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ShelterFish has addressed the currently main challenges for future development of organic trout production in Denmark, i.e. the parasitic disease costiasis (caused by Ichthyobodo necator) which is lethal for fry/smaller fish and the bacterial disease Red Mark Syndrome (RMS), which results in downgrading/rejection at slaughter. The issues were addressed by a holistic approach including interactions between the fish environmental conditions (water quality and welfare), the pathogens (health) and the fish. Hence, fish welfare was evaluated in response to providing artificial shelters for the fish. Rainbow trout were exposed to two types of submerged shelters: Full screens or partial Semi screens, and fish welfare was assessed and compared to a control group (without shelters) by evaluating fish growth and condition, extent of external lesions, and the neuroendocrine responses to acute and repeated stress. A separate study of potential effects of early exposure to shelters on the juvenile performance later in the life cycle showed, that shelter-grown fish performed less competitive compared to non-shelter-grown fish in challenging conditions favoring competition (low stocking density plus restricted feeding). However, this effect was clearly mitigated when letting shelter-grown fish to acclimate to non-shelter conditions before the competition tests. Finally, a field study was performed in an organic rainbow trout farm with simply designed shelters to investigate rainbow trout fingerlings’ preference for shelter, and the behavioral response to farm related stress, as well as the cortisol response and growth performance. Overall the experiments showed: • Fish showed a clear behavioral preference to use/get protected under the shelters, particularly when disturbed; • Shelters had no deleterious effect on fish performance, welfare indicators or survival. Though, shelter resulted in reduced fin damages. • Based on the results, in particular the field studies, it is suggested that future trials, designed to study the effects of shelter on rainbow trout welfare, would benefit from longer habituation period prior to stress testing and sampling. Hence, the studies performed showed potential for shelters to be used as a welfare promoting strategy in trout farming, but further research is needed to optimize the shelter type and design and the proper timing for its application. The serious parasitic pathogens Costia (Ichthyobodo necator), Ichthyopthirius multifilis (ICH-white spot disease) and different amoebae (Vanella sp.) have been identified in gill samples collected from trout in organic farms using Q-PCR array and histology. Test for establishment of Costia cultures have been performed at organic farm with positive results. Extracts of oregano, thyme, coriander, garlic and astaxanthin were tested in vitro and in vivo against the ciliate, Costia. These natural compounds showed an effect on the infection in the early stage but not after 8 days. Garlic exhibited the highest in vitro killing capacity towards theronts (the infective stage of the parasite), followed by oregano, thyme, and astaxanthin, whereas coriander had no in vitro parasiticidal effect. The results suggest that the investigated additives inhibit early parasite development directly as well as indirectly (i.e. by elevating the host immune response). However, more promising results were found with a novel biological control agent, the surfactant from Pseudomonas H6, a kind of biological soap, which opens the cell membrane of the parasite so the content float out and the parasite dyes. It was found that this agent had a strong effect on a series of organisms colonizing gills, skin and fins of organic trout. The compound could kill many of the organisms but more importantly the surfactant seemed to clean off the colonizers (Amoebae, Ichthyobodo, Trichodina and Ambiphrya). The auxiliary water treatment compounds, the biocides formalin, peracetic acid and hydrogen peroxide induced a strong inflammation in the fish but the surfactant H6 was very mild, although it induced mucus release from mucous cells in the skin. The biocides induced the mucus secreting cells on fish surfaces (gills, skin, and fins) to empty their content upon stimulation. Experiments on prophylaxis/treatment of gill pathogens showed that amoebae were killed at the following concentrations: 16.9 mg/ml (raw garlic-extract), 100 mg/L (hydrogen peroxide), 250 microgram/ml (bacteria surfactant), 17.9 mg/ml (oregano extract), 7.5 ppt (NaCl). No effect of shelters could be detected in gills, skin and fins on colonization of fish surfaces with amoebae and ciliates. Red Mark Syndrome (RMS) is a disease affecting rainbow trout under farming conditions. The disease is not lethal but is costly for the fish farmer as the hallmark symptoms of the disease are large, red skin lesions, which often appear in fish of market size. There are currently no good treatment options for this disease. RMS does rarely occur twice in the same fish population, therefore ShelterFish investigated whether early exposure to RMS as fingerlings could result in protective immunity throughout the remainder of the production cycle, thus preventing skin lesions in larger fish and thereby severely reducing the problems associated with RMS. Naïve specific pathogen free (SPF) rainbow trout fingerlings were exposed to RMS by cohabitation. Most of the cohabitants developed clinical signs of RMS during the following three months. The fish were now maintained until 13 months after initiating the first round of cohabitation, at which time they were once again exposed to RMS via cohabitation. This time, non-exposed control fish were also added. The second cohabitation was terminated after 77 days. By then, all negative controls had developed several RMS-lesions, whereas no skin pathology was observed in the pre-exposed fish. All experimental procedures were carried out at 12°C. The results showed that under the experimental conditions, protective immunity against RMS was induced in fingerlings and lasted for at least 13 months. Use of chemical disinfectants and organic aquaculture may seem contradictory. There are however no direct contradictions between these two terms, as long as they are developed and improved towards more sustainable solutions. A natural and immediate aversion to words like “sanitizers, chemicals and auxiliary compounds” are frequently met. Similarly, aquaculture production is often criticized and have a tarnished reputation. Organic aquaculture is a way to differentiate from conventional fish production. Some of the challenges still remain to be solved and during that process, ideally important knowledge and experience can also accelerate better management in the conventional aquaculture industry. With particular reference to organic aquaculture the following recommendations are given: • Reduce particulate organic matter, as the microbial water quality becomes improved by further removal of organic matter, i.e. lowered bacterial load, increased oxygen concentration and decreased dissolved CO2. • Increase water flow and circulation/internal recirculation to improve oxygen conditions and reduce retention time and potentially dampen intra specific aggression to change fish behavior from erratic to more streamlined swimming (welfare). • Proactively learn to use safe chemicals with caution to become confident with optimized chemical water treatment (dosages and fish behavior). Future research and development of organic aquaculture is recommended to include organic feeds and fish nutrition, fish health and welfare, environmental aspects including sustainable management and use of disinfectants from an environmental, ethical and economical perspective, consumers’ needs, food safety and trade. Finally, there is also an urgent need to improve management practice towards more sustainable fish production. Increased collaboration and openness between industry, consumers, authorities and academia will facilitate that process

The development of organic aquaculture in Denmark has been ongoing for two decades, currently representing 2 % of the national rainbow trout production. Organic aquaculture practice is subjected to a number of specific restrictions compared to conventional aquaculture operation, which pose challenges but also allows the certified producers to achieve a premium price of their product. Water treatment is one example; only easy degradable, sanitizers are allowed to be used in certified organic aquaculture production as specified in the current EU legislation. Formalin, an effective and commonly used biocide for aquaculture water control, is not permitted in organic aquaculture which forces new treatment practices to be developed and implemented. Here we describe issues related to the implementation of new water treatment practices and present potential practical solutions. The interaction between management and water quality is described and the implications for water treatment is emphasized. Results and experiences of using peracetic acid products and hydrogen peroxide in organic freshwater fish farms are provided. Current challenges and future research needs regarding water quality control are discussed in a context of fish health, fish welfare, worker safety, ethics and environmental justification. Finally, sustainable development of organic aquaculture is put into perspective based on the Danish lessons learned.

One of the aims of the Shelterfish project was to test whether simple shelters, easy to produce, install and remove, might have similar beneficial effects for fish welfare in aquaculture as observed before for fish used for re-stocking. The experiments performed showed that fish have a clear preference for shelter use and that shelters had no negative effects on the fish growth performance. These results alone can be considered positive for fish welfare, since animal preference is an important welfare aspect. However, effects on external lesions and general health were modest, and the ability of the fish to deal with stress was not altered. There is likely room for optimization in the use of shelters and other types of enrichment for increasing the welfare of farmed fish. In the particular case of the use of shelters for salmonid farming, shelter effects seem to depend on many different factors and there is a need for further research to optimize their use in terms of shelter type, sheltering extent and timing for its application during the fish life cycle.

Aquaculture is one of the world’s fastest-growing industries, with 6 % annual growth since 2010, and is becoming an increasingly important component of the world’s food production. European aquaculture has not kept up with the pace of change in other parts of the world, growing only 24 % since 1990, and only 6 % since 2007. As with all food production industries, aquaculture has a range of positive and negative impacts for the environment and the socio-economic system, which varies across production type, species, geography and biophysical context. The overall purpose of this study is to present the scientific basis of the positive and negative impacts of European aquaculture from an economic, environmental and social point of view, in order to facilitate a well-informed debate. However, the study does not seek to assess the magnitude or likelihood of impacts, compare magnitude or likelihood of impacts among different types of aquaculture nor compare the impacts identified to those of alternative food production systems. In order to achieve this aim, the project first undertook an extensive literature review to collate state-of-the-art scientific information on the positive and negative impacts of aquaculture. The study examined scientific peer-reviewed literature, supplemented by the Scientific, Technical and Economic Committee for Fisheries and European Data Collection Framework for aquaculture and focused on finfish culture (sea cages; ponds, tanks, and raceways; and recirculating aquaculture systems), shellfish culture (suspended, trays, and bottom culture), macroalgae and microalgae. To complement the impacts derived from the scientific literature a deeper analysis of impacts was conducted via 18 case studies across Denmark, Germany, France, Poland, Netherlands, Croatia, Greece, Ireland, Italy, Portugal and Spain. The case studies covered a range of production technologies and species types. The case studies were used to verify impacts identified in the scientific literature, to identify any impacts potentially overlooked by the scientific literature and to identify legislation and mitigation relevant to the aquaculture type at the national level. The case studies combined information from the literature review, supplementary scientific and grey literature of specific relevance to the case study, and key expert interviews (40 in total). Key experts consulted were primarily those from relevant national authorities and national research institutes. In parallel with the case studies, a review of the EU and national regulatory frameworks and associated mitigation measures was conducted. The review and the key expert interviews from the case studies were used to provide a preliminary analysis of the extent to which the regulatory framework mitigates negative impacts from aquaculture. The information from the literature reviews and the case studies was then collated and evaluated to provide an overview of the most important and most broadly identified positive and negative impacts for different aquaculture types. The evaluation made specific efforts to highlight consensus between the scientific literature and the opinions of key experts, as well as highlighting where these differ – indicating potential priority areas for future research.

Hudsnylteren Ichthyobodo (Costia) og dens betydning og kontrol i økologisk ørredopdræt. I Shelterfish projektet er der særligt fokus er på at bekæmpe infektioner med især hudsnylteren Ichthyobodo necator – også ofte benævnt Costia necatrix. Den ydre overflade på en fisk omfatter hud, finner og gæller, og alle dele kan tjene som fasthæftnings- og opholdssted for en lang række parasitter. Økologisk opdrættet regnbueørred angribes af flere typer af disse hudsnyltere, men den parasitiske flagellat Ichthyobodo necator er en af de værste. Der findes ikke vacciner mod denne infektion, hvorfor tilsætning af aktive stoffer til opdrætsvandet oftest benyttes. I Shelterfish-projektet undersøges et nyt bakterielt overflade aktivt stof mod hudsnylteren. Det bakterielle overfladestof har vist gode resultater mod fiskedræber og amøber i gæller hos regnbueørred.

Opdræt af regnbueørred, især økologisk ørred, er kritisk udfordret på grund af relativt mange hud/gælle infektioner forårsaget af forskellige patogener, især parasitten Costia (Ichthyobodo necator), som ultimativt er dødelig for yngel/mindre fisk. Dette kan være en trussel mod tilstrækkelig udbud af økologisk yngel til videre produktion, da regelsættet for økologisk akvakultur kræver 100% økologisk yngel. Endvidere forårsager en såkaldt ny ”Rickettsia-lignende" bakterie “rødpletsyge” (RMS), dvs. røde pletter i huden, som medfører ned-klassificering/kassation af op til 30% af fiskene ved slagtning. Behandling ved brug af antibiotika/hjælpestoffer er kun muligt i begrænset omfang i økologisk ørred produktion. Løsninger til forebyggelse og/eller behandling af Costia og RMS er derfor strengt påkrævet – ikke kun for blot at sikre produktion af økologisk ørred i Danmark, men også for at styrke grundlaget for en større produktion af robuste økologiske fisk. ShelterFish vil fokusere på løsninger i krydsfeltet: Fisk - Patogener – Opdrætssystem/miljø og vandkvalitet; omfattende 1) Test af skjul/skygge med henblik på at skabe bedre og robust opdrætsmiljø; 2) Test af urte ekstrakter og et nyt bakterielt overfladeaktivt stof til behandling af gæller/hud parasit infektioner; 3) Test af induceret immunitet mod ”rødpletsyge” og 4) Test af metoder til reduktion af belastning med organisk stof i økologiske dambrug og herved forbedre vandkvalitet/miljø, fiske sundhed og velfærd. Økologisk ørred opdræt sker efter fælles EU-regler, hvor fiskevelfærd har høj fokus.

Trout farming and in particular organic trout farms are critically challenged by relatively high skin/gill infections caused by various pathogens, especially the parasite Costia (Ichthyobodo necator), which is ultimately lethal for fry/smaller fish. Due to new organic regulations requesting also fry to be 100% organic, this in turn compromises supply of organic fry as basic for future production of organic trout. In addition, a Rickettsiales-like bacterium causes Red Mark Syndrome (RMS) with large red patches in the skin, which results in downgrading/rejection of up to 30% of the fish at slaughter. Treatment by use of antibiotics/ auxiliary compounds is only possible to a limited extent in organic trout production. Hence, solutions to prevent and/or treat Costia and RMS are urgently needed, not only to secure production of organic rainbow trout in Denmark, but also enable a larger and more cost efficient production with high animal welfare and minimal environmental impact. ShelterFish will focus on solutions addressing the interactions between fish - pathogens – farming environment and water quality; including 1) Test of artificial shelters (shade) to enrich environmental conditions; 2) Test of biological herb extracts and a new bacterial surfactant to treat gill/skin parasite infections; 3) Test of induced immunity to fight Red Mark Syndrome (RMS) and 4) Test of tools to reduce organic matter load in organic trout farms and hereby improve water quality, fish health/welfare. Fish welfare has high focus in as well the common EU regulations for Organic aquaculture as the English Animal protection organisation RSPCA standard. RSPCA has primarily focus on fish wellfare. But are there differences between the two standards as regards fish wellfare?

Opdræt af regnbueørred, især økologisk ørred, er kritisk udfordret på grund af relativt mange hud/gælle infektioner forårsaget af forskellige patogener, især parasitten Costia (Ichthyobodo necator), som ultimativt er dødelig for yngel/mindre fisk. Dette kan være en trussel mod tilstrækkelig udbud af økologisk yngel til videre produktion, da regelsættet for økologisk akvakultur kræver 100% økologisk yngel. Endvidere forårsager en såkaldt ny ”Rickettsia-lignende" bakterie “rødpletsyge” (RMS), dvs. røde pletter i huden, som medfører ned-klassificering/kassation af op til 30% af fiskene ved slagtning. Behandling ved brug af antibiotika/hjælpestoffer er kun muligt i begrænset omfang i økologisk ørred produktion. Løsninger til forebyggelse og/eller behandling af Costia og RMS er derfor strengt påkrævet – ikke kun for blot at sikre produktion af økologisk ørred i Danmark, men også for at styrke grundlaget for en større produktion af robuste økologiske fisk. ShelterFish vil fokusere på løsninger i krydsfeltet: Fisk - Patogener – Opdrætssystem/miljø og vandkvalitet; omfattende 1) Test af skjul/skygge med henblik på at skabe bedre og robust opdrætsmiljø; 2) Test af urte ekstrakter og et nyt bakterielt overfladeaktivt stof til behandling af gæller/hud parasit infektioner; 3) Test af induceret immunitet mod ”rødpletsyge” og 4) Test af metoder til reduktion af belastning med organisk stof i økologiske dambrug og herved forbedre vandkvalitet/miljø, fiske sundhed og velfærd. Fiskevelfærd har høj fokus i såvel det fælles EU regelsæt for økologisk akvakultur som i den engelske dyreværnsorganisations RSPCA standard. Økologisk ørred opdræt sker i dag efter fælles EU-regler. Fiskevelfærd er væsentlig for enhver akvakultur produktion og er særligt fremtrædende i det økologiske EU-regelsæt. Men der findes også andre regelsæt, der har primær fokus på fiskevelfærd som f. eks. den engelske RSPCA standard. RSPCA er forkortelsen for: Royal Society for the Prevention of Cruelty to Animals, der er en non-profit engelsk dyreværnsorganisation med sit eget “RSPCA Assured” mærke. Men tager det ene regelsæt mere hensyn til fiskevelfærd end det andet? Dette søges belyst i denne artikel i forhold til EU-regelsættet og RSPCA standarden.

Fiskevelfærd har høj fokus i såvel det fælles EU regelsæt for økologisk akvakultur som i den engelske dyreværnsorganisations RSPCA standard Økologisk ørred opdræt sker i dag efter fælles EU-regler. Fiskevelfærd er væsentlig for enhver akvakultur produktion og er særligt fremtrædende i det økologiske EU-regelsæt. Men der findes også andre regelsæt, der har primær fokus på fiskevelfærd som f. eks. den engelske RSPCA standard. RSPCA er forkortelsen for: Royal Society for the Prevention of Cruelty to Animals, der er en non-profit engelsk dyreværnsorganisation med sit eget “RSPCA Assured” mærke. Men tager det ene regelsæt mere hensyn til fiskevelfærd end det andet? Dette søges belyst i denne artikel i forhold til EU-regelsættet og RSPCA standarden. RSPCA er forkortelsen for: Royal Society for the Prevention of Cruelty to Animals, der er en non-profit engelsk dyreværnsorganisation med sit eget “RSPCA Assured” mærke.

Rainbow trout farming and in particular organic rainbow trout farms are critically challenged by the relatively high prevalence of skin/gill infections caused by various pathogens, especially the parasite Costia (Ichthyobodo necator) and amoebae, which are ultimately lethal for fry/smaller fish. In addition, a Midichloria-like bacterium causes the non-lethal skin disease Red Mark Syndrome (RMS), which results in downgrading/rejection of up to 30% of the fish when placed on the market. Treatment by use of antibiotics/parasitics/ auxiliary compounds is only possible to a limited extent in organic trout production. Hence, solutions to prevent and/or treat costia, amoebae and RMS are urgently needed, not only to secure production of organic rainbow trout in Denmark, but also enable a larger and more cost efficient production with high animal welfare and minimal environmental impact. ShelterFish will focus on solutions addressing the interactions between fish - pathogens – farming environment and water quality; including 1) Test of artificial shelters (shade) to enrich environmental conditions and lower stress; 2) Test of biological herb extracts and a new bacterial surfactant to minimize gill/skin parasite infections; 3) Test of induced immunity to Red Mark Syndrome (RMS) by early exposure; and 4) Test of tools to reduce organic matter load in organic trout farms and hereby improve water quality, fish health/welfare.

Opdræt af regnbueørred, især økologisk ørred, er kritisk udfordret på grund af relativt mange hud/gælle infektioner forårsaget af forskellige patogener, især parasitten Costia (Ichthyobodo necator), som ultimativt er dødelig for yngel/mindre fisk. Dette kan være en trussel mod tilstrækkelig udbud af økologisk yngel til videre produktion, da regelsættet for økologisk akvakultur kræver 100% økologisk yngel. Endvidere forårsager en såkaldt ny ”Rickettsia-lignende" bakterie “rødpletsyge” (RMS), dvs. røde pletter i huden, som medfører ned-klassificering/kassation af op til 30% af fiskene ved slagtning. Behandling ved brug af antibiotika/hjælpestoffer er kun muligt i begrænset omfang i økologisk ørred produktion. Løsninger til forebyggelse og/eller behandling af Costia og RMS er derfor strengt påkrævet – ikke kun for blot at sikre produktion af økologisk ørred i Danmark, men også for at styrke grundlaget for en større produktion af robuste økologiske fisk. ShelterFish vil fokusere på løsninger i krydsfeltet: Fisk - Patogener – Opdrætssystem/miljø og vandkvalitet; omfattende 1) Test af skjul/skygge med henblik på at skabe bedre og robust opdrætsmiljø; 2) Test af urte ekstrakter og et nyt bakterielt overfladeaktivt stof til behandling af gæller/hud parasit infektioner; 3) Test af induceret immunitet mod ”rødpletsyge” og 4) Test af metoder til reduktion af belastning med organisk stof i økologiske dambrug og herved forbedre vandkvalitet/miljø, fiske sundhed og velfærd.

The main objective of this work was to summarise current knowledge on fishmeal and fish oil as well as identify the research needs and create a roadmap for future industry-driven research. The main conclusion was that the quality of raw material, fishmeal and - oil are not yet well defined. The real focus by the industry has mainly been limited to nutrients, such as proteins and fats and other components that makeup fishmeal. There has been less focus on the health benefits of dietary contents of fishmeal and –oil and the relationship between processing methods and the nutritional and technical properties of fishmeal. In addition, to proactively strengthen the market position and competitiveness, it is crucial for the industry to achieve a common understanding of the needs of their customers in line with a clear profile of the benefits of their products. A communication strategy as well as a research strategy is needed.Finally, the identity of the industry needs to be clear and transparent to promote a story about the industry to provide a clear and positive image of the industry to be communicated to the society. This means, that a communication strategy as well as a research strategy must be established, as there is a lack of communication along the value chain from the industry to the consumers. There is still a lack of understanding by the consumers of why fishmeal is produced, the reasons must be communicated in such a way that it reaches the average consumer.The industry members are interested in moving forward to sustain the future growth of the industry. Fishmeal and fish oil production has been prosperous for a very long time, but to

The main objective of this work was to summarise current knowledge on fishmeal and fish oil as well as identify the research needs and create a roadmap for future industry-driven research. The main conclusion was that the quality of raw material, fishmeal and - oil are not yet well defined. The real focus by the industry has mainly been limited to nutrients, such as proteins and fats and other components that makeup fishmeal. There has been less focus on the health benefits of dietary contents of fishmeal and –oil and the relationship between processing methods and the nutritional and technical properties of fishmeal. In addition, to proactively strengthen the market position and competitiveness, it is crucial for the industry to achieve a common understanding of the needs of their customers in line with a clear profile of the benefits of their products. A communication strategy as well as a research strategy is needed. Finally, the identity of the industry needs to be clear and transparent to promote a story about the industry to provide a clear and positive image of the industry to be communicated to the society. This means, that a communication strategy as well as a research strategy must be established, as there is a lack of communication along the value chain from the industry to the consumers. There is still a lack of understanding by the consumers of why fishmeal is produced, the reasons must be communicated in such a way that it reaches the average consumer. The industry members are interested in moving forward to sustain the future growth of the industry. Fishmeal and fish oil production has been prosperous for a very long time, but to remain so, cooperation among all stakeholders is crucial for continued progress., Funding: AG-fund, EUfishmeal

Formålet med RobustFish projektet var at: • Styrke udviklingen af økologisk ørredproduktion i Danmark men også til gavn for konventionelt opdræt • Undersøge ørredyngels robusthed i forhold til start-fodrings adfærd, fedtsyreindholdet i foderet og følsomhed over for yngeldødeligheds-syndromet (YDS) • Effekt af vandbehandling med hjælpestoffer • Viden om markedsforhold, forbrugerkendskab, produktudvikling og øget afsætning. Robustfish har adresseret ovennævnte problemstillinger, og på grundlag af opnåede resultater kan der drages følgende konklusioner og deraf følgende anbefalinger og perspektiver for styrkelse af det økologiske opdræt af regnbueørred i Danmark. • Yngel med tidlig fødesøgnings adfærd (swim-up) viste tendens til større robusthed over for de anvendte stress påvirkninger. • Der var ingen statistisk forskel mellem dødelighed forårsaget af YDS-bakterien Flavobacterium psychrophilum og ”Tidlig”, ”Mellem” og ”Sen” swim-up adfærd. • Udskiftning af marine protein kilder (kun 10 % fiskemel i diæterne) med vegetabilske viste negativ effekt på foderindtag, vækst og dødelighed i regnbueørred yngel. • Lavt indhold af flerumættede fedtsyrer (HUFA) i foderet (> 1 % af total fedtsyrer (TFA)) havde tilsyneladende kun lille påvirkning på vækst, foderkonvertering (FK) og enzymatisk aktivitet indtil 100 dage efter startfodring – i foder med optimal marin proteinkilde. • Fedtsyre resultater indikerede, at ørred tilsyneladende kan syntetisere kortere kædede fedtsyrer til HUFA. • De godkendte hjælpestoffer anvendes med større sikkerhed og dambrugerne er blevet fortrolige med produkterne, ligesom fiskene tilsyneladende tilpasser sig de grønne hjælpestoffer. • Behov for optimering af driften med henblik på dels at sikre en bedre og mere stabil vandkvalitet – og derved reducere brugen af hjælpestoffer og dels sikre fiskevelfærd, herunder også vandcirkulation, beluftning, overdækning, mm.). • Det vurderes at der vil være gode muligheder for at opretholde en merpris (20 – 30 %) på økologiske ørreder, og at markedsføring skal fokusere mere på dyrevelfærd end miljø. • Forbrugerne havde en negativ opfattelse af opdrættet fisk, der blev forbundet med noget negativt - på linje med industrialiseret landbrug og i modsætning til ”vile fisk”. • Kun få forbrugere var i stand til at identificere regler for økologisk fisk og ofte sammenblandedes de med MSC, ASC og andre certificeringer. • Der behov for en systematisk kommunikations-/forbrugeroplysningskampagne med fokus på større bevidsthed om ”Økologisk fisk”, der er opdrættet og kontrolleret i forhold til specifikke regler for økologisk akvakultur og at økomærket adskiller sig fra f. eks. miljømærkerne MSC og ASC. • Stigende efterspørgsel efter økologiske produkter i Europa vil være et godt afsætningsmæssigt grundlag for at fastholde målsætningen i regeringens 2020-plan for dansk akvakultur. Det anbefales at der skabes yderligere incitament til omlægning af dambrug til økologisk produktion.

The Organic Regulation of fish farming states strong limitations on the sourcing of protein and fat (oil) ingredients in organic feed, i.e. aiming to phase out fishmeal (FM) and fish oil (FO) obtained from wild fish stocks and this may lead to a higher inclusion of other ingredients, especially of vegetable origin including proteins i.e. soybean; wheat; corn; barley; cottonseed; canola and peas, and oils i.e.: soybean; canola; linseed; sunflower; palm oil a.o. (Gatlin et al., 2007). A complete substitution of (FM) by vegetable protein alternatives may, however, lead to reduced performance in salmonids. Nutritional deficiencies and lack of essential amino acids; high dietary levels of antinutrients/ carbohydrates are typical factors leading to lower feed intake; lower digestibility,- feed utilization and growth and may have additional consequences for survival and robustness. Several studies have shown that a total substitution of FO by individual or mixtures of vegetable oils do have same negatively effect on growth or feed efficiency provided that essential n-3 (Ω-3) and n-6 (Ω-6) long chain polyunsaturated fatty acids (LC-PUFA) requirements are met by the lipids contained in fish meal (Bell et al., 2003; Richard et al., 2006). Diets free of both FM and FO will contain no LC-PUFAs known to have specific important physiological functions. The three main important LC PUFAs are arachidonic acid (20:4 ARA Ω-6), eicosapentaenoic acid (20:5 EPA n-3) and docosahexaenoic acid (22:6 DHA n-3). While ARA is particularly important in reproduction, EPA and especially DHA are essential for neural development and as part of forming membranes and maintaining their fluidity (Sargent 1995). The addition of LC- PUFAs to vegetable based diets may improve performance and robustness of the fish and act as immune stimulants. Several studies were performed with rainbow trout fry with supplementation of LC-PUFAs (EPA+ DHA in diets for which FM and /or FO had been partly or fully substituted with alternative ingredients of primarily vegetable origin. Survival growth performance, enzymatic activity; immune response and analytical FA composition were used to evaluate effects.

The Organic Regulation of fish farming states strong limitations on the sourcing of protein and fat ingredients in organic feed, i.e. aiming to phase out fish oil (FO) obtained from wild fish stocks and this may lead to a higher inclusion of other oils, especially vegetable oils (VO) as these are widely used. Several studies have been carried out to investigate the possibility of using plant-based diets in rearing fish. Only very few of them have challenged start feeding fish with diets in which both fishmeal (FM) and FO have been substituted, while studies on larger grow out fish have shown that a combined replacement of FM and fish oil (FO) is feasible without detrimental effects in growth performance when the theoretical requirements for essential amino acids and fatty acids are met by the diet. Some recent studies have revealed, that it is possible to completely substitute FM and FO in feeds for rainbow trout over a 3 –year production cycle, but observed some limitations, such as reduction in feed-intake, offspring viability; smaller egg size and lower growth (Lazarotto et al., 2015). Other studies on rainbow trout with use of all plant based ingredients have caused a higher lipid deposition in the perivisceral fat. The lower growth performance could be a combination of lower feed intake and lower feed efficiency. This poorer growth effect of a totally plant-based diet is believed to be mainly related to the replacement of FM and not to the FO substitution as reported for several species investigated, rainbow trout; European seabass and gilthead sea bream. While it may not be recommended to fully substitute both the FM and FO with alternatives (vegetables) in diets for rainbow trout fry, a fully or partial replacement of either FM or FO could be possible. Relatively little information exists about how and if dietary FO replacement with vegetable oils and concomitantly change in FA composition may affect not only performance and survival, but also physiological markers such stress resilience and immunocompetence. Obvious changes in muscle fatty acid (FA) signatures and membranes (i.e. LC PUFAs) occur with the replacement of FO by vegetable oils (VO). The possible effects on fish health and welfare merits interest for research in this area. Indeed, adequate nutrition is essential to maintain health and to reduce disease susceptibility and pathological changes, and dietary lipids (as well as other nutritional factors) have specific actions on the immune response. In gilthead seabream (Sparus aurata) both the redox balance (Saera-Vila et al., 2009) and the cortisol response after stress confinement (Ganga et al.2011) were altered by a high replacement of FO by VOs. Even lower VO replacement levels (50-60%) increased the cumulative mortality in gilthead seabream challenged with Vibrio alginolyticus.

The EU regulation (EC 710/2009) on Organic Aquaculture states that the principles of organic rearing shall include the whole trout production cycle, i.e. the fish production shall be based on organic fry. The Organic Regulation of fish farming states strong limitations on the sourcing of protein and fat ingredients in organic feed, i.e. aiming to phase out fish oil obtained from wild fish stocks and this may lead to a higher inclusion of other oils, especially vegetable oils as these are widely used. The main difference between vegetable oils (VO) and fish oils (FO) is related to the content of so called long chain essential n-3 (previously denoted Ω-3) and n-6 (previously denoted Ω-6) polyunsaturated fatty acids (LC- PUFAs). These are main constituents of primarily marine oils (i.e. fish oil) but are non-existing in vegetable oils. LC– PUFAs are considered important in early fish larval and fry ontogenesis for optimal physiological development. The dietary content and requirement of specific essential n-3 and n-6 fatty acids is however generally regarded as less important in freshwater fishes than in marine fish species, as some freshwater fishes such as salmonids i.e. rainbow trout to a certain degree are capable to synthesize some of these essential fatty acids for their physiological requirements. Thus, substitution of marine oils with vegetable oils in feeds for organic aquaculture causes a reduced content of LC- PUFAs. Studies on salmonids (salmon, trout) have examined consequences for growth and physiological influences on juvenile and ongrowing salmonid fish, but little is known regarding short and long term effects on start feeding fry and their immunecompetance and ability to cope with stress and robustness towards inflectional diseases.