INNOVATIVE REARING AND STUNNING OF FARMED TURBOT AND SOLE TO MEET FUTURE CHALLENGES<br/>REGARDING QUALITY OF PRODUCTION AND ANIMAL WELFARE

Final Report Summary - MAXIMUS (INNOVATIVE REARING AND STUNNING OF FARMED TURBOT AND SOLE TO MEET FUTURE CHALLENGES<br/>REGARDING QUALITY OF PRODUCTION AND ANIMAL WELFARE)

Executive Summary:
Turbot (Scophthalmus maximus) is identified as one of the most promising candidates for marine aquaculture in Europe, with several characteristics that make it an interesting species for commercial growers and European consumers. The species has tremendous potential as an aquaculture species but many of its attributes are currently unexploited utilize. European production of turbot has been increasing during the last 20 years from about 100 to over 11000 metric tons. However, in order to expand the production beyond this level, new bio- and technological solutions are urgently needed.
The overall objective of the project was to strengthen the aquaculture industry and European research area for marine finfish culture. The biological and technological focus in the MAXIMUS project has been on improving the rearing environment, optimized slaughter methods and improved fish welfare and quality of the produced products, including a comprehensive assessment of the economic ramifications of the proposed optimized rearing. These measures are all aimed at improving productivity of the turbot farms leading to more cost effective production and better use of the resources involved. By addressing the whole value chain it is foreseen that the current proposal may lay the foundation for more cost-effective production of turbot in Europe.
The approach of the project was multidisciplinary where the Project Consortium worked with those scientific and practical problems considered most important for future sustainable expansion by the SME proposers. This project brought together a balanced and integrated consortium of fish farmers and scientists, with wide project experience, in a number of interrelated disciplines; growth physiology, immunology/health, welfare, slaughter methods, quality aspects and fish economics; all concentrating on improving the culture of turbot. To increase the general applicability of the MAXIMUS project, the innovative slaughter methods will also be tested for sole (Solea solea, S. senegalensis). Sole is a promising European aquaculture species, cultured side-by-side with turbot facing similar technological challenges.

Project Context and Objectives:
The European aquaculture production sector, which is dominated by a few fish species has expanded extensively over the last decade. Along with expansion this sector has come under growing pressure with increasing competition from Southeast Asia, consumers’ focus on low prices, cost-conscious supermarkets and calls from non-governmental organizations (NGOs), and supermarkets to improve fish welfare. The aquaculture chain in Europe will be forced by these developments to promote diversification of species and to meet demands for fish welfare. In the case of turbot (Scophthalmus maximus = Psetta maxima), companies will need to optimize their aquaculture practices with respect to economics and fish welfare, establish control measures and quality assurance of improved processes with respect to welfare.

Aquaculture of turbot has, however, not expanded at the same rate despite the fact that this species and other flatfish species have been regarded as prime candidates for aquaculture. This is due to very space demanding production, where a traditional turbot farm requires approximately 2000 m2 of land for each 100 tonnes of yearly production. In addition, this production is very labour intensive, and has inefficient logistic solutions for large scale production. Thus, there is a need for new technology and more knowledge of the life history for this specie to increase the cost efficiency on the production. These constraints have clearly slowed down the diversification of the European aquaculture industry into the land-based farming of flatfish.

European production of turbot has been increasing during the last 20 years from about 100 to over 11000 metric tons per annum. At the Dana Feed Turbot Workshop in Horsens, Denmark, Jan. 2002, it was concluded that production of turbot juveniles may rise from 8 million in 2001 to 17 million, and the production of marketable fish to 12 - 17.000 tonnes per annum in the years to come. New markets are also emerging as European turbot producers are exporting increasing amount of juveniles to China where the aim is the production of several thousand tons of fish per annum for the Chinese market. However, in order to expand the production to this level, new bio- and technological solutions are urgently needed. In this project, the partner consortium will explore and expand into full scale some of the biological findings from an earlier CRAFT project (TURPRO, 6 FP 508070) that was developed, co-ordinated and carried out to a large degree by scientists who participate as RTD performers and SME’s proposers in this project. The biological focus in the present project will be on improving the rearing environment for turbot, the fish’s welfare and stunning methods to protect the fish’s welfare at slaughter. Recent developments show there is a need to protect welfare of farmed turbot at slaughter. In their 2009 report on stunning and killing of turbot the European Food Safety Authority (EFSA) concluded that. “As a matter of urgency, industry should be encouraged to test and develop commercially viable alternative methods such as electrical stunning followed by chilling or percussive methods, which induce immediate loss of consciousness. Standard operating procedures to improve the control of the slaughter process to prevent impaired welfare should be introduced and relevant practical welfare indicators developed”. In MAXIMUS the recommendations of EFSA will be followed in order to investigate welfare issues in relation to existing methods for killing and develop new methods for stunning turbot prior to killing, suitable for use on an industrial scale. Thus, welfare of turbot at slaughter can be protected by stunning, i.e. rendering unconscious without avoidable stress prior to killing. To increase the general applicability of the MAXIMUS proposal, the innovative slaughter methods will also be tested for sole (Solea solea, S. senegalensis). Sole is a promising European aquaculture species (Imsland et al. 2004), cultured side-by-side with turbot facing similar technological challenges.

We also include a comprehensive assessment of the economic ramifications of the proposed optimized rearing methodologies and humane slaughter developed. For the SMEs it is essential that the proposed innovation in rearing and slaughter can be controlled in practice with respect to welfare. For the control of improved processes we adapt an international acknowledged management tool, Hazard Analysis Critical Control Points and rework it for monitoring and safeguarding welfare of turbot in practice in our proposed project. At present the quality assurance concept is used throughout the food industry chain to control processing with respect to food safety. The concept is also used in retail shops that are run by one person. For application in this proposed project this quality assurance concept will be focused on monitoring and safeguarding of turbot welfare. These proposed research subjects are all aimed at improving productivity of the turbot farms leading to leading to more cost effective production, improved fish welfare and better use of the resources involved. At the same time when developing and applying these new production methods, the focus will be on improving flesh quality and an extensive economic evaluation will reveal the production advantages for the SME’s if they apply these new methods on their farms. By addressing the quality assurance of the whole value chain regarding fish welfare it is foreseen that the current proposal may lay the foundation for more cost-effective production of turbot in Europe. To summarize the proposed project will deliver the following advantages:

Benefits
• Improved rearing environment, health and animal welfare in turbot farming.
• Significantly reduced production time.
• Improvement of competitive position.
• Optimized slaughter methods applying with up-to-date EFSA regulations.
• Improved fish welfare and quality of the produced products.
• New quality assurance system to safeguard and monitor welfare in turbot during farming and at slaughter.
• Improved cost efficiency and profitability.
• Improving productivity of the turbot farms.
• More cost effective production and better use of the resources involved.

Main specific objectives of the project
Objective Specific target
Develop optimal environmental rearing regimes Reducing production cost by 20%
Develop commercially viable alternative slaughter methods New methods that induce immediate loss of consciousness, and construct a prototype for “dry” electrical stunning of turbot and sole
Improve post-harvest processing Increase yield and flesh quality by up to 15%.
Safeguarding welfare Improve the control of the slaughter process and develop relevant practical welfare indicators.
Improved economics Improving the production model of the SME proposer.

Project Results:
Important findings from WP 1-4 and their impact on the SME sector

WP 1 Optimal rearing protocol for turbot farming
Task 1.1 Photoperiod manipulation to enhance growth and control maturation in turbot
Aim/background
The main aim of this task was to find the optimal photoperiod to use in land-based commercial turbot culture. A group of juvenile turbot reared under 16 hours of light and 8 hours of darkness (LD16:8) will be transferred to continuous light regime (LD24:0) at different times of the production cycle. One group was kept on LD16:8 as control and another on kept on LD24:0. A sub-group within each experimental unit was individually tagged to follow the individual and size dependent growth during the experiment. Individual sex steroid profiles were sampled to monitor maturation in the different groups and samples taken for untagged fish to investigate the possible interrelationship of growth, maturation and flesh quality traits of the fish.

Results
Growth
The overall initial mean weight (SE) was 22.4 (1.5) g and did not differ (two way nested ANOVA, P > 0.75) among the groups assigned to different photoperiods. From October 2009 to March 2011 the LD16:8 (Control) and Group 2C groups had the highest mean weight (SNK test, P < 0.05) of the five experimental groups. From March to June 2011 and from March to June 2012 very low or negative growth was seen in the LD16:8 group (Figs. 2-3), whereas this growth dip was not as marked in groups 2A, 2B and 2C. Hence, the final mean weights of Groups 2C and 2B were 16 and 11 % higher than those of the Control group. Overall, long term rearing on continuous light reduced growth, as the LD24:0 group had the lowest mean weight (SNK test, P < 0.05) from May 2009, onwards displayed significantly lower growth during the first stages (Jan-May 2009) of the experiment (SNK test, P < 0.05).
The fish reared on the different photoperiod regimes differed in their growth patterns, as the GCM analyses revealed differences between the individual growth trajectories of the photoperiod regimes (MANOVA (PHOTOPERIOD), Wilk's lambda50, 880 = 0.37 P < 0.001). Growth in the LD24:0 group was lower compared to all other experimental groups in the first part of the trial (January – May 2009, SNK test, P < 0.05). In contrast the LD16:8 group displayed lower growth compared to the LD24:0 group in March – September 2010 and compared to the LD24:0 and Group 2C in March – June 2012 (SNK test, P < 0.05) when growth was negative in the LD16:8 group.

Steroid levels
The longitudinal steroid profiles differed between the experimental groups both for 11-KT (repeated measurements ANOVA, P < 0.001). In the LD16:8 group, male plasma 11-KT increased from 0.98 ng mL-1, in March 2011 to 6.67 ng mL-1, in July 2011 and was at that time significantly higher (SNK test, P < 0.05) than those of other experimental groups. Similar trend was seen in the following year although the rise in 11-KT was not as marked (from 1.17 g mL-1 in March to 2.82 g mL-1 in June) as sampling was done one month earlier compared to the previous year. 11-KT levels in the LD24:0 group were low throughout the trial period (0.82-1.42 g mL-1). In groups 2A and 2B a slight, non-significant, rise was seen during summer 2011. E2 values in all groups were low throughout the trial period and, with the exception of the June 2010 sample, no differences were seen between the experimental groups (two way nested ANOVA).

Flesh quality
No significant differences were seen in slaughter or fillet yield between the LD16:8 and the LD24:0 groups. Muscle pH changed according to season with significantly lower values in March as compared to October (SNK test, P < 0.05). No significant effects on texture attributes, such as shear force or breaking force, were observed between fish subjected to different photoperiods (MANCOVA, P > 0.15). However, in October for shear force in the continuous light group ranked highest, and at both dates the hardness (60 and 80%) in the LD24:0 ranked highest. There was also a significant seasonal effect with increasing breaking force with time (one way ANCOVA, P < 0.05). The hardness of the fillets (three way MANCOVA, P < 0.05) decreased from March to October (P > 0.001) and varied between photoperiod regimes (P < 0.05). In March the lightness (L*) and yellowness (b*) was higher in the LD16:8 group (SNK test, P < 0.05). In October no significant differences in flesh lightness (L*) or redness (a*) were observed, whereas the yellowness (b*) was higher in the LD16:8 group (SNK test, P < 0.05).

Discussion
Growth and maturation
In the present trial exposure to continuous light stimulated somatic growth and affected age at 1st maturity in turbot. Long term rearing on continuous light reduced growth, whereas short term exposure to continuous light stimulated growth and the final mean weights of Groups 2C and 2B were 16 and 11 % higher than those of the LD16:8 and the continuous light group. However, there was seemingly a seasonal and/or age related trend in how exposure to continuous light affected growth and sexual maturity. Rearing fish at continuous light during spring and summer (March – September 2010, Group 2C) one year before the 1st maturity did not result in lowered somatic growth as seen in the two other groups exposed to continuous light earlier in the trial (May – September 2009, Group 2A; September 2009 – March 2010). However, both short term (i.e. Groups 2A, 2B and 2C) and long term (i.e. the LD24:0 group) exposure to continuous light delayed the age of 1st maturity in turbot males as significantly lower 11-KT plasma values were found in these groups during summer of 2011 and 2012 compared to the LD16:8 group. Short term exposure to continuous light has previously been shown (Imsland et al., 2003) to decrease and delay maturation in adult female turbot. Imsland et al. (2003) transferred one group of 6 year old tubot from simulated natural photoperiod (LDN) to continuous light in March whereas another group was kept at LDN. Exposure to continuous light reduced the proportion of maturing females, spawning was delayed for four weeks, individual spawning frequency was lower (2.6 compared to 5.3 in the LDN group) and egg production was reduced by 90% (545 g compared to 5645 g in the LDN group). It was concluded that exposure to continuous light around spring equinox can significantly decrease and delay maturation in adult female turbot. Present findings are not fully comparable as turbot females did not maturate in the current trial. However, present data indicate that male maturation can be delayed by continuous light exposure thus avoiding negative effect of maturation on somatic growth seen in the LD16:8 group during the two latter summer periods (i.e. 2011 and 2012). The growth halt seen in the LD16:8 group during the latter stages of the trial may reflect the energy costs of reproduction as confirmed in photoperiod trials with turbot (Imsland et al., 2003) and in other marine teleosts (Karlsen et al., 2006; Taranger et al., 2006; Imsland et al., 2009, 2013)
Few studies have addressed the effect of photoperiod on growth and maturation in marine species. Studies on Atlantic cod Gadus morhua L. have shown that constant light in indoor systems throughout the juvenile stage has a growth promoting effect and reduces the incidence of maturation (Hansen et al. 2001) in indoor tanks. Imsland et al. (2013) found that exposure to continuous light at different times during the production cycle resulted in enhanced growth and delayed maturation for Atlantic cod in sea pens. Significant delay in age at 1st maturity was found in for Atlantic cod exposed to continuous light during autumn and winter one year prior to first maturation. Findings in Atlantic salmon Salmo salar L. reared in sea cages have highlighted the importance of continuous light timing in maturation control (Hansen et al., 1992; Taranger et al., 1999; Porter et al., 1999), as exposure to continuous light out of phase with the natural light cycle, i.e. during periods when fish had low energy stores and/or small body size (winter), caused fewer fish to mature which is similar to the findings in Group 2A, 2B and 2C in the present study. In males of Atlantic halibut, exposure to continuous light 15 and 5 months prior to spawning stimulated growth and accelerated the occurrence of first maturation by approximately 3 months (Norberg et al. 2001). Conversely, the transfer from continuous light to LDN 5 months prior to spawning delayed spawning by at least 6 months (Norberg et al. 2001). Delayed maturity in turbot exposed to continuous light during the juvenile stage has also been documented for first time spawners (Imsland et al., 1997). Taken together this might indicate that the timing of continuous light exposure is important with respect to subsequent maturation. Accordingly, it has been postulated (Taranger et al., 2001) that the decision to mature is a gated rhythm and that exposure to continuous light during winter advances the “gate open” position, thereby preventing some fish from reaching the developmental threshold during this period, and consequently postponing maturation. It is possible that the “gate open” position can vary between species according to their natural spawning season and timing of the initiation of the maturation process. This could help to explain the different effect of exposure to continuous light on timing of sexual maturation in different species (Imsland et al., 1997, 2009, 2013; Taranger et al., 1998; Hansen et al., 2001; Norberg et al., 2001).
In the study of Imsland et al. (1997), maturation in turbot was linked to differences in growth approximately one year prior to first maturation. In the present study Group 2C was reared at continuous light during this “critical period” (i.e. spring and summer 2010) and higher growth was seen in Group 2C compared to the LD16:8 group during this period, followed by a growth standstill during next spring. This is a clear indication that male turbot are recruited into first maturation. It is interesting to note that in Atlantic halibut, growth differences between maturing and immature fish were also found approximately one year prior to first spawning (Imsland and Jonassen, 2005). Based on these and present findings it may be hypothesized that manipulation of rearing conditions in this “critical” period may change subsequent maturity proportions in both turbot and Atlantic halibut. Further studies are needed to verify the validity of this hypothesis.

Flesh quality
Photoperiod regime had only minor effect on textural and flesh quality traits of turbot in the present trial. There was a tendency towards higher texture shear force and hardness in the continuous light group, and mean weight were lower in this group at the termination of the trial. This group exhibited the lowest growth during the trial period prior to sampling which may explain the harder texture. Similar effects of growth patterns have been noted earlier for turbot (Roth et al., 2010) Atlantic cod (Hagen and Solberg, 2010). Seasonal effect was seen in the present study with a tendency towards lower pH and higher hardness in March compared to October. This seasonal effect was possibly linked to higher growth during summer and autumn in the sampling year. Similar effect of growth pattern has been noted earlier for turbot (Roth et al., 2010) and Atlantic halibut (Haugen et al., 2006; Hagen et al., 2007; Foss et al., 2010). Muscle pH has been reported to influence the texture of fish muscle, particularly in relation to gaping (Lavety et al., 1988), although its impact on technological characteristics of the flesh have been debated (Roth et al., 2005; Hagen et al., 2007). It has been suggested that increased collagen concentration with reduced bindings is likely the main reason for softness in fast growing fish (Roth et al., 2005). In the present study, similar to Roth et al. (2010), only minor changes in textural and flesh quality traits were observed, suggesting that growth and maturation has a minor influes on the quality of turbot as compared to other aqucultural species.

Conclusion
Long term rearing on continuous light reduced growth, whereas short term exposure to continuous light stimulated growth and the final mean weights of Groups 2C and 2B were 16 and 11 % higher than those of the LD16:8 group (control group) and the continuous light group. Significantly higher male plasma 11-ketotestosteron levels were seen in the Control group in July 2011 (5.67 ng mL-1) and June 2012 (2.56 ng mL-1) compared to the other experimental groups indicating higher age at 1st maturity in groups exposed to continuous light. Estradiol 17- levels were low in all groups throughout the experiment indicating low or no female maturation. Photoperiod regime had only minor effect on flesh quality traits of the fish as fish from the Control group showed tendency towards softer texture compared to fish from the continuous light group. Based on current results we recommend to farm turbot at extended light (i.e. LD16:8) in combination with continuous light during spring and summer (i.e. Group 2C in this study) during the second production year. Results have been presented to the consortium SME’s delivering a full overview in workshops and reports as well as a press release and peer-review scientific publication.

Task 1.2 Optimal feed in turbot farming – protein replacement
Aim/background
Trials were run at a practical scale with graded amount of fish meal substitution in the diet for 500 g turbot in order to find the most economic raw material composition in feed to support maximum growth, minimum feed conversion ratio (FCR) and quality of turbot. Six diets with varying protein raw material composition were tested. Fishmeal was substituted by a mixture of different plant protein raw materials (Soya, wheat gluten meal, corn gluten meal and rape seed meal) in such a way that marine protein in the diet will vary from 93% down to 53%. Two industrial trials were performed, one in Iceland and one in Spain.

Results – trial 1
There was no difference in the final weight as can be seen of the R2 for the regression line through the value points of the final weight. There are no statistical differences between the diets even though there is a very slight tendency to higher SGR with increasing content of fishmeal protein in the diet.
Even though there is considerable variation in the mortality, there is no significant effect of treatments found.

Feed intake and feed conversion
The averages feed offered was 0.43% of average biomass per day. There is a very week tendency to reduced feed-intake with increasing proportion of FM protein in the diet.
There was a slight decline in FCR with increasing FM protein but the regression line shows no significant effect of FM protein in the dietary protein.

Sensory evaluation
There appears to be statistical different in attributes, it is however hard to see any direct correlation of the research question to the variability found in the results of the sensory analyses. Regression analyses (not shown) of the results did not show any correlation between FM protein in diet and the variables showing strongest significant differences between groups.

Results – trial 2
There is a considerable variability in the SGR in the different periods. Introducing a new type of feed can be a reason for this. It is a known fact that it can take some time for the fish to get used to new type of feed.

Conclusion
For turbot weighing more than 300 g the following conclusions were drawn:
- Minimum effect of protein composition on growth.
- Minimum effect of protein composition on FI and FCR.
- Minimum effect of protein composition on sensory attributes in prepared filets
- The least cost diet (Diet with 53.7% marine protein) is about 12% lower in RM cost than the all fishmeal diet.

Task 1.3 Optimizing flesh quality and yield in turbot aquaculture
Aim/background
The objective of Task 1.3 was to 1) identify mechanisms that explains the relationship between growth and maturation (Task 1.1) and the observed change of quality focusing on SGR and protolytic activity along with flesh quality, and 2) compare the sensory attributes between fish fed on different protein/lipid ratio diets in Task 1.2 monitoring changes in shelf life and rancidity, in addition to chemical verification of lipid oxidation. Shelf life on turbot was performed on fish undergoing different diets comparing fish Norway and Iceland. Results show that there was a significant difference between these groups, whereas any differences were overshadowed by the storing conditions.

Main findings and Conclusion
Results show small, but significant changes in physical and visual attributes such as texture and color. No gaping was observed. Only small changes in texture were observed explained by lack of myosin denaturation. The fillets became more white and yellow during storage, whereas the major changes occurred during the 1st week. A panel evaluating QIM and taste could not distinguish major differences in appearance and taste and over 15 d storage period, but were able to quantify the age by smell. Analysis of microorganisms on the epidermis displayed growth of Carnobacterium maltaromaticum, potentially inhibiting growth of other spoilage bacteria. Fish stored for 22 d were rejected by the taste panel caused by a stale smell and taste, but not bitter or rancid. It is concluded that turbot has a shelf life of at least 16 d.

TMA-N levels in turbot did appear after 21 days of ice storage. If TMA levels is the case for rejection is unclear, but this can partially be explained by the bacterial flora. The formation of TMA is often caused by bacteria, especially lactobasillicus, which in this case was not dominating bacteria. Never the less, the smell, which was not typical fishy and thereby TMA, was bacterial induces never the less TMA or not. Question riser whether the shelf life is solely dependent on the microflora rather than lipid oxidation. Although they never tasted the product, results from Rodrigous et al. (2006) show there might be an interaction as they had both an increase of TMA formation along with bacterial growth. Apparently the dominating bacteria in the present study was carnobacertrium, but it is unclear whether this is a bacteria that thrives in mucus of flatfish or not. The understanding of this bacteria and possibly impact on the shelf life is still poorly understood. In Rodrigous et al. (2006) observed a difference in both flora and trimethylamine-nitrogen (TMA-N) formation depending whether the fish were stored on flake ice or slurry. This combined with our study clearly suggest that the shelf life to turbot is possibly more related to bacterial growth than any another specie. Based on modern packing technology with SGS and initial hygiene this gives reason to believe that the shelf life of turbot can even be expanded utterly for one week or more.
We conclude that the shelf life of turbot is up to 3 wk limited by lactic acid bacteria and with effective chilling and hygiene routines the shelf life can be expanded even further. Results have been presented to the consortium SME’s delivering a full overview in workshops and reports as well as a press release and peer-review scientific publication.

Task 1.4 The influence of rearing regimes on the susceptibility of turbot to microbial pathogens
Aim/background
The objectives of the task 1.4 were to analyse the sanitary situation of the broodstock as well as larvae and juveniles reared in different sole and turbot farms located in Spain and Portugal (SMEs of the Project), study the effectiveness of the vaccination strategies employed, and determine the effect of different diets on diseases resistance and/or fish immune response.

Main findings
- Sanitary broodstock control: Sole Broodstock was controlled analysing individually each single fish by a non-lethal blood test to discard the presence of Nodavirus, based in Real Time PCR.
A total de 120 broodstock of sole were analysed, and all of them were negative for the Nodavirus presence. This result is very important because it is known that Nodavirus has vertical transmission and consequently their presence in the broodstock would possess a high risk of mortalities in the progeny causing serious economic losses.

- Health control of larvae and juveniles: In each production cycle of sole and turbot, samples of larvae and juveniles were analysed for bacteria and virus by conventional tests and PCR to assess the microbiological picture of the installations.
The results of the bacteriological and virological analysis of larvae and juveniles during the production cycle indicated a good sanitary quality of the installations. However, in the case of sole, a repetitive isolation of Tenacibaculum maritimum from the vaccinated fish was evidenced.
The important finding is that the serotype of this isolated T. maritimum strain was different of those included in the polyvalent vaccine used in the farm: Vibrio anguillarum (serotypes O1 and O2) and Tenacibaculum maritimum (serotypes O1 and O3). Therefore, the necessity of inclusion of this new serotype in the vaccine formulation for sole is strongly recommended.

- Effect of different diets on disease resistance of sole: The following diets were evaluated:
Control diet: non-commercial diet for sole containing 11% vegetal protein;
Ulva diet: control diet supplemented with 7.5% seaweed Ulva, and
Undaria diet: control diet supplemented with 7.5% seaweed Undaria.
Groups of sole (50-60 g) fed with the different diets were challenged with the following bacterial and viral pathogens: Vibrio anguillarum (V.a.) Edwardsiella tarda (E.t.) IPN Virus (IPNV) and Nodavirus (VNN). The experiments were conducted using single or mixed infections, employing the intraperitoneal injection (ip) route. Mortalities were recorded during a period of 30 days and were considered due to the inoculated strains if they could be recuperated in pure culture from the internal organs of inoculated fish.

Regardless of the diet, the highest mortalities were produced in the fish groups subjected to a mixed infection (bacteria+ virus). Although no significant effects of the seaweed supplement on the fish resistance to infections was found the Ulva diet seems to improve the resistance of sole to some pathogens.

- Effect of different diet composition on the health status and/or immune response of turbot:
Two different commercial diets (SKRETTING) were compared:
- Diet 1: Sinking pellets (Europa 22) (Protein 52%, Fat 20%)
- Diet 2: floating pellets (Europa 15) (Protein 55%, Fat 16%)
Fish were received in the farm with an average weight of 10.3 g. These fish had been vaccinated one month before with a divalent vaccine (Vibrio anguillarum + Tenacibaculum maritimum). Fish were divided in two groups and fed with the two different commercial diets.
After three, five and eight months feeding with the different diets, fish from two groups were analyzed to detect:
a) Differences on immunological status. For this purpose, blood from groups of turbot fed with each of the two diets was extracted from the caudal vain and the corresponded serum were assayed by ELISA for antibody titters against typical bacterial turbot pathogens: Vibrio anguillarum serotypes O1 and O2, Tenacibaculum maritimum serotypes O1, O2 , O3, Tenacibaculum soleae and Aeromonas salmonicida.
b) Differences on the health conditions based on microbiological and parasitological analysis conducted by classical and molecular procedures.
c) Differences on fish growth

Conclusion
No significant influence of the diet was found on the antibody titers of turbot against the different bacterial pathogens along the experimental period. In addition, regardless of the turbot diet, at 9 months post-vaccination, a significant decrease in the immunological response against the two pathogens included in the vaccine (Tenacibaculum maritimum and Vibrio anguillarum) was detected (Fig. 1 a, b, c).

Both groups of turbot were free of bacterial pathogens and external or internal parasitic infestations during the experimental feeding period

No differences were observed in the average weight of the experimental fish fed with the two different commercial diets during 9 months.

WP 2. Optimizing slaughter methods and improving welfare of turbot and sole
Task 2.1 Live chilling of turbot and sole
Objective
The objective of this task was to determine the effect of temperature drop (T) on the welfare defining four different levels of responses, 1) Release of primary stress responses, 2) Osmotic disturbance. 3) Respiration problems (hypoxia/hypercapnia), 4) Failure to thrive. Subsequently, we will assess whether a temperature drop that is tolerated by turbot results in loss of consciousness by recording EEG and ECGs. For this work turbot was acclimatized in a laboratory setting over a 3 months period to winter and summer temperatures in Southern Europe before the animals are exposed to a sudden change of temperature drop providing different levels of T (Foss et al. 2009). Analysing blood cortisol, ions, glucose, lactate, gases and pH will in combination with EEG and ECG provide the data needed.

Main findings
The present experiments demonstrated that turbot, as well as sole, respond with physiological alterations when exposed to rapid temperature drops down to 0°C (live-chilling), a method commonly used during slaughtering of both species. For turbot, it was evident that less severe drops, i.e. down to 4°C, did not affect the fish at any noticeable degree.

Conclusion
Live chilling of turbot and sole in ice slurry prior to slaughtering is a commonly used method in commercial facilities. The present study demonstrated that rapid temperature drops from 11 and 18°C to as low as 0°C may result in osmoregulatory disturbance, whereas less pronounced drops, i.e. to 4°C, will have less impact. Further, in turbot an increased heart rate post-immersion in ice water was observed. As to brain activity, the method of live chilling is not considered humane because it cannot be concluded that the fish are unconscious. There was also evidence that central brain activity remained, with (low level) response to nociception even at 75 min post immersion. The use of electric stunning followed by cold storage (ice slurry) is considered the most effective and humane method for slaughtering turbot and sole.

Task 2.2 Neurological assessment of stunning and killing turbot and sole
Objective
The objective for task 2.2 and 2.3 in WP 2 was to develop a slaughtering procedure for turbot and sole (S. senegalensis and S. solea) that enhances the welfare for these species. The objective of this task was to establish the specifications needed to achieve an instantaneous irrecoverable stun in turbot by applying “dry”electrical stunning. Subsequently, the stunned fish will be killed by live chilling or exsanguination or a combination thereof. It foreseen that this task comprised the following work: assess voltage and amperage needed to stun sea bass and sea bream after dewatering, using EEG and ECG recordings. Analyse outer appearance of fish and fillets (visual, colour, pH and rigor). Establish characteristics of the slaughter equipment, as required by the SMEs. The characteristics concern product quality, required throughput (slaughter rate), ease of use, safety for workers and compatibility with existing processing lines.

Main findings and Conclusion
We conclude that turbot can be rendered unconscious instantly after tail-first stunning by applying 2.3 ± 1 Arms (122.60 ± 7.97 Vrms) for 1 s (effective in 25 out of 26 fish). In sole, 9 out of 10 fish were immediately stunned by passing 1.20 ± 0.70 Arms (152.43 ± 0.52 Vrms) for 1 s through each animal. Therefore, further research is needed to establish immediate effectiveness for tail-first stunning. Furthermore, our results show that effective stunning and preventing recovery before death was obtained in 74-80% of the turbot following long (20 s) tail-first exposure to 4 ± 1.3 Arms (peak for 1 s) and 1 ± 0.4 Arms (maintenance stun for 19 s) and 80-87% of the sole to 1.2 ± 0.6 Arms (peak) and 0.4 ± 0.2 Arms (maintenance stun), followed by chilling in ice water.
Trials at the SMEs showed that for both turbot and sole the stunner worked according to the intended design. The species were efficiently stunned and the system works satisfactory for stunning at a commercial scale al in line with task 2.2. An electrical stunner for turbot and both sole species is therefore available for commercial sale.

Task 2.3 First design of equipment for “dry” electrical stunning of sole and turbot
Introduction
On basis of the outcome of work done in task 2.2 and discussions with the SMEs that slaughter turbot and sole a first design for the stunner was made by SeaSide and tested under commercial conditions.

Materials and methods
For electrical stunning of turbot and sole Seaside A/S, Stranda, Norway) designed and build a first prototype stunner, which is equipped with 8 rows of above-suspended positive electrodes spaced 7 cm apart was used. Each row consisted on 7 stainless steel electrodes of 5 cm and 25 cm length, which were the positive electrodes. The distance between these electrodes and conveyer, which is the negative electrode. The experimental unit was connected to a coupled direct (DC) and alternating (AC) power source providing DC current ripped with a 100 Hz AC current on top (Llonch et al., 2012).

Results
A first design of the stunner for turbot and sole was presented with the RP2 report. This was both tested for sole and turbot. For turbot the stunner worked as according to its intentions. Turbot were efficiently stunned and the system works satisfactory for stunning at a commercial scale al in line with task 2.2. An electrical stunner for turbot is therefore available for commercial sale. The same system was tested for sole. For sole however, the system used for turbot cannot be used as easily on sole. Unlike turbot, the sole is much lighter and slippery as the fish bends upwards once exposed to electricity. This causes the fish to be stuck in the system. Therefore the construction of the stunner had to be changed specifically for sole involving lighter metal rows and a griping system on the conveyer belt to ensure transport through the system. A electrical stunner for sole is therefore available for commercial sale.

A video of the stunner has been uploaded on-line with the Second Peridod Report of MAXIMUS.

WP 3 Quality assurance as a tool to safeguard and monitor welfare of turbot and sole
Task 3.1 Determine hazards
Results and discussion
A hazard in animal welfare risk assessment is a factor with potential to cause a negative animal welfare effect (EFSA, 2008). In this first stage hazards that may be detrimental to fish welfare have to be determined and preventive measures identified, which can be applied to control these hazards. Contrary to factors that affect welfare, a husbandry system or a factor can be beneficial for the animals. These benefits have to be taken into account in assessing the welfare. However, a model for risk-benefit has not been developed for fish by EFSA and therefore the existing model for risk assessment is used in this paper (Müller-Graf, 2007).
Hazards can be categorized as biotic, abiotic, managerial and environmental factors that may impair fish welfare. Interactions between these factors can also influence fish welfare. The factors depend on the fish species, life history stage, sex, physiological stage and the system (e.g. ponds, cages, flow-through or recirculation) used for production.
During the hazard analysis, the potential significance of each hazard should be assessed by considering its risk and severity. Risk is an estimate of the likely occurrence of a hazard.
Guidelines are available for risk assessments (RAs) to describe and quantify the hazard of introduction of infections in food. In the case of animal welfare, however, RAs cannot be performed in the same manner as is done in food safety issues (Müller-Graf, 2007). This is due to the lack of knowledge on the severity of impaired welfare for a fish, and on the probability of exposure to a hazard during fish production (Müller-Graf, 2007). Nevertheless, there is a need for a method to rank hazards for various purposes, e.g. to prioritize management measures at a fish farm. EFSA developed a semi-quantitative RA for ranking of hazards that may occur in aquaculture as described below.
Within the scope of the Maximus project a semi-quantitative hazard analysis was not feasible. We, therefore, used expertise available at the SMEs that farm S. senegalensis and turbot and expertise available at IMARELIVE for stunning and killing to identify hazards. All identified hazard are summarized in seven the FWAS plans in Deliverable 3.1. The FWAS plans are presented in the annex.

Task 3.2 Establish critical control points (CCPs)
Results and discussion
A CCP is a point, step, or procedure during on growing at which control can be applied and, as a result, deterioration of fish welfare can be prevented, eliminated, or reduced to an acceptable level.
The identification of a CCP is facilitated by the application of a decision tree. The decision tree is a series of questions that the Fish Welfare Assurance team asks about each step in the process of on growing and associated hazards, and control measures identified.
Application of the decision tree should be flexible, according to whether the operation is for production at farm, transport or slaughter.
If a hazard can be prevented then the process at the farm needs to be adapted. In practice, various preventive measures are identified by farmers and implemented. The hazard that is caused by a lack of oxygen for example can be prevented by aeration or oxygenation. Exposure of fish to predators can be avoided by having adequate anti-predator control measures in place at a farm.
Selection of the site where a farm is to be established is a preventive measure. By careful selection farmers avoid environmental conditions that result in low water quality due to e.g. poor water flow for fish that are grown in cages (EFSA, 2008).
Occurrence of diseases is a major hazard for fish welfare. However, absence of diseases does not necessarily imply good welfare, as is well known for terrestrial livestock. For health it is essential to focus on preventive measures.

Task 3.3. Establish critical limits for critical control points
Results and discussion
Criteria for husbandry of S. senegalensis and turbot
For criteria for husbandry of S. senegalensis and turbot, detailed information can be found on the websites www.maximusproject.com/f/lesdokument.aspx?fil=112 and www.maximusproject.com/f/lesdokument.aspx?fil=113 , respectively.

Criteria for stunning and killing of S. senegalensis, S. solea and turbot
Turbot can be rendered unconscious instantly after tail-first stunning by applying on average 123 Vrms for 1 s. Both sole species can be immediately stunned by exposure to 152 Vrms for 1 s through each animal. To preventing recovery before death, turbot should be exposed to 152 Vrms (peak for 1 s) and 52 Vrms (maintenance stun for 19 s) and both sole species to 123 Vrms (peak for 1 s) and 53 Vrms (maintenance stun for 19 s), followed by chilling of the three species in ice water.
Not all criteria are presented in the FWAS plans for reasons to ensure that the tables are readable.

Task 3.4 Monitoring activities
Results and discussion
A scheduled programme of measurements and assessments at the farm is essential for monitoring purposes in order to ensure that the process is under control at each critical control point. For Fish Welfare Assurance it is crucial to monitor CCPs at a farm level. For this so-called Operational Welfare Indicators (OIWs) are required. In the Wellfish project (Cost Action 867) OWIs are defined as measurements or assessments of welfare that can be made practically at commercial aquaculture facilities, as opposed to the biological measures of welfare that are often not practical or suitable for use at a commercial aquaculture facility.
A preferred set of OWIs for a fish farm will depend on variables such as farmed species, life stage and husbandry system and for open systems environmental conditions, such as temperature and photoperiod. OWIs that are associated with severe physical injury, severe infectious disease, or high mortality, can be direct indicators of failure in a major critical step/procedure (or several of these). For FWAS OWIs that are predictive of the potential for subsequent severe deterioration of welfare are required.
With regard to methods of prediction, ongoing data analysis can provide information that predicts the occurrence of a hazard at an early stage; a cumulative sum (CUSUM) control chart is such an example of a tool for establishment of an early warning system. This method was originally developed by Page (1954), and plots the cumulative sum of the deviations from a target value using samples from all prior observations. CUSUM control charts are often used in quality management, to monitor ongoing processes. Baer et al. (2008) showed this tool could predict increasing mortality rates at a turbot farm long before these rates exceeded a threshold level.
At a fish farm the following measurements/assessments are among those which may be used as OWIs: behavioural observations (including feed intake), physical injury, occurrence of visible infections, mortality and water quality data.

All identified monitoring activities are summarized in seven the FWAS plans.The FWAS plans are presented on the last pages of this report.

Task 3.5 Establish corrective actions
Results and discussion
It is necessary to establish actions to be undertaken when monitoring indicates a deviation from an established critical limit. These actions should include the following (NACMCF, 1997): determine and correct the cause of deviation;
determine the disposition of products that were produced during the process deviation; and record the corrective action taken.
Corrective actions are possible procedures conducted when a loss of control has occurred at a particular CCP. Sperber (1991) suggested all corrective actions that are a required part of the FWAS plan as well as responsibilities should be clearly outlined before FWAS is implemented. All records and corrective actions should be documented to prove that corrective actions can be conducted.
Corrective regarding CCPs are focused on adjustments of process parameters, for instance an increase of the intake of water when TAN levels have exceeded the operational limit, instructions given to personnel for cleaning and disinfection of the premises etc.

Task 3.6 Establish record keeping procedures
Results and discussion
An adequate record keeping system is the seventh principle of FWAS. Without records, there is no proof that a plant is actually doing what their FWAS plan indicates. The purpose of record keeping is to show that the FWAS plan is compliant with the documented system. Records are useful in providing a basis for trends and for systematic improvement of the process over time (Snyder 1991).
The following checklist is needed to assess whether or not the record keeping system is effective:
• Did you appoint a responsible person?
• Due diligence requirements
• Are the pre-requisite programs monitored and controlled?
• Are all procedures documented
• Are there records of cleaning and disinfection? Are filled in registration forms for monitoring of CCPs documented?
• Are corrective actions taken documented
• Is there document describing how, how often, by whom and when the FWAS system is reviewed?

Task 3.7 Establish verification procedures
Results and discussion
Verification boils down to setting up a process to ensure that the FWAS system works effectively and continues to work effectively through any changes made. The verification procedures are an integral part of the FWAS plans.
Verification can be performed by plant audits with the use of microbial, physical, and chemical tests. These tests take, in general, a few days to complete and this implies that the results become available while the products were sold.
Most tests for analysis of water quality can be performed online (except for microbiological analysis), so the latter test are part of the operational welfare indicators that can be used at the farm.
Audits are needed to review FWAS plans to ensure compliance with standards. The frequency of audits should be sufficient to verify that the FWAS program is effective. The terms validation and verification may lead to confusion. Verification determines compliance with the FWAS plan, where validation merely determines that the end results can be achieved.

Annex FWAS plans
The results of all activities that were undertaken to set up a FWAS system can be summarized in a table, the FWAS plan. We define the FWAS plan as follows. The FWAS plan is a document which sets out the application of the FWAS principles in a fish farm and slaughter house/facilities. The document may contain the FWAS procedures to be followed to ensure welfare of fish. Two selected cases in the MAXIMUS project were prepared and presented in the RP2 report for the project. All related charts and figures can be found in the report.

WP 4 Economic implication and added value for the SMEs

A. Future developments of turbot markets
Aim
In this section, we look at cost of production for a turbot farm with a production capacity of 400 tonnes, assuming the farm has reached full output. The methodology for the analysis is taken from Asche and Bjørndal (2011). We start by listing the assumptions. The assumptions have been arrived at after consultation with SME partners in the project as well as other turbot producers. All assumptions were updated in autumn 2012. With sensitivity analyses that will also be undertaken, we believe that the analysis will give a good representation of current cost of production in the industry.

Main findings and Conclusion
The current problems facing the farmed turbot industry have been highlighted in this report. To meet these challenges different measures are called for in the short run as opposed to the long run. In the short term marketing will have to focus on mitigating the shocks from the shortage in production after an important expansion in sales during 2012. Reduced supply will result in increased prices in 2013, and maybe a period of turbulence in the evolution of prices. Lack of price stability negatively affects interest by retailers and may affect the industry’s future sales and revenues. Securing stability in the markets will allow making improvements in the future, when production issues will be resolved.
The cost of production of farmed turbot in a farm with a production capacity of 400 tonnes is of €5.07 /kg. This leaves turbot producers with a good margin as wholesale prices in Spain for farmed turbot were €7.55/kg in 2012 and €9.42/kg in 2013 although transportation and other marketing costs need to be taken into consideration. While prices at the retail level are relatively speaking not that much higher compared to wholesale prices, on average retail prices of turbot in Spain (see table 5) reached €9.55/kg in 2011 and €9.01/kg in 2012.
A number of factors will influence the development of the market for turbot. It is noteworthy that as salmon production expanded and price came down, the luxury image of salmon disappeared. Turbot is still considered a luxury product, however, it is not likely to remain so if production increases so much that it must compete more on price as is the case of salmon today. This may also have consequences for market segmentation: wild product may largely target the restaurant market, while farmed product will increasingly focus on other parts of the Horeca segment as well as the consumer market.
The substantial difference in price between wild and farmed turbot is noticeable: in all years the price of wild is at least double that of farmed; in some years the price of wild is almost three times that of farmed. This is due to consumers’ preferences for wild fish rather than farmed, as well as larger sizes of wild turbot on average, compared to farmed fish. This behaviour is consistent with what can be observed in the markets for other farmed species such as sole, sea bream and sea bass. It is a challenge for the producers to adapt to this situation. They do, however, have several advantages as production expands. First, they are able to supply fish more or less continuously throughout the year and thereby adapt to seasonal differences in demand. Second, farmers will increasingly be able to supply the fish sizes demanded by their customers. In sum, they will be able to supply a high quality fresh product and adapt to the changing needs and requirements of the market place.
As production expands, cost of production will come down. This means that, even if price comes down, turbot farmers should be able to remain competitive. Overall, the results from this analysis suggest that there is room for considerable expansion of this industry in a way that is both sustainable and profitable for the producers and beneficial to the consumers.

B. Analysis of sole fisheries and markets
Aim
The main objective of this study was to undertake an analysis of sole fisheries in terms of landings, stocks and prices. The emphasis was on the North Sea, where the largest landings are made and the best data are available, but landings in the Mediterranean will also be considered. In 2011, total sole landings in the North Sea amounted to about 17,000 tonnes as compared to 16,700 tonnes in the Mediterranean. The analysis is in the main based on annual data from 1990 to the present. Farmed production was also considered.

Main findings and Conclusion
There are some important policy implications from the analysis that has been undertaken. Total landings of sole in the North Sea and the Mediterranean declined from 55,300 tonnes in 1995 to 33,700 tonnes in 2011, a 39% reduction. As noted, little is known about the sole stocks in the Mediterranean, so we will concentrate of the North Sea.
The analysis shows, the SSBs in Subarea IV, Divisions VIId and VIIe all have full reproductive capacity. Moreover, they are – or are in the process of – being managed on the basis of the MSY approach (stage two of the management plan). The only exception is Division IIIa, where the SSB is expected to be below MSY Btrigger in 2015; however, this is the smallest of the four stocks under consideration.
Nevertheless, it is only in the last few years that aggregate stock size has increased, while total landings have been in decline since 1999. The sole stocks are also dependant on strong year classes which occur at irregular intervals. It is to be expected that there can be only a small increase in quotas in coming years so as to allow further increases in stock.
Based on the bio-economic analyses of sole in Division VIIe, there should be substantial investment in the stock to allow it to grow to an optimal level. This can only be achieved by reducing harvest below natural growth for a period of years to allow the stock to recover. It is reasonable to expect that similar results would be obtained for the other areas.
Sole is a very valuable species. It has been shown that for area VIIe, the stock has the potential of yielding a fairly substantial resource rent if the stock is rebuilt and fishing effort controlled. Again, there is every reason to believe this is true also for the other areas.
Finally, the combination of reduced harvests and high price indicates that there may be a potential for expanded production of farmed sole, provided the biological production process is under control and cost of production is such that profitable production is feasible.

C. Farming of sole: markets and prospects
Aim
Although there is much interest in the farming of sole (see e.g. Imsland et al., 2003), most of the literature is on biological and technical aspects of farming. The purpose of this WP was to analyse the potential economic advantages of the optimal farming technology that has been developed in this project and as applied to sole farming. First, for the farming technology developed, an analysis of investment in a sole farm and associated cost of production was performed. This was done on the basis of a model farm. A production plan was established this farm and associated investments will be considered. On this basis cost of production was analysed under different assumptions. Second, the markets for sole were analysed. Finally, by combining analyses of cost of production and markets we will be able to say something about future prospects of sole farming as they relate to the economic advantages of the farming technology under consideration.

Main findings
Analysis of a farm with an annual production capacity of 350 tonnes was conducted. The current production of farmed sole is very small and with only few active farms in business. Accordingly, knowledge about important variables and parameters such as growth and mortality is limited. Also, the market for juveniles is very “thin” which means it is impossible to observe market prices. Assumptions were based on Garcia Garcia et al. (2006), Kamstra et al. (2001) and meetings with farm representatives and other industry sources. The methodology is based on Asche and Bjørndal (2011). A number of sensitivity analyses were undertaken.
Average cost of production was calculated to € 9.62/kg. Cost of production is largely driven by juvenile costs which are € 3.77/kg or slightly more than 39% of cost of production. A lower juvenile cost will also reduce interest on working capital and insurance.
Feed is the second most important cost component with €1.52/kg or 15.8% of cost of production. Operating, labour and maintenance costs combined amount to €1.84/kg or 19.1% of cost of production. Interest on working capital, with € 0.83/kg or 8.6% of cost of production, is fairly substantial. This is a reflection of the long production period in which capital is tied down in fish.
Interest and depreciation on investments are € 1.24/kg or 12.9% of cost of production. This is a fairly small share of cost of production, indicating limited economies of scale. This is due to the ability to add more raceways at a limited investment cost.
For comparison, in salmon aquaculture, the cost share of juveniles (smolts) is 12 %, feed 54 %, while financial cost and depreciation represent 10 % (Asche and Bjørndal, 2011). The main trends in cost of production for farmed salmon is that, over time, the juvenile cost has come down, both in absolute and relative terms due to better quality of juveniles giving improved growth and reduced mortalities. Similarly, the cost share of interest and depreciation has come down due to increased production and improved efficiency. The cost share of feed, on the other hand, has increased substantially. The feed quality has improved, while the feed conversion ratio has decreased.
While the technology in salmon farming is different from that of sole, we would nevertheless expect to witness similar qualitative trends over time as the farming of sole expands.

Conclusion
The development of commercial sole farming still faces many challenges. This relates both to the production side and to the markets. On the one hand, efficiency in production must be achieved so as to reduce cost of production. On the other hand, new markets for farmed sole must be developed both in terms of supermarkets and the HORECA channel. It is, however, evident that the research capability relating to sole farming that has become established in the key problem areas will help overcome challenges faced by this industry.
According to Howell et al., (2009), the industry has not grown as expected and several producers on the Mediterranean coast have been forced to close due to disease problems. From a commercial perspective, Howell et al. (2009) state that immediate priorities should focus on key issues limiting production and are seen to be as follows: Improve egg and larval quality particularly with respect to hatchery reared stocks. This is very much supported by the cost analysis we have undertaken, where in the base case juveniles represent slightly more than 39% of cost of production. Is is essential that this cost share can be reduced over time.
According to Howell et al. (2009), sole farming is still a marginal business with costs of production around €8-9/kg before interest, administration and sales costs. Adding these costs would likely bring production up to more than € 10/kg, also when taking inflation into account. The minimum viable capacity for a production unit is more than 100 mt which is still not proving to be attractive to investors considering the risks involved.
The results of this study are more optimistic. In the base case, cost of production is € 9.62/kg. The sensitivity analyses showed how cost of production would come down due to improved efficiency and reduced prices of input factors. In particular, with a 60% investment grant, a juvenile cost of €0.90 and a feed cost of €1.20/kg the cost of production becomes € 7.53/kg a 21.7 % reduction compared to the base case. In this case, juveniles represent 37.6 % of cost of production, as compared to more than 39% in the base case. This does not take into consideration economies of scale and reduction in operating and labour costs over time. The cost share of juveniles is extremely high and is likely to come down as the production of juveniles increases. It will also come down as a consequence of improved quality of juveniles, leading to higher growth and reduced mortality. Overall, it is not unreasonable to expect that cost of production will be reduced towards € 7.00/kg over time.
There are also challenges on the market side. In order to serve supermarkets, farms must be able to supply larger quantities than at present. An important issue is also that of fish size. Price observations show that large sole command a much higher price than small sole. Moreover, the HORECA channel in particular prefers sole of larger size than most of the current farm production. In addition, many consumers prefer wild product to farmed.
There are, however, also advantages for farmers. As production expands, they will be able to provide consistent supply over the year, also in line with seasonal trends in consumer demand. This, of course, necessitates efficient logistics. Moreover, with improved control of the production process, fish size can also be adapted to market demand. In addition, farmers have control with many aspects of the quality of the product. Altogether, the prospects for expansion in sole farming in the coming years are good.

Potential Impact:
1. Potential impact
A. Improved competitiveness of SME proposers and the end-user
The socio-economic benefits of the increase in European aquaculture, resulting in further development of European marine aquaculture, also provide economic justification for the MAXIMUS research project. Currently the European aquaculture industry in general is in need of diversifying into new species to ensure further growth of the industry and to ensure maintenance of the level reached today. When the European marine aquaculture industry is provided with new and improved rearing methods and techniques, a prototype for “dry”electrical stunning and a quality assurance system to ensure optimal welfare of turbot, it could very well improve the prospects and secure the future of the whole sector. The current project contributes in that direction, and thus promotes further growth in the European aquaculture industry and its related production chain. Further growth enhances economic activities and generates employment opportunities within the whole production chain. In addition, it leads to a more diverse supply of high quality aquaculture products throughout the year, promoting fish consumption among European consumers, and thus contributing to an increased demand for fish products.

Implementation of the results of the MAXIMUS project will greatly contribute to the exploitation of turbot and other flatfish species in Europe as a number of distinct protocols for rearing and on-growing will be available. Furthermore, the project provides evaluation of different on-growing systems suited for different areas in Europe. This is very important for the implementation and exploitation of the project results. The project is designed such that each SME works with their own farming unit, ensuring easy implementation as fast as experiences are gained during the project, both on their own sites and those of the other partners within the project.

A number of steps are foreseen in order to ensure that the SME participants are able to assimilate and exploit the results of the project. The consortium clearly sees the importance of active research participation by the SMEs in cooperation with the RTD performers at their own on-growing system. All of the SMEs have adequate scientific expertise for such participation. During the project RTDs and SMEs will work together and communicate extensively. Outside the set meetings, communication between the partners will be frequent and intensive and will involve practical experience exchange at the various sites of the project. In order to promote and facilitate this, the project has been designed in such a way that SME proposers and RTDs work together on the same tasks. The idea to turn the project results into protocols for production, originates from the SME’s themselves. Therefore the protocols will be established according to the needs and the wishes of the SME’s involved ensuring accessibility to the results. The protocols will be practical manuals rather than scientific papers. In addition, as a result of the short lines and close co-operation between RTD’s and SME’s during the whole project, transfer of information is natural and direct, and the SME’s are basically involved in establishing the protocols.

This project is aimed at further strengthening the competitiveness of producers of farmed turbot by determining the optimal rearing environment for farmed turbot which maximizes the productivity of the farms per unit input. To this end, the project will investigate, and define, several topics in relation to improved biological and technological performance of turbot culture. Emphasis is on testing the environmental conditions experienced by turbot farms in Southern Europe, particularly with respect to water temperature. Although this project is specifically aimed at turbot, the results and a successful production strategy will be transferable to other species of interest to the European aquaculture industry, hence increasing Europe’s competitiveness in fish farming. This project will contribute to the development of turbot culture in Europe which is still in its infancy, but with huge possibilities. In addition, the scope will be substantial as it addresses a wide problem in aquaculture: the need for production optimization. Optimization can only be achieved after extensive research and development. Results from the MAXIMUS project, and the new biological rearing methods are available to the whole European aquaculture sector (end-user). The successful launching of new rearing concepts will make it far more attractive to start new businesses and ensure better use of the resources available, because of lower investments per production capacity and lower cost per unit produced. Overall, the project will have a clear economic impact for the SME participants in terms of economic growth (higher production efficiency) thereby stimulating increased employment in the aquaculture sector.

B. Socio-economic impact and the wider societal implications
Creating new and expanding existing markets
Diversification of the aquaculture industry into high-valued flatfish species, such as turbot and sole, will expand as soon as a profitable production concept is at hand. The proposed new biological, technical and processing concept might be a concept that will significantly accelerate the development of an industry that has increased far more slowly than has been seen for Atlantic salmon, rainbow trout, sea bass and sea bream production in the 90s. Europe has good opportunity to be almost self-sufficient on a wide range of seafood products and to be a net exporter of some of these. The land-based optimized turbot farm concept will make bio-production possible in regions otherwise excluded from it. This research project will contribute to a breakthrough in the biological and technological optimization of commercial European turbot aquaculture. This will increase the variety of fish products available to consumers, and possibly stimulate the consumption of healthy fish among Europeans. As compared with turbot originating from wild stocks, cultured turbot offers several advantages. These include controlled food safety, year-round supply and adjustment of the product to consumer demands.

The flatfish industry in Europe is still mainly applying modified land-based salmon technology. To expand and to ensure sustainability and competitiveness, the industry must modernise. This should be done in a concerted European context, to ensure that new results and improvements will be widely disseminated. Farming of sea bass and sea bream in Europe has expanded greatly in the 1990s. Turbot and other flatfish species were expected to display a parallel trend, but the situation has actually been characterised by stagnation. One of the main obstacles has been the very high start-up cost of typical land-based flatfish farms.

Issues related to farmed fish welfare, especially at slaughter, are now appearing in various media, which are leading to increasing consumer awareness on fish welfare. Moreover, the European aquaculture sector has come under growing pressure with increasing competition from Southeast Asia, consumers’ focus on low prices and cost-conscious supermarkets. These developments show there is a need for SMEs involved in turbot production to optimize their aquacultural practices, including stunning, with respect to economics and fish welfare, establish control measures and quality assurance of improved processes with respect to welfare.

With the successful approach of the current proposal, a new concept for flatfish farming will be launched. This concept specifically attacks the main obstacle, the high start-up cost and also the relatively high operation costs. The biological optimization, combined with more efficient recirculation systems will significantly reduce the investment and running costs. The new turbot farming concept maximizes the utilisation of all involved resources, including natural resources such as the European seafront.

The new farming and processing concept proposed in MAXIMUS will satisfy consumer needs for high quality fish produced with minimal environmental impact and maximal quality assurance of all production parameters. Further, the new rearing protocols developed in MAXIMUS will provide the farmers with increased knowledge on the effects of, and the opportunity to measure, water quality in the production system and will improve working conditions in the farm, fish health quality and monitoring.

The project objectives will be achieved by addressing the scientific questions raised in the MAXIMUS project by transfer of knowledge from other scientific sectors, where the participating multidisciplinary consortium already has research experience. The RTD consortium of the MAXIMUS project has a strong interdisciplinary character, and is able to address efficiently biological, technical and processing research topics. All the SME and RTD personnel involved in the project have a long lasting experience in working with this species both under laboratory and full-scale conditions. The knowledge obtained in the project may be applied by existing turbot producers, and will promote the SME’s production capability for high quality fish, which is of great demand within the EU. It will also enable new farmers to establish turbot farming in previously unsuitable locations. A successful outcome of the MAXIMUS project might make possible its application to other aquatic species of interest to the EU. Overall this project may significantly increase EU competitiveness in fish farming.

Contribution to Community Societal Objectives
The aquaculture industry has to address the increasing constraints from environmental concerns and from competition for coastal land and aquatic resources. The future of the aquaculture industry largely depends on easy access to natural resources, such as space, water and fish meal for animal feed. With regard to the present focus on matters concerning conservation and environmental protection, interactions between aquaculture and the environment are subject to increasingly strict control and regulation. Solution for environmental problems could come from technologies, which already exist, but require a substantial technological advance, such as systems allowing the recycling of the water used for farming. MAXIMUS addressed these policy issues.

This research project will contribute to a breakthrough in the technical and biological optimization of European aquaculture. This will increase the variety of fish products available to consumers, and possibly stimulate the consumption of healthy fish among Europeans. As compared with fish originating from wild stocks, cultured fish offers several advantages. These include controlled food safety, year-round supply and adjustment of the product to consumer demands and wishes. Also farmed fish can be subjected to farm-to-fork quality control allowing the product to be produced in compliance with national and international quality standards, for example, organically. This would help meet the increasing consumer demand for such foods, which demand cannot be met by the wild product which, of course, can only be covered by post-harvest quality control standards, not lifetime quality control as for the farmed fish.

The new rearing technology, the construction of a prototype for “dry”electrical stunning and the development of a quality assurance system to ensure optimal welfare or turbot MAXIMUS in MAXIMUS will satisfy consumer needs for high quality fish produced with minimal environmental impact and maximal quality assurance of all production parameters, including welfare. The new rearing methods provides excellent opportunities to measure water quality in the fish tanks and will improve working conditions in the plant, fish health quality and monitoring.

As far as the RTDs are concerned, the MAXIMUS project offered them the opportunity to expand their knowledge and skills through research, but also through co-operation and transfer of experimental results directly to the industry. The MAXIMUS project enhances co-operation between RTDs in Europe, improving research quality. It also enhances co-operation among SMEs, resulting in transfer of experience and technology, and stimulates co-operation between RTDs and SMEs, resulting in practical implementation of research results. In general the development of new technologies improves the skills of existing workers. It may also encourage employment of younger workers and support local labour in less developed regions.

Turbot producers that depend on energy input to reach the optimal rearing temperatures for turbot will benefit from the project. Need for energy input in northern countries is a competitive disadvantage compared to south European producers. Successful technology implementation as indicated in this proposal will provide equal opportunities and the ability to compete in the European turbot market. Currently, the markets for turbot are by 2/3 provided by fisheries. The annual catch fluctuates as a result of differences in year class strength and it is hard to predict how turbot landings will develop on the long term, although the trend has been a declining catch over the last decade. Considering the discussion on the sustainability of the fisheries and increasing pressure to close parts of the North Sea, it is obvious that landings are more likely to decrease than increase. The gap between total landings and market demand must be filled by products from the aquaculture industry. The market price for turbot varies between 8 and 14 €/kg for the average sized turbot. It is not expected that a gradually increased aquaculture production of turbot will influence the price significantly, such as the price reductions experienced in the salmon, sea-bass and sea-bream aquaculture sector. It should be safe to conclude that there is a large market for high priced turbot and that cultured turbot can be sold at this market without disturbing it.

2. Main Dissemination activities and outreach
The RTDs have ensured that the technology is appropriate and transferred to the SMEs by having SME technical staff working together with the researchers at the RTD research facilities for an appropriate amount of time. The RTDs have send scientists to the SME facilities to work together with the SME technicians to ensure that the improvements are effective and to supervise the demonstration trials.
The consortium intends to exploit the results to improve competitiveness through introduction of the new rearing concept for European turbot aquaculture. It will also promote the utilisation of the findings with respect to the optimized rearing protocol, improved diets, new stunning and killing methods and economic assessment. In addition, the quality assurance system will be an essential tool for the SMEs to monitor and safeguard welfare of turbot at a company level. The SMEs proposers have allowed the free use of scientific results obtained through the proposed project after their presentation through publications, international conferences and open workshops. These results will, therefore, be available to all EU aquaculture industry, insofar as this does not conflict with the Consortium Agreement on Knowledge and IPR rights.

A public web site - This website will be used as a dissemination tool for the presentation and outcome of the project and will serve as a communication and collaboration interface with the relevant stakeholders. Project results will be made accessible to the public provided that IP rights are respected. Website activities will comprise the disclosure of information to third parties such as the scientific community and the general public. The website contents and design will focus on external communication to relevant stakeholders and as a support tool to outreach activities such as report publishing. The website has also updated technical edition of relevant information concerning research and business areas complementary to the MAXIMUS project.

Publications - Project results have been published through relevant journals, magazines and conference proceedings by individual participants.

Participation in Conferences, Workshops and Events (all partners) - Dissemination materials will be made available if requested and appropriate to present and demonstrate the results of the project at conferences, workshops, seminars, exhibitions and annual international events.

3. Exploitation of results

1. Identify changes of flesh quality during maturation
Although turbot appears to be less prone to early rancidity and changes of flesh quality caused by stress, there are many factors in feeding and rearing methods that will affect the quality of the end product. The flesh quality of turbot is also affected by sexual maturity, growth rate, size and season, but it remains to be investigated, and quantified, how rearing conditions, maturity and feed compositions affects the end quality, taste and shelf life. The partner consortiums aims at monitor seasonal changes in turbot flesh quality and relate those changes to sex, maturation, growth rate and size of turbot reared at different photoperiods. This may improve post-harvest processing parameters such as yield and flesh quality by 15-20%. The knowledge gained by the project will most likely be publishable for a general scientific audience, although the situation could arise where a novel finding may represent a patentable technique or protocol.

2. Identified tolerance levels of turbot for temperature shocks, &
3. Established whether the tolerated temperature shock results in loss of consciousness
An alternative to an instantaneous stun by using electricity can be the application of controlled exposure of turbot to a temperature drop, combined with exsanguination as killing method. The rationale for exposure of turbot is that the fish may tolerate a well-controlled drop in temperature. In the EFSA report on stunning and killing of turbot (EFSA, 2009) it is stated that “the temperature tolerance limits of turbot with regard to pre-slaughter live chilling are not clearly understood and need investigation”. Thus, research is needed to establish which level of temperature decrease is tolerated by the fish species, taking into account the temperature at which the animal is reared. Subsequently, when physiological and behavioural data reveal which controlled temperature drop is tolerated, EEG and ECG recording will be performed to establish whether consciousness is lost without recovery during killing by exsanguination. ECG recording will be used to assess whether changes in the pattern can be indicative for stress. The tolerance level of turbot for temperature shocks having been validated in a commercial scale trial will be made available to the aquaculture industry in Europe through scientific publications and presentation on trade conferences, as dictated by the SME partners.

4. Establish conditions for instantaneous “dry” electrical stunning
It is known that the parameters associated with electrical stunning are complex and a patent is not a protocol for effective electrical stunning with high standards of product quality for fish species. The patents for "dry" electrical stunning of fish (patented by SMEP 7) do not contain details for optimal electrical stunning of turbot and other species under various conditions (e.g. in water or after dewatering). The major factors, which determine whether electrical stunning is optimal (immediate loss of consciousness and high product quality), are the fish species tested (here turbot and sole), the waveform of the electrical current. the applied voltage and current, the choice to stun fish in water or after dewatering ("dry" stunning) and the size and number of electrodes used for "dry" stunning. No satisfactory electrical stunning equipment can be designed for "dry" stunning of turbot on commercial scale by using only reported studies. In addition, in an EFSA report, which was published in 2009 (EFSA, 2009), it is clearly stated that electrical stunning of turbot is still in an experimental stage. The knowledge gained by the project will most likely be publishable for a general scientific audience, although the situation could arise where a novel finding may represent a patentable technique or protocol.

5. Assessment of the future development in turbot markets
As a consequence of the fact that turbot farming is still in its infancy, little attention has been devoted to production economics for this species. Turbot is a high valued product that currently is mainly consumed in fine restaurants with Spain, France, Italy and the UK as major geographical markets. As part of other EU funded projects, limited market analyses for turbot have been undertaken, but these need to be expanded. In particular, the relationship between market quantity and price needs to be analysed. Moreover, as production expands, new markets need to be developed, and information about willingness to pay for the product must be investigated. The result could be made available to the European aquaculture industry through scientific publication and by feature article in a non-technical trade magazine.

6. Changes of shelf life and rancidity in line with diets
As is the case for most farmed fish, the production of turbot is targeted at the established fresh fish markets in Europe and Asia. Besides being a high quality fish, turbot has a remarkably long shelf life stored at -1.5/-1°C (around 30 days) compared to other species. The impact of lipid content and oxidation on shelf life is well established, also in turbot, but it remains to be investigated, and quantified, how rearing conditions, maturity and feed compositions affects the end quality, taste and shelf life. Fish is a very perishable product, and its sensory quality depends on how or how long it is stored, storage temperature and preparation. Changes in production methods e.g. related to welfare, such as different levels of stress prior to slaughter, have also been found to have effects on the sensory quality of the fish and to some extent consumer liking. This will be highlighted in MAXIMUS. The result will be made available to the European aquaculture industry through scientific publication.

7. Constructed prototype for “dry”electrical stunning
On basis of the outcome 2 -4 (see above) SMEP 7 (SeaSide) has, in close collaboration with involved SME and RTD’s construct a prototype for “dry”electrical stunning of turbot and sole that can be tested under commercial conditions. The partner consortium has developed new stunning methods for improved welfare and optimized harvesting in farmed turbot and sole. These methods have been developed without compromising the quality of the end product (flesh quality, content and yield). For testing in a commercial setting a prototype for “dry” electrical stunning has been designed, constructed and tested at a full commercial scale. The prototype has also been tested on European sole. Part of this knowledge may be patented, whereas certain aspects may be published in scientific peer review publications, as long as this does not encroach on the intellectual property of the owners.

8. A quality assurance system to monitor and safeguard welfare of farmed turbot during farming and at slaughter
The internationally acknowledged quality assurance system (HACCP) has been developed to control food safety at an industrial level, as well as at the level of retail shops run by one person. Hence, this system is focussed on different category of hazards, connected to a product contamination and spoilage, whereas the proposed quality assurance system in this project proposal focuses on fish welfare. Obviously different hazards are expected to occur in case of food production and in fish welfare. Hence a major adaptation of the quality assurance system defining of hazards related to fish welfare is needed. The hazards are strongly specific both to produced fish species and technology applied at the farm and at slaughter. The partner consortium of MAXIMUS aims at reworking an internationally acknowledged quality assurance system to monitor and safeguard welfare during rearing and at slaughter. The concept is currently used at companies as tool to control processes. It is foreseen that the system can be adapted for monitoring and safeguarding welfare of turbot during farming and at slaughter. Certain aspects may be published in scientific peer review publications, as long as this does not encroach on the intellectual property of the owners.
The objective for WP 3 was to develop quality assurance system to monitor and control welfare of turbot and sole during husbandry and slaughter. To achieve this main objective, all participating SMEs were visited twice in the project. The SMEs were provided with background information on fish welfare, biosecurity in aquaculture, instruction on how to establish critical control points, how to use critical limits, tool for the construction of flow charts and how to summarize all relevant information in the FWAS plans. As part of the on-going dissemination of the FWAS manual, SME partners in the Netherlands, Spain and Portugal will be visited during the autumn of 2014 to assist them to tune in to the needs of each farmer.

9. Optimal rearing protocols (see also knowledge item 14)
Recent findings on Atlantic halibut by Partner 1 (APN) have clearly demonstrated the huge potential of using continuous light to enhance growth and delay maturation, as 25% growth enhancement has been achieved in fish reared under continuous light for 7 months during the second and third year of on-growing. Such an improvement could dramatically increase the profitability of turbot culture in land based facilities where both temperature and photoperiod can be controlled. The consortium intents to rear a group of juvenile turbot throughout the juvenile period until harvest and rear the fish under different combinations of commercial photoperiod currently in use and different exposure period with continuous light. This will gain information that can be used to develop optimal rearing protocol for turbot.
Results from commercial trial at SMEP3 production facility indicate that: Long term rearing on continuous light reduces growth, whereas short term exposure to continuous light stimulates growth in turbot (up to 16% biomass gain). Optimal combination of extended light (LD16:8) and continuous light can significantly reduce maturation without any negative effects on flesh quality traits. The result will be made available to the European aquaculture industry through scientific publication. The results are currently being worked into a peer reviewed article to be submitted to the journal “Aquaculture”.

10. Optimal feed for turbot
Fish meal and fish oil have been the primary ingredients in feed for fish European aquaculture. They are limited resources, and even though fish are the most efficient farm animal in transforming feed to food, there is an increasing demand for new raw materials to be used to produce sufficient feed to support the growth of aquaculture, currently growing by 9-10% a year on a global scale. Results of recent research have demonstrated that it is possible to substitute a significant part of the fish meal in fish feed with other protein raw materials such as plant proteins. The success of fish meal replacement is dependent on the ability of the diet formulation to meet the need of the fish for nutrients. There also appears to be species differences in the ability to replace fish meal by alternative raw materials and it cannot be excluded that the possibility of replacement is size dependent. As the bulk of feed use in turbot farming is in the grower out phase of the fish (0.5 – 1.5 kg) it is important to find the potential for fishmeal substitution in turbot in this size interval. A dose-response trial with feed from SMEP 4 is on-going at SMEP3 and another trial underway at SMEP5. So far the findings indicate that fish meal in turbot diet can be significantly reduced without negative effect on growth. The least cost diet (Diet with 53.7% marine protein) is 12% lower in raw material cost than the all fish meal diet and this may lead to 6% lower production costs in turbot culture. The optimal feed for turbot having been validated in commercial scale trials will be made available to the aquaculture industry in Europe through scientific publications and presentation on trade conferences, as dictated by the SME partners.

11. Optimal end-quality of in turbot
As found for salmon and halibut, the flesh quality of turbot is also affected by sexual maturity, growth rate, size and season. Along with growth and maturation, the fat-deposits will change accordingly. The consortium intends to identify mechanisms that explain the relationship between growth and maturation and the observed change of quality focusing on SGR and protolytic activity along with flesh quality, and to monitor changes in shelf life and rancidity, in addition to chemical verification of lipid oxidation. Although turbot appears to be less prone to early rancidity and changes of flesh quality caused by stress, there are many factors in feeding and rearing methods that will affect the quality of the end product.
Despite the fact that turbot has been reported to have an exceptional long shelf life ranging from 17-40 days, the industry and market is operating with shelf life ranging between 8-12 days. The reason for this discrepancy is unclear. One reason would be the discrepancies in sensory attributes in example microbiological growth and smell. There exist only a few studies on the microflora development on the dermis of turbot and even less on species specific bacteria. The aim of this part of MAXIMUS is to test the shelf life of turbot combining physical, bacterial and sensory analysis during a 3 weeks storage period in order to find ways to prolong the shelf-life for commercial use. Results may be published in trade magazines or peer reviewed publications at the SME partners' discretion.

12. Understanding markets and demonstrating the economic advantages of the optimal farming technology
As part of previous EU funded projects, some work has been undertaken on the cost of production, but again there is need for this work to be expanded. This must be done on the basis of cost and production data from actual farming operations. The final objective of this project is commercialisation and improved profitability. In order to achieve a good response in the market, excellent quality must be guaranteed. With this objective in mind, a comparison of the economics of the new farming technology system versus conventional farming systems will be performed. The purpose of the cost of production analysis is to obtain estimates of cost of production per kg turbot once the farms have achieved steady state production and to undertake associated sensitivity analyses for changes in important parameters such as growth and mortality rates. In the lifetime of the project such analysis has been done for both species. The work has been undertaken in close collaboration with participating SME partners; other farmers and project partners, consultants and industry representatives have also been consulted. This includes several site visits to SMEs thereby linking the project activity with the needs of the SMEs.
The consequences of expanded production due to economies of scale will be quantified. Sensitivity analyses will be undertaken also in this context, changing the values of numerous parameters, e.g. growth and mortality rates, feed conversions ratios, and prices of various inputs used in the production process. Special attention will be given to the long-term perspective of implementation of the optimized farming concept for future expansion in terms of profitability and increased revenue. Results may be published in trade magazines or peer reviewed publications at the SME partners' discretion.

13. Changes in microbial pathogens in turbot subjected to different rearing conditions
Samples of fish subjected to different rearing methods and feeding conditions will be monitored in order to determine the possible presence of pathogens as carrier fish. In order to detect the low levels of bacterial and/or viral load present in these carrier fish, rapid and sensitive PCR based methods will be carried out using specific primers sets for each of the target pathogen. In the majority of the cases non-lethal assays will be conducted using blood and/or mucus as target tissues. In addition, experimental challenges studies with proven turbot pathogens such as Tenacibaculum maritimum, Vibrio anguillarum, Edwardsiella tarda, Aeromonas salmonicida, Streptococcus parauberis and nodavirus, will be conducted in order to compare the LD50 values of each pathogen among the different turbot groups. The result could be made available to the European aquaculture industry through scientific publication and by feature article in a non-technical trade magazine.

14. Maturation control (see also knowledge item 9)
The main aim of this of this knowledge item is to identify the appropriate photoperiod regime that will allow control of maturation in the on-growing phase and detect early indices of the onset of puberty in order to develop methods to delay or block maturation. Under the lead of Partner 1 (APN) commercial scale trial has been performed where a group of juvenile turbot was reared from early juvenile stage until harvest at mean weight of 2.7 kg. In order to delay maturation the fish were reared under different combinations of commercial photoperiod currently in use and different exposure period with continuous light. Significantly higher male plasma 11-ketotestosteron levels were seen in the Control group in compared to the other experimental groups indicating higher age at 1st maturity in for males in groups exposed to continuous light. Estradiol 17-B levels were low in all groups throughout the experiment indicating low or no female maturation. Based on current results we recommend to farm turbot at extended light (i.e. LD16:8) in combination with continuous light during spring and summer (i.e. Group 2C in this study) during the second production year as this will lower maturation. The result will be made available to the European aquaculture industry through scientific publication. The results was been published in the scientific journal Aquaculture.

List of Websites:
Project website:
http://maximusproject.com/no/

Project coordinator
Name: Albert K. Imsland
Address: Akvaplan-niva, Iceland Office, Akralind 4, 201 Kópavogi, ICELAND
Tel: + 354 562 58 00
Mobile: +354 691 07 07
Fax: + 354 564 58 01
E-mail: albert.imsland@akvaplan.niva.no
Web: http://www.akvaplan.niva.no

Final Report Summary - MAXIMUS (INNOVATIVE REARING AND STUNNING OF FARMED TURBOT AND SOLE TO MEET FUTURE CHALLENGES<br/>REGARDING QUALITY OF PRODUCTION AND ANIMAL WELFARE)

Share this page

Download