Nitrogen fixing bacteria, Azotobacter sp. in aquatic sediment

Non-symbiotic, free living, nitrogen fixing bacteria, Azotobacter sp. was estimated in sediments of estuarine, marine, backwater and mangrove environments of Portonovo. Number of colony forming units (CFU) of Azotobacter sp. was less (5 to 27 cells/g of dry sediment). CFU of total heterotrophic bacteria (THB), actinomycetes and fungi were between 4.1x10 super(6) and 4.5x10 super (7), 0.8x10 super(5) and 4.9x10 super(5), 1.1x10 super(5) and 3.8x10 super(5)/g respectively. Mangrove sediments contained more CFU of the above microbial groups.

Environmental impact of wild shrimp seed collection with non-selective gears on coastal aquatic biodiversity

Collection of wild tiger shrimp (Penaeus monodon) seed with non-selective gears and its impact upon the coastal aquatic biodiversity has been investigated. Loss of undesired species as by-catch was estimated to be 1,075 individuals for collection of every desired shrimp seed which amounted to be 132 billion in a study area stretching 3 km long coastline of the Sagar Island under the Sunderban Biosphere, West Bengal, India. Non-penaeid shrimp seed and crab larvae accounted to be maximally destroyed as their overall contribution towards the by-catch were 56.5% and 29.44%, respectively. Though, rate of bycatch loss was found to be inversely correlated with the rate of shrimp seed collected per gear (r=-0.82, p<0.05) during the peak season (May-September), the overall relationship between them exhibited a linear relationship (r=0.73, p<0.05). By-catch loss for every shrimp seed collection tended to increase up to a daily collection of 2,500 numbers of shrimp seeds per gear followed by a decline. Coastal aquatic community was maximally damaged when the heterogeneity and stability as reflected by different diversity indices were higher.

Report of the regional workshop in transboundary aquatic animal health issues, Bangkok, Thailand, 12-13 January, 2012

This workshop was implemented as part of the Transboundary Diagnostic Analysis (TDA). The main focus was on the shrimp and fish aquaculture sectors and addressed issues such as aquatic animal health and transfers of aquatic animals and plants.

The comparison of inhibitory effects of barley and rice straws to control of algae and aquatic weeds in fish ponds

Bioassays were carried out to consider the relative effect of barley and rice straw extracts on the growth of 12 problematic freshwater algae. The laboratory results demonstrated that growth of Microcystis aeruginosa; Aphanizomenon flos–aquae, Anabaena flos–aquae, Synura petersenii, and Dinobryon sertularia were all inhibited, whereas Oscillatoria tenuis, Asterionella formosa, Spirogyra sp., and Hydrodictyon reticulatum grown were stimulated by the barley straw extract. No significant effect was also found on the growth of Chlorella kessleri, Scenedesmus subspicatus, and Navicula pelliculosa.

Aquatic agricultural systems in Cambodia: national situation analysis

The objective of the current report produced for the CGIAR Research Program on Aquatic Agricultural Systems (AAS) is to provide basic information on key constraints driving poverty and vulnerability in aquatic agricultural systems in the Tonle Sap region in Cambodia. Six objectives and corresponding research themes are included in the program: sustainable increases in productivity; equitable access to markets; resilience and adaptive capacity; empowering policies and institutions; reduced gender disparity; and expanded benefits for the resource-poor. In this report, the authors review the main aquatic agricultural systems (status, specific policies and strategies, interventions, challenges, and options), then review the main drivers of change. This leads to an identification of plans and strategies important to AAS, with a particular focus on perspectives, gaps and opportunities in national policies, community engagement, increased benefits, adaptive capacity, and gender. This review, of potential interest to decision makers and all development partners, leads to conclusions and recommendations aimed at policymakers and institutional as well as private investors in development.

Strategies for sustainable use of living aquatic resources

Recommendations of the Department of Environment and Natural Resources (Philippines) to conserve biodiversity, maintain the integrity of the environment, protect fishery stocks, involve fishing communities in the management, and use environment-friendly technologies for enhancing fishery production.

Sulfide as a toxicant in aquatic habitats

The toxic effects of sulphide are best understood in mammals and are generally similar in aquatic organisms. At the physiological level sulphide has 2 major effects on mammals: 1) local inflammation and irritation of moist membranes including the eye and respiratory tract; and, 2) cardiac arrest due to paralysis of the respiratory centres of the brain. The toxicity of sulphide to plants, macroinvertebrates, freshwater fish and marine fish is discussed in detail. It is concluded that the role of sulphide in mass kills of fish, shrimp and other animals in brackishwater earthen ponds, lakes and sea cages should be determined.

Research in development: learning from the CGIAR Research Program on Aquatic Agricultural Systems

This working paper aims to synthesize and share learning from the experience of adapting and operationalizing the Research in Development(RinD) approach to agricultural research in the five hubs under the The CGIAR Research Program on Aquatic Agricultural Systems. It seeks to share learning about how the approach is working in context and to explore the outcomes it is achieving through initial implementation over 3 ½ years. This learning can inform continuation of agricultural research in the second phase of the CGIAR research programs and will be useful to others aiming to implement research programs that seek to equitably build capacity to innovate in complex social-ecological systems. Each of the chapters in this working paper have shown that RinD has produced a range of outcomes that were often unexpected and broader in scope than might result from other approaches to agricultural research. RinD also produces innovations, and there is evidence that it builds capacity to innovate.

The major aquatic systems of the Victoria and Kyoga lake basins

The Victoria and Kyoga lake basins form the major aquatic system of this study (Fig. I). The two lake basins share a common evolutionary history and have similar native fish faunas (Graham 1929, Worthington 1929). The two main lakes have also had similar impacts by introduction of Nile perch Lates niloticus and therefore these two lakes can be considered to be similar for ichiogeographical purposes. These lake basins have many satellite lakes isolated from one another and from the main lakes Victoria and Kyoga by swamps and other barriers. Some of these satellite lakes still possess stocks of endemic fish species which are almost extinct from the main water bodies. It was therefore considered that understanding of these lakes would contribute to the knowledge base required to solve some of the problems experienced in Lake Victoria and Kyoga especially the loss in trophic diversity arising. The study was carried out in these two main water bodies (Kyoga and Victoria) and on other satellite lakes e.g Wamala, Kachera, Mburo, Kayanja and Kayugi in the Victoria lake basin and lakes Nawampasa, Nyaguo, Agu, Gigate, Lemwa and Kawi in the Kyoga lake basin (Figs. 2, 3, 4, 5 & 6).

Physical and chemical characteristics of major aquatic ecosystems in the Victoria and Kyoga lake basins

The physical-chemical characteristics of any aquatic ecosystem include pH, conductivity, and temperature, water transparency, nutrient and the chlorophyll-a levels. Physical and chemical factors of any ecosystem determine the type and quality of flora present in it and these forms the basis on which the system operates. The elements required in largest amounts for plant productions are carbon, phosphorus, nitrogen, and silicon, which is important for diatoms as a major component of the cell wall. Nutrients may limit algal productivity in the tropics despite the high temperature there allowing rapid nutrient recycling. Nutrients most likely to be limiting African lakes are nitrogen (Talling & Talling 1965; Moss 1969; Lehman & Branstrator 1993, 1994) and phosphorus (Melack.et al l982; Kalff 1983) while silicon may limit diatom growth (Hecky & Kilham 1988). The objective of the study is to investigate the impact of physical-chemical characteristics on the distribution and abundance of organisms in the major aquatic ecosystems.

The diversity of aquatic flora and their importance in the Victoria and Kyoga lake basins

A great part of Uganda is endowed with water bodies in the forms of rivers and open water lakes. These bodies are never alone. They are either flanked or associated with plants, which are adapted to the wet conditions. They are so characteristic that they are part and parcel of the aquatic ecosystems. They occupy various positions depending on the amount of water in the relevant habitats.

Biodiversity values of different aquatic systems, habitats and organisms in relation to restoration and sustaining of biodiversity

Biodiversity values provide objective data and advice from which policy makes could assess the conservation options and determine optimal policies that would balance the needs of conservation with the socia-economic needs of the people in the area.

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring no. 10 and reservoir baseline, 23rd – 30th April 2012

The results reported on were from a monitoring survey No. 10 undertaken between 23 rd and 29th April 2012 during construction period of the Bujagali Hydropower Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far, during construction phase of the project, nine monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009, October 2009, April 2010, September 2010, April 2011, September 2011and the present one, in April 2012. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: water quality determinants biology and ecology of fishes and food webs fish stock and fish catch including economic aspects of catch and sanitation/vector studies (bilharzias and river blindness) During this survey, baseline assessment of the above mentioned studies was conducted in the reservoir behind the dam, including studies on algae, zooplankton and benthic macroinvertebrates which had been restrained since April 2008. The findings of baseline assessment of the reservoir are also contained in this report and are compared with those obtained from Transect 1(Upstream) and Transect 2 (Downstream).

Aquatic ecology monitoring, water quality, fish, fish catch, sanitation and disease vectors: monitoring no. 11, 4th – 9th September 2012

This monitoring survey No. 11 undertaken between 4th and 9th September 2012 is the second one to be conducted after completion of construction of Bujagali Hydropower Dam. Two pre-construction baseline surveys in April 2000 and April 2006 were conducted and during construction phase, eight monitoring surveys (September 2007, April 2008, April 2009, October 2009, April 2010, September 2010, April 2011, September 2011) were conducted.

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring No.7, 4-7th September 2010

The results reported on were from a monitoring survey No.7 undertaken between 4 th and 7th September 2010 during construction period of the Bujagali Hydropower Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far, during construction phase of the project, six monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009, October 2009, April 2010 and the present one, in September 2010. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: I. water quality determinants 2. biology and ecology of fishes and food webs 3. fish stock and fish catch including economic aspects of catch and 4. sanitation/vector studies (bilharzias and river blindness)