Digital library

The world’s population has been predicted to rise to over nine billion by 2050 (e.g. FAO, 2009a; Lutz and Samir, 2010), with most of this increase predicted to occur in low and middle income (developing) countries (Alexandratos and Bruinsma, 2012; Government Office for Science, 2011; Lutz and Samir, 2010). The proportion of the population living in urban areas and income levels are also expected to rise (with at least 3 billion people entering the global middle classes) which is likely to increase demand for more nutritious and higher quality foods (i.e. more resource-intensive foods such as meat and vegetable oils; Searchinger et al., 2013 and references therein).

The question of how to achieve such increases in food production to feed this larger, increasingly affluent population, whilst ensuring sufficient food calories to adequately feed the entire global population, in a sustainable manner (i.e. that ensures food production that contributes to inclusive social and economic development whilst reducing environmental impacts and pressures on limited resources), is the subject of current discussion and research (e.g. Searchinger et al., 2013; Alexandratos and Bruinsma, 2012; The Government Office for Science, 2011). An increased global population will also necessarily have greater energy requirements.

The Scottish Aquaculture Research Forum (SARF) and WWF-UK commissioned this study to investigate whether the pressure on land and freshwater for future food and energy resources, and impacts on the climate, related to greenhouse gas (GHG) emissions, may be reduced through expansion of global mariculture. The study has undertaken a high level assessment of the ‘environmental footprint’ of global mariculture and terrestrial-based food and energy production systems through the collation and assessment of available Life Cycle Assessments (LCA) for key food products (beef, pork, chicken, freshwater finfish, marine finfish, shellfish and crustacean species) and biomass (terrestrial and algal) for energy production. The outputs of the footprint comparison were then used to assess the risks and benefits of increasing global mariculture, through the development of projected future scenarios in which mariculture contributes differing proportions of projected future food requirements. The analysis also qualitatively considered the socio-economic and wider environmental risks and benefits (e.g. in relation to ecosystem services) of global mariculture expansion, where expansion may occur geographically and whether future technological developments may help mitigate against identified impacts.

The study identifies the key uncertainties and limitations of the risk/benefit analysis and makes prioritised recommendations on how these limitations can be addressed and the analysis developed for more regional or site-specific assessments.

Biofuels from Opihi Algae. 10 to 15 years of technology development. Current business exists in high quality, fresh algae. Research needed on strains, biomass production, enviornmental manipulation, harvest, processing. Cost must be competitive with petroleum.

Mosquito-borne diseases are a big global concern, being responsible for 300 million of annual cases of infection, according to World Health Organization (WHO), and being one of the main causes of deaths worldwide. Some of these diseases were reduced in the last centuries, particularly in the XX century, but many are remerging and also appearing in places that they were not used to. The genera of mosquitos with more medical importance are Anopheles, Aedes and Culex, but this work focus on Aedes aegypti (Ae. Aegypti). Most of these diseases do not have a vaccine or treatment, so the best way to fight against them is controlling the vectors – in this case Ae. aegypti, and some authors defend that this control is easier when applied in larvae stage. Four main strategies have been used: physical, genetic, chemical and biological control. Chemical control, namely the use of phytochemicals such as seaweed extracts, is receiving more attention lately, once the other methods pose problems like the environmental persistence, hazard in non-target organisms, and resistance by the insects. Seaweed are a big source of compounds that have a wide range of bioactivities serving several applications, as antibacterials, antifungals, antivirals, antitumorals, among others. In this work, the mosquito larvicidal potential of five organic extracts from two macroalgae species - Fucus vesiculosus (F. vesiculosus) and Ulva lactuca (U. lactuca) – were accessed in Ae. aegypti. The extracts were obtained with the solvents ethanol, methanol, chloroform, hexane and dichloromethane. Mortality assays, according WHO guidelines, were performed counting the dead larvae after 24 and 48 hours of exposure. Body length and the weight of surviving larvae were also measured to investigate potential gross impacts of the extracts on larval growth/development. From these assays, dichloromethane extract from F. vesiculosus was the only one that showed significant differences compared with the control, reaching 58% mortality after 48 hours of exposure. Body size measurements and weighings showed no differences between treatments. Assays with Artemia salina (A. salina) were also carried out with 24 hours of exposure, to access possible effects of these extracts in non-target aquatic organisms. In the same concentration used in mosquito larvae, no significant differences were observed between the extracts and the control. However, in a higher concentration, three extracts from F. vesiculosus showed toxicity, namely ethanol, chloroform and dichloromethane. The results showed that dichloromethane extract from F. vesiculosus could be a useful source of larvicidal compounds to fight mosquitos, the most important disease vectors for transmitting diseases to Humans. The A. salina data support that lethality in non-target species is only attained at higher concentrations of extract when compared with those for the mosquito. Anyway, a wider range of non-target organisms should be assayed. Having the present work as basis, further studies could try to elucidate the mode of action of the extracts effects when inducing lethality, in addition to isolate and characterize the compounds present in the most promising extracts. By other hand, screening tests using combinations of extracts could be useful to pinpoint yet unknown synergy or potentiation effects. At last, our data support that more studies should be done on a wider range of seaweeds, as extracts from different species do present quite different bioactivities.