Considering the different context of use of, and composition in trash fish, the working groups suggested that the term should be better referred to as low value fish. The main perceived contributors to low value fish of the catch are those that have no preference (or may be unsuitable/unsafe) for direct human consumption or that have suffered from improper handling of catch. Since the term "value" is relative to the consumer it was also suggested that lowest value fish might be used. The range of definitions for trash fish or lowest value fish is variable across the region and this affects how the catches that would fall into this category are reported.
The difference in utilization of low value fish is perhaps most marked between inland fisheries producing areas and coastal areas. In inland fisheries the "low value" fish caught are almost entirely used for human consumption. They may be processed as a means of preservation during periods of seasonal abundance. The emergence of aquaculture in some of these inland fisheries areas is presenting an alternative channel for use. In coastal areas, low value fish may be caught by near-shore artisanal fishers and this catch is often used directly for human consumption or in local aquaculture operations.
It was reported that data and information on trash fish production (species, size) and uses were patchy and often poor in quality in many countries in the region. In Viet Nam no data are available on the proportion of trash fish used for feed production/direct feed for aquaculture and livestock and for the production of fish sauce, although some recent estimates based on indirect methods are available.
The exact portion of fish meal going to aquaculture compared with that going to livestock feed is also unknown although it is known that the share for aquaculture is increasing. Chinese production of fishmeal is about 500 000 - 600 000 tonnes, requiring almost 2.5-3.0 million tonnes of wet fish. Three kinds of feeds are used in China for aquaculture: trash fish used for direct feeding; moist pellets and dried pellets.
It was questioned why science, as a basis for fisheries management, is so unreliable. Whereas trawl survey data for the Gulf of Thailand indicate that catch per unit effort and biomass estimates have declined to only 10 percent of what they were at the beginning of the time series, these data could under-estimate the decline, because there are now some commercial catches coming from areas outside the Gulf of Thailand, or from areas which are not covered by the trawl surveys. MSY estimates from the equilibrium methods may not be reliable and may be too high, as the time series used for the calculations are only from a period when the stocks have been already over-fished. MSY estimates from the Maximum Likelihood method are more conservative and have the advantage that they have associated error bounds. Unfortunately, there are large discrepancies between the methods making the provision of advice to decision-makers difficult.
There is currently a lack of hard data available to indicate with certainty, whether the biomass increases caused by "fishing down the food chain" can be sustained at current levels or increased or it will collapse. This is an area which requires further significant analysis.
Fisheries management needs to be linked to poverty alleviation strategies. A goal may be to provide disincentives to the large-scale trawler operations and through the reduction of this effort bring benefit to the small-scale fishery sector. The artisanal level of the fishery is able to value to low value fish using traditional methods, thus further strengthening their income generation from the fishing livelihood.
The workshop noted that rather than blaming aquaculture for creating a demand for low value/trash fish which in turn leads to a deterioration in the state of fishery resources through over-fishing, it may be more realistic to view aquaculture as taking the opportunity of increasing supplies of low value/trash fish that result from the failure of fisheries management to prevent extensive "fishing down the food-webs".
While noting that trends of low value/trash fish will be contextual depending on areas and scale of fisheries, the workshop considered that future trends of low value/trash fish will generally be:
Where there is no proper management of fisheries in place, the proportion of low value/trash fish in the total catch may increase due to irresponsible fisheries leading to fishing down the food-web.
This will mostly derive from trawlers and push netters that lack storage facility on-board or that have poor handling facilities; it will also derive from small pelagic fisheries (e.g., purse seine) and freshwater Dai fisheries (in Discarding is not a prominent issue in the region, except in few isolated fisheries.
The price of fishmeal and particularly fish oil will increase in the region and probably globally. There will be increasing prices of fish; including low value/trash fish due to:
- reducing amount of low value/trash fish in the total catch, as a result of the improvement efforts of current management of fisheries;
- decreasing total fish supply for human consumption, which will result in turning some part of low value/trash fish to higher value;
- increasing demand of fish in response to growing human population in general and inaccessibility of high value fish among the poor;
- increasing demand from aquaculture expansion even considering attempts to identify non-fish protein sources; and
- there will be increasing demand for high value aquaculture species, both in local and international markets. This is linked generally to increased demand for healthy (EFAs, etc.) functional foods.
This demand for fish will also be linked increasingly to the need for traceability and certification (either for safety of the product or production method).
Increasing urban populations will demand more standardised products and/or consistent supply - including the food safety element.
Some cultured species produced currently depend on direct feeding of low value/trash fish e.g. groupers and other carnivorous finfish, lobsters, Babylonia snail. The reasons for this use are:
the feeding method has evolved this way out of practical considerations and is therefore now considered habitual/traditional;
the convenient supply availability of the fish locally, particularly during certain seasons;
low value/trash fish is still relatively cheap for aquaculture (this is also seasonally affected); and
fisher/aqua-farmers are able to catch the feed by themselves (feed costs are offset as opportunity cost of the fishers time).
It was noted that targeted fisheries for trash fish for aquaculture are developing (e.g. for lobster & Babylonia snail in Khanh Hoa province) where pelleted feeds are not yet a viable/acceptable alternative.
In terms of both direct feeding and using low value/trash fish in fish meal/oil, the need for fresh fish was highlighted if it is to provide a good ingredient/feed for aquaculture (amino acids, EFAs, etc.). There are well known problems with low quality fresh fish as direct feed for aquaculture (thiaminase, transfer of diseases etc.) but there is still a widespread perception in the region that direct feeding of low value/ trash fish is better because:
it may be more acceptable than a pellet feed;
there is often limited availability of pelleted feed;
farmers lack experience of pellet feeding and therefore are uncertain of profit margins and the feeding methods;
agricultural products inclusion (food/health safety issues); and
there is a general difficulty of weaning some species onto pellets.
The workshop identified a range of factors that would deter the direct use of low value/trash fish in aquaculture. These would be:
Factors that affect the profitability of operation
increase of the price of low value/trash fish;
increased competition for alternative uses (e.g. for direct human consumption);
scaling up of production units - requires pellet feeds; and
Factors that affect the efficiency of operation
general unavailability in some areas, or seasonal/uncertain decreases in supply (this limits larger operations but small scale operators may be able to overcome this);
pelleted feed readily available at reasonable price;
availability of fingerlings weaned onto formulated diets;
information, knowledge, education and demonstration about value of pellet feeds;
increasing knowledge about inefficiency of poor quality of trash fish (farm economics, water quality & wider environmental pollution);
overcome taste issues using pellet fed fish; and
increased availability of cost-efficient substitutes (e.g. plant proteins, terrestrial animal meals, catfish processing by-products, etc.).
Factors relating to the legality/compliance of operation
legislation against polluting aquaculture practices;
legislation/policy to prevent targeted catch;
pressure from "consumers" for sustainably produced aquatic products (environment, social, economic); and
need for feed ingredient traceability to allow export marketing (EU legislation).
The Working Groups concluded that overfishing will ultimately lead to a decline in overall supply. (it was acknowledged that there maybe short term increases but will decline in the longer term). The effects of this would be that: price of low value/trash fish will increase the use of trash fish for direct feeding will decrease there will be a drive towards improved post-capture technology and adoption of this technology. The result would be that more of the fish landed would be fit/acceptable for direct human consumption and more low value/trash fish would go to human food and less for aquaculture. For some high value aquaculture species, the quality of low value/trash fish for aquaculture might also improve. there will be a tendency for introduction of legislation for more targeted fisheries and exclusion devices to minimise catch of low value/trash fish species. demand from aquaculture of high value species can out compete traditional uses of low value fish e.g. fish sauce manufacture.
The Working Groups concluded that the aquaculture of high value species will probably out compete livestock industries for trash fish and fish meal as it had larger profit margins and the increasing price of fish. The increased competition for fish and fish meal tend to drive towards increased use of pelleted fish feeds. There would also be increased competition with the emerging Surimi industries and such like. It should be noted here that since this requires human food quality fish, the competition here may be less.
There will be an increasing availability of appropriate formulated feeds (farm made and commercial pellets) in the region. However, the formulated feeds for shrimp, fish fingerlings, marine finfish and lobsters still require high quality trash fish for fishmeal production.
If prices of fish meal rise substantially this will also be accompanied by and increasing substitution of fish meal, fish oil, low value/trash fish. This will be most quickly seen in feeds for less carnivorous species. There is still currently limited knowledge of the nutritional requirements for many culture species.
Whereas growth in the use of trash fish is not sustainable, the growth in aquaculture production is because aquafeeds can be used. At present the conversion of low value/trash fish to pellets which are more efficient feeds is not an economic proposition, but this may well change in the future.
Feed development for shrimp is a good example of what the industry can achieve if there is sufficient demand. Feed formulations for tilapia and catfish feeds are relatively simple. The diversity of marine fish species requires different feed formulations (e.g. specific feed formulations for sea bass, various groupers and cobia) and this represents a constraint to the level of the demand for a specific feed.
Currently formula aquafeeds contain much fishmeal though dependence on fishmeal can be reduced in the future. Although for rearing species such as grouper, fishmeal will continue to be needed, dependence on low value/trash fish can be greatly reduced through the use of pelleted feeds. Such a change will be essential for aquaculture expansion to continue.
Fish oil supplies are likely to run out long before supplies of fishmeal. Alternatives to fish oil in aquafeeds need to be sought urgently. It was pointed out that, at present, Viet Nam does not produce fish oil expect for Pangasius oil (low value). All fish oil is imported. Attention was drawn on the constraints in the availability of fish oil and on its importance as a primary source of nutritional element in particular of Omega III fats.
For those countries that have a large number of poor people dependent on low value/trash fish a decline in supply may have negative implication on food security. In general, the disposition of low value/trash fish is market driven and dependent upon local economic mechanisms. The flow of disposition will depend on the relative "buying power" of livestock and aquaculture production versus uses in direct human consumption (bearing in mind, that there is always part of this catch that is unsuitable for direct consumption and part that might be).
The meeting was informed that different grades of low value/trash fish are used for different purposes. For example in Thailand only high quality low value/trash fish (anchovies) are now utilized for fish sauce production. However, in Viet Nam low value/trash fish are still consumed by poor families for domestic consumption.
The channels for sale and disposal of low value/trash fish is not confined to larger trawlers and the spread of the economic linkages from the low value/trash fish landed extends into surrounding rural areas. It may also extend even further if the fish are processed into fish meal and thence into fish feeds.
the increase in total fishing pressure is leading to loss of aquatic biodiversity and overfishing;
incentive to identify/use non-fish protein sources for human consumption and aquaculture feeds (including more efficient feeding methods and farm management);
lower food security from fish and negative impact on poverty, as fish will be less affordable, particularly for the poor for food consumption and as feeds for aquaculture as alternative livelihoods;
possible expansion of fisheries particularly industrial/large-scale;
small-scale/traditional fish processors may be edged out by larger processing operators;
possible change in aquaculture types from carnivorous species to herbivorous species or poly culture; and
there will be shifts in the rural/urban consumption patterns of fish.