Aquaculture effluent : impacts and remedies for protecting the environment and human health

Knowledge in the field of environmental health is growing rapidly. Within the context of external factors that define its boundaries, environmental health has evolved over time into a complex, multidisciplinary and ill-defined field with uncertain solutions. Many of the key determinants and solutions to environmental health lie outside the direct realm of health and are strongly dependent on environmental changes, water and sanitation, industrial development, education, employment, trade, tourism, agriculture, urbanization, energy, housing and national security. Environmental risks, vulnerability and variability manifest themselves in different ways and at different time scales. While there are shared global and transnational problems, each community, country or region faces its own unique environmental health problems, the solution of which depends on circumstances surrounding the resources, customs, institutions, values and environmental vulnerability. This work will contain critical reviews and assessments of environmental health practices and research that have worked in places and thus can guide programs and economic development in other countries or regions.

Responsible aquaculture and trophic level implications to global fish supply

Hunger and malnutrition remain among the most devastating problems facing the world’s poor and needy, and continue to dominate the health and well-being of the world’s poorest nations. Moreover, there are growing doubts as to the long-term sustainability of many existing food production systems, including capture fisheries and aquaculture, to meet the future increasing global demands.Of the different agricultural food production systems, aquaculture (the farming of aquatic animals and plants) is widely viewed as an important weapon in the global fight against malnutrition and poverty, particularly within developing countries where over 93% of global production is currently produced, providing in most instances an affordable and a much needed source of high quality animal protein, lipids, and other essential nutrients. The current article compares for the first time the development and growth of the aquaculture sector and capture fisheries by analyzing production by mean trophic level. Whereas marine capture fisheries have been feeding the world on high trophic level carnivorous fish species since mankind has been fishing the oceans, aquaculture production within developing countries has focused, by and large, on the production of lower trophic level species. However, like capture fisheries, aquaculture focus within economically developed countries has been essentially on the culture of high value-, high trophic level-carnivorous species. The long term sustainability of these production systems is questionable unless the industry can reduce its dependence upon capture fisheries for sourcing raw materials for feed formulation and seed inputs. In line with above, the article calls for the urgent need for all countries to adopt and adhere to the principles and guidelines for responsible aquaculture of the FAO Code of Conduct for Responsible Fisheries.

Fish oil in aquaculture : in retrospect

The use of fish oils by aquaculture is the key impediment on the future growth and sustainability of the industry. Fish oil, the key provider of health-beneficial omega-3 long-chain polyunsaturated fatty acids, fluctuates drastically in supply and cost, and is extracted unsustainably from world oceans. Resultantly, its persistent use has fueled a heated global debate and sparked a generation of research focus into possible means of reducing the aquaculture industry's dependence on this resource. This chapter introduces the subject of fish oil usage in aquaculture on a global basis, and briefly traces the history of related issues. Accordingly, the major fish species utilized for fish meal and fish oil production are traced and the chemical and nutritional characteristics of fish oils of different origins are provided. The future expected availability of fish oil for aquaculture and the sustainability of the reduction industry are subsequently discussed.

Transforming salmonid aquaculture from a consumer to a producer of long chain omega-3 fatty acids

Recommendations to endorse the sustainability of wild fish stock utilisation, supporting the health of marine ecosystems, are clashing with those to increase omega-3 fatty acids (n−3 LC-PUFA) consumption and promoting human health.

The objective of this study was to evaluate the role of salmonid aquaculture as a user or supplier of n−3 LC-PUFA, as a means of understanding the potential of the sector in conserving or depleting wild fisheries. A case-study feeding trial was implemented on rainbow trout up to commercial size, in which fish were fed a fish oil- or a linseed oil-diet. Harvested fish were analysed for fatty acid composition and difference and liking using consumers. The n−3 LC-PUFA input/n−3 LC-PUFA output ratio was computed. Consumers showed no preference, but were able to distinguish between samples. The fatty acids of the fillets were significantly modified by the diets. On the input side, for the production of 100 g of fish fillet, it was necessary to use 8.6 g of n−3 LC-PUFA to produce an output of 1.9 g of n−3 LC-PUFA in the fish oil-fed fish; in contrast it was only necessary to use 270 mg of n−3 LC-PUFA to produce 560 mg of these fatty acids in the linseed oil-fed fish. It was showed that the substitution of fish oil with linseed oil in aquafeed is an easily implemented tool to transform salmonids farming from a consumer into a net producer of health promoting n−3 LC-PUFA and accomplish its role in conserving wild fisheries in the future.

Recent advances in omega-3: health benefits, sources, products and bioavailability

The joint symposium of The Omega-3 Centre and the Australasian Section American Oil Chemists Society; Recent Advances in Omega-3: Health Benefits, Sources, Products and Bioavailability, was held November 7, 2013 in Newcastle, NSW, Australia. Over 115 attendees received new information on a range of health benefits, aquaculture as a sustainable source of supply, and current and potential new and novel sources of these essential omega-3 long-chain (LC, ≥ C20) polyunsaturated fatty acid nutrients (also termed LC omega-3). The theme of "Food versus Fuel" was an inspired way to present a vast array of emerging and ground breaking Omega-3 research that has application across many disciplines. Eleven papers submitted following from the Omega-3 Symposium are published in this Special Issue volume, with topics covered including: an update on the use of the Omega-3 Index (O3I), the effects of dosage and concurrent intake of vitamins/minerals on omega-3 incorporation into red blood cells, the possible use of the O3I as a measure of risk for adiposity, the need for and progress with new land plant sources of docosahexaenoic acid (DHA, 22:6ω3), the current status of farmed Australian and New Zealand fish, and also supplements, in terms of their LC omega-3 and persistent organic pollutants (POP) content, progress with cheap carbon sources in the culture of DHA-producing single cell organisms, a detailed examination of the lipids of the New Zealand Greenshell mussel, and a pilot investigation of the purification of New Zealand hoki liver oil by short path distillation. The selection of papers in this Special Issue collectively highlights a range of forward looking and also new and including positive scientific outcomes occurring in the omega-3 field.