The Asia-Pacific region dominates many aspects of world fisheries in terms of production, value and employment. Throughout the Asian region, captured and cultured marine fisheries continue to play an important role in the food security, poverty alleviation and in the economies of many countries. Within the Asian region, marine fisheries resources have been heavily exploited and as a result, development of coastal aquaculture has been encouraged to provide the protein, income, and employment and export earnings for some countries. This pressure on aquaculture development further contributed to fisheries overexploitation and ecosystem degradation. In 2003, 24 percent (or 32 million tonnes) of world fishery production was reduced to fish meal or other non-food uses. There is a general lack of accurate information of how much trash fish is presently used in the Asia-Pacific region, but a conservative estimate of 25 percent for livestock and aquaculture feed was given by the authors. The uses of trash fish are diverse and include: (i) local consumption (e.g. fresh, dried), (ii) direct feed (e.g. livestock, high value species aquaculture), (iii) fish meal production (e.g. for poultry, aquaculture) and (iv) value-added products (e.g. fish sauce, surimi, protein concentrates).
The issues relating to the different types of trash fish are inter-related. One major issue in the region is the increasing demand for trash fish for both aquaculture and animal feeds. Recognizing the effects of declining marine capture fisheries, many governments have turned to aquaculture as a means to increase fish supply, provide employment and generate foreign income. On one hand, aquaculture development can be seen as a viable option to utilize trash fish yet, on the other hand, it is increasing fishing pressure on the already overexploited fish stocks in the region. Over the last decade, the price of trash fish has risen considerably, and it is predicted to increase over the next few years due to increased demand for fish meal and fish oil to meet market demands for aquaculture of carnivorous fish (and well as a source of affordable food). Declining stocks of many trash fish species such as Japanese anchovy, chub mackerel and filefish will aggravate the situation. Given that aquaculture is predicted to grow while that of capture fisheries remains stable, it will be difficult to meet the demand for trash fish.
There is a general concern that the rapid expansion of aquaculture may ultimately be constrained by the dependence on trash fish and fish meal, popularly referred to as the "fish meal trap". The Asia-Pacific countries may need to increase imports of fish meal from the global market for the aquaculture industry, or replace these with other feed materials. The replacement of fish meal in aquaculture diets is hence a major international research priority. There is also an increasing conflict between the use of trash fish for feed or for human consumption. This means there are trade offs between direct food benefit and the indirect employment and income generation opportunities afforded by feeding to aquaculture and livestock. Poor handling and post-harvest in small-scale fisheries continues to play a role in the supply of trash fish. The benefits of improved post-harvest handling are probably outweighed by the costs of capital investments.
Direct use of trash fish occurs for some cultured species (such as grouper and mud crabs) and are also used as supplemental feeds of other species such as tilapia, prawns and milkfish. Trash fish are also being increasingly used as the raw ingredient in local production of fish meal and fish oil in the Asia-Pacific region. The feed mill industry is a major sector in the region with a large number of factories spread across many States. They produce large quantities of aquaculture, poultry and livestock feeds. Many governments have encouraged aquaculture development as a means to provide food and income to local communities to offset the overexploited marine fishery resources. Such policies often create high demand for low value fish as they are raw materials for fishmeal production. All countries reported that low value fish are directly consumed by poor people as they are cheap and provide good source of protein.
Another issue related to fish landed by larger industrial vessels. These fish are typically landed at a single point (port) and typically in a poor state of preservation or severely damaged from the capture method used. Utilization of this fish is either through conversion into fish meal or direct use for livestock or aquaculture in the general vicinity of the landing site. The question is whether better post-harvest handling and processing would yield a better return for this limited resource.
Another distinctly different, but related issue, is the capture of juvenile fish of potentially important commercial species (so-called "growth over-fishing"). Trash fish currently constitute about 60 percent of the total trawl catch from the Gulf of Thailand and between 18 to 32 percent of trash fish are juveniles of commercially important fish species. Given a chance to grow to a larger size, these species would provide much more benefits in terms of production, but more importantly, in terms of value.
Utilization of low value fish for fishmeal production is likely to continue, particularly in China and Thailand where several fishmeal plants are in operation and products from aquaculture earn high export income. Appropriate estimation and recording of low value fish landings is needed to determine the extent of fishing. A starting point for this is clear identification/characterization of these low value fish into juveniles of different fish species or family. This is needed to reduce the statistical reporting of ‘mixed fish’, ‘miscellaneous systems. It is recommended that social impact assessment (SIA) could be conducted to determine the total benefits and losses of catching low value fish for aquaculture production or allowing them to grow to marketable sizes. Indexes derived from SIA could be used as an indicator to suggest policy directions for sustainable fisheries management.
For the purpose of the Workshop, trash fish was defined as:
"Fish that have a low commercial value by virtue of their low quality, small size or low consumer preference - they are either used for human consumption (often processed or preserved) or used for livestock/fish, either directly or through reduction to fish meal/oil".
One obvious but important conclusion from the presentation was the strong inter-dependency between capture fisheries and aquaculture, which will require more coordinated management in the future.
The utilization of fish for food and non-food is not routinely monitored in China. In order to test sample survey methodologies as a possible means for monitoring catches and fish utilization, pilot sample surveys were undertaken at three Chinese fishing ports. The surveys revealed that very large quantities of trash fish (for non-food use) and low value fish (for human consumption) are taken by trawl and sail stow net gears. The proportion of trash fish is highest in trawl catches for December to May when it constituted over 50 percent of the catch. Between 25 percent and 70 percent of low value fish are small-sized species of commercially important fish species and between 32 percent and 50 percent of trash fish are juveniles of commercially important fish species.
Increased fishing pressure for low value fish and trash fish is almost certainly resulting in overexploitation of commercial fish stocks in the East China Sea, with a consequent negative impact on sustainable development of marine capture fisheries in China. Even if fishing for trash fish and low value fish can be justified on economic grounds (which is far from clear), there are serious concerns about impacts on the ecosystem and biodiversity. Issues relating to the increasing fishing effort for low value fish and trash fish require urgent attention from national fisheries authorities and regional fisheries organizations such as APFIC to determine whether such fisheries are justifiable on economic, social and ecological grounds.
There was a concern that, in the future, the rapid expansion of aquaculture may be constrained by increasing dependence on low-value marine trash fish and fish meal. From a reported aquaculture production of 0.65 million tonnes in 1999, the Vietnamese government is planning to double their production to 1.15 million tonnes by 2006 and triple to 2 million tonnes by 2010. It is thus timely to describe the production, uses (including alternatives) and trends of trash fish, fish meal and fish oil to assess if the availability of trash fish will restrict future expansion of their aquaculture. The presentation was based on information from field visits and interviews carried out in Hai Phong, Khanh Hoa, Baria-Vung Tau, An Giang and Kien Giang provinces as well as in Hanoi and Ho Chi Minh City from 9 to 26 February 2003.
There are conflicting data on the volume of trash fish landed. The inshore fishery in Viet Nam is heavily over-fished but the total fish catch, as well as the proportion of biomass of trash in the total catch, continue to rise. There has been a dramatic rise in the use of trash fish in aquaculture with probable doubling its price, indicating a finite supply. It is unlikely that aquaculture based on traditional use of trash fish as a direct feed can expand considerably.
There are two types of fish meal in Viet Nam: "fish powder" produced in a traditional artisanal way by sun-drying and grinding; and fish meal product from industrial process in which raw materials are cooked before drying. Fish powder is mainly used to feed livestock. Feed mills in Viet Nam only use domestically produced fish meal for livestock and some freshwater fish for grow-out feed as it is generally of poor quality.
Fish meal for high quality feed for fish fingerlings and crustaceans is imported and represents about 90 percent of the total fish meal used. Fish oil for aquafeed manufacture is also imported. Future demand for fish meal is expected to increase dramatically as aquaculture production increases and some species, such as catfish, are increasingly fed pelleted diets containing fish meal. While high market value species such as grouper, lobster and shrimp may be able to compete for fish meal on the local market, catfish and tilapia will need to be fed increasing amounts of plant-based proteins.
The use of inland (freshwater) trash fish for aquaculture is rare in north eastern Thailand and Lao PDR, because selling of preserved small freshwater fish as food is more profitable than using these to feed carnivorous fish. Fish preservation is primarily by fermentation, drying or salting. Preserved fish products are generally more valuable than fresh fish.
The composition of feed for carnivorous or omnivorous fish varies across northeast Thailand and Lao PDR. In pond culture of striped snakehead, by-products of Indo-Pacific mackerel and chicken intestines from processing plants are used. In cage cultivation of Pangasius bocourti, waste from Cirrhinus mrigala and Labeo rohita processing are used as feed. In small-scale cage cultivation of sand goby (Oxeoletris marmoratus), inland trash fish is used as feed. The use of inland trash fish as feed for giant snakehead and snakehead cage culture is practised at Ban Xai Oudom, Nam Ngum Reservoir (in Lao PDR). This cage culture relies mainly on small fish, Pla Keo and Pla Kao, as feed. Seasonal shortage of inland trash fish, and the availability of alternatives limit the potential of inland trash fish as feed material. In comparison with downstream countries (Cambodia and Viet Nam), it seems that current usage of inland fish as trash fish is minimal or negligible in the Mekong Basin, in Thailand and Lao PDR. Marine fish (Indo-Pacific mackerel) caught in the Gulf of Thailand is transported inland to processing factories and the wastes are fed to inland water aquaculture in the northeast of Thailand.
In Viet Nam, at least 11 species of freshwater trash fish and 15 species of marine trash fish were identified in the trash fish fed to common cultured species. Price of trash fish and feed ingredients has tripled since 2001. Almost all the trash fish are small with low market value while captured fish are of low quality due to bad preservation method. Both freshwater and marine trash fish are used as feed
for fish cultured in An Giang and Dong Thap provinces. Farm made feed for carnivorous species the proportion of freshwater trash fish is only 13.6 percent while marine trash fish is around 86.4 percent. For omnivorous species, freshwater trash fish consist only 0.3 percent whereas marine trash fish consists 36.3 percent.
In Cambodia, aquaculture of carnivorous and omnivorous fish species and crocodile is highly dependent on inland fisheries of low value, the so-called trash fish for sourcing key dietary nutrient inputs. Thousands of tonnes of low value fish are also used for producing fish feed and other animal meal and for human consumption. This study provides clear understanding of the status of low value fish. In order to achieve this goal, five objectives were developed: (1) to identify and characterise these low value fish into different species, genus or family; (2) to determine approximate quantities or proportions, to the extent possible, of trash fish; (3) to identify issues relating to the utilization of trash fish in Cambodia; (4) to examine research needs or strategies to address the identified issues; and (5) to look at the implications for aquaculture development and sustainable fisheries management in Cambodia’s Mekong Basin.
It was reported that marine fish caught in the Gulf of Thailand are transported to northeast Thailand for processing. Marine trash fish (i.e. "processing waste" of Indo-Pacific mackerel in particular) are utilized in feeding freshwater aquaculture in the northeast of Thailand which represent a by-product of this processing and so their use is economically sustainable.
The composition of trash fish is highly diverse, over 97 families within Southeast Asia and China. This is due to the numerous types of fisheries that contribute to trash fish and the fact that most comes from trawl fisheries, which are relatively unselective. Most of the trash fish families have another commercial value and yet can comprise a substantial proportion of the trash fish. The market pathways for trash fish vary at different locations within countries, depending on the local markets and demand. They also appear to change rapidly through time. There is also movement of trash fish between states/provinces. The main source of trash fish within Malaysia, Thailand and the Philippines are the trawl fisheries. In Thailand, trash fish and low value fish production have been reasonably constant over recent times, but a greater proportion is coming from outside the Thai Exclusive Economic Zone. In Malaysia, trash fish production is increasing and most comes from the fisheries on the west coast of Peninsular Malaysia.
Aquaculture demand for trash fish for both direct feeding and via pellet feeds has increased with rising fish production. The trash fish for direct feeding is likely to be mainly met by local trash fish production. Within Southeast Asia and China, China has the greatest estimated demand for trash fish, Viet Nam and the Philippines are the most dependent on it, with an estimate of over 94 percent of their production reliant on trash fish. The natural fish stocks that contribute to trash fish show trends that should be of concern. In Thailand and Malaysia, most of the dominant families in trash fish examined show a decline in their relative abundance. This stock assessment results should be treated with caution given the data limitations, but they do suggest that several families are being exploited at levels greater than estimated maximum sustainable yields. This is more apparent in those families that have other commercial value aside from trash fish.
The future projections for increased aquaculture growth will result in increased demand for trash fish unless feeding practices change. If this increased demand is met within the region by increased fishing pressure on trash fish families, this is unlikely to be sustainable. For families that contribute to fisheries outside of trash fish, increased take by trash fish fisheries will be detrimental to these fisheries. Given the fisheries do not appear to be able to contribute more sustainably, the increased demand may result in shifts of families from other market pathways to aquaculture. However, the social and economic implications of this are not clear, e.g. they may move away from direct human consumption. The management of trash fish in capture fisheries is a significant challenge, even in comparison to the challenge of managing other types of fisheries in the region. Trash fish generally comes from non-target fisheries, using relatively unselective gear. The landings are particularly difficult to monitor as they are often away from major landing sites. There is a strong demand for trash fish that is also changing rapidly as markets evolve. These market drivers are also occurring at a very local scale, which is difficult to monitor or influence. Developing management strategies that will be effective given the combination of these factors should be the focus of future discussion.
Aquaculture production will increase due to the growing demand for aquatic animal products to meet global food demand. Because much of this demand will be for species that require feeding, the demand for aquatic animal feed (aquafeed) will also increase. Several factors will influence feed demand and use, including regional and global trade issues, economics, increasing intensification of aquaculture systems and the species farmed. Coastal aquaculture will see growth in marine fish and shrimp farming, and a proportional increase in aquafeed demand. Improving hatchery technologies are likely to further stimulate growth of marine finfish production in the Asian region due to greater availability of seed stock.
Aquafeeds and aquaculture development in the region rely heavily on wild capture fisheries. The use of wild capture fisheries for aquaculture feed is diverse, including direct use of so-called low value/trash fish, the ingredients in moist diets, and the conversion to fishmeal and fish oils for incorporation into formulated diets. Globally, fish meal and fish oil used for aquaculture has been estimated at 17.7 million tonnes in 2001. Including the direct use of trash fish largely used in the Asian region, possibly about 20-25 million tonnes of capture fishery products are being used for aquaculture production. Further research is required to improve the database.
Aquaculture growth based on direct feeding of trash fish is unlikely to be sustainable in the long term. The challenge for aquaculture is clearly to seek alternatives to direct feeding of trash fish and to make better use of existing resources. The challenges will be technical, environmental, social, economic and political concerns. There are also transboundary issues - stocks and trade - requiring collaboration among countries. The change will have social implications. The stakeholders involved include feed companies, small and large-scale fishers, employees on and off shore, aquaculture farmers and employees, traders, governments and others. The collection and use of trash fish for aquaculture, directly or indirectly, involves many poor people and change will have significant implications for the people involved. There will inevitably be conflicts that will need to be managed effectively. Incentives and support are needed for the change. Collaboration and networking will be useful to address the challenges. NACA and the marine finfish network look forward to the outcome of the Workshop recommendations for collaborative follow up actions.
Trash fish remains the traditional method of feeding marine carnivorous fish throughout the Asia-Pacific region and is likely to remain so for some time yet. However, marine seacage aquaculture expansion continues in the region. The socio-economic and environmental consequences of its reliance on trash fish will be increasingly felt to the detriment of all. The paper outlined some of these consequences in terms of the impact of trash fish feeding on near-shore fishery stocks, the damage to the coastal environment and its potential to introduce disease in the cultured fish. Also described was the results of the regional collaborative grouper aquaculture research project to develop compounded grow-out feeds as alternatives to feeding trash fish. The processes carried out by the project team to disseminate these finding through organization of regional industry workshops and the dissemination
of the information through electronic and hardcopy publications are also described. Building on the success of the original project, a follow-on project has commenced to promote the use of compounded feeds as replacements for trash fish and also to address concerns which deter fish farmers in the region from using compounded feeds.
The Training Department (TD) of SEAFDEC has completed a wide range of experimental fishing trials on the use of Juvenile and Trash Excluder Devices (JTEDs) over recent years. These trials investigated the effectiveness of the rigid sorting grid, rectangular window and semi-curved window JTEDs in releasing juveniles of commercially important fish species and trash fish from demersal fish trawling operations.
Experimentation began in the provinces of Chumpon and Prachuap Kirikhan of Thailand in 1998. This initial work led to the identification of the rigid sorting grid device as an effective tool in the exclusion of juvenile and trash fish from fish trawls. Further experimentation focusing on the effects of grid spacing on the performance of this JTED was completed in Brunei Darussalam and Viet Nam during 2000 and 2001.
In September 2001, fishing trials using the rigid sorting grid JTED were conducted in Malaysian waters. This work focused on the effects of grid spacing and day/night influences on JTED performance. Grid spacing of 1.2 cm is highly effective in reducing capture of juveniles and trash fish in fishing areas adjacent to the Malaysian Peninsular. JTED performance was also generally greater during day-time fishing trials.
In 2002, TD has completed trials in the Indonesian waters and in the Philippines. The results from the Arafura Sea region of Eastern Indonesia trials suggested that the rigid sorting grid device with the 4 cm spaced sorting grid achieved the highest releasing rates of juvenile and trash fish. In 2003, investigations completed in the Philippines highlighted that the rigid sorting grid device with a grid spacing greater than 1 cm was generally more effective in the exclusion of juvenile and trash fish than the rectangular and semi-curved window JTEDs.
During 2004, demonstrations and experiments on the use of JTEDs were completed in Myanmar and Cambodia to provide a complete coverage of relevant SEAFDEC member countries. Researchers are confident that the above mentioned activities have been effective in developing regional understanding of the use of JTEDs. All work have been completed in close collaboration with the fisheries departments of the Member countries involved in the project. This has been effective in capacity building for regional governments and fisheries personnel to be responsive to the needs of fishers as they move toward the development of more sustainable fish trawl practices.
The research and developmental works of SEAFDEC/MFRD on utilization of underutilized and low value small demersal and pelagic fish catch are aimed at maximizing utilization. Through R&D, researchers have found that small demersal fish species are suitable raw materials for making frozen surimi and fish jelly products. The breakthrough coupled with transfer of technology has led to the dramatic growth of surimi industry in the region. MFRD has also developed a range of value added products such as, fish sausages, fish nuggets, fish tofu, sweet meat and fish floss from small pelagic fish species.
Two theoretical model analyses of the interaction between aquaculture and wild capture fisheries were applied to the fishery of the Gulf of Thailand. The first model considered the interaction at the output level only and concludes that expanding fish supplies through aquaculture can reduce the harvesting pressure on wild stocks. However, when considering also the interaction at the input level, that is the use of fish as feed (or seed) an alternative model found that while in the short term aquaculture can increase fish supply, in the long run, aggregate fish supply from aquaculture and capture fisheries could be lowered by the expansion of aquaculture. This dire outcome would arise in situations where there exists open access to wild capture fisheries.
The open access condition in many Asian marine fisheries has caused overfishing, loss of biodiversity, large share of low value species or size categories in the catch, low product quality, preponderance of unselective gear types, primarily trawl and pushnet, and marginal profitability. In this situation, the revenues made through the bycatch or targeted catch of low value fish are often important for the vessels’ financial viability. There is, therefore, an fish as input into aquaculture and the development of the fishing fleets and fishing effort in the marine capture fisheries of the region.
In another study, it was found that fishmeal is not a unique product among protein meals and contributes only a small share to total global production. While no other industry than aquaculture has increased as rapidly its demand for fishmeal during the last two decades, there is little evidence that fishmeal cannot, or has not been, substituted by other protein meals, especially soybean meal. Whether demand for fishmeal becomes more inelastic as the rapid growth trend in aquaculture continues in future or not, this will depend on the technological progress in aquafeed and farm management. Greater reliance of future aquaculture growth in the region on formulated pellet feed would lessen its dependency on both low value fish caught domestically and on imported fish meal.
There does not, therefore, need to be a trade-off between future aquaculture growth and the recovery of marine fisheries in the region. Based on the example of the Thai demersal fisheries in the Gulf of Thailand, the paper noted that a recovery strategy of marine capture fisheries would generate significant income to the national economy and reduce the threats to the sustainability of marine ecosystems. Social and economic support measures to facilitate the reduction of fishing fleets, especially of push-netters and trawlers, would be needed but would yield high returns to the economy, the fishing industry and the marine environment.
