Aquatic Ecosystem Health and Management最新文献

{"title":"A tribute to Dr. Göran Dave: Memories of a super scientist, close friend and founding patron of the Aquatic Ecosystem Health and Management Society","authors":"M. Munawar, I. Munawar, N. Munawar","doi":"10.14321/aehm.026.01.92","DOIUrl":"https://doi.org/10.14321/aehm.026.01.92","url":null,"abstract":"","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129228807","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}

{"title":"Protection of fish breeding areas in Lake Baringo and the potential for sustainable resource management","authors":"James Mugo, C. Odoli, K. Nyakeya","doi":"10.14321/aehm.025.04.53","DOIUrl":"https://doi.org/10.14321/aehm.025.04.53","url":null,"abstract":"Lake Baringo (located in Kenya, East Africa) fishery is currently under perturbation with diverse annual fluctuations in the catch landings. In an attempt to remedy the declining fishery, Kenya Marine and Fisheries Research Institute, Fisheries Department and Beach Management Units, identified and demarcated three fish breeding areas for protection. To assess the effectiveness of these protected fish breeding areas, three fleets of multifilament gillnets (mesh sizes; 25.4 to 203.2 mm) were set between February and December 2018. One fleet was set inside the breeding area, whereas the other two fleets were set 200m and 400m outsides. Fish species abundance, size structure and maturity stages were analyzed from the catch. Fish species abundance was higher within fish breeding areas (67.8%) than outside (32.2%). Labeobarbus intermedius was the most abundant (55.3 %), followed by Oreochromis niloticus baringoensis (29.9%), Labeo cylindricus (13.2%) and Clarias gariepinus (1.7%). Even though larger fish sizes were recorded outside than inside fish breeding areas, they were not statistically different irrespective of seasons (P>0.05). Majority of the fish (approx. 70%) both inside and outside the breeding areas were in gonad stages 1 and 2. The results indicate that the three areas have great potential to increase fish productivity through fish recruitment and subsequent spillover into fishing grounds. It is recommended that stakeholders, especially Beach Management Units and County Government Department of Fisheries, focus on actualizing the protection of fish breeding areas through enhanced monitoring and surveillance. Fishers should also be sensitized on protected areas concept, coupled with the need to use proper mesh sizes and fishing effort. Beach Management Units should be strengthened as co-management units to guarantee sustainable fisheries resource utilization in Lake Baringo.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116712779","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}

{"title":"Cage farming in the environmental mix of Lake Victoria: An analysis of its status, potential environmental and ecological effects, and a call for sustainability","authors":"K. Nyakeya, F. O. Masese, Z. Gichana, Jane M. Nyamora, A. Getabu, J. Onchieku, C. Odoli, Robert Nyakwama","doi":"10.14321/aehm.025.04.37","DOIUrl":"https://doi.org/10.14321/aehm.025.04.37","url":null,"abstract":"Lake Victoria is the second largest freshwater lake in the world that was once a biodiversity hotspot hosting over 500 endemic haplochromine cichlids that were later decimated by exotic introductions and anthropogenically driven environmental and ecological changes. The environmental and ecological changes in the lake over the years have been attributed to overfishing, eutrophication, introduction of exotic species, pollution and possibly climate change. The lake's capture fishery, which is the main economic activity directly and indirectly supporting over 40 million people, has continued to decline after experiencing a boom between the 1970s and 1990s following the introduction of Nile Perch (Lates niloticus) and Nile Tilapia (Oreochromis niloticus). In order to augment capture fisheries from the lake, cage culture was introduced in 2005, but its sustainability and influence on the ecology of the lake are not well understood. In this review, we examine the genesis of degradation of Lake Victoria and assess the role of cage culture as both a solution to the current situation and a cause for concern for the ecology of the lake. To compile this review, we utilized data in the grey and published literature. Studies show that the degradation of the lake can be traced back to the 1930s when the trophic status and ecology of the lake started showing signs of anthropogenic influence. The Nile Perch was introduced in early 1960s to replenish the fishery but its ecological impacts were felt in 1970s and 1980s when the native haplochromine species started to disappear from catches. Progressively, the ecological changes and management concerns in the lake have become a complex mix of exotic species introductions, eutrophication, and overfishing. In this mix of persistent ecological changes, the once thriving capture fisheries revolving around the two exotic species (L. niloticus and O. niloticus) have significantly declined threatening the livelihoods of millions of people directly and indirectly involved in the fisheries. These declines necessitated the introduction of cage culture in 2005 to fill the increasing demand for fish from the lake. Ever since, cage numbers have increased tremendously (>6 000 by 2020) and is now operated by over 60 different firms which are owned either individually or by groups. Over 70% of the cages have been installed in shallow areas within the Winam Gulf which goes against the guidelines on cage installation and operation; regulations on cage farming were introduced after the activity had gained momentum in the lake. Limnological data in areas of the lake that have been stocked with cages has shown evidence of negative effects on water quality. This decline in water quality can be attributed to remnant feeds used in cages, of which 50% are the sinking types, and wastes from fish excretion and egestion. Although data are limited, the potential influence of cage farming on the already altered ecology and environment of Lake Vi","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129934698","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}

{"title":"Emerging frontiers for blue growth in African Great Lakes: The potential for recreational fishing industry in Lake Victoria, Kenya","authors":"H. Nyaboke, J. Nyaundi, M. Owili, C. Nyamweya, C. Aura, Nicholas N. Gichuru, J. Okechi, H. Owiti, V. Sudoi, D. Liti","doi":"10.14321/aehm.025.04.03","DOIUrl":"https://doi.org/10.14321/aehm.025.04.03","url":null,"abstract":"Sport fishing for Nile Perch and Tilapia are key attractions to recreational anglers on Lake Victoria. Existing hospitality establishments promote sport fishing with angling as the main form of recreational fishing. Development of this industry is expected to generate accrued benefits of eco-tourism and community empowerment by providing alternative sources of income from the already strangled commercial and subsistence fisheries calling for diversification within the fishing industry. Key informant questionnaires were administered to County tourism and fisheries representatives, hotel directors or managers, and officials of Beach Management Units while questionnaire-led-interviews were conducted at the beaches or community recreation sites. Seven tourist resorts, one yacht club, and seven beaches/fish landing sites were assessed. The study aimed to assess the current status of recreational fishing and identify growth opportunities within the industry. Recreational fishing was concentrated around Mfangano Island targeting Nile Perch using artificial baitfish as a tackle. On average, boat hire charges including fishing tackle were USD 30 per trip (< 3 hours) and USD 100 per day per fishing trip. “Blue tourism” rating was low across the respondents with the 2007 political unrest said to have heavily impacted the number of tourists to the region. Water Hyacinth and poor water quality remain a key challenge within Winam gulf while overfishing posed a major concern in the open lake with the number of longline fishers reported to be on the rise. Resource spatial planning should be instituted to cater for the different players in the Blue Economy. The strict enforcement of the Nile Perch slot size is recommended and cooperation among industry players on access and use of the products from recreational fishing. A national census survey on recreational catches should be conducted if its full potential is to be realized in promoting blue growth.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124454901","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}

{"title":"Future demand and supply of aquafeed ingredients: Outlines to commercialize non-conventional protein ingredients to enhance aquaculture production for food security in sub-Saharan Africa","authors":"Robert Ondiba, E. Ogello, E. Kembenya, Z. Gichana, K. Obiero","doi":"10.14321/aehm.025.04.75","DOIUrl":"https://doi.org/10.14321/aehm.025.04.75","url":null,"abstract":"Aquaculture, being the fastest growing food sector, is expected to provide the highly needed animal protein for about 9.7 billion people globally by 2050. The world population is likely to consume 178 million tons of food fish/aquatic animals by 2028, whereby 58% of fish will likely be from aquaculture. Growth of food fish production is expected to increase overall production of aquafeeds to over 87 million tons by 2025. Aquafeed production relies largely on fishmeal which is getting expensive due to its multiple use and scarcity. A remedy to this situation is the use of non-conventional protein sources, which may be of plant (leaves, cereals, pulses etc.) or animal (insects, worms, etc.) origin. This paper demonstrates the potential of non-conventional ingredients for aquaculture. It was found that crude protein levels of selected non-conventional plant ingredients ranged from 25-71% while those of animal origin were from 66-72%. Inclusion levels of 5-40% and 25-66% were recommended in aquafeeds, respectively, from ingredients of plant and animal origin. Performances of fish fed aquafeeds containing selected non-conventional ingredients have been reviewed. Presence of anti-nutrients, chitin and high lipid in feed ingredients, and shortcomings in processing and mass production technologies, have been identified as the main challenges limiting the commercialization of the selected feed ingredients. To remove the unwanted factors and to enhance inclusion of non-conventional ingredients in aquafeeds, authors suggested varied strategies. The strategies such as defatting, heat treatment, extrusion cooking, solvent extraction, dehulling, fermentation, ensiling, genetic modification and inclusion of enzyme are identified as some of the most efficient methods. Effective and affordable technologies to improve nutritional value should be validated through research for adequate and consistent supply of aquafeed in Sub-Saharan Africa. Consequently, provision of sufficient, quality and affordable aquafeeds will promote sustainable aquaculture production and reduce fishing pressure and pollution in natural aquatic ecosystems.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124173823","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}

{"title":"Feasibility for cage farming in Africa: The case of the Kenyan part of Lake Victoria","authors":"Z. Shitote, Norman Osieko Munala, J. S. Maremwa","doi":"10.14321/aehm.025.04.22","DOIUrl":"https://doi.org/10.14321/aehm.025.04.22","url":null,"abstract":"Fish catches in Lake Victoria have been on the decline, while demand for fish has been increasing because of rapid human population growth and awareness of the health benefits of fish. This decline is attributed to socioeconomic activities around the lake and climate change effects. To bridge the gap, cage culture has presented itself as a new socioeconomic frontier with good prospects for income in Lake Victoria, besides conserving declining wild fish stocks. However, these cages are greatly influencing the biodiversity of the lake both negative and positive. The study adopted a descriptive survey research where a total of 200 cage fish farmers were targeted. A sample of 60 fish farmers was selected using purposive and simple random sampling methods. Interview schedules and self-administered questionnaires were the main tools for data collection. Both primary and secondary data were collected and analyzed using Statistical Package for Social Sciences. The results were: the majority of cage fish farmers were male (87%) while the female was 13%, with a majority (75%) of the secondary and tertiary level of education. The beach management units and fish farmers were responsible for siting of cages. The fish farmers experienced several challenges including high cost of feeds leading to the use of poor quality feeds that sink and increase eutrophication, which enhances the growth of algae and water hyacinth in the lake. Overstocking leads to the emergence of diseases and fish kills, and fish theft resulting in economic loss. Most (80%) of respondents were not aware of policy guidelines on cage culture in Lake Victoria, while (75%) were not aware if cage culture was promoting climate change effects in Lake Victoria. This paper recommends the government to create awareness of policy guidelines on cage fish farming.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129965972","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}

{"title":"Challenges to the lake fisheries, and factors affecting the effectiveness of a co-management regime in African Great Lakes: A case study of Lake Victoria, Kenya","authors":"C. Odoli, H. Owiti, J. Mwamburi, P. Oduor-Odote, H. Nyaboke, C. Nyamweya, C. Aura","doi":"10.14321/aehm.025.04.28","DOIUrl":"https://doi.org/10.14321/aehm.025.04.28","url":null,"abstract":"There is a common agreement that establishment of co-management could be of benefit to fisher community and other stakeholders across the African Great Lakes. This could aid in promoting community livelihoods and sustainability of the fishery and lakes ecosystem. However, the effectiveness of established co-management regimes remains unknown. This study evaluated the effectiveness of established co-management units, specifically Beach Management Units, along Lake Victoria, Kenya. Data was collected through site observations, and questionnaire led interviews involving the key informants and Beach Management Units' members. The study depicted presence of illegal gears (5.7%), pollution (10.2%), insecurity (3.4%) and targeting of undersized fish (1.1%) among others. The role of the management units in lessening aforesaid challenges was reported overall to be below 36%. Features donating to overall performance, enforcement, conflict resolution, welfare and awareness creation, were rated at 17.6%, 33.8%, 35.5% and 13.2% correspondingly. The low rating of such measurable attributes advocates lack of effectiveness of co-management in Lake Victoria, Kenya. Albeit key registers and records were known to most of the members, there were no signs of progressive growth in the management units. This was attributed mainly to lack of continuous awareness creation amid the changing lake environmental conditions and dynamics in the specific species fishery. There is need to sustain the achievements so far attained in promoting co-management and ecosystem sustainability, as enforcement of laws and regulations can be a challenging undertaking without government support. Governments should ensure financial and material provision in expanding capacity of co-management units in promoting community livelihoods and fishery sustainability.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128277273","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}

{"title":"Performance of diets composed of Artemia biomass and fish meal fed to juvenile marine Tilapia in cages","authors":"Esther W. Magondu, D. Mirera, Douglas Okemwa","doi":"10.14321/aehm.025.04.60","DOIUrl":"https://doi.org/10.14321/aehm.025.04.60","url":null,"abstract":"Mariculture development in Kenya has previously relied on culture of fish in intertidal earthen fish ponds that are fertilized to enhance primary production and use of limited supplementary feeds. Most of the supplementary feeds used have previously been obtained from those of freshwater fish due to lack of marine fish feeds in the country. Cage culture is being introduced to utilize the open space in the sea and hence introduction of more species for farming, that require new feeding strategies that are feasible. Therefore the need to develop marine based fish feed formulations. Taking this into consideration, Kenya Marine and Fisheries Research Institute is developing a feed formula that brings ingredients from the coastal environment that are unique: i.e. seaweeds, coconut husks and Artemia for development of a marine feed. Initial assessments of the developed feed indicate that marine Tilapia grows at 1.2 g day-1, Rabbitfish at 1.9 g day-1 and Milkfish at 1.4 g day-1. The formula is being refined and validated over time before being given out for commercial use in the feed industry to enhance production from mariculture. The treatments were carried out in replicate during a culture period of 138 days. Locally formulated and prepared diets containing 30% crude protein were applied. Treatment 2, a fish meal omena (Rastrineobola argentea) based feed showed better growth outcome as compared to treatment 1 (Artemia based feed) in terms of weight gain, specific growth rate (0.93), survival rate (70%) and feed conversion ratio (2.2). Frequent data collection for both water quality and growth parameters is recommended to enable visualize better growth trends and culture conditions. Further research at different stocking densities with larger juveniles (50g weight) that can withstand the cage environment is recommended.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125627977","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}

{"title":"Toxic cyanobacteria blooms of Mukhor Bay (Lake Baikal, Russia) during a period of intensive anthropogenic pressure","authors":"I. Tikhonova, A. Kuzmin, Galina Fedorova, E. Sorokovikova, Andrey Krasnopeev, A. Tsvetkova, Yu. R. Shtykova, S. Potapov, Maria Ivacheva, Tatyana Zabortzeva, Oksana Evstropyeva, I. Tomberg, N. Zhuchenko, A. Galachyants, O. Belykh","doi":"10.14321/aehm.025.04.85","DOIUrl":"https://doi.org/10.14321/aehm.025.04.85","url":null,"abstract":"The status of Lake Baikal as a UNESCO World Heritage Site, due to its unique ecology and value as a global aquatic resource have resulted in strict environmental regulations to protect the watershed and biota it supports. Despite this, the ecosystem of the lake is being exposed to negative anthropogenic impact and deteriorating water quality. In this article, we describe the bioecological state of Mukhor Bay – the warmest bay of Lake Baikal and one which is actively visited by tourists. We try to highlight the environmental problems of Baikal and aim to change attitudes towards water resources in this unique ecosystem. We present data on the taxonomic, genetic, and biochemical characteristics of cyanobacteria blooms that develop in the plankton of the bay. Further, we establishing their risk to human health and provide information for the environmental state management. Toxic blooms of Dolichospermum lemmermannii (cyanobacteria) were detected in the phytoplankton of Mukhor Bay. The nutrients content and chlorophyll concentration was low and corresponded to the oligo-mesotrophic status. Microcystins were detected in the dried phytoplankton biomass and the water, coastal samples contained a higher amount of this toxin. We hypothesize that one of the factors contributing to toxic cyanobacteria growth in the Mukhor Bay is the nutrient loadings due to surface and groundwater runoff from surrounding area.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133066583","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}

{"title":"Water pollution and its Impact on the Blue Economy Initiative: A Lesson Learned from the Kenyan Coast","authors":"E. Okuku, G. Owato, C. Mwalugha, V. Wanjeri, L. Kiteresi, S. Mwangi","doi":"10.14321/aehm.025.04.12","DOIUrl":"https://doi.org/10.14321/aehm.025.04.12","url":null,"abstract":"Water, sediment and biota samples were collected from selected locations along the Kenyan Coast. The nutrient levels in surface water were relatively elevated as a result of sewage and riverine inputs. As, Cd, Pb, Hg and Ag levels in sediment from Kilindini Harbor pose minimal threat to marine life whereas Cu, Zn and Ni in the sediment pose a moderate threat to marine life while Cr levels in the sediment may have a severe impact on marine life. The concentrations of trace metals, PCBs, and DDT in the surface sediment were lower than the ERL thus posing a low threat to marine organisms. DDD+DDE/DDT ratios were above 0.5 suggesting historical input of DDT from rivers Tana, Sabaki and Ramisi. Trace metal concentrations in biota from Mtwapa, Makupa and Tudor creeks were below the WHO permissible levels of heavy metals in fish. The study concludes that sound management of marine environment is crucial for promoting fisheries as one of the sectors of the Blue Economy.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130764576","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}