short lapse of time, together with any fish that may have sought shelter amongst them. Brush parks are found in several of the West African coastal lagoons such as Lagos and freshwater environments in Niger State, Nigeria. The study examined the profitability of the brush parks in two states in Nigeria. Data was collected by means of semi-structured questionnaire administered to 200 fishermen with brush parks selected in a random manner from Niger and Lagos States of Nigeria. Independent samples t-test was used to compare the means of two independent samples for test of significance. Chi square (χ 2 ) was used to investigate the significant relationships between pairs of categorical variables. Relationships between pairs of quantitative variables were tested using Pearson correlation. The profitability indices showed that brush parks are profitable in the two states. The brush parks are more profitable in Lagos State because net return was significantly (p=0.001) higher in Lagos than Niger State. Rate of income (91%) and benefit-cost ratio (10.3) were also higher in Lagos than Niger State. Production of fish from brush parks should be supported and encouraged. Support could be in the form of technical assistance, infrastructure development, extension services or subsidies.
{"title":"A comparative study of the profitability of brush parks in two states in Nigeria","authors":"G. Ahmed","doi":"10.5897/IJFA15.0512","DOIUrl":"https://doi.org/10.5897/IJFA15.0512","url":null,"abstract":"Brush parks consist of branches of trees or shrubs stuck into muddy bottoms of lagoons, lakes or rivers at a depth of 1 to 1.5 m. The branches are placed in water to form aggregations, which are removed after a short lapse of time, together with any fish that may have sought shelter amongst them. Brush parks are found in several of the West African coastal lagoons such as Lagos and freshwater environments in Niger State, Nigeria. The study examined the profitability of the brush parks in two states in Nigeria. Data was collected by means of semi-structured questionnaire administered to 200 fishermen with brush parks selected in a random manner from Niger and Lagos States of Nigeria. Independent samples t-test was used to compare the means of two independent samples for test of significance. Chi square (χ 2 ) was used to investigate the significant relationships between pairs of categorical variables. Relationships between pairs of quantitative variables were tested using Pearson correlation. The profitability indices showed that brush parks are profitable in the two states. The brush parks are more profitable in Lagos State because net return was significantly (p=0.001) higher in Lagos than Niger State. Rate of income (91%) and benefit-cost ratio (10.3) were also higher in Lagos than Niger State. Production of fish from brush parks should be supported and encouraged. Support could be in the form of technical assistance, infrastructure development, extension services or subsidies.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115651361","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}
G. E. Odo, J. E. Agwu, F. Iyaji, J. Madu, N. I. Ossai, L. N. Allison
In this research, mass production of freshwater rotifer, Branchionus calyciflorus, for aquaculture in south-eastern Nigeria, using different food types (Chlorella sp., Spirulina sp and Baker’s yeast) was investigated. Rotifer stock culture was prepared using Nitrogen phosphorus Potassium, (NPK) + urea (50 : 2.5 g) and chicken droppings (25 g) with freshly grown alga. Different food concentrations (150, 300, 650 and 1000 mg/ml) and feeding intervals (2x and 3x per day) were used to grow B. calyciflorus in a Batch culture method. The highest population growth was attained with 650 mg/ml of Chlorella sp. (213.81±9.94 individuals/ml), followed by Baker’s yeast (196.67±8.18 individuals/ml) and 300 mg/ml of Spirulina sp. (151.90±7.98 individuals/ml). The least population growth of B. calyciflorus was recorded with 150 mg/ml concentration of Chlorella sp. and Spirulina sp. (81.43±6.19 and 75.71±5.12 individuals/ml, respectively), and 1000 mg/ml of Baker’s yeast (from local market) (65.24 ±3.86 individuals/ml). The peak population growth was attained on day 8 of experiment (p < 0.05). This study indicated that both the quantity and quality of food type have significant role on mass production of rotifer for aquaculture. Key words: Branchionus calyciflorus, mass production, aquaculture, fish farm, Nigeria.
{"title":"Mass production of rotifer (Branchionus calyciflorus) for aquaculture in south-eastern Nigeria","authors":"G. E. Odo, J. E. Agwu, F. Iyaji, J. Madu, N. I. Ossai, L. N. Allison","doi":"10.5897/IJFA15.0497","DOIUrl":"https://doi.org/10.5897/IJFA15.0497","url":null,"abstract":"In this research, mass production of freshwater rotifer, Branchionus calyciflorus, for aquaculture in south-eastern Nigeria, using different food types (Chlorella sp., Spirulina sp and Baker’s yeast) was investigated. Rotifer stock culture was prepared using Nitrogen phosphorus Potassium, (NPK) + urea (50 : 2.5 g) and chicken droppings (25 g) with freshly grown alga. Different food concentrations (150, 300, 650 and 1000 mg/ml) and feeding intervals (2x and 3x per day) were used to grow B. calyciflorus in a Batch culture method. The highest population growth was attained with 650 mg/ml of Chlorella sp. (213.81±9.94 individuals/ml), followed by Baker’s yeast (196.67±8.18 individuals/ml) and 300 mg/ml of Spirulina sp. (151.90±7.98 individuals/ml). The least population growth of B. calyciflorus was recorded with 150 mg/ml concentration of Chlorella sp. and Spirulina sp. (81.43±6.19 and 75.71±5.12 individuals/ml, respectively), and 1000 mg/ml of Baker’s yeast (from local market) (65.24 ±3.86 individuals/ml). The peak population growth was attained on day 8 of experiment (p < 0.05). This study indicated that both the quantity and quality of food type have significant role on mass production of rotifer for aquaculture. \u0000 \u0000 \u0000 \u0000 Key words: Branchionus calyciflorus, mass production, aquaculture, fish farm, Nigeria.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131867815","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}
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