Expert opinion

9 commentslast update:6 Aug 2012

Fish eating fish = not sustainable

We hear a lot about the boom in aquaculture. Some industry pundits are even asking how long can it last? The answer is simple: as long as the feed holds out. And that time may not be all that far away.

We hear a lot about the boom in aquaculture. Some industry pundits are even asking how long can it last? The answer is simple: as long as the feed holds out. And that time may not be all that far away.

The main problem is the fish we like to consume are the species that eat other fish for a living. The salmonid sector alone consumes more than half the fish oil produced. Shrimp are another huge consumer of fishmeal. Sea bass, barramundi, eels, catfish and grouper all require highly refined diets. As the farming of cod becomes wide spread the call on the finite fodder fish harvest will increase commensurate with that growth. The problem is that, as the world's wild harvest plateaus out, so does global fishmeal production.

So far we ve seen the grain and legume industries offer their products as alternative sources of protein to fish farmers and despite the time and money poured into research and trials, little of any lasting value has come from it. The main outcome has been loss of production, loss of fish quality and increased nutrient loads in ponds. In many cases, financially and environmentally disastrous increases in nutrient loads.

The truth of the matter is that there is no alternative to fishmeal as an efficient protein source for aquaculture diets, and until such time as the global research community makes a concerted effort to determine the specific nutrient requirements of the individual species of commonly farmed fish, this situation will not change.

Nutrient retention in the body of the fish is dependent on the nutrients required being present in the food at the correct levels for maintenance and growth. Any nutrients surplus to this requirement is simply eliminated, thus increasing the resultant pollutant load in the environment in which the fish must breathe and live. Therefore, the first step in the process of reducing the global requirement for fish meal is to determine the exact nutrient requirements for growth and maintenance, followed by an investigation to determine or design suitable raw ingredients from which to manufacture suitably balanced diets.

It could well be that the answer lies not in finding an alternative protein source for fishmeal, but an alternative source of raw material from which to manufacture fishmeal. Could fish farmers of the future find themselves growing herbivorous species on cheaply sustainable diets of phytoplankton to feed carnivorous species to meet the demands of the high order predator species favoured by the global cuisine? Could the aquaculture industry cut out the middle fish altogether and grow zooplankton as a source of essential amino acids for aquaculture diets.

One thing is certain. If the aquaculture industry is to supply the ever rowing demand for seafood it is going to have to find some way of keeping the rations it feeds its charges at a cost efficient and sustainable level and to minimize metabolic waste from their production systems. While at the same time targeting the nutrient profile of the species being farmed to maximize production efficiency. It is the industry's challenge for the 21st Century and its time starts now!


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    Margreet van Vilsteren

    As a comment, an interesting link can be the project website of the AquaMax project. The strategic goal of this project is to replace as much as possible of the fish meal and fish oil currently used in fish feeds with sustainable, alternative feed resources. See: <>

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    Philip Seletto

    The same principle applys to all livestock feeds. Feed and agronomist science needs to continually research into those feed materials that will supply the greatest levels of digestible nutrients, not only for fed efficiency, but also to reduce environment polution.
    Expanding population and food demand, requires maximum utilisation of the feed.

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    Jake Piscano

    What you say is basically true. As a participant in the industry, the challenge to growers is essentially to survive by making some profit from the operation. Unfortunately, fish meal, as well as other animal-based protein sources (MBM, PBM, etc.) now cost more, and will continue to cost more in the future. fish products dependent on these inputs, therefore will continue to rise even with further imporvement of FCRs. The result will be dimishing returns for farmers growing carnivorous species.

    One radical approach is to push for herbivorous species like tilapia, milkfish and carp. Herbivores leave smaller ecological footprint, are better converters of plant protein.

    The challenge is to develop products from these species to approximate those made from high value species (carnivores). Changes in our perspective of food and their production are needed for a long-term solutions for fishfarming, it's market and the environment.

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    Dieter Moeckel

    An essential ingredient in aquaculture - and other food production is product acceptability. Most Australian aquaculture is involved in high value end product.
    Europeans are prepared to eat Carp, Bassa is simply a Mekong catfish and the Chinese eat white shrimp...
    meanwhile Australian aquaculture produces Barra, Salmon, abalone and tiger prawns. All upper end of market.
    Aquaculture needs to follow the chook model and cultivate the rats of the sea and freshwater.

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    brett roe

    See this article.


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    Mark Rottmann - GE Water & Process Technologies

    >5MM tons of 'regular' fishmeal is currently produced in the world, yet there is potential to capture millions more from fish waste processing - a major impediment to capture the additional material is 'critical mass' - anywhere large waste exists, it is already converted to fishmeal - but a key issue is the small tonnage increments ie) 5,000 per site .... or material in highly dilute liquid fish proteins/oils (1-3%solids) which are discarged because converting it is not 'core' business for the producer.

    Utlization of Membrane Technology can econimically harvest Liquid Fish Protein at 3% solids and convert it to near 50% volume solids - IF the AuqaFeed market will adjust its processing to incorporate these liquid products (rather than dry fishmeal) they will have a large new supply. Further more, the Liquid Feed is more potent because it has not been denatured in the drying process, this would further extend the existing 5MM tons of fishmeal (making it the equivalent of 7.5mm tons !) The liquid fish protein can be econimically produced -- it just needs the AquaFeed companies to make slight changes to incorporate it. +1 513 300-0007

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    Enyidigwe uche

    Fish production is certainly highly sustainable. The issue of usages of fish meal and fish oil is a thing that has been addressed and is also being addressed. We are carrying out several researches and findings on alternatives to fish meal. There are many findings at the moment. More findings are still coming and these are clear cut fact supporting sustainability of fish culture. There is no priced fish that is under aquaculture that has not got plant based nutrient utilized in its feed production. The trend also is towards reducing pollution arising from effluent discharges. These measures go hand in hand as alternatives are provided for fish meal. However many people that are not involved in fisheries and aquaculture would not know what we are doing in the profession. But humanity will certainly depend much more on fish produced in ponds, cages, tanks and flow through systems or reservoir for sustainability of fish consumption in the present and near future. There is no hope of wild stock resuscitation given the scope of environmental pollution and the global weather change. Much effort must be made towards aquaculture and fish feed development and processing. These hold the ace for the future of human fish consumption.

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    Paulo Tabajara Costa-Brasil

    YES,it is true:fish eating fish.
    A lot of non sense or ignorance.
    Now a days we can fed a Salmon fish, whithout any animal protein, including fish or feather meal.
    SPC-70 : Soya protein concentrate, 70% CP, without CHO and mostlly NSP.
    It cost less than fishmeal and provide all aminoacids that fish needs. Just look what scandinavians are doing with brasilian soy-concentrate.

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    Coexistent of all aquatic organisms in nature made provisions for either carnivorous or herbivorous. The comparative advantage of herbivores is they produce more and are good roughphage converters. Consumers will accept whats available with same quality. Hence ,reseachers and producers should make more efforts towards producing species that will support sustainable aquaculture in terms of feed

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