Usipa Engraulicypris sardella is the most abundant small pelagic species in Lake Malawi. It plays an important part in the lake communities’ economy and food security. However, much remains unknown on their stock status and bioeconomic importance. This study is carried out to estimate the maximum economic yield and maximum sustainable yield for Usipa fishery in the South-east arm of Lake Malawi. Structured quantitative questionnaire was used to collect information from 139 informants on the price of usipa landings and cost of fishing effort. Catch and effort data for Usipa were used in a biomass dynamic model (ASPIC) to estimate key parameters (r, q and k). A bioeconomic model was further developed based on the Gordon- Schaefer model using cost and revenues of the Usipa fisheries to derive the Maximun Sustainable Yield (MSY) and the Maximum Economic Yield (MEY). Model estimates of MSY and MEY were 9,228.8 and 8,227.1 tonnes, respectively. The corresponding fishing effort was estimated to be 40,000 net-hauls and 30,000 net-hauls at MSY and MEY, respectively. Revenues at MSY were estimated at MWK42.280 billion, while at MEY the revenues were MWK39.309 billion. The analysis shows that the current effort of 65,232 net-hauls has a yield of 6,000 tonnes, indicating that the Usipa fishery is currently overexploited over the optimum bio-economic level and even beyond the open access yield. We recommend reducing the fishing effort by 54% to realize the best economic benefits (Production at MEY) and end overfishing to protect the fishery from biological and economic collapses. Key words: Usipa, bioeconomic, chilimira, catch per unit effort, maximum economic yield, South east arm.
{"title":"Bioeconomic analysis of Engraulicypris sardella (USIPA) in South east arm of Lake Malawi","authors":"Innocent Gumulira, G. Forrester, N. Lazar","doi":"10.5897/IJFA2018.0714","DOIUrl":"https://doi.org/10.5897/IJFA2018.0714","url":null,"abstract":"Usipa Engraulicypris sardella is the most abundant small pelagic species in Lake Malawi. It plays an important part in the lake communities’ economy and food security. However, much remains unknown on their stock status and bioeconomic importance. This study is carried out to estimate the maximum economic yield and maximum sustainable yield for Usipa fishery in the South-east arm of Lake Malawi. Structured quantitative questionnaire was used to collect information from 139 informants on the price of usipa landings and cost of fishing effort. Catch and effort data for Usipa were used in a biomass dynamic model (ASPIC) to estimate key parameters (r, q and k). A bioeconomic model was further developed based on the Gordon- Schaefer model using cost and revenues of the Usipa fisheries to derive the Maximun Sustainable Yield (MSY) and the Maximum Economic Yield (MEY). Model estimates of MSY and MEY were 9,228.8 and 8,227.1 tonnes, respectively. The corresponding fishing effort was estimated to be 40,000 net-hauls and 30,000 net-hauls at MSY and MEY, respectively. Revenues at MSY were estimated at MWK42.280 billion, while at MEY the revenues were MWK39.309 billion. The analysis shows that the current effort of 65,232 net-hauls has a yield of 6,000 tonnes, indicating that the Usipa fishery is currently overexploited over the optimum bio-economic level and even beyond the open access yield. We recommend reducing the fishing effort by 54% to realize the best economic benefits (Production at MEY) and end overfishing to protect the fishery from biological and economic collapses. \u0000 \u0000 Key words: Usipa, bioeconomic, chilimira, catch per unit effort, maximum economic yield, South east arm.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116888272","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}
Binta Eric Pacôme Goli Bi, T. M. Kamelan, K. B. Kien, S. Berté, E. P. Kouamelan
This study aims to characterize the spatio-temporal variation of the fish assemblages in relation to the environmental variables of Buyo Dam Lake. Sampling was performed from July 2017 to June 2018 using experimental fishing and commercial fishing. Spatio-temporal analysis indicated a significant variation (p <0.05) in pH, electrical conductivity, total dissolved solids, and water transparency. A total of 45 species from 27 genus and 15 families were collected in the samples sites. Two species (Chrysichthys johnelsis and Malapterurus barbatus) are reported for the first time in the lake of Buyo. Among the fishes sampled, of Cichlidae (35.04%) and Claroteidae (16.43%) were the most abundants. The abundant species are Oreochromis niloticus (15.55%) and Chrysichthys nigrodigitatus (15.15%). The analysis of the structure of fish assemblages (H' from 2.28 to 2.75, E from 0.68 to 0.84) revealed a fairly diverse lake environment. The canonical correspondence analysis revealed the significant influence of water pH, electrical conductivity, dissolved solids content, water transparency and nitrite in the distribution of fish species in the lake of Buyo. This work constitute a baseline study for future investigations and will contribute to the implementation of a sustainable management plan for fisheries resources in the continental water. Key words: Environmental parameters, fishes, settlement, Lake of Buyo, Cote d’Ivoire.
{"title":"The spatio-temporal dynamics of the fish assemblage of the man-made Lake Buyo (Cote dIvoire, West Africa)","authors":"Binta Eric Pacôme Goli Bi, T. M. Kamelan, K. B. Kien, S. Berté, E. P. Kouamelan","doi":"10.5897/IJFA2018.0720","DOIUrl":"https://doi.org/10.5897/IJFA2018.0720","url":null,"abstract":"This study aims to characterize the spatio-temporal variation of the fish assemblages in relation to the environmental variables of Buyo Dam Lake. Sampling was performed from July 2017 to June 2018 using experimental fishing and commercial fishing. Spatio-temporal analysis indicated a significant variation (p <0.05) in pH, electrical conductivity, total dissolved solids, and water transparency. A total of 45 species from 27 genus and 15 families were collected in the samples sites. Two species (Chrysichthys johnelsis and Malapterurus barbatus) are reported for the first time in the lake of Buyo. Among the fishes sampled, of Cichlidae (35.04%) and Claroteidae (16.43%) were the most abundants. The abundant species are Oreochromis niloticus (15.55%) and Chrysichthys nigrodigitatus (15.15%). The analysis of the structure of fish assemblages (H' from 2.28 to 2.75, E from 0.68 to 0.84) revealed a fairly diverse lake environment. The canonical correspondence analysis revealed the significant influence of water pH, electrical conductivity, dissolved solids content, water transparency and nitrite in the distribution of fish species in the lake of Buyo. This work constitute a baseline study for future investigations and will contribute to the implementation of a sustainable management plan for fisheries resources in the continental water. \u0000 \u0000 Key words: Environmental parameters, fishes, settlement, Lake of Buyo, Cote d’Ivoire.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114394584","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}
Effect of ‘Earleaf’ plant (Acacia auriculiformis) as feed additive was examined on Clarias gariepinus fingerlings (4.2±0.5 g) over a period 56 days against farm-made feed which served as the control. A. auriculiformis leaves were collected, air-dried (under shade), powdered and added at varying inclusion levels (0, 0.5, 1.0, 1.5 and 2.0%) to basal diets containing 40% crude protein. Fish were randomly distributed into tanks at 10 fish tank-1 with each treatment in triplicate. C. gariepinus were fed at 5% body weight between 8:00 – 9:00 and 16:00 – 17:00 h for 56 days. At the expiration of the feeding trials, results showed significant differences (p<0.05) in growth performance and nutrient utilization indices measured. The highest weight gain (WG), feed intake (FI), specific growth rate (SGR), protein efficiency ratio (PER) and best feed conversion ratio (FCR) were recorded in C. gariepinus fed A. auriculiformis at 1.5% supplementation level. Fish fed A. aurculiformis supplemented diets had higher WG (3.60 and 5.73 g) than those fed the control diet. Incorporating A. auriculiformis into fish diets did not have any adverse effect on the physiochemical water parameters measured as they were within the recommended ranges for raising warm water fish species. Results showed that diet supplementation with A. auriculiformis at 1.5 and 2.0% gave best growth performance and higher protein conversion, hence, the recommendation for diet supplementation at 1.5 or 2.0% inclusion levels. Key words: Catfish, growth, Acacia auriculiformis, utilization.
{"title":"Growth and feed utilization in Clarias gariepinus fingerlings fed on Acacia auriculiformis leaf supplemented diets","authors":"Afe Oluwafunmilola Eunice, Omosowone Olajumoke Olamiposi","doi":"10.5897/IJFA2018.0677","DOIUrl":"https://doi.org/10.5897/IJFA2018.0677","url":null,"abstract":"Effect of ‘Earleaf’ plant (Acacia auriculiformis) as feed additive was examined on Clarias gariepinus fingerlings (4.2±0.5 g) over a period 56 days against farm-made feed which served as the control. A. auriculiformis leaves were collected, air-dried (under shade), powdered and added at varying inclusion levels (0, 0.5, 1.0, 1.5 and 2.0%) to basal diets containing 40% crude protein. Fish were randomly distributed into tanks at 10 fish tank-1 with each treatment in triplicate. C. gariepinus were fed at 5% body weight between 8:00 – 9:00 and 16:00 – 17:00 h for 56 days. At the expiration of the feeding trials, results showed significant differences (p<0.05) in growth performance and nutrient utilization indices measured. The highest weight gain (WG), feed intake (FI), specific growth rate (SGR), protein efficiency ratio (PER) and best feed conversion ratio (FCR) were recorded in C. gariepinus fed A. auriculiformis at 1.5% supplementation level. Fish fed A. aurculiformis supplemented diets had higher WG (3.60 and 5.73 g) than those fed the control diet. Incorporating A. auriculiformis into fish diets did not have any adverse effect on the physiochemical water parameters measured as they were within the recommended ranges for raising warm water fish species. Results showed that diet supplementation with A. auriculiformis at 1.5 and 2.0% gave best growth performance and higher protein conversion, hence, the recommendation for diet supplementation at 1.5 or 2.0% inclusion levels. \u0000 \u0000 Key words: Catfish, growth, Acacia auriculiformis, utilization.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116712427","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}
The study of the socio-economic characteristics of any group is a requirement to a successful implementation of effective government assisted programme. The study examined the socio-economic characteristics, production processes and production constraints of small-scale catfish fishing enterprises in Obio/Akpor Local Government Area in Rivers State, Nigeria. Simple randomized sampling technique was used to select 60 small-scale catfish farming enterprises. Structure questionnaires were used to collect primary data from the respondents. The collected information were analyzed using simple descriptive statistics. The results showed that majority of the farmers were females (58%), married (74%), within the age group (31-40 years), Christians (92%), Igbo tribe (22%), and had university degree (58%) with household size (6-10). Majority have fish farming as primary occupation (32%), 1-5 years of experience, non-members of association (83%) and chose fish farming for profit maximization (50%). Based on this study, different aquaculture production systems were identified at the study area such as concrete tanks (34%), plastics tanks (20%), concrete+plastic (20%), earthen ponds (12%), earthen+concrete (8%), and earthen+plastics (6%). Respondents purchased land (66%), kept record (52%), used imported feed (52%), flow-through techniques (88%), monoculture as culture system (66%), stocked Clarias gariepinus (88%), bore-hole as water source (96%), procured fingerlings from private farms (84%) and personal savings as source of funding (86%). Some of the constraints like lack of extension service (76%), disease outbreak (52%), lack of capital (44%), lack of electricity (38%), preservation and processing (18%), lack of skilled human labour (10%), and lack of government assisted programmes (0%) were faced. In conclusion, catfish farming promises to improve in the area if there is adequate government assistance. Key words: Catfish, Clarias gariepinus, production constraints, production processes, small-scale.
{"title":"Socio-economic characteristics of small-scale catfish farming enterprise in Obio/Akpor Local Government Area, Rivers State, Nigeria","authors":"D. Amachree, N. Jamabo, Dorah E. Joseph","doi":"10.5897/IJFA2018.0695","DOIUrl":"https://doi.org/10.5897/IJFA2018.0695","url":null,"abstract":"The study of the socio-economic characteristics of any group is a requirement to a successful implementation of effective government assisted programme. The study examined the socio-economic characteristics, production processes and production constraints of small-scale catfish fishing enterprises in Obio/Akpor Local Government Area in Rivers State, Nigeria. Simple randomized sampling technique was used to select 60 small-scale catfish farming enterprises. Structure questionnaires were used to collect primary data from the respondents. The collected information were analyzed using simple descriptive statistics. The results showed that majority of the farmers were females (58%), married (74%), within the age group (31-40 years), Christians (92%), Igbo tribe (22%), and had university degree (58%) with household size (6-10). Majority have fish farming as primary occupation (32%), 1-5 years of experience, non-members of association (83%) and chose fish farming for profit maximization (50%). Based on this study, different aquaculture production systems were identified at the study area such as concrete tanks (34%), plastics tanks (20%), concrete+plastic (20%), earthen ponds (12%), earthen+concrete (8%), and earthen+plastics (6%). Respondents purchased land (66%), kept record (52%), used imported feed (52%), flow-through techniques (88%), monoculture as culture system (66%), stocked Clarias gariepinus (88%), bore-hole as water source (96%), procured fingerlings from private farms (84%) and personal savings as source of funding (86%). Some of the constraints like lack of extension service (76%), disease outbreak (52%), lack of capital (44%), lack of electricity (38%), preservation and processing (18%), lack of skilled human labour (10%), and lack of government assisted programmes (0%) were faced. In conclusion, catfish farming promises to improve in the area if there is adequate government assistance. \u0000 \u0000 Key words: Catfish, Clarias gariepinus, production constraints, production processes, small-scale.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134069073","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}
Kingsley Kamtambe, James Banda, Barnett Kaphuka, O. Msiska
The benthic zone of Lake Malombe was sampled for invertebrates, fungi and bacteria using an Ekman Grab measuring 15.2 cm by 15.2 cm. Thirty-six stations were surveyed for macro-invertebrates which were identified to the lowest taxa and enumerated to estimate abundance for the lake. Snails were the most dominant macro fauna, belonging to four genera Melanoides, Bellamya, Bulinus and Lanistes with the mean densities of 177.5, 34.7, and 4.3 and 0.1 m-2 individuals, respectively. Blood worms and Tubifex were also present. Although there are few such studies in Malawi, it was generally postulated that dominance of snails is a recent phenomenon following previous studies which showed that the invasion of a form of Melanoides of Asian origin; its success might be responsible for its proliferation. The benthic substrate was mainly composed of mud, clay granules, sand and bedrock. The biomass of macro-fauna is being reported here for the first time and coincides with a decline in fish catches on Lake Malombe. The prevalence of Melanoides species and other high pollution tolerance species suggests that there is high ecosystem modification due to anthropogenic activities including sediment and nutrient loading from agricultural practices in the surrounding area. Compared to Lake Malawi and Upper Shire, Lake Malombe is by far the most productive. There were significantly higher (P<0.5) densities of aerobic, anaerobic bacteria and fungi, demonstrating the importance of the detrital food chain. Therefore, future programs aimed at enhancing fish restoration in Lake Malombe would be advised to include a suite of bottom feeding fish species. The state of benthos found in Lake Malombe is an indication of confounding impacts of over-fishing, climate change and catchment-wide activities. Thus, use of QIIME software could unravel microbiome characteristics, including climate change signatures. Similarly, further studies on food webs could contribute to a better understanding of the Lake Malombe trophic functions. Key words: Benthic invertebrates, aquatic snails, fungi, bacteria, ecosystems, food chain, Lake Malombe.
在Malombe湖的底栖动物区，使用15.2 cm × 15.2 cm的Ekman抓斗对无脊椎动物、真菌和细菌进行了采样。调查了36个站点的大型无脊椎动物，确定了最低的分类群，并对其进行了计数，以估计湖泊的丰度。钉螺是最大的大型动物区系，分别隶属于黑蜗牛属、贝蜗牛属、布蜗牛属和蜗牛属4个属，平均密度分别为177.5、34.7、4.3和0.1 m-2。血虫和管虫也存在。虽然在马拉维很少有这样的研究，但人们普遍认为蜗牛的优势是最近的现象，此前的研究表明，一种亚洲起源的黑素体的入侵;它的成功可能是其扩散的原因。底栖基质主要由泥、粘土颗粒、砂和基岩组成。这里首次报告了大型动物的生物量，与此同时，马伦贝湖的捕鱼量也在下降。黑素体物种和其他高污染耐受性物种的流行表明，由于人类活动，包括沉积物和农业实践的养分负荷，周围地区的生态系统发生了高度的改变。与马拉维湖和上郡相比，马伦贝湖是迄今为止产量最高的湖。好氧菌、厌氧菌和真菌的密度显著增高(P<0.5)，说明了碎屑食物链的重要性。因此，未来旨在加强马隆贝湖鱼类恢复的计划将被建议包括一套底食鱼类。马伦贝湖底栖生物的状况表明，过度捕捞、气候变化和整个流域的活动造成了复杂的影响。因此，使用QIIME软件可以揭示微生物组的特征，包括气候变化特征。同样，对食物网的进一步研究可能有助于更好地了解马伦贝湖的营养功能。关键词:底栖无脊椎动物，水生蜗牛，真菌，细菌，生态系统，食物链，Malombe湖
{"title":"The abundance, distribution and diversity of benthic invertebrates of Lake Malombe","authors":"Kingsley Kamtambe, James Banda, Barnett Kaphuka, O. Msiska","doi":"10.5897/IJFA2018.0688","DOIUrl":"https://doi.org/10.5897/IJFA2018.0688","url":null,"abstract":"The benthic zone of Lake Malombe was sampled for invertebrates, fungi and bacteria using an Ekman Grab measuring 15.2 cm by 15.2 cm. Thirty-six stations were surveyed for macro-invertebrates which were identified to the lowest taxa and enumerated to estimate abundance for the lake. Snails were the most dominant macro fauna, belonging to four genera Melanoides, Bellamya, Bulinus and Lanistes with the mean densities of 177.5, 34.7, and 4.3 and 0.1 m-2 individuals, respectively. Blood worms and Tubifex were also present. Although there are few such studies in Malawi, it was generally postulated that dominance of snails is a recent phenomenon following previous studies which showed that the invasion of a form of Melanoides of Asian origin; its success might be responsible for its proliferation. The benthic substrate was mainly composed of mud, clay granules, sand and bedrock. The biomass of macro-fauna is being reported here for the first time and coincides with a decline in fish catches on Lake Malombe. The prevalence of Melanoides species and other high pollution tolerance species suggests that there is high ecosystem modification due to anthropogenic activities including sediment and nutrient loading from agricultural practices in the surrounding area. Compared to Lake Malawi and Upper Shire, Lake Malombe is by far the most productive. There were significantly higher (P<0.5) densities of aerobic, anaerobic bacteria and fungi, demonstrating the importance of the detrital food chain. Therefore, future programs aimed at enhancing fish restoration in Lake Malombe would be advised to include a suite of bottom feeding fish species. The state of benthos found in Lake Malombe is an indication of confounding impacts of over-fishing, climate change and catchment-wide activities. Thus, use of QIIME software could unravel microbiome characteristics, including climate change signatures. Similarly, further studies on food webs could contribute to a better understanding of the Lake Malombe trophic functions. \u0000 \u0000 Key words: Benthic invertebrates, aquatic snails, fungi, bacteria, ecosystems, food chain, Lake Malombe.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"206 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116125862","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}
A. Nasr-Allah, O. Habib, M. Dickson, H. Charo-Karisa
Although, High Dam Lake small-scale fisheries is an important source of fish for residents of Aswan in Upper Egypt, there is limited information available about the performance of small-scale fisheries value chain. Structured questionnaires with fishers, traders, and processors were used to collect input and output data at each node of the chain. Focus group discussions meeting with stakeholder collected qualitative information about and critical factors influencing performance across the chain. Catch distribution composed mainly from tilapias 75%. While pebbly fish (Alestes spp.) and tigerfish (Hydrocynus spp.) accounts for 13% of catch. Fish processing is an important subsector in lake fisheries. Fishers obtained a relatively low percentage (49%) of the final consumer price. The recorded average catch per fisher 20 kg/day and the average total fishing cost in the three landing sites was EGP 5210 / t. Every 100 metric tons of fish catch and sell provides around 30 full-time equivalent jobs. This study revealed that fish stock is under pressure of overfishing. Critical factors facing the small-scale fisheries and influencing profitability are numerous. This value chain study improves our understanding of the performance of small-scale fisheries and identified limiting factors and action needed to support fisheries development in the lake. Key words: Small-scale fisheries, value chain, tilapia, tigerfish, pebbly fish.
{"title":"Value chain analysis of small-scale fisheries in the High Dam Lake in Egypt","authors":"A. Nasr-Allah, O. Habib, M. Dickson, H. Charo-Karisa","doi":"10.5897/IJFA2018.0663","DOIUrl":"https://doi.org/10.5897/IJFA2018.0663","url":null,"abstract":"Although, High Dam Lake small-scale fisheries is an important source of fish for residents of Aswan in Upper Egypt, there is limited information available about the performance of small-scale fisheries value chain. Structured questionnaires with fishers, traders, and processors were used to collect input and output data at each node of the chain. Focus group discussions meeting with stakeholder collected qualitative information about and critical factors influencing performance across the chain. Catch distribution composed mainly from tilapias 75%. While pebbly fish (Alestes spp.) and tigerfish (Hydrocynus spp.) accounts for 13% of catch. Fish processing is an important subsector in lake fisheries. Fishers obtained a relatively low percentage (49%) of the final consumer price. The recorded average catch per fisher 20 kg/day and the average total fishing cost in the three landing sites was EGP 5210 / t. Every 100 metric tons of fish catch and sell provides around 30 full-time equivalent jobs. This study revealed that fish stock is under pressure of overfishing. Critical factors facing the small-scale fisheries and influencing profitability are numerous. This value chain study improves our understanding of the performance of small-scale fisheries and identified limiting factors and action needed to support fisheries development in the lake. \u0000 \u0000 Key words: Small-scale fisheries, value chain, tilapia, tigerfish, pebbly fish.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131008877","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}
Any adverse change in the environmental conditions affects the life of aquatic organisms in water. Fish death was suddenly observed in Lake Kabo. To investigate its cause and look for solution, a research team started to consider the Lake. The present study was conducted to identify the reason for the fish deaths that accidentally occur in the lake. To achieve the objective samples were collected from four different sampling sites on the lake from October 2017 to August 2018. The four sampling stations on the lake were selected based on criteria and were coded. Sample collection was made every month. Data were analyzed using SPSS version 23. Experimental activities were carried out both on the spot and in laboratory. The results analyzed were compared with permissible limits prescribed by WHO, FAO, BIS and other references. In this study, the pH (6.1-8.7), total dissolved solid (TDS) (60-251.3 mg/L) and total alkalinity (101-195 mg/L) of the lake followed the prescribed limits set by WHO (1993) and BIS (1991). Critical dissolved oxygen (DO) value (2.8-4.7 mg/L) and temperature (T°) (25-30°C) of the lake were found below the specified limit for tilapia Fish. In this study, the reasons for the sudden death of tilapia fish in the lake include: highly fluctuated values of T°, DO and pH value of the lake water especially in rainy season. The study concluded that tilapia fish could not tolerate the fluctuation of DO value which is less than 3 mg/L. The result from secchi-disk also supported the less value of DO. The mean nutrients values for Ca++, PO4-3 and (Cl-) of the lake were 7.6 ± 2.6, 0.1039±0.15 and 1.5102±0.7 mg/L, respectively. The reduced level of DO and extreme fluctuation of pH were the expected reasons for the sudden fish death in the lake during rainy season. Key words: Lake Kabo, pH, dissolved oxygen (DO), total dissolved solid (TDS), Secchi-disk.
{"title":"Identification of possible causes of fish death in Lake Lake Kabo","authors":"Sefawdin Berta Bedassa","doi":"10.5897/IJFA2018.0721","DOIUrl":"https://doi.org/10.5897/IJFA2018.0721","url":null,"abstract":"Any adverse change in the environmental conditions affects the life of aquatic organisms in water. Fish death was suddenly observed in Lake Kabo. To investigate its cause and look for solution, a research team started to consider the Lake. The present study was conducted to identify the reason for the fish deaths that accidentally occur in the lake. To achieve the objective samples were collected from four different sampling sites on the lake from October 2017 to August 2018. The four sampling stations on the lake were selected based on criteria and were coded. Sample collection was made every month. Data were analyzed using SPSS version 23. Experimental activities were carried out both on the spot and in laboratory. The results analyzed were compared with permissible limits prescribed by WHO, FAO, BIS and other references. In this study, the pH (6.1-8.7), total dissolved solid (TDS) (60-251.3 mg/L) and total alkalinity (101-195 mg/L) of the lake followed the prescribed limits set by WHO (1993) and BIS (1991). Critical dissolved oxygen (DO) value (2.8-4.7 mg/L) and temperature (T°) (25-30°C) of the lake were found below the specified limit for tilapia Fish. In this study, the reasons for the sudden death of tilapia fish in the lake include: highly fluctuated values of T°, DO and pH value of the lake water especially in rainy season. The study concluded that tilapia fish could not tolerate the fluctuation of DO value which is less than 3 mg/L. The result from secchi-disk also supported the less value of DO. The mean nutrients values for Ca++, PO4-3 and (Cl-) of the lake were 7.6 ± 2.6, 0.1039±0.15 and 1.5102±0.7 mg/L, respectively. The reduced level of DO and extreme fluctuation of pH were the expected reasons for the sudden fish death in the lake during rainy season. \u0000 \u0000 Key words: Lake Kabo, pH, dissolved oxygen (DO), total dissolved solid (TDS), Secchi-disk.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133415899","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}
Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represents an important source of low cost protein in the Senegalese market. The objective of this study was to determine the age, growth and mortality parameters of S. aurita obtained from the Senegalese coastal waters. Age, growth parameters and mortality rates of this species were estimated using FiSAT II (FAO–ICLARM Stock Assessment Tools) software. A total of 5104 specimens of S. aurita were collected monthly between March 2012 and February 2013 from commercial landings in three sites of Senegalese coasts (Joal, Mbour and Kayar). Mean growth parameters for the entire period were estimated as L∞= 32.82 cm, K= 1.10 year-1 and t0 = -0.14 year. Instantaneous total mortality (Z = 2.77 year-1) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Natural mortality (M = 1.49 year-1) was estimated using the Pauly’s empirical equation and fishing mortality (F = 1.28 year-1) by the difference between total and natural mortality values. The exploitation rate (E) of 0.46 indicated no over-fishing on this species. Key words: Round sardinella, age, growth, mortality, Senegalese coast.
aurita沙丁鱼是塞内加尔小规模渔业捕捞的主要品种，是塞内加尔市场上低成本蛋白质的重要来源。本研究的目的是确定从塞内加尔沿海水域获得的金黄色葡萄球菌的年龄、生长和死亡率参数。使用FiSAT II (FAO-ICLARM种群评估工具)软件估计该物种的年龄、生长参数和死亡率。2012年3月至2013年2月期间，在塞内加尔海岸的3个地点(Joal、mour和Kayar)每月采集了5104个aurita标本。整个时期的平均生长参数为L∞= 32.82 cm, K= 1.10 year-1和t0 = -0.14 year。利用捕获曲线和基于捕获鱼的平均长度的方法估计每年瞬时总死亡率(Z = 2.77 -1)系数。自然死亡率(M = 1.49 year-1)采用保利经验方程估算，捕捞死亡率(F = 1.28 year-1)采用总死亡率与自然死亡率之差估算。捕捞率(E)为0.46，表明未发生过度捕捞。关键词:圆沙丁鱼，年龄，生长，死亡率，塞内加尔海岸。
{"title":"Age, growth and mortality rates of round sardinella, Sardinella aurita (Valenciennes, 1810) from the Senegalese coasts (West Africa)","authors":"A. Sarr, I. Ndiaye, W. Ndiaye, A. Faye, M. Diouf","doi":"10.5897/IJFA2018.0716","DOIUrl":"https://doi.org/10.5897/IJFA2018.0716","url":null,"abstract":"Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represents an important source of low cost protein in the Senegalese market. The objective of this study was to determine the age, growth and mortality parameters of S. aurita obtained from the Senegalese coastal waters. Age, growth parameters and mortality rates of this species were estimated using FiSAT II (FAO–ICLARM Stock Assessment Tools) software. A total of 5104 specimens of S. aurita were collected monthly between March 2012 and February 2013 from commercial landings in three sites of Senegalese coasts (Joal, Mbour and Kayar). Mean growth parameters for the entire period were estimated as L∞= 32.82 cm, K= 1.10 year-1 and t0 = -0.14 year. Instantaneous total mortality (Z = 2.77 year-1) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Natural mortality (M = 1.49 year-1) was estimated using the Pauly’s empirical equation and fishing mortality (F = 1.28 year-1) by the difference between total and natural mortality values. The exploitation rate (E) of 0.46 indicated no over-fishing on this species. \u0000 \u0000 Key words: Round sardinella, age, growth, mortality, Senegalese coast.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123743413","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}
D. A. Campelo, Matheus Henrique Correa Marques, Odinilson Pereira Marim, L. B. Moura, Bruno José Corecha Fernandes Eiras, M. F. Brabo, G. C. Veras
The aim of this study is to evaluate the effect of different feeding rates and frequencies on angelfish (Pterophyllum scalare) and severum (Heros severus) larvae. For this purpose, two similar experiments were conducted in parallel. For each experiment, a total of 360 larvae were distributed in 36-1 L aquariums. The experiments were done using a factorial 3x3 completely randomized design, with four replicates. The feeding rates of 50, 100 and 150 artemia nauplii larvae-1 and the feeding frequencies of one, two and four meals day-1 were tested. Parameters of growth performance, uniformity of the batch and survival rate were determined at the end of both experimental periods. No interaction was observed between feed rates and frequencies in angelfish for all parameters evaluated; growth performance was higher in fish fed with 150 nauplii larvae-1, which were divided in two and four meals day-1. The severum larvae presented interaction between feeding rates and feeding frequencies; growth performance was higher in fish fed with two and four meals day-1. Thus, in order to facilitate feed management and reduce manpower costs during ornamental angelfish and severum larvae production, it is recommended to supply 150 artemia nauplii larvae-1 divided in two meals day-1 to fish. Key words: Angelfish, feeding practices, ornamental fish farming, severum.
{"title":"Effects of feeding rates and feeding frequencies on growth performance, uniformity of the batch and survival rate of Amazon ornamental fish larvae","authors":"D. A. Campelo, Matheus Henrique Correa Marques, Odinilson Pereira Marim, L. B. Moura, Bruno José Corecha Fernandes Eiras, M. F. Brabo, G. C. Veras","doi":"10.5897/IJFA2018.0705","DOIUrl":"https://doi.org/10.5897/IJFA2018.0705","url":null,"abstract":"The aim of this study is to evaluate the effect of different feeding rates and frequencies on angelfish (Pterophyllum scalare) and severum (Heros severus) larvae. For this purpose, two similar experiments were conducted in parallel. For each experiment, a total of 360 larvae were distributed in 36-1 L aquariums. The experiments were done using a factorial 3x3 completely randomized design, with four replicates. The feeding rates of 50, 100 and 150 artemia nauplii larvae-1 and the feeding frequencies of one, two and four meals day-1 were tested. Parameters of growth performance, uniformity of the batch and survival rate were determined at the end of both experimental periods. No interaction was observed between feed rates and frequencies in angelfish for all parameters evaluated; growth performance was higher in fish fed with 150 nauplii larvae-1, which were divided in two and four meals day-1. The severum larvae presented interaction between feeding rates and feeding frequencies; growth performance was higher in fish fed with two and four meals day-1. Thus, in order to facilitate feed management and reduce manpower costs during ornamental angelfish and severum larvae production, it is recommended to supply 150 artemia nauplii larvae-1 divided in two meals day-1 to fish. Key words: Angelfish, feeding practices, ornamental fish farming, severum.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127720292","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}
Fish sustainability in an aquatic environment involves continuous and judicious management towards optimum production of resources, for rational utilization and availability for future generation. Stomach composition of Oreochromis niloticus collected from a tropical brackish water environment was investigated to assess food availability towards optimum fish productivity for rational public utilization. Oreochromis niloticus, a fish of high economic importance and a generalize omnivore endemic to fresh and brackish water of Sub-Saharan Africa, and Asia, was reviewed to know the food availability status of the Lagos Lagoon, Nigeria. The conditions of stomach contents of O. niloticus samples collected were visually determined and subjected to frequency of occurrence, dominance, numerical, volumetric and relative index methods. Analytical and descriptive statistics were used to show occurrence, prevalence and availability of food organisms, within Lagos Lagoon. Results of the investigation revealed the presence of phytoplankton, dinoflagellates, sand grains, insect parts, plants parts, fish parts and unidentified constituents in O. niloticus stomach contents. O. niloticus revealed herbivorous feeding habit and Bacillariophyceae food item with highest occurrence. Food items satisfy requirements for optimum sustainability. Key words: Stomach contents, tropical, Oreochromis niloticus, Lagos Lagoon, Nigeria.
{"title":"Assessment of stomach contents of Oreochromis niloticus from the Lagos Lagoon, Nigeria","authors":"A. O. Abidemi-Iromini","doi":"10.5897/IJFA2018.0687","DOIUrl":"https://doi.org/10.5897/IJFA2018.0687","url":null,"abstract":"Fish sustainability in an aquatic environment involves continuous and judicious management towards optimum production of resources, for rational utilization and availability for future generation. Stomach composition of Oreochromis niloticus collected from a tropical brackish water environment was investigated to assess food availability towards optimum fish productivity for rational public utilization. Oreochromis niloticus, a fish of high economic importance and a generalize omnivore endemic to fresh and brackish water of Sub-Saharan Africa, and Asia, was reviewed to know the food availability status of the Lagos Lagoon, Nigeria. The conditions of stomach contents of O. niloticus samples collected were visually determined and subjected to frequency of occurrence, dominance, numerical, volumetric and relative index methods. Analytical and descriptive statistics were used to show occurrence, prevalence and availability of food organisms, within Lagos Lagoon. Results of the investigation revealed the presence of phytoplankton, dinoflagellates, sand grains, insect parts, plants parts, fish parts and unidentified constituents in O. niloticus stomach contents. O. niloticus revealed herbivorous feeding habit and Bacillariophyceae food item with highest occurrence. Food items satisfy requirements for optimum sustainability. \u0000 \u0000 Key words: Stomach contents, tropical, Oreochromis niloticus, Lagos Lagoon, Nigeria.","PeriodicalId":415026,"journal":{"name":"International Journal of Fisheries and Aquaculture","volume":"121 36","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120818679","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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