Rowena Valmonte-Santos

Global Water and Food Security: Megatrends and Emerging Issues

Feeding the world’s growing population will depend to a large extent on irrigation, but the future of irrigation water supplies is increasingly constrained by growth in other sectors. Other challenges, including declining water quality, falling groundwater tables, and growing environmental demands for water further constrain water availability for irrigation. Moreover, globalization and trade liberalization will increasingly impact water use and food production. Some of these challenges will be mediated by what we label the new ABCs of the future of water and food security: Aquaculture, Biotechnology, and Climate Change. In order to address these old and new challenges, fundamental changes in water management are necessary. With the right reforms in water management, implementation of appropriate economic incentives and investments in water infrastructure and agricultural research, progress can be made toward solving these challenges.

Change and Diversity in Smallholder Rice-Fish Systems: Recent Evidence from Bangladesh

Efforts to unlock the genetic potential of both rice and fish, when combined with efforts to improve the management of rice–fish systems, have considerable proven potential for increasing agricultural productivity and food security. In Bangladesh, estimates suggest that the country’s potential rice–fish production system encompasses between two and three million hectares of land. Despite three decades of research on biophysical and technical aspects of rice–fish systems, this potential has not been realized fully due to insufficient attention given to the social, economic, and policy dimensions of system improvement. This paper provides a characterization of the diverse and changing nature of rice–fish systems in Bangladesh by combining data from a novel upazilla-level (sub-district-level) survey of fishery officers with household surveys, focus group discussions, and a meta-review of the literature on aquaculture in the country. The resulting analysis sheds new light on the economic viability of different rice–fish systems and recommends policy and investment options to further improve the development and delivery of rice–fish technologies. Findings indicate that in addition to concurrent rice–fish systems, alternating rice–fish systems and collectively managed systems offer considerable potential for increasing productivity and farm incomes in Bangladesh. Findings also suggest that although the emergent innovation system around these rice–fish systems is fairly dynamic, there is a need for more supportive policies and investments—and analysis of the intended and unintended impacts of these policies and investments.

Potential of Transgenic Crops in Bangladesh: Findings from a Consultation of Bangladeshi Scientific Experts

This note summarizes the results of a consultation of scientific and regulatory experts in July 2005 on the potential of transgenic crops in Bangladesh. We find that Bangladeshi experts are optimistic on the potential of agricultural biotechnology to respond to biotic and abiotic stresses in their country in the future. Public research is constrained by human capacities, infrastructure and capital investment, and transgenic crop development will require the active involvement of outside partners, such as international organizations or collaboration with private companies. We also find that social acceptance of genetic engineering is not considered a major issue, but could become one, and prompted experts to call for a wider awareness campaign on the technology.

Economic assessment and policy recommendations of fisheries development strategies in Vanuatu

The freshwater prawn, Macrobrachium rosenbergii is a more popular crustacean cultured widely in monoculture system in India. It has got high nutritional value in the human diet. Hence, understanding its enzymatic and body composition is important in order to judge its flesh quality. Fish oil specially derived from Indian oil sardine is a good source of highly unsaturated fatty acid and lipid source in fish/prawn diet. A 35% crude protein diet with graded levels of Sardine oil as a source of fat was incorporated at four levels viz, 2.07, 4.07, 6.07 and 8.07% maintaining a total lipid level of feed at 8.11, 10.24, 12.28 and 14.33% respectively. Diet without sardine oil (6.05% total lipid) was served as basal treatment. The giant freshwater prawn, Macrobrachium rosenbergii was used as test animal and the experiment was lost for 112 days. Significantly higher gain in weight of prawn was recorded in the treatment with 6.07% sardine oil incorporation followed by higher specific growth rate, food conversion rate and protein efficiency ratio. The 8.07% sardine oil diet produced the highest RNA: DNA ratio in the prawn muscle. Digestive enzyme analyses in the digestive tract and midgut gland showed the greatest activity in prawns fed the 8.07% diet.S of the Background: Macrobrachium rosenbergii is one of the most important prawns in freshwater aquaculture. Male giant freshwater prawns grow faster and reach higher weights at harvest than females, which make the culture of all-male populations desirable. The purpose of this study is to explore the molecular information of new gene and its potential physiological function on sex regulation. Methodology & Theoretical Orientation: The gene expression pattern was studied using Real-time RT-PCR. The functional role of gene in vivo by RNA interference (RNAi) was utilized and its effect on sex regulation was evaluated. Findings: In this study, a novel gene of the full-length cDNA encoding a masculinizing factor from the giant freshwater prawn Macrobrachium rosenbergii was termed Mr-Masc. Real-time RT-PCR analysis revealed that Mr-Masc gene expression was obviously difference between male and female prawn, and dominantly expressed in the ovary of the reproductive tract in female prawn. To elucidate the functional role of Mr-Masc in vivo, the Mr-Masc gene was disrupted by RNA interference (RNAi). In vivo silencing of the gene, by injecting the all-male and monosex postlarvae with Mr-Masc double-stranded RNA, sex-revsersed females (neofemales) were obtained. Moreover, all-male progeny was produced by mating neofemales with normal males and these all-male populations showed good growth potential and market value in the aquaculture. Conclusion & Significance: It was firstly reported the full and functional sex reversal of male freshwater prawns through the silencing of a single Mr-Masc encoding gene. Neofemales capable of mating and spawning were produced by the RNAi technology at a sufficiently early stage of larval development. This finding offered an insight regarding the biology and evolution of sex differentiation regulation. Since sexual dimorphic growth patterns are common among decapod crustaceans, it is obvious that the results of this study will have applied significance for many aqua cultured species.