Adsorptive Media Investigations and Testing for Improved Performance of Stormwater Treatment Systems in the Tahoe Basin

Retrofit activities, such as improving hydrology and incorporating more advanced treatment methods into systems where feasible, may improve phosphorus (P) removal performance of current Best Management Practices (BMPs). In the recent past, chemical treatment systems such as chemical dosing and the use of adsorptive media have become more prevalent for treating stormwater and hold promise for improving the P removal performance of stormwater treatment BMPs (Bachand et al., 2005; Patel et al., 2005). Our primary objective for this project has been to investigate whether adsorptive media hold any promise for improving P removal performance of stormwater basins and treatment wetlands at Lake Tahoe.... (PDF contains 99 pages)

Assessing the sustainability of brackish water aquaculture systems in the Phillipines. Working Paper 1: A typology of brackish-water pond aquaculture systems in the Philippines

Aquaculture in the Philippines is a long-standing activity but has witnessed relatively recent, rapid, technical change with the introduction of hatchery technology and commercial feed-mills changing the production possibilities for a fishpond operator. We are confronted with a diversity of aquaculture practices in the coastal areas of the Philippines, with new technologies being incorporated into more traditional systems. As a first step to understanding the sector, we therefore present a typology of farming systems with the motivation of generating domains (farm “types”) over which we can compare performance on a number of indicators. Our typology, restricted to brackish-water pond systems, is constructed using multivariate methods (principal components analysis, cluster analysis). Eight variables are used relating to the management of the farm across all the major factors of production. A stratified net sample of 136 observations provides the data for the analysis, from a farm-level survey carried out between January and June 2003 in the two main brackish-water production regions in the Philippines. We define five farm types from this analysis. In later work we will show how the use of this typology can be used for comparative study of economic, social and ecological performance at the farm-level. [PDF contains 42 pages]

Assessing the sustainability of brackish water aquaculture systems in the Philippines. Working Paper 4: Aquaculture and poverty - a case study of five coastal communities in the Philippines

After reviewing the rather thin literature on the subject, we investigate the relationship between aquaculture and poverty based on a case study of five coastal communities in the Philippines. The analysis relies on a data set collated through a questionnaire survey of 148 households randomly selected in these five communities. The methodological approach combines the qualitative analysis of how this relationship is perceived by the surveyed households and a quantitative analysis of the levels and determinants of poverty and inequality in these communities. There is overwhelming evidence that aquaculture benefits the poor in important ways and that it is perceived very positively by the poor and non-poor alike. In particular, the poor derive a relatively larger share of their income from aquaculture than the rich, and a lowering of the poverty line only reinforces this result. Further, a Gini decomposition exercise shows unambiguously that aquaculture represents an inequality-reducing source of income. We believe that the pro-poor character of brackish water aquaculture in the study areas is explained by the fact that the sector provides employment to a large number of unskilled workers in communities characterized by large surpluses of labour. Our results also suggest that the analysis of the relationship between aquaculture and poverty should not focus exclusively on the socio-economic status of the farm operator/owner, as has often been the case in the past. [PDF contains 51 pages]

The nature of small-scale farmer managed irrigation systems in North West Province, Sri Lanka and potential for aquaculture

RRAs were carried out in two Small Tank Cascade systems (STCs) of North West Province, Sri Lanka (less than 1000 ha total watershed area). A total of 21 tanks and 7 villages were investigated with primary emphasis on two upper watershed communities. The two systems differ primarily in their resource base; namely rainfall, natural forests and proximity to large scale perennial irrigation resources. [PDF contains 86 pages]

Potential for poverty focused integration of aquaculture into irrigation systems in Batticaloa District

The visit highlighted the vital contribution of the inland fisheries sector to provision of basic food security within the uncleared area (farmers report very low consumption frequencies for all other fish or meat protein substitutes). A 30-mile system of Brackish water lagoons which demarcates the cleared and uncleared areas is the main source of retailed fish in the uncleared area. Second in importance is the inland tank fishery, where the bulk of production emanates from 17 major irrigation reservoirs. [PDF contains 29 pages]

Acid precipitation and its effects on aquatic systems in the English Lake District

There is no evidence of an increase in the acidity (lower pH or alkalinity) of water-bodies in the Lake District over the last 50 years. Brown trout occur in acid streams and upland tarns where pH is 4.5-5.2 throughout the year. Their occurrence in such waters in Britain and Ireland has been known for most of this century and there is no previous evidence of harmful effects on salmonid fisheries, though numbers of fish are naturally low. However, many benthic invertebrates that are common in hill-streams where pH is above 5.7 do not occur in more acid streams. This phenomenon occurs in the headwaters of several western rivers in Cumbria. It is not a recent response to "acid rain". Harmful effects of pH are undoubtedly more pronounced in waters that are poor in other dissolved ions. Low concentrations of sodium, potassium, calcium and chloride are especially important and may limit the distributions of some aquatic animals even where pH is above 5.7. The concentration of sulphate ions is usually relatively high but this is not important to the fauna; concentrations are at least two times higher in productive alkaline water-bodies than they are in unproductive acid waters.

Mono- and polyculture of silver barb (Puntius gonionotus) in deepwater rice systems in Bangladesh

Experiments with fish enclosures were conducted at the Deepwater Rice Farming Systems Research Site at Shuvullah, Mirzapur, Bangladesh. The objective was to study the performance of silver barb (Puntius gonionotus) called Thai sharputi or rajputi in Bangladesh in mono-and-polyculture with grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio), catla (Catla catla) and rohu (Labeo rohita). Each enclosure measured 21 m x 21 m with an approximate net height of 3.5 m. The stocking densities per cubic meter were 1 fingerling for Thai sharputi monoculture (enclosure 1), and 2 fingerlings for the polyculture systems (enclosure 2 and 3). The species ratio for enclosure 2 was 0.37:0.27:0.02:0.34 (grass carp:Thai sharputi:common carp:catla) and for enclosure 3, 0.4:0.4:0.2 (catla:rohu:Thai sharputi). In monoculture (enclosure 1), Thai sharputi performed well. This relatively good production was mainly attributed to the use of appropriately sized fingerlings and rapid growth from consumption of an abundant supply of azolla in addition to feed given. For the polyculture in enclosure 2, the average weight gain of common carp was the highest (673 g) followed by grass carp (475 g) and Thai sharputi (286 g). For the polyculture in enclosure 3, the length and weight gains for Thai sharputi were almost the same as for the monoculture.

Solomon Islands: Essential aspects of governance for Aquatic Agricultural Systems in Malaita Hub

In late 2012, a governance assessment was carried out as part of the diagnosis phase of rollout of the CGIAR Aquatic Agricultural Systems Program in Malaita Hub in Solomon Islands. The purpose of the assessment was to identify and provide a basic understanding of essential aspects of governance related to Aquatic Agricultural Systems in general, and more specifically as a case study in natural resource management. The underlying principles of the approach we have taken are drawn from an approach known as “Collaborating for Resilience” (CORE), which is based on bringing all key stakeholders into a process to ensure that multiple perspectives are represented (a listening phase), that local actors have opportunities to influence each other’s understanding (a dialogue phase), and that ultimately commitments to action are built (a choice phase) that would not be possible through an outsider’s analysis alone. This report begins to address governance from an AAS perspective, using input from AAS households and other networked stakeholders. We attempt to summarize governance issues that are found not only within the community but also, and especially, those that are beyond the local level, both of which may need to be addressed by the AAS program.

Integrated aquaculture-agriculture adoption and impact in rainfed farming systems in Sakata, Malawi

ICLARM introduced integrated aquaculture-agriculture (IAA) in Sakata, Malawi three years ago. Since that time, and without extension support, the number of farmers with ponds increased from 4 in 1993/94 to 12 in 1995/96. To learn why and how IAA is spreading, a study of impact and adoption was conducted in the 1995/96 production season. Interviews were conducted with farmers to discuss lAA and collect data on farm function through the use of bioresource flow diagrams. Motivations given by farmers as to why they adopted IAA were to improve household nutrition and income. Constraints to adoption identified by farmers were availability of labor and capital to purchase inputs

Suitability of rich-fish culture under mono and polyculture systems in the boro rice ecosystem

An experiment was conducted in farmers’ fields under Paikgacha thana, Khulna to study the suitability of integrated rice-cum-fish culture. Three treatments namely T1 (Puntius gonionotus), T2 (Puntius gonionotus and Cyprinus carpio) and T3 ( Cyprinus carpio) were included for the study each having three replicates. The fish were stocked at a density of 3750/ha in all the rice plots. The physicochemical parameters of water viz., water depth, temperature, dissolved oxygen, pH, salinity, nitrate and phosphate etc. recorded during the study period were found within optimum range. Of the two cultured species C. carpio attained the highest average individual weight (160g) and survival (81.06%). With respect to biomass and income, highest average fish production and net profit per hectare (306.74kg and Tk. 8177.91) were obtained in T2 and the lowest (184.17kg and Tk. 2049.41) obtained in T1 and a significant variation (p<0.05) in fish production was observed among the treatments while for rice production, it was insignificant. The cost benefit ratio of fish production found were 1:1.29, 1:2.14 and 1:1.90 for T1, T2 and T3, respectively.

Sustainable livelihood approach of prawn production and marketing systems in Mymensingh, Bangladesh

An investigation was carried out in Phulpur upazila, Mymensingh to examine the current production practices of freshwater giant prawn, Macrobrachium rosenbergii and its marketing systems with sustainable livelihood approach. The livelihoods of a considerable number of rural poor are associated with prawn production in Phulpur upazila. Based on a sample of 50 farmers, about 94% farmers were found to culture prawn with fish in their ponds. Only 4% and 2% farmers were found to culture prawn-fish-dike crops and only prawn respectively. Prawn marketing is almost exclusively a preserve of the private sector where the livelihoods of a large number of people are associated with its distribution and marketing systems. The market chain from producers to consumers passes through a number of intermediaries. About 40% of the produced prawns are exported and the rest 60% are sold to local markets. The price of prawn depends on quality, size and weight. The average farm-gate price of prawn varied from Tk. 110 to 160/kg, whereas it's [sic] market price varied from Tk. 150 to 350/kg. Most of the farmers and traders have improved their socio-economic conditions through prawn farming and marketing activities. However, concerns arise about the long-term sustainability of prawn farming and marketing systems due to lack of technical knowledge of prawn farming, poor road and transport facilities, higher transport cost, poor supply of ice, lack of cash and credit facilities. It is therefore essential to provide institutional and organizational support and credit facilities for sustainable prawn production and marketing systems.

Reliability and need for standardisation of electrical systems in small wooden fishing vessels

The working condition and atmosphere in a wooden fishing vessel are generally most injurious to the electrical systems. Therefore great care has to be taken in designing electrical systems for small c1afts. This paper deals with the difficult operating conditions and standardisation of electrical systems as applicable to small fishing vessels.

Review of fisheries data collection systems in BOBLME countries

The review focuses on small pelagics, Hilsa shad and Indian Mackerel in particular, with the exception of the Maldives, but the findings are generally applicable to national systems of data collection. Recommendations are given for each country.

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.