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ARTICLES
Perspectives on Salmon Feed: A Deliberative
Assessment of Several Alternative Feed Resources
Frøydis Gillund •Anne Ingeborg Myhr
Accepted: 12 January 2010 / Published online: 28 January 2010
Springer Science+Business Media B.V. 2010
Abstract The future of salmon aquaculture depends on the adoption of alternative
feed resources in order to reduce the need for fish meal and fish oil. This may
include resources such as species from lower trophic levels, by-products and
by-catch from fisheries and aquaculture, animal by-products, plants, genetically
modified (GM) plants, nutritionally enhanced GM plants and products from
microorganisms and GM microorganisms. Here, we report on a deliberative
assessment of these alternative feed resources, involving 18 participants from
different interest groups within Norwegian salmon aquaculture. The participants
defined a broad range of appraisal criteria concerning health and welfare issues,
economical issues, environmental issues, and knowledge and social issues. A
number of uncertainties, in the form of incomplete knowledge, diverging opinions,
and context specific factors were identified when the participants evaluated the
alternatives. Our findings support the need for more research on the suitability of
alternative feed resources for farmed salmon. Additionally, the study underlines the
importance of facilitating deliberative assessments in order to map the plurality of
perspectives and explore qualitative aspects of uncertainty. Such initiatives improve
the information base upon which decisions on future feed resources for farmed
salmon are made.
Keywords Salmon aquaculture Feed resources Multicriteria mapping
Scientific uncertainty Decision making
F. Gillund (&)A. I. Myhr
Genøk—Centre of Biosafety, The Research Park, 9294 Tromsø, Norway
e-mail: froydis.gillund@genok.org
A. I. Myhr
e-mail: anne.myhr@genok.org
123
J Agric Environ Ethics (2010) 23:527–550
DOI 10.1007/s10806-010-9237-7
Introduction
Almost half of the seafood found on grocery store shelves today comes from a farm.
Aquaculture has maintained an average annual growth of 8.7% since 1970 and is
thereby growing more rapidly than any other food producing sector in the world.
Farmed fish is expected to play an important role in global food supply, especially
as wild fisheries are declining due to overharvesting (FAO 2009). Economic
incentives have contributed to this trend and led to rapid expansion of the
production of carnivorous finfish species in marine aquaculture (Deutsch et al.
2007). Global production of farmed salmon has roughly quadrupled in volume since
the early 1990s and is currently the world leader in farmed carnivorous finfish
production and value, with Norway as the largest producer (Le Curieux-Belfond
et al. 2009).
Salmon feed has largely been based on fish meal (about 40–60%) and fish oil
(about 20–30%) from wild marine fish such as anchovies, pilchards, mackerel,
herring, and blue whiting. This is primarily because these resources satisfy the
nutritional requirements of carnivorous fish species. Secondly, they secure high
levels of marine fatty acids (omega-3 polyunsaturated fatty acids) in the fish fillets
with beneficial impacts on human health (Connor 2000). Aquaculture currently
absorbs approximately 56 and 87% of world supplies of fish meal and fish oil
respectively (FAO 2009), and the demands are expected to increase as the
industry expands. Hence, in a short time the marine resource base will not be able
to sustain the demand for fish meal and oil coming from aquaculture and other
industries (primarily poultry, pig, and pet feed, as well as functional food and
pharmaceutical industries). Increasing demands for finite resources consequently
lead to increasing prices. Feed represents the largest expense in intensive
aquaculture. Between mid-2005 and mid 2008, the prices of fish meal and fish oil
rose 50 and 130%, respectively (Naylor et al. 2009). Thus, limited availability and
increasing prices of marine resources are the main forces pushing the search for,
and development of, alternative feed ingredients (Naylor and Burke 2005; Tacon
and Metian 2008).
Despite major advances in feed formulation, feed manufacturing technology, and
feed management at the salmon farm level in recent years, salmon farming
continues to consume more marine resources than it produces (Naylor et al. 2000).
The ratios of wild fisheries inputs to farmed fish outputs presented in current
literature varies. For instance, according to Naylor et al. (2009) the ‘‘fish-in to fish-
out’’ ratio for farmed salmon is currently 5.0, while Ellingsen et al. (2009),
calculated that 2.3 kg of fish is needed to produce enough oil for 1 kg round
consumable salmon. This is close to the numbers presented by the Norwegian
Seafood Federation (2009), who claims that it takes about 2 kg of wild fish to
produce 1 kg of farmed salmon in Norway. In any case, farming salmon results in a
net reduction of marine resources. This, along with concerns regarding discharges
from fish pens (e.g., feed surplus, fish excrements, antibiotics, and chemicals),
farmed fish escapes, and transmission of parasites and diseases to wild salmon, have
led to growing demands for more environmentally friendly production practices
from consumers, retailers (Frankic and Hershner 2003), and policymakers (see for
528 F. Gillund, A. I. Myhr
123
instance; Holmenkollen guidelines for sustainable aquaculture 1998; FAO 1995;EU
Commission 2002b; Norwegian Ministry of Fisheries and Costal Affairs 2009).
Thus, the challenge facing the salmon feed industry is to identify alternative feed
resources that are economically viable, sustainable and of high nutritional quality.
A number of alternative feed resources are currently being explored or are
already in use (see for instance Gatlin et al. 2007; Tacon et al. 2006; Turchini et al.
2009; Waagbø et al. 2001). As shown in Fig. 1salmon diets in Norway are for
instance currently based on approximately 60% marine ingredients, the remainder
being plant oils, plant proteins, and various minerals, vitamins and color (Ellingsen
et al. 2009). There is, however, a recognized need for more research on the
suitability of different feed resources before large-scale adoption of these
alternatives takes place (Norwegian Research Council 2008; Norwegian Scientific
Committee for Food Safety 2009; Waagbø et al. 2001).
Here we present results from a deliberative assessment of alternative feed
resources for farmed salmon, involving 18 participants from different interest
groups within Norwegian salmon aquaculture. The study was conducted in order to:
(1) map some of the key issues to be addressed when evaluating alternative feed
resources for farmed salmon, (2) gather knowledge and perceptions about
alternative feed resources among different actors in Norwegian aquaculture, and
(3) address uncertainties associated with the alternatives. We applied a deliberative
assessment tool—Multicriteria Mapping (MCM)—which has been developed in
order to open up evaluation processes and explore how values, interests, and
underlying assumptions influence the assessments (Stirling 2005; Stirling 1997;
Stirling and Mayer 2001). We start by presenting the feed resource alternatives that
were evaluated by the participants. Then, we briefly introduce the MCM method and
describe how it was applied in our study. When presenting the results from the
exercise, we focus on: (1) the range of criteria defined by the participants and the
significance given to them, (2) how the performance of the alternatives differed
between the interest groups, and (3) areas identified as associated with uncertainty.
Finally, the implications and relevance of facilitating this type of comprehensive
and deliberative assessments are discussed.
Fish meal
33 %
Fish ensilage
5 %
Fish oil
23 %
Vegetable proteins
24 %
Vegetable oil
12 %
Minerals, vitamins
and color
3 %
Fig. 1 Typical composition of
ingredients in feed for farmed
Atlantic salmon (based on data
from Ellingsen et al. 2009)
Perspectives on Salmon Feed 529
123
Alternative Feed Resources
Species from Lower Trophic Levels
Various species of zooplankton, mesopelagic fish, and some species of squid are
considered suitable for salmon feed production (Waagbø et al. 2001). Antarctic and
North Atlantic krill are, due to high abundance, viewed as the most promising feed
resource (Nicol and Endo 1999; Nicol and Foster 2003). Antarctic krill is currently
harvested commercially and used as additives in fish feed (Nicol and Foster 2003)
and pharmaceutical and nutraceutical products (Naylor et al. 2009). Krill represents
an excellent source of omega-3 polyunsaturated fatty acids as well as vitamins,
minerals, essential amino acids and natural carotenoids (astaxanthin), nucleotides,
and organic acids (Suontama et al. 2007a). It has been reported that full substitution
of fish meal with Antarctic krill does not change the health condition or product
quality of Atlantic salmon (Olsen et al. 2006; Suontama et al. 2007a,b). Concerns
have been raised regarding the high level of fluorine in the krill exoskeleton, but no
studies have shown a negative influence on fish health and it is assumed that it
contributes only marginally to human exposure (European Food Safety Authorities
2004; Norwegian Scientific Committee for Food Safety 2005). It has been reported
that chitin in the krill exoskeleton may lower lipid uptake in fish and induce
diarrhoea, but it is also documented that it can function as a prebiotic and
immunostimulant (Olsen et al. 2006). The global catch quota for krill is nearly 6
million metric tons (mmt), but total harvest is currently less than 1 mmt (Nayor
et al. 2009). Still, major concerns are raised regarding potentially serious ecosystem
impacts of harvesting krill. Krill is at the base of aquatic food webs and harvesting
could reduce food resources for predators such as penguins, seals, and whales.
Moreover, krill is particularly sensitive to environmental variables, including
climate change. Thus, it has been warned that the understanding of the population
dynamics of krill is currently not sufficient to define sustainable catch quotas
(Naylor et al. 2009; Suontama et al. 2007b).
By-products and by-catch from fisheries and aquaculture
33% of the raw material supplied to the fishmeal and oil sector in Europe came from
fish by-products in 2002 (Huntington 2004). As over 30% of processed seafood is
inedible for human consumption (Miller et al. 2008), better utilization of these by-
products may become an important source of marine raw materials in salmon feed
production (Tacon et al. 2006). However, high ash content in fish meal produced
from by-products (as most of the fish muscle is removed when making fillets) may
cause mineral deficiencies in farmed fish. The ash content can be reduced when
processing the feed, but this will require investment and thereby increase processing
costs. The use of by-products is at present highly regulated in order to prevent the
spread of diseases and bioaccumulation of contaminants such as PCBs and dioxins
(see for instance The European Union Animal by-products regulation, European
Commission 2002a). Turchini et al. (2009) report that there is no documentation of
fish disease outbreaks associated with the transmission of fish pathogens via fish
530 F. Gillund, A. I. Myhr
123
meal and fish feed. Oidtmann et al. (2003) have, however, shown that fish have
DNA that codes for the production of prion proteins and thereby theoretically can
produce prion diseases such as transmissible spongiform encephalopathies (TSE).
Hence, intra-species recycling of feed resources is currently prohibited in Europe
(European Commission 2003b).
By-catch is non-target fish and other aquatic animals caught while fishing. The
global weighted discard rate is estimated to be 8% of total recorded landings
(Kelleher 2005), and includes by-catch but also target species that are not
considered suitable to bring ashore. Better utilization of by-catch is encouraged, but
also contested, as relaxed by-catch regulations may pose a threat to the already over
exploited wild fish stocks. Thus, management strategies that limit landings of
by-catch are in place (Scottish Executive Central Research Unit 2002).
Animal By-products
Animal by-products, such as bone, meat skin, and feathers from various land
animals, may represent a possible protein and lipid source for salmon feed. Studies
have shown that animal fats can be a valuable ingredient in fish feed (Turchini et al.
2009). Animal by-products are generally rich in protein, but do often have a high
ash content as bone and other non-muscle materials constitute a large part of the by-
products. This problem can be dealt with by improving the processing practices in
order to increase the digestibility and quality of these ingredients (Bureau et al.
1999). The use of animal by-products is currently limited, partly because of low
digestibility and variable quality, but most importantly due to fear of disease
transmission. The European Union Animal by-products regulation (European
Commission 2002a) only allows for the use of processed blood meal from non-
ruminant animals. European salmon manufacturers do, however, not currently use
feeds with animal by-products as they fear consumers’ reactions.
Plants
Both the use of plant proteins and oils as ingredients in fish feed have been
intensively investigated (Gatlin et al. 2007), and indeed the fish feed industry has
already used a large degree of plant resources in their feed formulations for many
years. Soy protein products are among the most studied and perhaps the best
accepted protein source due to high protein content, steady supply, and reasonable
prices. Other plant resources utilized in aquaculture are primarily rapeseed, corn
gluten, wheat gluten, barley, pea and lupin meals and oil from palm, soybean,
maize, rapeseed, coconut, sunflower, linseed, and olive (Tacon et al. 2006). Turchini
et al. (2009) report that vegetable oil can replace substantial amounts of fish oil in
the diets of many fish species without affecting growth or feed efficiency, as long as
omega-3 polyunsaturated fatty acids are supplied in the diet. The main challenges in
using plant protein sources in diets for carnivorous fish are related to their low levels
of protein and high levels of starch, unfavorable amino acid and mineral profiles,
high levels of fiber and the presence of anti-nutritional factors and/or antigens. A
report published by the Norwegian Scientific Committee for Food Safety (2009)
Perspectives on Salmon Feed 531
123
concludes that there is a lack of studies about the interactive effects when
exchanging both fish meal and fish oil with plant ingredients in diets for Atlantic
salmon.
Genetically Modified Soy and Maize
About 70% of soy and 25% of maize cultivated globally is genetically modified
(GMO compass 2009). Thus, genetically modified (GM) soy and maize represents
the major GM crops currently cultivated. The most commonly expressed traits are
herbicide tolerance and insect resistance or a combination of these. The cultivation
and use of GM plants in food and feed have revealed a broad range of views among
scientists regarding their documented and potential health and environmental
impacts (see Andow and Zwahlen 2006; Weaver and Morris 2005 and references
therein). For instance, Flachowsky et al. (2005) report that genetic modification of
plants can lead to alterations in the amount and profile of antinutrient factors
between the GM variety and its near-isogenic parental line, with potential
implications for its suitability as a feed resource. Furthermore, DNA from herbicide
tolerant soya has been identified in the epithelial cells in salmon intestine after
feeding (Sanden et al. 2006), but the biological significance of GM DNA persistence
in the intestines remains unresolved. The Norwegian Scientific Committee for Food
Safety (2009) are not able to draw any clear conclusions regarding the effect on fish
health from the use of GM plants in salmon diets, although they do claim that
growth, digestibility, feed utilization, and other health parameters seem to be more
influenced by the plant material as such, rather than whether the plant is GM. EU
requires labeling of food and feed products containing more than 0.9% of an
approved GM ingredient (European Commission 2003a), whereas animals fed with
GM feed are not labeled as GM. The use of GM in food and feed production is
generally not well accepted among European consumers. This is not only due to
concerns for potential risks to health and the environment, but also because GM
may have unwanted economical, social, and ethical implications (Melo-Martin and
Meghani 2008; Wynne 2001).
Nutritionally Enhanced GM Plants
Gatlin et al. (2007) describe how plant genetic research can facilitate altered levels
of many important antinutrients (e.g., phytic acid) and nutrients (e.g., lysin,
b-glucan and micro nutrients such as vitamin E) and change the starch structure and
oil content of plants—all characteristics that will improve the plants’ qualities as a
feed resource. Qi et al. (2004) were the first to report successful accumulation of
omega-3 polyunsaturated fatty acids in GM plants, but the accumulated levels of
these fatty acids are still low. Robert (2006) does, however, emphasize that plant
oils from GM plants producing omega-3 polyunsaturated fatty acids do not need to
match the fatty acid composition of fish oil, as research has shown that fish
maintains its health benefits with reduced amounts of fish oil in the diet.
Accordingly, it is advocated that this strategy provides a more sustainable source of
omega-3 polyunsaturated fatty acids compared to the use of marine sources (Napier
532 F. Gillund, A. I. Myhr
123
et al. 2006; Robert 2006). Others express concerns regarding the potential
unintended health and environmental consequences, similar to those already
referred to for GM soy and maize. There is also a lack of understanding of whether
unintended metabolites with potentially unintended impacts on health and the
environment can be produced in the plants along with the nutritional molecules
(Schubert 2008).
Products from Microorganisms
Bacteria, yeasts and unicellular and filamentous algae can, through a fermentation
process using natural gas as an energy source, produce proteins and fatty acids for
fish feed production (Naylor et al. 2009; Miller et al. 2008; Tacon et al. 2006). It has
been documented that an inclusion of 20% bacterial proteins in diets for farmed
Atlantic salmon resulted in a slightly reduced growth rate. No significant effects on
the sensory characteristics such as taste, smell, or texture were detected (Berge et al.
2005). Tacon et al. (2006) consider this a promising resource, as it has both high
protein content and nutritive value and no anti-nutrients, but emphasize that there is
a need for further research on health effects. The main concern regarding products
from microorganisms, such as bacterial proteins, is the physiological impacts from
the nucleic acid fractions in the products (Waagbø et al. 2001). The availability of
this resource is still limited, due to technical production constraints, and the price is
consequently high (Naylor et al. 2009).
Products from GM Microorganisms
Microorganisms can be genetically modified to produce components that are
beneficial for fish. This includes components such as essential amino acids, omega-3
polyunsaturated fatty acids, vitamins, pigments, or enzymes for the break down of
antinutrient factors (Waagbø et al. 2001). Products from GM microorganisms are
currently not commercially available and very little research has been carried out,
both regarding how to produce them and their impact on fish and human health.
Multicriteria Mapping
Multicriteria assessment exercises cover a variety of non-monetary evaluation
techniques sharing a basic framework under which a number of alternatives can be
scored against a series of defined criteria and to which users attach weights
reflecting the relative importance of the criteria (Gough and Shackley 2006). These
techniques intend to broaden the scope of assessments and promote deliberative and
participatory approaches, thereby facilitating more inclusive and comprehensive
decision making processes. Stirling is particularly interested in how the outcomes of
assessments are conditioned by values, interests, and underlying assumptions, and
developed MCM as an attempt to ‘‘open up’’ assessment processes in order to
‘‘ explore the way in which different pictures of strategic choices may change,
depending on the view that is taken—not prescribe a particular ‘best choice’’’
Perspectives on Salmon Feed 533
123
(Stirling 2005: 5). MCM was initially used to assess perspectives on risks related to
food production (Stirling and Mayer 2001), but has now been tested for appraisal of
options and management strategies in a number of fields ranging from energy policy
(McDowall and Eames 2007), development of criteria for the evaluation of public
consultation and engagement processes (Burgess and Clark 2006), strategies to
prevent obesity (Stirling et al. 2007), carbon storage options (Gough and Shackley
2006), and public health responses to the shortage of kidney donors (Burgess et al.
2007).
The MCM exercise is based on individual interviews (lasting 2–3 hours) where
participants, supported by the researcher, work interactively with a piece of
dedicated computer software (MC-Mapper) in order to complete four basic steps:
(1) discuss the proposed alternatives and possibly identify additional ones, (2) define
a range of criteria for the assessment of the proposed alternatives, (3) assess scores
to each alternative under each criterion. The participants are asked to assign two
scores to each alternative—one reflecting performance under the most favorable
assumptions, the other under the most pessimistic assumptions. In this way the
participants are able to express uncertainties and to take context specific factors, that
could influence the performance of the alternative, into account. A criterion can also
be defined as a principle. In this case each alternative is evaluated as either
‘‘acceptable’’ or ‘‘unacceptable’’ under the given principle. Finally, the participant is
asked to (4) assign weights to each criterion in terms of their relative importance,
reflecting the participant’s individual judgments and values. This information is
used to produce real time simple charts that visualize the overall performance of
each alternative. These charts are produced by the software using a weighted sum of
normalized criteria scores. As participants are asked to assign both ‘‘best’’ and
‘‘worst’’ performance scores, the rankings are not expressed as single numbers, but
as intervals. (A more detailed presentation on the mathematical operations
performed by the software can be found in Stirling 2005). Throughout the interview
the participants are free to return to and make changes to the different steps in the
MCM process. Thus, the method is very flexible—the participants are asked to
develop their own appraisal criteria, define their own additional alternatives, and
perform their own assessments. The interviews are audio recorded and the
participants are encouraged to explain the rationale behind their choices and
assessments in as much detail as possible. In this way the exercise provides both
quantitative and qualitative data.
For this specific study, it is important to mention that each of the feed resource
alternatives defined for the study consisted of a variety of species/types of products.
Additionally, there were considerable differences between the alternatives with
regard to current use or developmental stage, primarily due to technological,
economical, and legal restrictions. Moreover, the participants were asked to
evaluate the feed resource alternatives within a 20 year perspective, which meant
that they had to make predictions about the future. Finally, salmon feed is typically
based on a combination of different feed resources and the composition of feed
ingredients might vary during the production cycle in order to optimize feed and fish
quality. When evaluating each of the alternative feed resources the participants
were, however, asked to consider each alternative as the only resource used in the
534 F. Gillund, A. I. Myhr
123
feed, irrespective of this resource’s share in current or potentially future feed
formulations for farmed salmon.
Selection of Participants
We recruited participants from a broad group of people who held different roles,
interests, and areas of expertise regarding salmon farming in Norway (Table 1). In
order to do this we used a ‘‘snowball sampling’’ technique, where we started by
asking scientists with whom we were communicating during the development of the
study, to suggest relevant groups and people to participate in the study. When they
were invited, we sought their suggestions for other potential participants, and so
forth. In the end we had contacted 35 people and among them 18 agreed to
participate in the study.
The participants were asked to participate in the study as individuals, presenting
their personal point of view. The study does not aim for statistical representation
and the results should not be interpreted as representative for all actors involved in
Norwegian salmon aquaculture. Still we believe that the group of participants was
sufficiently representative to explore and open up for a diversity of issues and
perspectives related to alternative feed resources for farmed salmon.
Results
Criteria Defined by the Participants
In total, 87 criteria (of which two were defined as principles) were defined by the
participants. These were categorized in four main categories, divided into 11
subcategories (Table 2). The categorization of the criteria was based on the
participants’ explanations when defining their criteria, as well as their comments
Table 1 Categorization of
participants into perspectives
and number of participants in
each of the categories
a
One of them works for an
organization that represents both
fish farmer and feed industry
b
One of them is an organic fish
farmer
Perspective Number of
participants
Feed industry 4
a
Fish farmer 3
b
Scientist
Researcher in fish nutrition 2
Researcher in fisheries economics 1
Researcher in animal welfare 1
Researcher in marine ecology and fish nutrition 1
Market analyst for Norwegian Salmon 2
Environmental NGO 2
Policy advisor 2
Perspectives on Salmon Feed 535
123
when assessing the alternatives. One participant defined seven criteria when
assessing the alternative feed resources, whereas most participants defined between
four and six criteria and two participants defined three criteria for their assessment.
As seen from Table 2, most criteria concerned either health and welfare issues or
economical issues. About one-fourth of the criteria concerned environmental issues,
and six criteria concerned knowledge and social issues.
Health and Welfare Issues
The criteria selected by the participants concerning health and welfare issues
included criteria about fish and human health and welfare, centered on four key
questions:
•To what extent does the feed resource meet the nutritional requirements of
farmed salmon?
•How does the feed resource influence the ability of the fish to master its
environment?
•Does the feed resource contain components that are poisonous or unhealthy to
consumers?
•Does the feed resource maintain human health benefits from consuming farmed
salmon?
These questions were primarily assessed by evaluating the nutritional quality of
the feed resource (e.g., type and composition of amino acids, fatty acids, energy
sources, vitamins, and minerals). Some participants also evaluated the content of
components such as immunostimulants, disease vectors, environmental pollutants
(including medicine and pesticide residuals), and antinutrients. Criteria on animal
Table 2 Main categories (bold
font) and subcategories (normal
font) of defined criteria, and
number of criteria defined under
each main/subcategory
a
Two of these criteria were
defined as principles
Criterion Total number of criteria defined
under each main/subcategory
Health and welfare issues 31
Fish health 18
Animal welfare 3
Consumer health 10
Economical issues 30
Price 7
Resource availability 7
Consumer acceptance 9
Product quality feed 4
Product quality fish 3
Environmental issues 20
a
Knowledge and social issues 6
Knowledge 4
Social considerations 2
536 F. Gillund, A. I. Myhr
123
welfare issues concerned whether the feed resource could cause disease, deficiency
symptoms, pain, and deformations, as well as its impact on the health, growth, and
well being of the fish. Human health benefits were generally evaluated by the
content of omega-3 polyunsaturated fatty acids in the feed resource.
Economical Issues
When evaluating economical issues, the participants addressed the following key
questions:
•What is the price of the feed resource?
•Is the feed resource available in sufficient amounts and with stable availability
over time?
•What is the quality of the feed resource?
•Does the feed resource secure fish of good quality?
•Will consumers accept the use of this feed resource?
Price was always evaluated relative to the quality of the feed resource and
depending on availability. The quality of the feed resource was determined by the
nutritional characteristic of the feed resource, occurrence of unknown or toxic
components, impact on the feed conversion ratio and physical characteristics of
the feed pellet (e.g., texture). Parameters for assessing fish quality included
sensory qualities such as color, texture, and taste, as well as nutritional quality
and maintenance of human health benefits. Consumer health benefits, food safety,
and environmental impacts were most frequently mentioned as important aspects
influencing consumers’ acceptance of the feed resource. In addition, other
consumer concerns mentioned were whether the feed resource is part of the
natural diet of the fish, its impact on fish welfare, its appearance (e.g., physical
defects or waste product), and whether it was genetically modified.
Environmental Issues
The criteria defined by the participants concerned two main questions:
•What are the environmental impacts from harvesting or cultivating the feed
resource?
•Is the harvest, production, and use of the feed resource sustainable?
Sustainability was generally described as a practice that secures future use of the
resource without irreversible damage to the environment or changes in the
ecosystem from where the feed resource originate. When assessing the sustainability
and environmental impacts of the feed resource alternatives, the participants
focused on: (1) impacts from discharges of feed surplus on the environment
surrounding the fish farm, (2) resource and energy requirements during cultivation,
harvesting or processing of the resource, (3) CO
2
emissions during transport of the
feed resource, as well as (4) potential alternative uses of the resource.
Perspectives on Salmon Feed 537
123
Knowledge and Social Issues
When defining criteria concerning knowledge and social issues, the participants
raised the following questions:
•What is the level of scientific knowledge regarding environmental and health
impacts from harvesting, cultivating, and using this feed resource?
•What are the impacts on local communities where the feed resource originated?
Regarding the level of knowledge, the participants were concerned with
knowledge gaps that can result in unintended adverse consequences. Another
important issue was related to power (e.g., who controls the knowledge and
knowledge production and whether the information is well documented and
available for consumers). Impacts on the local communities included an evaluation
of harvesting and cultivation methods and to what extent this activity was controlled
by the local communities or would generate employment for local people. Adverse
effects on local communities from harvesting or cultivating the resource were also
addressed.
The Participants’ Definitions and Weighting of Criteria
The participants would generally define a range of criteria belonging to different
subcategories (Fig. 2). Seven participants did, however, select two or three criteria
belonging to the same subcategory, which reflected their specific interest or area of
expertise. For instance, one of the researchers in fish nutrition only defined criteria
78
4
3
8
2
11
9
3
1
4
4
3
2
6
3
41
2
2
0
5
10
15
20
25
30
35
Heath and welfare
issues
Economical
issues
Environmental
issues
Knowledge and
social issues
Feed industry (4) Fish Farmer (3) Scientist (5)
Market analyst (2) Environmental NGO (2)Policy advicor (2)
Fig. 2 Number of criteria defined by participants belonging to the same interest groups for each main
criteria category
538 F. Gillund, A. I. Myhr
123
concerning fish health, and the other two researchers in this field each defined three
criteria concerning fish health. All the criteria selected by the researcher in fisheries
economics concerned economical issues and nearly 1/3 of all the criteria concerning
environmental issues were defined by people working for environmental NGOs. The
criteria concerning knowledge and social issues were selected by four of the
participants (the researcher in fish welfare, two participants working for environ-
mental NGOs, and one of the policy advisors).
The participants were asked to indicate relative criteria importance by
distributing 100 weighting ‘‘points’’ among the criteria they had defined. Criteria
concerning fish health and consumer health and environmental issues were
generally given high weighting among participants who had defined these criteria,
whereas criteria concerning resource availability were generally given low
weighting. Figure 3shows that there are certain trends in the assigning of weight
that correspond with the participants’ interests or area of expertise. For instance, all
Scientist
H
ealth and welfare issues
Economical issues
Environmental issues
Knowledge and social
issues
Fish farmer
H
ealth and welfare issues
Economical issues
Environmental issues
Knowledge and social
issues
Feed industry
0 102030405060708090100
0 102030405060708090100
0 102030405060708090100
H
ealth and welfare issues
Economical issues
Environmental issues
Knowledge and social
issues
Policy advisor
Health and welfare issues
Economical issues
Environmental issues
Knowledge and social
issues
Environmental NGO
Health and welfare issues
Economical issues
Environmental issues
Knowledge and social
issues
Market analyst
0 10203040506070 809010
0
0 10203040506070
80 90 10
0
0 10203040506070 809010
0
Health and welfare issues
Economical issues
Environmental issues
Knowledge and social
issues
Fig. 3 The six charts show the overall value of weight assigned to criteria from the same category by
participants belonging to the same interest groups
Perspectives on Salmon Feed 539
123
researchers in fish nutrition gave highest weighting to criteria concerning fish
nutrition, while the market analysts gave highest weighting to criteria concerning
consumer health and consumer acceptance. Both participants working for an
environmental NGO gave highest weighting to criteria concerning knowledge. All
the participants working in the feed industry gave criteria concerning consumer
health the highest weighting and criteria concerning consumer acceptance and
resource availability the lowest weighing. Two of the fish farmers gave highest
weighting to criteria concerning fish health whereas the third fish farmer gave the
lowest weighting to this criterion. The two participants who were policy advisors
gave the highest weighting to criteria concerning environmental issues. Two of the
participants (one fish farmer and one working for an environmental NGO) chose to
define sustainability as a principle as they considered this a non-negotiable issue.
Feed industry
S
pecies from lower trophic
levels
Fishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Fish farmer
0 1020304050 60708090100
0 1020304050 60708090100
S
pecies from lower trophic
levels
F
ishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Scientist
0 1020304050 60708090100
S
pecies from lower trophic
levels
F
ishery by-products/catch
Animal by-products
Plants
GM soy and maize
N
utritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Market analyst
Species from lower trophic
levels
Fishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Environmental NGO
0 10203040506070809010
0
0 10203040506070809010
0
Species from lower trophic
levels
Fishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Policy advisor
0 10203040506070809010
0
Species from lower trophic
levels
Fishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Fig. 4 Aggregated performance scores among participants belonging to the same interest group. The
x-axis is a relative 1–100 scale showing performance, with better performing alternatives further to the
right. Bar length is a result of the degree of difference between pessimistic and optimistic scores, and is
thus a function of the degree of uncertainty
540 F. Gillund, A. I. Myhr
123
Overall Assessment of the Feed Resource Alternatives
All the participants agreed with the proposed feed resource alternatives and none
included additional alternatives in their assessment. As shown in Fig. 4, the overall
assessment of the alternatives differed considerably between the interest groups,
both with regard to alternative performance (expressed by how far to the right the
bar extends) and uncertainties (expressed by bar length). No particular pattern
describing trends in the performance of the alternatives emerges, except that by-
products from fisheries and aquaculture were given high scores by all interest
groups. Furthermore, one of the participants who worked for an environmental NGO
defined sustainability as a principle and ruled out species from lower trophic levels
and the three alternatives that involved GMOs, as he did not consider these
alternatives to be in accordance with the principle of sustainability. As each chart
shows the aggregated performance score among all participants for each interest
group, the length of the bars is also an expression of the diversity of assessments
among participants belonging to the same interest group. This is exemplified in
Fig. 5, which shows how each of the policy advisors evaluated the alternatives and
the uncertainties associated with these alternatives. These two charts express
considerable differences both with regard to alternative performance and degree of
uncertainty. When comparing the aggregated performance score among all
participants for each alternative (Fig. 6), we see that all alternatives were centered
Policy advisor 1
0 102030405060708090100
Species from lower trophic
levels
Fishery by-products/catch
Land animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Policy advisor 2
0102030405060708090100
Species from lower trophic
levels
Fishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Fig. 5 Performance scores for each of the policy advisors. See Fig. 4for explanation of the bars
Perspectives on Salmon Feed 541
123
on a mid score (50) and there was only minor variance between the performance and
uncertainties associated with the various alternatives.
Uncertainties Associated with the Feed Resource Alternatives
The participants were asked to give special attention to the exploration of
uncertainties when evaluating the alternatives, which was technically done by
assigning two scores for each option, reflecting the performance of the alternative
under favorable and pessimistic assumptions. In this way, the participants were able
to express uncertainties in the form of incomplete knowledge and to take context
specific factors that could influence the performance of the alternative, into account.
Additionally, diverging opinions regarding benefits and concerns among the
participants, which contribute to further uncertainty, were identified.
Areas Characterized by Incomplete Knowledge
Many participants emphasized that the current understanding of the nutritional
requirements of farmed salmon is generally limited, especially the relationship
between the fish’s diet and its vulnerability to diseases. More specifically, the
participants identified the following areas as characterized by incomplete knowl-
edge when evaluating health and welfare issues: (1) transmission of diseases from
animals to humans if by-products from animals are used as a feed resource, (2)
transmission of fish diseases to salmon fed on by-products and by-catch from
fisheries and aquaculture, (3) impacts, especially on the fish’s regulatory system, of
replacing both fish meal and fish oil with plant resources, and (4) occurrence of
toxic compounds and high levels of nucleic acids in products from microorganisms.
With regard to economical issues, a need for more research was recognized by
the participants in order to: (1) improve the harvesting technology for species from
lower trophic levels, (2) improve the production technology for microorganisms,
and (3) develop nutritionally enhanced GM plants and GM microorganisms.
When evaluating environmental issues the participants identified the following
areas as characterized by incomplete knowledge: (1) the population dynamics of
All participants
0 10203040506070 8090100
Species from lower trophic
levels
Fishery by-products/catch
Animal by-products
Plants
GM soy and maize
Nutritionally enhanced GM
plants
Products from micro
organisms
Products from GM micro
organisms
Fig. 6 Aggregated performance scores for all participants. See Fig. 4for explanation of the bars
542 F. Gillund, A. I. Myhr
123
species from lower trophic levels, (2) long term environmental impacts from
cultivating GM soy and maize and nutritionally enhanced GM plants, and (3)
impacts from GM feed surplus on the environment surrounding the fish farm. The
three participants who defined criteria concerning the level of knowledge
emphasized that the knowledge about disease transmission from animal by-products
and environmental and health consequences from GM soy and maize is limited.
Diverging Opinions Among the Participants
The participants expressed highly diverging opinions about benefits, concerns, and
uncertainties when evaluating GM soy and maize, nutritionally enhanced GM
plants, and species from lower trophic levels. For instance, when evaluating GM soy
and maize under criteria concerning health and welfare issues, six participants (four
from the feed industry, one researcher in fisheries economics, and one policy
advisor) considered GM soy and maize as identical to non GM plants. The other ten
participants assessing similar criteria expressed concerns regarding potential
unintended health impacts from GM soy and maize both for the salmon and
consumers—referring, for instance, to the fact that transgenes from the feed have
been detected in the fish a long time after feeding, as well as to the observed
increase in intolerance and allergies to foodstuffs among consumers. The same
concerns were raised when evaluating nutritionally enhanced GM plants.
When assessing environmental issues, the participants expressed opposing views
with regard to whether current knowledge about species from lower trophic levels is
sufficient to define sustainable levels of harvest. Moreover, the sustainability of
plant production in industrial agriculture, and particularly the cultivation of GM
plants, were contested issues. One of the policymakers argued that ‘‘GM is the only
way to promote an optimal and fully sustainable feed production for aquaculture’’
and that ‘‘Nutritionally enhanced GM plants is the most sustainable feed resource
alternative as it uses the photosynthesis for feed production.’’ Other participants
expressed concerns about the possibility for long term environmental impacts, both
from the cultivation of GM plants and from discharges of GM feed surplus into the
environment surrounding the fish farm.
Context Specific Factors
The most frequently mentioned context specific factor was timescale, as the
participants were asked to assess the alternatives based on the current situation and
expectations about the future (20 years from now). Most participants found it
difficult to make predictions about future situations, particularly regarding future
availability, price, and consumer reactions. Some participants expected, for
instance, that consumers will support the use of species from lower trophic levels
as a feed resource because it is beneficial to human health and an abundant resource
that can be harvested sustainably. Other participants, however, expected low
consumer acceptance, arguing that consumers would see this as ‘‘stealing food from
the whales.’’ Similarly, whereas some participants believed that consumers are
positive to the use of plants in feed production due to environmental concerns, other
Perspectives on Salmon Feed 543
123
participants believed that consumers might be skeptical, as ‘‘salmon is not naturally
a vegetarian.’’
Variability within the feed resource alternatives was the second most frequently
mentioned context specific factor. This can also be attributed to the way the study
was designed, as each alternative consisted of a variety of species/types of products.
For instance, the use of by-products and by-catch from fisheries and aquaculture
were included in the same alternative, but most participants emphasized that the
environmental impacts from using these resources differs considerably. Whereas the
use of by-products from fisheries and aquaculture is considered environmentally
friendly, since this resource would otherwise become waste, many participants
feared that the use of by-catch might lead to increased by-catch and thereby further
increase the pressure on wild fish stocks.
Additionally, the participants commented that the price of the feed resource
depends on availability, and is relative to nutritional quality and consumers’
willingness to pay for the final product. Availability may depend on regulation (e.g.,
current regulation limits the use of animal by-products and GM products). Species
and type of by-product, as well as origin or place of cultivation and harvesting time
were mentioned as context specific factors influencing the nutritional quality of a
resource. Finally, factors such as management regimes and regulations, intensity
and level of harvest, and alternative use of the resource (especially whether it was
suitable for direct human consumption) influence the performance of the alterna-
tives when assessed under environmental criteria.
Discussion
Mapping Perspectives on Feed Resources for Farmed Salmon
The study shows that different actors within Norwegian salmon aquaculture
represent an important source of knowledge about alternative feed resources for
farmed salmon. Thereby, the study provides valuable inputs to the aquaculture
industry and policy-makers when deciding on future feed strategies for farmed
salmon. As we see it, one of the most insightful outcomes of the study lies in the
broad range of criteria identified by the participants, including (1) health and
welfare issues, (2) economical issues, (3) environmental issues and (4) knowledge
and social issues. Within these categories the most frequently defined criteria
concerned fish health, consumer health, consumer acceptance, price, resource
availability and environmental impacts. The criteria point to issues that are
important to take into consideration when assessing and making decisions on future
feed resources for farmed salmon. Interestingly, some criteria such as impacts on
local communities from where the feed resource originate and the various
environmental criteria, exceed what is typically seen as driving feed resource
substitution, such as price, availability, and consumer acceptance (Naylor and Burke
2005; Tacon and Metian 2008). Thus, the wide range of criteria identified underlines
the need for comprehensive evaluations that are broad in scope.
544 F. Gillund, A. I. Myhr
123
The participants found all the feed resource alternatives relevant and no
additional alternatives were suggested during the exercise. No clear conclusions
regarding what constitutes the most desirable feed resources can, however, be drawn
from the study. Rather, it shows how the suitability of an alternative depends on
which criteria the alternative is evaluated against and how these criteria are
understood and prioritized. The evaluation of species from lower trophic levels
exemplifies that criteria could be conflicting. All participants assigned high scores
when this alternative was evaluated under criteria concerning health and welfare
issues, whereas low performance scores or uncertainties were generally expressed
under criteria concerning environmental issues. Furthermore, conflicting views on
the same topic were frequently expressed among the participants, especially with
regard to what constitutes sustainable practices. The different views were partly
depending on timeframe, significance attached to uncertainties, and whether the
sustainability of an alternative was evaluated relative to other practices.
Most participants experienced MCM as a useful exercise that stimulated
reflection and provided a good overview about the suitability of alternative feed
resources, and how this varied depending on appraisal criteria. Some did, however,
express that they did not think that the final chart sufficiently described all the
nuances and complexities involved in decision making on future feed strategies.
This was primarily because the assessments of the alternatives involved highly
context dependent judgments, reflected in the numerous ‘‘this would depend on…’’
comments made by the participants when evaluating the alternatives. As already
described the most frequently mentioned context specific factors were time scale
and variability within the feed resource alternatives. These factors can primarily be
attributed to the study design, as many of the alternatives the participants were
asked to assess consisted of different species/types of products and as they were
asked to make predictions about the future. As the intention of the study was to
gather perspectives on a range of alternative feed resources, including alternatives
not yet in use, we purposely chose broad definitions and long-time frames for the
assesment. We do, however, recognize that this posed additional challenges for the
participants.
Qualitative Aspects of Uncertainty
Several areas characterized by incomplete knowledge were identified by the
participants. These may guide future research priorities and support the need for
more knowledge regarding the suitability of the different feed resource alternatives
(Norwegian Research Council 2008; Norwegian Scientific Committee For Food
Safety 2009; Waagbø et al. 2001). In discourses on science for decision making,
increasing awareness is, however, given to uncertainties that are not necessarily
reduced through more research, and several typologies characterizing different types
of qualitative dimensions of uncertainty have recently emerged (e.g., Felt and
Wynne 2007; Funtowicz and Ravetz 1990; Stirling 2007; Stirling 1999; Stirling and
Gee 2002; Walker et al.2003; Wynne 1992). These may be synthesized as (1)
indeterminacy—describing knowledge as conditional and fallible due to the
impossibility of including all relevant factors and interactions into research on
Perspectives on Salmon Feed 545
123
complex, open and interacting systems, (2) ambiguity—describing uncertainties
resulting from different framing conditions, as knowledge generated about a system
depends on how researchers frame the systems and impacts they are interested in,
and the way they approach, interpret, and understand the knowledge and
calculations generated about them, and (3) ignorance—describing situations where
we don’t know what we don’t know, and thus completely unexpected events may
occur (Wickson et al. 2009). MCM is developed in order to address these qualitative
dimensions of uncertainty, particularly how different values, interests, and
underlying assumptions held by the participants influence their assessments—
above referred to as ambiguity. Ambiguities identified in this study are illustrated in
Fig. 4, which shows the differences in the aggregate performance scores between
different interest groups, and in Fig. 5, which shows the differences in performance
scores given by each of the policy advisors. As previously described, the
participants’ view on occurrence and significance of uncertainties was particularly
diverging when they assessed GM soy and maize, nutritionally enhanced GM plants,
and species from lower trophic levels. The participants who characterized these
alternatives as very uncertain emphasized that it is difficult to predict long term
impacts on health and environment. This underlines that agricultural and aquatic
ecosystems are highly complex, open, and interactive systems, which are typical
features of systems characterized by indeterminacy and ignorance. Thus, the study
illustrates how ambiguities particularly prevail under such conditions.
There are no simple answers as to what constitutes the best solution in situations
characterized by ambiguity, indeterminacy, and ignorance, as multiple and equally
plausible descriptions of a problem—and how to solve it—exist. It is under these
conditions that MCM may provide important insights to policy-makers, by simply
mapping the plurality of scientific and socio-political perspectives on a problem. As
we see it, the richness of this study is the broad range of criteria identified, and that
it shows how the performance of the alternatives is influenced by the values and
interests of the participants, reflected in the definition and weighting of criteria and
in the evaluation of the performance (scoring) of each feed resource alternative
under these criteria. In this way, the study helps to ‘‘open up’’ the evaluation process
and thereby strengthens the information base upon which future choices can be
made.
Conclusion
In this MCM exercise we wanted to map different perspectives on alternative feed
resources for farmed salmon. One of the most insightful findings from the study was
the broad range of criteria identified, including (1) health and welfare issues, (2)
economical issues, (3) environmental issues, and (4) knowledge and social issues.
This underlines the need to facilitate comprehensive assessments that go beyond the
concerns that are typically seen as driving fish meal and fish oil replacement, such as
price, availability, and consumer acceptance. No clear conclusions regarding the
suitability of the feed resource alternatives can be drawn from the study. It describes
different forms of uncertainties associated with the feed resource alternatives, which
546 F. Gillund, A. I. Myhr
123
originate in incomplete knowledge, diverging opinions among the participants, and
context specific factors. Furthermore, the study shows that individual values and
interests held by the participants influence the assessments. This underlines the
importance and usefulness of carrying out deliberative processes in the early stages
of development in order to explore the plurality of scientific, social, and political
perspectives on the issue. We believe that comprehensive assessments where a
broad range of issues are taken into account, can contribute to improving the
information base for decision making on feed strategies for farmed salmon.
Acknowledgments This work is funded by the Norwegian Research Council (project no. 172 621/S40).
We would like to thank Ragnar L. Olsen for valuable advice during the development of the study and the
18 anonymous participants of the study and the anonymous reviewers of an earlier version of this paper
for their helpful suggestions.
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