Sustainable aquaculture

111 Pages·2009·6.73 MB·English

A handbook for
Sustainable
aquaculture
Project N°: COLL-CT-2006-030384
Sixth Framework Programme Integrated approach for a sustainable and
healthy freshwater aquaculture
SUSTAINAQUA HANDBOOK

CONTENTS

Preface 3
1. SustainAqua – An Introduction 4
2. Sustainability in aquaculture 6
3. Technology and production of main freshwater aquaculture types in Europe 11
3.1. Pond fish farming 11
3.2. Flow-through aquaculture systems 12
3.3. Recirculation Aquaculture Systems 12
3.4. Cage cultures in freshwater lakes and rivers 13
4. Regulatory framework and governance in European freshwater aquaculture 14
4.1. Common Fisheries Policy (CFP) and related documents 15
4.2. Environmental policies with major impact on aquaculture development 18
5. Product quality and diversification – Market opportunities for aquaculture farmers for their fish
products and by-products 20
5.1. Product quality – the Polish case 20
5.2. Wetland crops for the bioenergy industry – the Hungarian case 21
5.3. Hydro-culture plants and tropical fruits for the cosmetic industry – the Swiss case 22
6. Water treatment of intensive aquaculture systems through wetlands and extensive fish ponds
– Case study in Hungary 24
6.1. Constructed wetlands as a sustainable method to treat aquaculture effluents and produce
valuable crops (African Catfish Site) 24
6.2. From a case study to a fish farm: How to treat the effluents of a catfish farm? 29
6.3. Combination of intensive and extensive aquaculture for the sustainable utilisation of water and
nutrients (Intensive-Extensive Site) 33
6.4. From a case study to a fish farm: Design of a theoretical combined system 38
7. Improved natural production in extensive fish ponds – Case study in Poland 41
7.1. New species and methods in pond fish culture: Module POLYCULTURE 41
7.2. Practical recommendations and conclusions for stocking paddlefish in pond polyculture 47
7.3. Using agricultural waste nutrients in pond fish culture: Module CASCADE in Poland 50
7.4. From a case study to a fish farm: Designing a cascading module 55
8. New methods in trout farming to reduce the farm effluents – Case study from Denmark 58
8.1. Introduction – General description of the case study 58
8.2. Feed and feeding - Environmental impact from model trout farms 60
8.3. Energy consumption on model trout farms 62
8.4. Cultivation of pond plants in the lagoons of model farms 65
8.5. Cultivation of alternative Fish Species in the lagoons of model farms 66
8.6. Summary – Success factors and constraints 67
8.7. From a case study to a fish farm: How to manage a model trout farm producing 500 t fish per
year (Ejstrupholm Model Trout Farm) 68
9. Tilapia farming using Recirculating Aquaculture Systems (RAS) - Case study in the
Netherlands 70
9.1. Module - Manure Denitrifying Reactor (MDR) 70
9.2. From a case study to a fish farm: Integration of a denitrifying USB-MDR in a 100 MT tilapia RAS 74
9.3. Module – Periphyton Turf Scrubber (PTS) 92
9.4. From a case study to a fish farm: How to manage a model fish pond producing 5 metric tonnes
fish per year with the PTS module 93
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10. Tropical polyculture production with the integrated “Tropenhaus” concept – Case study in
Switzerland 95
10.1. Introduction – General concept of the Tropenhaus in Switzerland 95
10.2. Integration of crustaceans in tilapia production and fish feed from tropical plants 96
10.3. Warm water aquaponic filter in a "tropical" polyculture system 98
10.4. From a case study to a fish farm: The design of a warm water aquaponic filter system in the
“Tropenhaus Wolhusen” 101
References and recommendations for further readings 105
Authors of the handbook 109
Acknowledgements 110

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Preface

Preface
All over the world, aquaculture is developing rapidly, due to the combination of a strong increasing demand
for seafood products and depleted fish stocks in the world's oceans. To avoid the same mistakes of the
European agricultural and fisheries sector, aquaculture farmers need to address simultaneously the equally
and mutually important considerations of environmentally sound, economically viable and socially acceptable
development – that is the principles of sustainability – for the healthy development of the sector.
Ultimately, each aquaculture farmer, irrespective of whether farming fish in RAS or ponds, has to face the
same issues: how to utilise feed nutrients more efficiently to save feeding costs, achieve higher production
and have less nutrients in the effluent? How to improve wastewater treatment and decrease its discharges,
in order to reduce water pollution charges, due to the authorities? How to meet all legal requirements and
restrictions, demonstrate to consumers that the cultured products are of the highest quality, that they are
produced in environmentally friendly systems whilst providing sufficient income to make a living for the
farmer and ensure the jobs of employees?
The EU project SustainAqua aimed to answer several of these questions. With the overall aim to make the
European freshwater aquaculture industry more sustainable by improving production methods, research
potential market applications and increase product quality, SustainAqua undertook five different case studies
in Europe representative of the most relevant freshwater aquaculture systems and fish species. Various
practical techniques were tested, on how to strengthen the diverse aquaculture farms in Europe in a
sustainable way, from extensive and semi-intensive pond systems, which predominate in Central and
Eastern Europe, to intensive recirculation aquaculture systems (RAS) as they are practiced in North-Western
Europe. The main findings are described here in this SustainAqua handbook.
As a starting point, we discuss 'sustainability' and what this implies for aquaculture. We present the
indicators for sustainability that have been developed for evaluating the different SustainAqua case studies.
The different technologies in the sector – pond fish farming, flow-through and RAS – are briefly introduced to
classify the subsequent sections satisfactorily. As we all know, the work of fish farmers and the future
development of their farms are heavily influenced by the various national and European regulations which
are applied to the sector. Therefore, an introduction to the European regulatory framework is given. A very
important criterion for maintaining competitiveness on the market is excellence and proven fish quality and
the innovative utilisation of aquacultural by-products. One chapter in the handbook presents the impact of
different cultural systems on product quality and potential market applications for aquaculture by-products.
The core of this handbook consists of a description of the different modules researched in the five
SustainAqua case studies. The traditionally cultivated pond areas of Central Europe are represented by the
Hungarian and Polish case studies. In Hungary, water treatment of intensive flow-through fish production is
improved through constructed wetlands, deployed as biofilters. In addition, the advantages of combining
intensive and extensive aquaculture for the efficient use of water and nutrients are presented. The Polish
case study integrates aquaculture with the requirements of a modern agricultural farm in a ‘cascading’ pond
system by utilising animal manure to produce plankton as feed for carp polyculture. The general decrease in
demand for carp in Eastern Europe is addressed by introducing paddlefish as a new species into polyculture
to diversify species production, efficiently use nutrients and to increase the profitability of carp farms’.
In Denmark and the Netherlands, techniques for application in outdoor and indoor recirculation systems were
tested. Whilst in Denmark, rainbow trout was studied at so-called model farms with the aim to optimise
feeding management and to reduce the environmental impact and energy costs. The Dutch case study
looked at intensive tilapia production in RAS, using two different modules with a Manure Denitrifying Reactor
and Periphyton Turf Scrubber to reduce water use, energy consumption and the emission of nutrients. As a
unique case in Europe, the Swiss case study rounds off this project through rearing tilapia and tropical fruits
in a polyculture greenhouse system, using available waste heat, in order to prove that ‘waste’ can be used
as a multifunctional resource to produce economically and ecologically viable fish and co-products.
To make our scientific results transferable to farmers, the chapter "From a case study to a fish farm"
presents on-hand-information for implementing the modules, preceded by a general description, its
principles, the assessment of SustainAqua indicators, the factors contributing towards both success and
constraints as well as major benefits of sustainable aquaculture systems.
Freshwater aquaculture in Europe expects challenging times and looks forward to a bright future, so long as
we continue to combine our forces, both as researchers to further develop systems and the industry to
implement technologies for a sustainable aquaculture, and towards a sustainable European community.

Dipl. Ing. Alexandra Oberdieck Prof. Dr. Johan Verreth
Bremerhaven, Germany, June 2009 Wageningen, Netherlands, June 2009
Coordinator SustainAqua Scientific Manager SustainAqua
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SustainAqua – An Introduction

1. SustainAqua – An Introduction
European freshwater fish farmers are fighting a battle on two fronts: On the one hand, with the spread of
globalisation they are increasingly forced to compete with producers from countries with far lower costs of
production. On the other hand, they have to conform to the stringent demands of European and national
legislation with regard to product quality, environment and health. In addition, there are legal restrictions on
the discharge of effluents, water extraction, the use of chemicals and genetic modification. The success of
Europe’s freshwater aquaculture sector depends, to a great extent, on farmers’ abilities to face these
challenges.
Concept of SustainAqua
SustainAqua is a three-year collective research project, co-funded by the European Union under the Sixth
Framework Programme with the overall aim to make the European freshwater aquaculture industry more
sustainable and thereby to help farmers to become globally more competitive. The overall objective of the
project is to expand the knowledge base of European freshwater aquaculture farmers by training them to:
• Improve production methods, process efficiency and profitability
• Research potential market applications of different aquaculture by-products for alternative industries,
such as the energy and cosmetics industry
• Increase product quality (taste, nutritional value) as marketing tools to boost consumer acceptance of
farmed freshwater fish and thus, to improve the industry’s image.
The project will present a variety of technological possibilities and information on how to upgrade different
conventional aquaculture systems. The new technologies are expected to have significantly lower
construction, maintenance and running costs than conventional systems particularly in the case of
wastewater treatment.
Case studies – applied research
In order to meet the general objectives, the consortium accomplishes five different case studies from
Hungary, Poland, the Netherlands, Denmark and Switzerland. Each site represents one of Europe’s most
relevant freshwater aquaculture types and fish species with trout, carp, tilapia and catfish. Each case study
develops and researches different options for optimisation of production processes, quality improvement,
and product diversification. In detail, the project consortium will research:
• Different techniques for optimising the nutrient, water and energy management by
o Reducing energy costs by increasing energy efficiency;
o Reducing wastewater treatment costs by decreasing wastewater volume and waste discharge;
o Reducing costs for fish feed by higher nutrient utilisation efficiency;
o Reducing labour costs per produced product;
• Taste and nutritional value of fish produced in different production systems,
• Compounds and the economic value of different potential aquaculture by-products,
The consortium intends to transfer the highly effective nutrient management principles of natural systems
into competitive aquaculture systems. One example is efficient nutrient management: Alongside fish
production, organic material will be exploited as far as possible for the production of marketable products like
macroinvertebrates, algae or plants for different industrial applications. This optimised nutrient chain reduces
waste, avoids the implementation of expensive wastewater treatment and filter technologies and reduces
costs. These principles are tested in different extensive, semi-intensive and intensive aquaculture systems.
In addition, as "health" and "taste" are important consumer demands, the consortium investigates by
professional sensory and analytical tests whether the foreseen optimisation steps will have a positive
influence on the quality of the fish products.
Short introduction to the five case studies
The Hungarian case study looks at African and European catfish produced in tanks and in-pond cages as
well as at effluent-water treatment in serially-connected ponds, producing different carp species and
wetlands crops such as willow and reed. These are produced as by-products, whilst also acting as cost
effective and efficient biological wastewater treatment systems. In addition, their potential as a renewable
resource for the bioenergy industry is being researched.
In Switzerland tilapia is being reared in a hydro-culture system with tropical fruits, such as banana, mango
and guava, as co-products. The rearing system “Tropenhaus Ruswil” is a 1 500 m² polyculture greenhouse
type system which uses waste heat from a natural gas densification plant as its energy source. The case
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study aims to prove that “waste” can be used as a multifunctional resource in a polyculture system to
produce economically and ecologically viable fish and co-products.
In the Polish case study, carp is reared in two modules. One goal is to produce feed from recycled
wastewater using a “cascading” pond system where organic agricultural waste is used to farm fish and plant
biomass. This allows fish to be produced without using external feed sources. In addition, new species were
introduced into the traditional polyculture setup to increase product diversity of pond farms and to improve
carp farms’ profitability.
The Netherlands case study looks at intensive tilapia production in recirculating aquaculture systems (RAS)
using two different experiments with a Manure Denitrifying Reactor (MDR) and Periphyton Turf Scrubber
(algae and biomass were able to recover pollutants from water). The aim is to reduce water use to less than
25 litres/kg of feed, to reduce energy consumption and the emission of dissolved and particulate nitrogen,
phosphorus, carbon dioxide and organic matter.
In Denmark rainbow trout production is being studied at eight model farms, with the aim to optimise feeding
and farm management and to reduce the environmental impact and energy costs. The model farms combine
technologies from intensive recirculating fish farms with effluent treatment in constructed wetlands to achieve
substantial increases in fish production while reducing or even eliminating the environmental impact.
Importance of Sustainability
The sustainability of aquaculture is crucial if the industry is not to go the way of the fisheries sector. About 75
percent of the world's most valuable marine fish stocks are either fished to the limits or over-fished. At the
same time world fish consumption has increased from 45 million tonnes in 1973 to more than 130 million in
2000 and the FAO estimates an additional 40 million tonnes of seafood will be required by 2030, just to
maintain current levels of consumption.
In order to serve this increasing demand in the long run, sustainable alternatives have to be strengthened.
The most promising of these is the aquaculture industry. With a growth rate of 8% per year since the 1980’s,
aquaculture is probably the fastest growing food-production industry, that today accounts for almost half the
fish consumed globally, up from 9% in 1980.
Knowledge transfer
The SustainAqua project with its different AQUA+ modules provides different practical techniques and broad
information on how to upgrade the different conventional aquaculture systems to improve production process
profitability, environmental performance, product quality, and to diversify the product range. These options
will help aquaculture farmers to comply with current and upcoming European and national legislation, and to
meet future sustainable quality standards and Codes of Conducts – an important tool for the farmers’
advertising strategies. Most of the AQUA+ modules have more than one simultaneous function, as for
instance wastewater treatment, effective nutrient management and the production of economically efficient
by-products. With the diversification of their products farmers will be more flexible and their enterprises less
susceptible to market fluctuations.
The generated know-how from the case studies will be promoted via 22 training seminars for aquaculture
farmers in Austria, Denmark, Germany, Hungary, Poland, Sweden, Spain, and Turkey and two e-learning
seminars between May and July 2009. The training and information activities include this training handbook,
the SustainAqua-wiki and an E-learning platform summarising benefits, risks and costs, success criteria as
well as technical information on the different research modules. Eight national contact points coordinated by
the responsible aquaculture associations will serve as individual advisory platforms for aquaculture farmers
even after the duration of the project, giving farmers ready access to the knowledge generated by the
project. With the help of these tools, farmers will be encouraged to restructure part or all of their production
to make it more sustainable, efficient, and with long-term economic and environmental benefits.

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Sustainability in aquaculture

2. Sustainability in aquaculture
The term "sustainability" or also "sustainable development", often used as nothing more than a catch-phrase,
has much more to offer. It is a concept to guarantee a liveable environment for all people in the long term,
encompassing at least three fundamental components of sustainable development: preservation of a
functional environment, economic welfare and social equity. Accordingly, also in the field of aquaculture,
aiming for sustainability requires not only the achievement of environmental objectives, but also to provide
clear economic advantages for aquaculture farmers in the long term.
However, the term "sustainability" is often diluted and weakened, being used by politicians, entrepreneurs
and the public, in a general way on numerous occasions, very often in a superficial or misleading way and
with an incorrect definition, just to exploit the positive connotations of the term (as was the case with the
terms "bio" or "eco" in the 1990's).
The following text will describe the context in which the SustainAqua project was developed and carried out,
through first providing a short insight into the background and original definition of the term "sustainability",
then introducing the topic of "sustainability and aquaculture" followed by its application in SustainAqua.
Introduction – Background to "sustainability"
One important origin of the concept of "sustainability" or "sustainable development" is found in the report
"Our Common Future", more commonly known as the Brundtland Report. Its key statement is that
sustainable development 'meets the needs of the present without compromising the ability of future
generations to meet their own needs'. Such sustainable development (in agriculture, forestry, fisheries
sectors) conserves land, water, plant, and animal resources, is environmentally non-degrading, technically
appropriate, economically viable, and socially acceptable.
Sustainable development is based on long-term considerations, being an integrative, not a sectoral
approach. The term is usually presented in three dimensions: ecological, economic and social sustainability.
Each dimension is of equal importance and and each influence each other in an interdependent way. They
cannot be separated. First, this model of the three dimensions with their equal importance was considered to
improve the standing of environmental concerns. However, since then, thinking on the dependency of each
dimension on another, it has been criticised for not adequately highlighting that economy and society
fundamentally rely on the natural world and resources (see figure 1).

Figure 1: Framework of sustainability
However, at the beginning of the 21. century, it must be clearly stated that a better integration of these three
objectives is needed to achieve sustainable development. The current focus is primarily on the economy,
often neglecting social and environmental aims. It is therefore of great importance to balance the three pillars
of sustainability by applying a higher focus on environmental and social sustainability to compensate for the
current overweighting of the economy. Certainly, in this process the Rio Declaration on Environment and
Development must be considered, indicating that environmental protection shall constitute an integral part of
the overall development process and cannot be considered in isolation from it. Whilst it is acknowledged that
no activity in industry, agriculture or aquaculture will take place if it is not economically profitable, it is the task
of politics and society to find ways to equally achieve all three objectives of sustainability. An important tool
to achieve this criterion – "sustainability" – correspondingly in all three dimensions, is to research and apply
innovative or optimised technologies. In the area of freshwater aquaculture, this was exactly the objective of
SustainAqua.
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Sustainability and aquaculture
Aquaculture, as with all other food production and also industrial practices, is facing the challenge of
sustainable development. Aquaculture has grown exponentially over the last 50 years from the production of
less than 1 million tonnes of product in the 1950s to 51.7 million tonnes in 2006. Whereas capture fishery
production is static and has even been decreasing for years, aquaculture continues to grow more rapidly
than any other animal food-producing sector. Aquaculture will continue to play a large and increasing part in
the world's fish production to meet the globally rising demand for fishery products.
It is therefore essential to continuously pursue methods and means to make production practices in
aquaculture more sustainable, efficient and cost-effective by, for instance, improving human capacity,
resource use and environmental management. SustainAqua can be understood particularly in this context:
SustainAqua firstly researches concrete solutions as technical and methodological tools and secondly offers
diverse training activities to inform aquaculture farmers on the complex results of the project to achieve a
more sustainable aquaculture in Europe.
It is, however, essential, that various initiatives on a national, European and also global level develop and
permanently update codes of conduct, sustainability indicator and certification systems, etc. in order to
achieve a common and accepted understanding of sustainability in aquaculture among all stakeholders and
how to achieve these goals in practice. To name just a few existing instruments:
• FAO "Code of conduct for responsible fisheries" (1995)
• FEAP "Code of conduct for European Aquaculture" (2000); currently being reviewed
• EVAD “Guide to the co-construction of sustainable development indicators in aquaculture” (2008)
• Agreement of Global Aquaculture Alliance (GAA) and GLOBALGAP to develop and harmonise
certification systems for the aquaculture sector world-wide (2009)
Under the EU project CONSENSUS (2005-2008), for instance, a "Multi-stakeholder involvement towards
protocols for sustainable aquaculture in Europe", developed a set of sustainability indicators as a starting
point for a certification system for sustainable aquaculture and for a benchmarking process that is based on
low environmental impact, high competitiveness and ethical responsibility with regard to biodiversity and
animal welfare. All major organisations and associations within aquaculture production were involved.
SustainAqua "completed" CONSENSUS through investigating several technological improvements to make
different European freshwater aquaculture systems more sustainable (see chapter 1). Therefore, the
description of sustainability that is presented here aims, primarily, to give a clear direction for the research
carried out within SustainAqua in order to develop methods and technologies for more sustainable
aquaculture production in Europe. In this way, SustainAqua anticipates future legislation and labels, that are
currently still under discussion, and provides guidelines and technical solutions on more sustainable
aquaculture practices.
Limits of the system
To keep the practice of "sustainability and aquaculture"
manageable and practicable, it is important to define the
limits of the system for which sustainability is defined.
For SustainAqua, three levels of system limits can be
differentiated, visualised in three concentric circles in
figure 2:
1. "Farm level": includes the factors that can be

directly influenced by the farmer, for instance water
quality, nutrient and energy management, fish
Figure 2: Three levels of system limits for which
health, etc.
sustainability is defined in SustainAqua
2. "Second level": addresses the factors directly linked
to the farm processes for which the farmer does not have direct influence, but on which he could
potentially have an influence if he/she wanted or needed to. For instance: fish feed quality, how fish feed
is composed/ processed, distance of transportation for the feed, the kind of energy the farmers uses
(renewable or non-renewable), markets for the products (distant markets – requiring long transport
distance, local markets – requiring short transport distance), etc. The farmer might also "transfer" some
factors of the second level into the "farm level", e.g. by producing fish feed on the farm, using energy
produced on the farm or by selling the products directly from the farm.
The first two circles are the most relevant for the SustainAqua project.
3. The "Third level": contains factors that are indirectly linked to the farm processes but which can normally
not be influenced by the farmer. These are factors like sustainability of the packaging material
(production, material, etc.), the type of fuel for the transportation of the fish, etc.
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SustainAqua focuses on the farming process itself ("farm level"). The most relevant factors from the second
circle are also considered, for instance fish feed production, energy production, energy for water supply of a
certain quality, transportation energy, and potential markets.
For completeness, the "regulative level" needs to be taken into account as well, such as EU, national or
regional regulations, norms, etc. They affect all levels in different ways, but cannot be influenced by the
farmer directly. In SustainAqua only those regulations are taken into account, which are directly relevant for
the first and the second circles.
Sustainability indicators and certification
The limited availability of natural resources coupled with increasing energy prices emphasise the need to
move forward in aquaculture to become more sustainable. The aquaculture industry is already working on
this demanding task, but there is still a long way to go. Compared to other animal production systems,
aquaculture is put under special pressure to become more sustainable, because of their use of important
natural resources, such as freshwater, wetlands, coastal areas and also the wild catch of fish for fish feed
production or stock recruitment.
The sustainability of an activity and its measurement is not a static topic as, by definition, it incorporates
economic, environmental and social considerations (see Figure 3). Each approach to sustainability as well
as being based on indisputable facts contains some level of attached societal values and value judgements,
which may be under discussion or may change over time. This means it is not always possible to decide
unambiguously whether a process is sustainable or not. Often there are transitions between non-sustainable
to sustainable processes.

Figure 3: Sustainable freshwater aquaculture combines ecological, economical and social aspects
The different Codes of conducts and criteria systems mentioned earlier aim to resolve this issue of how to
achieve sustainability and are intended to support a sustainable cultivation of aquaculture products. But up
until now there have been no complete and practicable European criteria, indicators, and related labelling
systems which are really able to certify the sustainability status of a fish product. The SustainAqua project
intents to contribute to the development of criteria which are currently being developed by various initiatives
(see above). As mentioned before, SustainAqua does not intend to compete with indicator systems that were
already developed in a broad stakeholder-oriented approach, e.g. by CONSENSUS. The selected criteria
presented below are focused on the five SustainAqua case studies and shall provide a clear direction on
how sustainability could be increased in such aquaculture farms. They are primarily designed to give a
measurable orientation to the transferability and practicability of the research carried out in the five
SustainAqua case studies in order to develop applicable methods and technologies for more sustainable
aquaculture production in Europe. It is not the task of SustainAqua to judge, if a certain freshwater
aquaculture farm is sustainable or not, but to provide an unambiguous direction, on what can be done in a
case study or at a specific farm to improve sustainability.
SustainAqua Sustainability Indicators
The SustainAqua consortium developed 28 indicators at the beginning of the project for the three dimensions
of environmental, economic and social sustainability. However, as SustainAqua could not cover all possible
areas of researching and improving sustainability on an aquaculture farm, the final number of indicators was
filtered down to eight which are then applied to the five case studies of the project, as can be seen in
Table 1. The eight indicators were selected upon the basis of the following four criteria:
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• Action relevant: The indicator is sensitive to changes of management according to the objective and is
useful to measure whether the actor works towards the objective or not.
• Plausible: The indicator is understandable for the actor.
• Measureable: It is possible to measure the indicator.
• Feasible: It will be possible to measure and record this indicator within the foreseen resources (budget,
time) of the project

Environmental dimension
Specific objective/ criterion Indicator Unit
y
g Energy efficiency: To reduce the necessary Energy input per produced output (fish, kWh/ kWh output (differentiated
ner energy input as far as possible biomass) for each product)
E
Input: To reduce the amount of freshwater input
Water supply per produced product
from outside the system (re-use water as far as l/kg product
(fish, biomass)
er possible)
at Outflow per produced product (fish,
W Output: To reduce the amount of wastewater
biomass) -excluding
discharge (for quality aspects see Nutrients/ l/kg product
evapotranspiration and seepage, but
Output)
including precipitation
Utilisation efficiency: To use the nutrient input as Nutrient retention efficiency (NRE) - kg nutrient (N, P, COD) retained
effectively as possible (to produce from a certain nutrient retention in produced product in product/kg nutrient input [%]
unit of nutrient input as many marketable products per kg nutrient input to the system as a (TOD calculated from COD and
at as high a quality as possible) whole (fish, biomass) N)
s
utrient Oworaugstaptneuiwtc (amsteeaert e darilsisacol h lowasragsteee sr())n: uTtori erendt,u mcein tehrea las manodu nt of Aqumaoliutyn t of nutrients/ wastewater Ncpor,o nPdd,uu CcctOt ipvDrito,y d eduleicscectdhri acragl ed per kg
N
kg nutrient retention in the
Nutrient re-use to produce valuable secondary Nutrient retention of reused N/P for secondary products per kg
products within the fish farm valuable secondary products nutrient input to the system as a
whole [%]
Economical dimension
Specific objective/ criterion Indicator Unit
n
uctiosts To increase productivity per unit of labour rperqoudiurectd a wt ocrokminmg etirmciea l pfaerrm p rloedvuecl ed h/kg product
do
oc (model-based assumption)
Pr
Buffering market uctuations Idmisperaosvein ogu ptbroredaukcst safety/ fish health: To reduce Treatments/ production cycle treatments/ production cycle
fl
Table 1: Sustainability indicators for the 5 SustainAqua case studies
In the case-study chapters frequent reference will be made to these indicators as they establish the basis for
evaluating the research in the five case studies of SustainAqua and for transferring the results for practical
application.
The remaining 20 indicators have neither been measured nor evaluated in detail, as their assessment was
beyond the scope of this project. Among them were indicators such as "Water and Climate: To support local
climate stabilisation by increasing evapotranspiration through increasing the amount of constructed
wetlands/ open water" or all indicators found for the social dimension, such as "To support the development
of additional jobs" or "To support rural development". More details on this issue can be found in the
SustainAqua wiki on http://wiki.sustainaqua.org.
Application of sustainable principles to aquaculture
In the following paragraphs, the principles of each sustainability area will be introduced in detail. In addition,
general suggestions are made on how to make an aquaculture system more sustainable by considering
these principles. Practical examples of these potential application of principles can be seen in the different
SustainAqua case studies presented in this handbook.
Improving ecological sustainability
Water, nutrients, the area used for the farm, and energy are the most important topics related to the
ecological sustainability of aquaculture farms. Regarding water, both the amount needed and the quality are
important aspects. Freshwater may be obtained from surface sources, such as lakes or rivers, or from the
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