Use of wild fish and other aquatic organisms as feed in aquaculture; a review of practices and implications in the Asia Pacific

Global and Asian aquaculture have witnessed a ten-fold increase in production from 1980 to 2004. However, the relative percent contribution to production of each of the major commodities has remained almost unchanged. For example, the contribution of freshwater finfish has declined from 71 to 66 percent in Asia but has remained unchanged globally over the last 20 to 30 years. This fact has dictated trends in the use of fish as a feed for cultured stocks. The growth in the sector has gone hand in hand with an increasing dependence on fish as feed, either directly or indirectly. In a number of countries in the Asia-Pacific region, the aquaculture sector has surpassed the capture fisheries sector in its respective contributions to the gross domestic product (GDP). Aquaculture’s increased contribution to national GDPs can be taken as a clear indication of the contribution of the sector to food security and poverty alleviation. The use of finfish and other aquatic organisms as a feed source can be through direct utilization of whole or chopped raw fish in wet form, through fishmeal and fish oil in formulated feeds, and/or as live fish, although the latter is uncommon and the overall amounts used are relatively small. In the first two categories, the fish used are often termed “trash fish/low-value fish”. Although attempts have been made to define this term, all definitions have a certain degree of ambiguity and/or subjectivity. In this regional review, the amount of fish used as feed sources based on the above categories was estimated primarily from the production data, supported by assumptions on the inclusion levels of fishmeal in formulated feeds and observed feed conversion efficiencies for both formulated feeds and for stock fed trash fish/low-value fish directly. A scenario for the use of fish as feed was developed by starting from the levels of aquaculture production recorded in 2004 and assuming increases in production volumes of 10, 15 and 20 percent by 2010, respectively, for the three trajectories. In parallel, the pattern of wild fish use as feed was projected to change as fish and shrimp farmers increasingly replace farmmade feeds by incorporating trash fish/low-value fish with manufactured feeds that include fishmeal. Also, the fishmeal inclusion rates in manufactured feeds are falling slowly, and this has been incorporated into the projections. The regional review also deals with the production of fishmeal using trash fish/low-value fish in the Asia-Pacific region. Regional fishmeal production as a whole is relatively low when compared with that of major fishmeal-producing countries such as Chile, Iceland and Norway, amounting to approximately 1 million tonnes per year. However, there is a trend towards increasing the use of fish industry waste, such as from the tuna canning industry in Thailand. The fishmeal produced in the region is priced considerably lower than globally traded fishmeal, but its quality is poorer. Total fishmeal use in Asian aquaculture in 2004 was estimated as 2 388 million tonnes, the highest proportion of this being used for crustacean aquaculture (1 418 million tonnes). Based on growth predictions (to year 2010) in the sector and improvements to feed quality and management, it is expected that the quantity of fishmeal used in Asian aquaculture will be slightly less than at present. An estimated 240 000 tonnes of fish oil is used in Asian aquaculture, principally in shrimp feeds. Based on production estimates of commodities in 2004 that rely on trash fish/low-value fish as the main feed source, this regional review suggests that Asian aquaculture currently uses between 2 465 and 3 882 million tonnes, an amount that is predicted to decrease to between 1.890 and 2 795 million tonnes by 2010. The use of trash fish/low-value fish and fishmeal by the aquaculture sector has been repeatedly adjudicated as a non-sustainable practice, and globally the sector is seeking to reduce its dependence on fish as feed through improved feed management practices and development of better quality feeds and feed formulations using alternative ingredients. Over the next few years, decreases in the use of trash fish/low-value fish are also expected to be achieved through better conversion of raw materials into fishmeal and fish oil during the reduction processes. The “way forward” in addressing the issue of the use of fish as feed in aquaculture in the Asia-Pacific region includes the need for a concerted regional research thrust to reduce the use of fish as feed sources in aquaculture, as has been achieved in the animal husbandry sector. Secondly, there is a need to increase farmer awareness on the use of trash fish as feed. This is achievable, considering the similar progress that has been made by the region’s shrimp farming sector, which almost exclusively involves small-scale practitioners who are often clustered in a given locality. The analysis also suggests that the use of trash fish/low-value fish in aquaculture may be compatible with improving food security and alleviating poverty. In Asia, trash fish/low-value fish is mostly landed in areas where there are other suitable fish commodities for human consumption. To make the trash fish/low-value fish suitable and available for human consumption would involve some degree of value-adding and transportation costs, which are likely to increase the price to beyond the means of the consumer, particularly in remote rural areas. Under such a scenario, the direct or indirect use of this perishable resource as a feed source to produce a consumable commodity appears to make economic sense and appears to be the most logical use for overall human benefit. In this manner, trash fish/low-value fish contributes to food security by increasing income generation opportunities and hence contributes to poverty alleviation. Another factor that needs to be taken into account is the large numbers of artisanal fishers who harvest this raw material. The continued use of trash fish/low-value fish, therefore, allows these fishers to maintain their livelihoods¹. Admittedly, this is an area that warrants more detailed investigation, from resource use, livelihoods and economic viewpoints.

Industrial wastewater minimization

Industrial pollution emitted to the environment has created a drastic damage to the environment. Natural purification processes such as dilution and dispersion are not applicable due to the enormous amounts of discharged wastes, as they exceed the assimilative capacity of the local environment. Concern about the environment by the general public has forced governments to establish effluent standards for industrial wastes and emissions. Increasing numbers of industries each year has exerted pressure on the environment compelling regulators to further tighten the standards. This has led to modification and improvement in the existing end-of-pipe treatment facilities resulting in higher investment as well as operation and maintenance cost, whereas in recent years, implementation of proactive methods of waste minimization is gaining much attention within industrial sectors. Various waste minimization techniques such as improved housekeeping, change in process technology, change in product, change in input materials, recycling of chemical and raw materials, and recovery of byproducts are discussed in detail. A number of successful examples discussed in this paper indicate that substantial benefits can be gained by implementing waste minimization programs.

Reclaiming spent liquor from cotton reactive dyebaths using nanofiltration membrane for possible reuse of water and salt

During dyeing, salts are placed in a dyebath to aid the fixation of various dyes on to the fabric while bases are added to raise the pH from around neutral to pH 11. Afterwards, the used dyebath solution, called dyebath spent liquor, is discharged with almost all the salts and bases added as well as unfixed dyes. Consequently, a lot of raw materials are lost in the waste stream ending up in the environment as pollutants. In this study, possibilities of reusing water and salts of dyebathes were investigated, using a nanofiltration membrane. When the salt concentration in the spent liquor was increased from 10 to 80 g/L, the salt rejection by membrane was found to decrease initially; however, the salt rejection increased over the time, which was not expected. The aggregation of dye was also studied and found to decrease in the concentrate when the salt concentration was increased. This may be due to the aggregation of salt in the concentrate, which explains the increase in salt rejection. This information is useful for the textile industry in evaluating the treated water quality for the purpose of reuse.

Nanofiltration for the possible reuse of water and recovery of sodium chloride salt from textile effluent

During the reactive dyeing of cotton, salts such as sodium chloride (NaCI) are placed in a dyebath to aid the exhaustion of various dyes onto the fabric while bases are added to raise the pH from around neutral to pH 11 to achieve fixation. Afterwards, the used dyebath solution, called dyebath spent liquor, is discharged with almost all the salts and bases added as well as unfixed dyes. Consequently, many raw materials are lost in the waste stream ending up in the environment as pollutants. In this study possibilities of reusing the water and salts of dyebaths were investigated using a nanofiltration membrane. When the NaCI concentration in the spent liquor was increased from 10 to 80 g/L, the NaC1 rejection by the membrane was found to decrease initially; however, the NaC1 rejection increased over time, which was not expected. The aggregation of dye was also studied and found to decrease in the concentrate when the salt concentration was increased. This information is useful for the textile industry in evaluating the treated water quality for the purpose of reuse.

Production of green nanomaterials

While our awareness towards sustainable society and environment grows, the importance of ‘green’ materials and manufacturing is gaining significant recognition. We have demonstrated that naturally-occurring fibers as renewable raw materials can be converted into nanoparticles and nano fibers using simple top-down methods without introducing hazardous chemicals. This new class of green nanomaterials will have a wide range of environmental and biomedical applications owing to the inherent biocompatible, biodegradable and carbon-neutral nature.

Identifying film takes for cinematic analysis

In this paper, we focus on the ‘reverse editing’ problem in movie analysis, i.e., the extraction of film takes, original camera shots that a film editor extracts and arranges to produce a finished scene. The ability to disassemble final scenes and shots into takes is essential for nonlinear browsing, content annotation and the extraction of higher order cinematic constructs from film. In this work, we investigate agglomerative hierachical clustering methods along with different similarity metrics and group distances for this task, and demonstrate our findings with 10 movies.

Synthesis and characterization of nanocrystalline hexagonal boron carbo-nitride under high temperature and high pressure

A study of the synthesis of hexagonal boron carbo-nitride (h-BCN) compounds via a two-step high-temperature and high-pressure (HTHP) technique using melamine (C 3N 6H 6) and boron oxide (B 2O 3) as raw materials is presented. An amorphous BCN precursor was prepared at 1000K under vacuum in a resistance furnace and then single-phase h-BCN nanocrystalline was synthesized at 1600K and 5.1GPa in a multi-anvil apparatus. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the final products were pure h-BCN crystals with the lattice constants a ≤ 0.2510nm and c ≤ 0.6690nm. The average grain size was about 150nm. X-ray photoelectron spectroscopy (XPS) results confirmed the occurrence of bonding between C-C, C-N, C-B and N-B atoms. Raman scattering analysis suggested that there were three strong Raman bands centered at 1359, 1596 and 1617cm -1, respectively. The band at 1617cm -1 was considered to be consistent with the characteristic Raman peak of h-BCN.

Impact of fermented mulberry leaf and fish offal in diet formulation of Indian major carp (Labeo rohita)

Large quantities of fish offal and mulberry leaf are generated globally. The present study aimed to understand their potential utilization in aqua diet formulation, after proper fermentation, as raw materials to replace fish meal in Indian major carp (Labeo rohita) compounded diet. Fish offal meal (FOM) and mulberry leaf meal (MLM) were used in a 2 × 3 factorial design, to evaluate (i) two different fermented mixtures with the inclusion of both FOM and MLM or only MLM and (ii) to replace three different level of dietary fishmeal: 50, 75 or 80 %. An indoor trial, to evaluate diet intake and digestibility and an outdoor trial to evaluate growth performances were impended in Indian major carp fingerlings. The results showed that FOM and MLM are promising raw materials that can be successfully used in the formulation of diet for the Indian major carp. Specifically, the addition of a proper amount of MLM in the fermentation of FOM produced a fermented mixture that could successfully replace up to 80 % of FM in the diet formulation.

Preparation of silica abrasives from water glass and application in silicon wafer polishing

Chemical mechanical polishing technique is more frequently adopted for planarization in integrated circuit fabrication. The silica abrasives in colloidal state are fabricated with the sodium silicate solution as raw materials through the polymerization reaction among silicic acid molecules. By continuous injection of silicic acid into the preexisting silica solution, the diameter of silica nanoparticles increases. The different sized silica nanoparticles are imaged by scanning electron microscopy, and the dried silica are characterized by X-ray diffraction and thermal analysis. The polishing test on silicon wafer with as-fabricated silica abrasives shows that the surface flatness reaches 1.1 nm roughness, however, micro scratches are still present in the surface.

Variation in the softness and fibre curvature of cashmere, alpaca, mohair and other rare animal fibres

Softness of apparel textiles is a major attribute sought by consumers. There is surprisingly little objective information on the softness properties of rare animal fibres, particularly cashmere, alpaca and mohair. Samples of these and other rare animal fibres from different origins of production and processors were objectively measured for fibre diameter, fibre curvature (FC, crimp) and resistance to compression (softness). While there were curvilinear responses of resistance to compression to FC and to mean fibre diameter, FC accounted for much more of the variance in resistance to compression. Fibre type was an important determinant of resistance to compression. The softest fibres were alpaca, mohair and cashgora and all of the fibres measured were softer than most Merino wool. Quivet, llama, camel, guanaco, vicuña, yak wool, bison wool, dehaired cow down and Angora rabbit were also differentiated from alpaca, mohair and cashmere. There were important differences in the softness and FC of cashmere from different origins with cashmere from newer origins of production (Australia, New Zealand and USA) having lower resistance to compression than cashmere from traditional sources of China and Iran. Cashmere from different origins was differentiated on the basis of resistance to compression, FC and fibre diameter. Cashgora was differentiated from cashmere by having a lower FC and lower resistance to compression. There were minority effects of colour and fibre diameter variation on resistance to compression of cashmere. The implications of these findings for the identification and use of softer raw materials are discussed.

China's "South-South" trade with Southeast Asia: unequal exchange and combined and uneven development

China’s unprecedented emergence as an economic and political power has created a new geopolitical economy for semi-industrialised and developing economies in Southeast Asia. This paper examines China’s trade relationships with Thailand and Indonesia using the concepts of uneven and combined development (UCD) and unequal exchange. The mass of surplus value obtained through China’s trade with the developed economies has flowed into the considerable expansion in China’s imports from developing countries since 2000. China has maintained a consistent trade deficit with the latter. While the developing countries concerned have benefitted from this set of relationships, the extent to which they have done so has been determined by national strategies. In countries like Thailand – where manufacturing capital and a significant working class has emerged – exports expanded on the basis of mutually advantageous technologically and skills intensive goods. These are produced with a similar organic composition of capital as in China. The result has been a further consolidation of the hegemony of manufacturing capital. Indonesia, however, has a political system and economy long dominated by resource exploitation linked fractions of capital. The result has been a surge in primary goods exports. The current commodity price cycle has meant these goods exchange at prices above their value. The current looming price correction, however, may have negative repercussions. In the meantime, the concentration in raw materials exports is helping to prevent the emergence of a circuit of productive capital in manufacturing. The evidence from these contrasting cases suggests that the degree to which developing economies can benefit from China’s own historically unparalleled combined development remains highly contingent on the strength of the combined development possibilities and efforts within these other national social formations. Above all, there is the degree to which manufacturing sectors of capital can obtain hegemony.

Fermentation of omega-3 and carotenoid producing marine microorganisms

 The objective of the thesis was to understand and develop the process of fermentation in marine microorganisms for the production of omega-3 fatty acids and carotenoids. Among marine microorganisms, thraustochytrids that belong to phytoplankton group was identified as sources of omega-3 fatty acids and other valuable co-products. In this research, more efficient and cost-effective production of omega-3 oils and other value added products was discussed by addressing the below key objectives. Fermentation strategy using lower cost raw materials, particularly carbon. Screening for new strains that can naturally produce high levels of PUFAs together with useful co-products that can be harvested along with the omega-3 oil.

Dietary micronutrients and in vivo n-3 LC-PUFA biosynthesis in Atlantic salmon

Aquaculture, and in particular Atlantic salmon culture, is expected to deliver n. -3 long-chain polyunsaturated fatty acid (n. -3 LC-PUFA) rich products. Nevertheless, the availability of n. -3 LC-PUFA rich raw materials for aquafeed is dwindling, and at an ever increasing market price. Thus, there is the need to better understand the in vivo n. -3 LC-PUFA biosynthetic capabilities of cultured fish to enable the possible maximization of dietary 18:3n. -3 (ALA) bioconversion to 20:5n. -3 (EPA) and 22:6n. -3 (DHA). The cofactors and coenzymes involved in this metabolic pathway have so far received limited research attention. In this study, juvenile Atlantic salmon were fed an ALA-rich diet with no, normal, or over-fortified inclusion of those micronutrients reported to be essential cofactors (iron; zinc; magnesium) and coenzymes (riboflavin; biotin; niacin) for the fatty acid elongase and desaturase enzymes. The results showed that reduced dietary inclusion of these micronutrients impaired the normal n. -3 LC-PUFA biosynthetic capabilities of fish, whereas the over fortification did not provide any additional benefit. This study provides new knowledge on micronutrients and lipid metabolism interactions in a commercially important cultured species, and is envisaged to be a useful contribution towards developing more sustainable and commercially viable aquafeed for the future.Statement of relevance. This work is the continuation and extension of a previous study (Lewis et al., 2013, Aquaculture 412/413, 215-222) in which we explored the physiological roles and potential effects of micronutrients on fatty acid metabolism in cultured fish. The present study differed from the previous in the blend of minerals and vitamins used, the species, the fatty acid composition of the test diet, and the inclusion also of a negative control. The results are most interesting, showing that riboflavin (B2), biotin (B7), and niacin (B3), Iron (Fe), Magnesium (Mg) and Zinc (Zn) are all required for proper fatty acid bioconversion, but also that a dietary over-fortification does not translate into proportional improved bioconversion.