Aquatic Ecosystem Health and Management最新文献

{"title":"Sustainable crab fishery for Blue Economy in Kenya","authors":"E. Fondo, Benrick Ogutu","doi":"10.14321/aehm.024.01.05","DOIUrl":"https://doi.org/10.14321/aehm.024.01.05","url":null,"abstract":"Lakes, rivers and oceans provide unique resources and support fisheries and aquaculture worldwide. The fisheries and aquaculture sector of Kenya contributes approximately 0.8% to the country's GDP. Marine production is about 9 000 tonnes per year. Marine finfish form the bulk of the marine production, while shellfish (e.g. prawns, lobsters and crabs), molluscs (e.g. octopi and squids) are underexploited. The Fishery sector has the potential of about USD 5 billion for the Blue Economy in Kenya. Crab fishery in Kenya is active in some areas of the south and north coast. The crab resources along the Kenyan waters are diverse and a variety of species are edible. The most commonly fished crab by artisanal fishers is the Mangrove Mud Crab Scylla serrata. Semi-commercial and industrial fishers usually have portunid and other deep sea crabs as by-catch in trawl and longline fisheries, which in many cases are unutilized. Exports of live crabs have increased over the years, with exports mainly to Asian countries. Export of frozen crabs started recently. The need to sustainably utilize lake, river and ocean resources is recognized and important in promoting Blue Economy. Sustainable development of crab fishery provides a potential area for the Blue Economy development in Kenya. Research is essential to crab fishery development.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130770234","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":"Growth and survival of Mud Crab, Scylla serrata, reared in bottom and floating cages within Mida Creek mangroves, coastal Kenya","authors":"J. Mwaluma, B. Kaunda-Arara","doi":"10.14321/aehm.024.01.06","DOIUrl":"https://doi.org/10.14321/aehm.024.01.06","url":null,"abstract":"Mud Crab fattening is a relatively new business idea in Kenya and is highly lucrative due to the reasonable prices offered at tourist hotels. This study was aimed at developing appropriate culture techniques for Mud Crabs to maximize harvestable biomass by the local communities and avoid recruitment overfishing. Growth and survival rates for mixed sex Mud Crabs was investigated for a period of 230 days in Mida Creek, Kenya, using bottom and floating cages, and two feed types in a crab fattening experiment. Crabs attained harvestable weight by the third month for both floating (466.2 ± 137 g) and bottom cages (542.2 ± 109.3 g). There was no significant difference in mean total weight of mixed-sex crabs in the two culture systems (t = 1.75, p>0.05), however males showed significantly higher total weight gain compared to females. A higher overall survival rate was found for crabs cultured in floating cages (63.8%), compared to bottom cages (44.9%). There was no significant difference in growth performance between crabs fed gastropod tissues and those fed fish offal. The long-term specific growth rate for floating cages (0.69 g d-1) was not significantly different from that of bottom cages (0.92 g d-1). An analysis of potential return on investment showed the floating cages to be more profitable per production cycle compared to the bottom ones. The floating cage system and mono-sex male crab culture are recommended to farmers within mangrove tidal flats in Kenya.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133767298","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":"The effects of situation analysis practices on implementation of poverty alleviation mariculture projects in the coast of Kenya","authors":"J. O. Odhiambo, J. Wakibia, M. Sakwa, Fridah Munyi, H. Owiti, E. Waiyaki","doi":"10.14321/aehm.024.01.13","DOIUrl":"https://doi.org/10.14321/aehm.024.01.13","url":null,"abstract":"The importance of situation analysis in the project cycle cannot be overstated. This research was carried out in twelve sites where mariculture was practiced in Kilifi, Mombasa and Kwale Counties in the coast of Kenya. The general objective of the research was to assess the effects of situation analysis practices on implementation of mariculture projects in Kenya. The specific objectives were to:- examine the effect of stakeholder analysis on implementation of poverty alleviation mariculture projects, establish the effect of problem analysis on implementation of mariculture projects, and determine the effect of needs assessment on implementation of poverty alleviation mariculture projects. The research was based on quantitative research approach with a cross sectional survey design. Simple random sampling was used to select the number of subjects that represent the target population in the survey. Guided questionnaire administration was adopted to capture responses from members of organized mariculture groups. Factor analysis and regression analysis were conducted on the data collected from the questionnaire survey. Results showed that the poverty alleviation mariculture projects in Kenya are dominated by female actors compared to male actors. Factor analysis revealed that degree of success and degree to which the mariculture projects have addressed their objective of poverty alleviation were the most important measures of project implementation and were named effectiveness. Regression analysis showed that there was a significant positive relationship between stakeholder analysis and effectiveness (β = 0.726; t = 12.59; p = 0.000). Being the single most significant factor influencing mariculture project implementation, stakeholder analysis should be undertaken at the situation analysis stage so that it informs project design. It was concluded that improvements in situation analysis practices brought about by improvements in stakeholder analysis would address poverty among coastal fisher communities by improving implementation of poverty alleviation mariculture projects.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116037185","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":"What affects fisheries in African lakes: Climate change or fishing effort? A case study from Lake Kariba","authors":"B. Marshall","doi":"10.14321/aehm.024.01.03","DOIUrl":"https://doi.org/10.14321/aehm.024.01.03","url":null,"abstract":"Lake Kariba, created in 1958, experienced changes, notably the decline of the Limnothrissa miodon fishery, which have been attributed to climatic change. Air temperatures rose abruptly by 1.1°C between 1980 and 1981, but the temperature of the lake did not follow this pattern. Temperatures at 10 m depth increased by 8% between 1961 and 1971, remained stable until 1984, then declined and by 1992 the temperature was about 7% lower than in 1961. The causes of this are unclear but it followed the hot and dry El Niño droughts of 1982-83 and 1991-92. The lake warmed again by 2007-2011 with temperatures at 10 m being about 10% higher than in 1961, while at 40 m it was 16% higher indicating a faster warming rate in deeper waters. The thermocline fell from 15-20 m in 1968 and 1986 to 20-25 m in 2011 and the temperature gradient decreased by > 50%. The epilimnion became more homogenous, with no evidence of anoxia in the upper 20 m in 2007-08, and the normal monomictic thermal regime may change, thus affecting nutrient circulation and the seasonal abundance of plankton. Both zooplankton and phytoplankton communities have evolved since the lake was created, but these changes occurred before any evidence of warming. The fishery has been declining since 1996 but there is no evidence that climate change is responsible; the number of fishing vessels is presently about three times the recommended level and fishing effort is almost certainly the main cause of the problems. All African lakes support fisheries and it is essential to consider fishing, which changes fish species composition, demographics and abundance, characters that could also be affected by climate change.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130953623","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":"The status of seagrass beds in the coastal county of Lamu, Kenya","authors":"J. Uku, L. Daudi, V. Alati, A. Nzioka, C. Muthama","doi":"10.14321/aehm.024.01.07","DOIUrl":"https://doi.org/10.14321/aehm.024.01.07","url":null,"abstract":"Biodiversity assessments within seagrass beds were conducted in six sites in Lamu, Kenya; namely, Kiweni, Tauzi, Wange, Ntopate, Manda toto and Ngoi. The objective of the assessment was to collect baseline information of the seagrasses of Lamu County in Kenya. Our findings revealed that nine out of the twelve seagrass species found in Kenya were found in the study sites. The dominant seagrass species Thalassodendron ciliatum was found to occur in deeper subtidal areas, while the pioneering species occurred in intertidal shallower areas. Average shoot densities per site ranged from 2.4 ± 1.7 shoots m-2 of Cymodocea serrulata to 1025.9 ± 139.3 shoots m-2 of Syringodium isoetifolium in Ngoi. Canopy heights ranged from 0.1 ± 0.1 cm of Halodule ovalis in Tauzi to 16.3±1.3.5 cm of Syringodium isoetifolium in Ngoi. Although the seagrass species characteristics were much lower than that found in similar mangrove fringed seagrass beds of Gazi Bay, the majority of the fish found in these seagrass areas were invertivores which indicates that these seagrass sites form a refugia for adult fish populations with nursery grounds being located elsewhere. This study forms the first comprehensive assessment of the seagrasses of Lamu and it provides important baseline information on seagrass beds. Such biodiversity information provides important support for decision-making for coastal areas that are targeted for infrastructural development such as Lamu. Biodiversity information of such critical habitats form a critical data base for marine spatial planning and can be used to effectively guide the integration of biodiversity and coastal livelihoods in the sustainable development of Kenya's coastal areas.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115703347","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":"Kenya marine fisheries: The next frontier for economic growth?","authors":"J. Njiru, J. Omukoto, E. Kimani, C. Aura, M. van der Knaap","doi":"10.14321/aehm.024.01.14","DOIUrl":"https://doi.org/10.14321/aehm.024.01.14","url":null,"abstract":"The economic potential of Kenya marine resources is critical for the socioeconomic development. The current study reports fisheries output from marine systems in Kenya as a priority for Blue Economy investment in order to rival the current production from inland systems as a trigger for sustainable development. The assessment of fish landings and economic value was based on Catch Assessment Surveys, cruises and secondary literature. Kenya's inland capture fisheries contributes about 83%, aquaculture 12%, and marine artisanal fisheries 5%. Lake Victoria that contributes up to 90% of inland capture fish production has shown decline in catches in the recent past and the trend indicates that the fishery may not be sustainable. The Kenya Exclusive Economic Zone has a coast line of about 647 km and an area of 142,000 km2 that constitutes about 42% of the country's surface area and has several commercially important species that are barely exploited; yet it produces a paltry 26,000 mt annually that is estimated at an export value of about USD 50 million. However, recent estimates have found that Kenya Exclusive Economic Zone could contain up to 2 million mt of fish that is valued at about USD 130 million. Furthermore, additional worth along the value chain and with substantial trickle-down effect that could have a positive impact on the Blue Growth in Kenya and other developing nations with oceanic potential – triggering the possibility for sustainable exploitation.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126887389","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":"GLOW 9 Synthesis: Blue Economy, a long way to go","authors":"M. van der Knaap, M. Munawar, J. Njiru","doi":"10.14321/aehm.024.01.15","DOIUrl":"https://doi.org/10.14321/aehm.024.01.15","url":null,"abstract":"Aquatic Ecosystem Health & Management, 24(1): 105–107, 2021. Copyright © 2021 Aquatic Ecosystem Health & Management Society. ISSN: 1463-4988 print / 1539-4077 online. DOI: 10.14321/aehm.024.01.15 At the conclusion of each GLOW Conference, a plenary session is held to discuss whether its objectives have been achieved. This year’s participants presented roughly 200 papers and posters in two and half days, which on its own was already an enormous accomplishment. All presentations were well attended and interesting discussions, albeit brief, developed after each one. Despite the attention for Blue Economy, Blue Growth Initiatives, Blue Bonds, Blue Justice and other such topics, it became clear that many a participant appeared to struggle with the “Blue” concept of their research, overviews and conclusions, as that was not always the original purpose of their studies. Consequently, many manuscripts were concerned with ongoing research, without highlighting the “Blue” aspect. Traditionally, the GLOW series of conferences centre on African Great Lakes, as well as on other Large Lakes. However, for this conference, as a result of the introduced Blue Economy concept, many marine and river papers were accepted and presented. Overall, the presentations comprised traditional fisheries papers as well as climate change and biodiversity topics, but aquaculture issues enriched this conference considerably, mainly due to emerging Tilapia cage culture in the large and great lakes as well as to crabs, seaweed and oysters in the marine sector. The interesting discussion that developed concerning the exploitation of juvenile Nile Perch versus that of adults led to surprised reactions from traditional fisheries managers; they claim that fishers should catch only adult fish that have spawned at least once, which about two decades ago yielded the “slot size” for Nile Perch. This management measure implied that perch were exploitable between 50 and 85 cm total length to protect the immature fish as well as the large spawners that could procreate millions of offspring. One of the keynote addresses discussed the amount of feed and space required for millions of new-born perch if all of them had to recruit to the fishery. In the light of the cannibalistic behaviour of the Nile Perch, it does not appear strange that they consume specimens of their own species. This theory would put fisheries management in a different light and fishing gear currently considered illegal would become efficient, allowing young fish for an ever-growing riparian human population, as markets for the juvenile fish have already developed. It became clear that the discussion on this theory has only just begun. Clearly, the GLOW conferences provide a lively platform for discussion of such topics and particularly for research on African situations not covered elsewhere. The question of illegal fishing in African waterbodies remains a topic of interest, especially whether the state should be in control, ","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127137028","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":"Using the Multi-metric Index of Biotic Integrity methodological approach to determine the major river catchment that most pollutes a lake","authors":"C. Aura, C. Nyamweya, J. Njiru, R. Omondi, J. Manyala, S. Musa, H. Owiti, F. Guya, C. Ongore, Z. Ogari, J. Mwamburi","doi":"10.14321/aehm.024.01.04","DOIUrl":"https://doi.org/10.14321/aehm.024.01.04","url":null,"abstract":"We present the Multi-metric Index of Biotic Integrity methodological approach that allows for the ranking of major river catchments based on pollution status in the Kenyan portion of Lake Victoria, Africa. The study has a broader applicability to all of Lake Victoria, other African Great Lakes, and all lakes that have riverine discharge. The method presented utilizes water quality and environmental data, local knowledge, and pre-existing literature. The parameters considered were sampled from 2016 to 2018 during the dry season (July sampling) and the wet season (March sampling). Separation power of Mann-Whitney U test (p < 0.05) qualified 11 discriminant metrics for both macroinvertebrate and fish samples into the scoring system of 1, 3 and 5 in the formulation of final Multi-metric Index of Biotic Integrity methodological approach. Rivers in the northern section had lower Multi-metric Index of Biotic Integrity methodological approach scores, as compared to southern counterparts. The Multi-metric Index of Biotic Integrity methodological approach ranking herein was validated by community perceptions on pollution levels. River Nzoia catchment emerged as the most polluted, followed by River Yala, River Kuja, and Sondu-Miriu. Siltation, domestic washing, litter and refuse emerged as the main agents of pollution. Management authorities ought to reinforce a balanced utilization of the vital water resources to minimize future impacts, and promote catchment wide practices that ensure ecological health sustainability of the lake ecosystem.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"R-26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126626652","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":"The role of women in freshwater aquaculture development in Kenya","authors":"Fonda Jane Awuor","doi":"10.14321/aehm.024.01.11","DOIUrl":"https://doi.org/10.14321/aehm.024.01.11","url":null,"abstract":"For many years, aquaculture has been erroneously viewed as a male-dominated sector, offering women inadequate opportunities partly due to the high capital investment requirement and or the technologies linked to the venture. Women work in all areas of the aquaculture value chain but their opportunities have not kept pace with aquaculture growth. Hence, they form a larger component of the poor, limiting their income-generating activities and asset building potential. Gender disaggregated statistics that could track women's engagement in aquaculture activities in Kenya are scanty. Hence, women's presence, influence and interests are invisible. All aquaculture labour practices should embrace the Sustainable Development Goals 5 that focus on gender equality and empowerment of all women and girls. To that end, gender equality must be mainstreamed into aquaculture planning, development, monitoring and evaluation. This will require concerted political efforts by sector leaders, advocates and gender champions, supported by new technical instruments for implementation. The study leverages on incorporating gender lens and making gender visible in every phenomenon, questioning if, how and why processes, opportunities and standards differ systematically for women and men and not solely for women. Finally, it proposes sections where women's engagements can be strengthened to increase the importance of aquaculture production in Kenya.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122880791","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":"Socioeconomic dynamics and characterization of land-based aquaculture in Western Kenya","authors":"J. Abwao, S. Musa, Robert Ondiba, Z. Ogari","doi":"10.14321/aehm.024.01.10","DOIUrl":"https://doi.org/10.14321/aehm.024.01.10","url":null,"abstract":"With the global decline in capture fisheries, aquaculture remains alternative in bridging the gap and meeting the demand for fisheries products. Currently, aquaculture contributes approximately 50% of world total fishery production, hence becoming an important intervention in promoting food and nutritional security, and employment creation. Western Kenya is suitable for aquaculture production due to favorable climate and good soil as well as high demand for fish. The present survey purposed to assess the Socio-demographic characteristics of fish farmers, fish feed and seed producers in 9 Counties within Western Kenya. The information obtained included socio economic dynamics and challenges to fish farming. Fish farming mainly occur in rural areas in Western Kenya where the most dominant system is earthen ponds, measuring 300 m2. Aquaculture in the region is male dominated and majority of players practice individual enterprises. The majority of the hatcheries are authenticated and the lack of credit facility was mentioned as the most important challenge. However, for feed producers lack of adequate raw materials was the most important bottle neck. From this study, both environmental and social factors in the region must be synergized to achieve aquaculture sustainability. There is need for empowerment of farmers through capacity building and availability of credit facilities whereas hatcheries and feed producers must be empowered with adequate skills and infrastructure in order to adhere to good standards.","PeriodicalId":421207,"journal":{"name":"Aquatic Ecosystem Health and Management","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134223231","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}