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  • Periodic Report Summary 2 - DIVERSIFY (Exploring the biological and socio-economic potential of new/emerging candidate fish species for the expansion of the European aquaculture industry)

Periodic Report Summary 2 - DIVERSIFY (Exploring the biological and socio-economic potential of new/emerging candidate fish species for the expansion of the European aquaculture industry)

Project Context and Objectives:
The European aquaculture sector is a modern industry employing 190,000 people (directly or indirectly), with a €7 billion ex-farm value. Many world-class researchers and facilities exist in research centers and universities throughout Europe, while the private sector employs highly skilled and educated personnel, with modern production facilities. This sector is well situated to be among world leaders in the efficient and sustainable production of safe seafood of the highest quality and nutritional value, taking into account consumer preferences and lifestyles, and the immense diversity of aquatic products from the wild, to which the consumer is accustomed.

Aquaculture is undertaken in all EU states, and plays an important role in the supply of high quality seafood to the European consumer. Europe has an increasing demand for a diverse range of fish products especially for fish fillets or processed products. However, while the worldwide contribution of aquaculture towards fish consumption is just shy of 50%, in the EU only 10% of the seafood consumption originates from EU aquaculture and the consumption of imported seafood is currently at 65% today. This situation can be attributed partially to a lack of diversity of aquaculture products and, perhaps more importantly, a lack of processed aquaculture products.

Even though some 35 aquatic species are cultured in Europe, finfish aquaculture production is dominated both in volume and value by a handful of species --such as Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio), European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata)-- that in turn limit the number of aquaculture products available in the market. An efficient, sustainable and market-oriented expansion of the EU aquaculture sector based on new species and products will reduce the dependence of the EU consumer on imports from countries of questionable, often, production, health, environmental and social standards, and reduce the pressure on over-exploited fisheries in the EU.

DIVERSIFY will provide knowledge where needed to solve bottlenecks in juvenile production, grow-out, nutrition and feeding husbandry, new product development and marketing of six new/emerging species. DIVERSIFY focuses on meagre (Argyrosomus regius) and greater amberjack (Seriola dumerili) for marine warm-water cage culture, wreckfish (Polyprion americanus) for warm- and cool-water marine cage culture, Atlantic halibut (Hippoglossus hippoglossus) for marine cold-water culture, grey mullet (Mugil cephalus) a euryhaline herbivore for warm-water pond, extensive and integrated culture, and pikeperch (Sanders lucioperca) for freshwater intensive culture using Recirculation Aquaculture Systems (RAS). These species were selected based both on their biological and economical potential, and to cover the entire European geographic area and stimulate different aquaculture types. Given their large size and/or fast growth, these species provide for high dress-out and fillet yield, short time to market and suitability for product diversification and development of value-added products. The expertise in the consortium and lessons learned could provide in a 5-year period what took the Atlantic salmon industry 20 years of development.

A strong socioeconomic component is also included in DIVERSIFY, in order to address issues that are presently important bottlenecks in aquaculture consumption and diversification --which are beyond biological/production issues. The socioeconomic part of the project has an applied market development approach. In this component the perception of aquaculture products in general and products specifically, market demand, consumer and professional buyer preferences, new product development, value adding to raw products and market development have a central role. An important bottleneck in aquaculture consumption is that in many countries and/or segments of the EU market, aquaculture fish have a weaker image than wild fish. This threat to the expansion of the aquaculture sector must be recognized and addressed in parallel to any technological improvement of production methods or the addition of new fish species or products by the aquaculture industry.

The combination of biological, technological and socioeconomic research activities planned in DIVERSIFY are expected to support the diversification of the aquaculture industry and help in expanding production, increasing aquaculture products and development of new markets.

Project Results:
In the area of Reproduction & Genetics, spawning was obtained from all species for which the aim was to improve reproductive control. A protocol for paired spawning with male rotation and in vitro fertilization methods has been developed in meagre, in order to enable the implementation of breeding programs. The study of wild and captive-reared greater amberjack showed that under some rearing conditions severe impairment of gametogenesis occurred in captivity. In other cases, greater amberjack produced good quality eggs from spontaneous natural and GnRHa-induced spawnings, either when maintained in tanks (Atlantic broodstocks) or in sea cages (Mediterranean broodstocks). Treatment of Atlantic halibut F1 breeders with GnRHa implants induced and synchronized ovulations without any effect on egg quality or quantity, and provides an approach to ensure predictable ovulations. In wreckfish, we obtained spontaneous natural spawning in tanks, GnRHa induced spawning in tanks and stripped gametes for in vitro fertilization, though egg production and quality is still not considered optimal. Grey mullet recombinant follicle stimulating hormone was produced and was used to enhance and synchronize gametogenesis.

In the area of Nutrition, studies with meagre demonstrated that weaning diets must be optimized increasing HUFA levels, as well as vitamins E and C to spare these essential fatty acids from oxidation. Maximum growth of greater amberjack larvae was achieved in the range of dietary 8-16% EPA when low dietary DHA was provided. Rotifers enriched marine lecithin combined with carotenoids resulted in a significant advantage in larval growth, survival and welfare. For greater amberjack broodstock nutrition, histidine supplementation increased the number of eggs, percentage of fertilization, hatching rate and larval survival. In pikeperch larvae, the combination of high phospholipid (PL) content and high DHA content improved larval growth. A protocol for weaning of Atlantic halibut at 28 days post first-feeding has been developed, while growth and juvenile quality was not improved by feeding on grown Artemia. For grey mullet, a significant effect of taurine enrichment of rotifers on larval and juvenile growth from 12 to 44 days post hatching (dph) has been described, while there appears to be no added benefit of feeding taurine enriched Artemia on larval weight.

In the area of Larval husbandry, very significant achievements have been made during this period. In meagre, our studies concluded that larvae can be weaned from live feed to an artificial diet as early as 10 dph. A great success was achieved in the greater amberjack larval rearing season of 2016 (Mo 31-32). Even though the complete analysis is pending, the results are significant because the very high survival rates achieved are reported for the first time in greater amberjack, indicating a significant technological step in the larval rearing of this species, which will enable its commercial production. The study of pikeperch larvae recommended a light intensity of 50 lux, water renewal rate of 100%, afternoon tank cleaning and water entering the tank from the bottom for best larval performance. Although experiments with wreckfish were limited by few and poor quality spawns, we succeeded for the first time to rear wreckfish larvae to 22 dph. In grey mullet, a study concluded that rotifer consumption and survival of larvae and juveniles were dependent on algal turbidity, but independent of algal type.

More work in the area of Grow out husbandry has been implemented during this period. In meagre, different net depth in cages resulted in no differences in growth, but mortality and feed conversion ratio (FCR) were lower in deep nets. Behavioral studies demonstrated that (a) meagre is able to be trained and to remember specific stimuli that are associated with feeding time and (b) light is an acute stimulus to which the fish respond very quickly (from the second day of its application). Environmental temperature affected significantly the performance of greater amberjack juveniles, as fish held at 26°C grew better than those held at 22°C. Regarding the stocking density, fish at high density exhibited lower growth rate, condition index and feed intake. Pikeperch juveniles prefer sinking feed than floating one, but a strong synergy was observed with the feed type and light spectrum, temperature, photoperiod and oxygen saturation levels. In grey mullet, fishmeal substitution up to 75% by a mixture of plant protein in weaning diets did not affect fish growth, survival, digestive capacity or the innate antioxidative stress response.

In the area of Fish health, a study of Systemic Granulomatosis (SG) of meagre showed that vitamin D did not affect the development of SG. Histological assessment of all fish gave new insights into the development of the disease including the possible implication of rodlet cells and the unique inflammatory response of the fish. In addition we have seen that both high inclusions of Phosphorus and astaxanthin have beneficial effects concerning the severity of SG. In the study of Chronic Ulcerative Dermatopathy (CUD), results confirm the hypothesis that the disease is related to the use of borehole water. Further, qPCR analysis has indicated that there is overexpression of the genes that are connected with the specific osteolytic enzymes showing that the mechanism of the disease involves the activation of the osteoclasts by the increased CO2 in borehole water. We also carried out work on the characterization of the immune system. In meagre, several incidences have been recorded with an outbreak of monogeneans in broodstock and of mycobacteriosis in cage cultured fish being the most significant. Work with greater amberjack during the current reporting period included a) morphological studies on the incidence of monogenean parasites in greater amberjack skin, b) determination of environmental conditions that can modulate greater amberjack resistance to parasitic infection, c) formulation of a diet supplemented with mucus stimulation products, and d) standardization of monogenean cultures. In Atlantic halibut, we have managed to express the nodavirus capsid protein in all three systems. However, it was only in the E. coli system that we achieved sufficient and high expression for further use of the protein as antigen for vaccination purposes.

In the area of socioeconomics, work indicates that sector experts have difficulty to identify the market opportunities, since not all species are well-known in all markets. However, the analysis shows that most countries have a stimulation program to consume more fish. A main obstacle for acceptance of new products in the chain is that buyers and category managers of supermarkets are no longer experts of the category they cover. Therefore the difference between local for local and global sourcing is difficult to explain. What is anyhow necessary is positioning of the species towards other animal proteins, since these are dominant in some of the EU markets. In the development of new products, fish seems to be a food category that does not have a saturated market yet. New product introductions in the market already explain that retailers also see possibilities in this food category for growth. Of the selected products, prototypes have been produced that have been sensory tested. The segmentation study has identified a clear group of consumers that could be early adopters of these aquaculture species in the five selected countries and the market size of these segments. Especially the research regarding the institutional and organizational context shows that in the past there has been hardly any consumer research done in positioning of products. Given the dominance of salmon, trout, Pangasius and carp in the EU market, all other products have to be positioned around these market leaders.

Potential Impact:
DIVERSIFY is expected to advance the current knowledge beyond the state-of the art and impact on the current and near future activity of the European aquaculture industry. The diverse and complementary nature of the consortium will allow a number of key basic questions of various fields such as reproduction, development, growth, nutrition, adaptation and immunity to be addressed for a multitude of species. DIVERSIFY was designed to solve the main bottlenecks identified by the sector with regards to the incorporation of new fish species. These improvements will be set up on the conjunction of two sources of information: i) basic knowledge on biological processes affecting fish culture and ii) applied knowledge on the development of species-specific protocols for fish culture optimization. In particular, expected results and their potential impact on aquaculture science include:

Reproduction: The controlled availability of gametes is imperative for sustainable aquaculture. DIVERSIFY will provide improved understanding of the regulation of reproduction, as well as define optimal broodstock management conditions and broodstock diets in order to assure optimal gamete quality, and will develop species-specific spawning induction protocols. Improved reproductive function may, in turn, reduce the occurrence of skeletal deformities and poor larval and juvenile performance. In addition, specific tools such as ELISA assays for reproductive hormones will be developed with multiple scientific and industrial applications.

Genetics: DIVERSIFY will focus on the genetic characterization of actual broodstocks of meagre and pikeperch, the two species with current relevant industrial production, in order to overcome future inbreeding problems in these two species and solve current problems with variable growth rates (meagre) and stress sensitivity (pikeperch). Thus, the genetic characterization of fast and slow growing meagre (SNP approach) and the genetic diversity and stress sensitivity in pikeperch (microsatellite approach) will provide useful tools for improvement of actual culture practices, and establishing the basis for selective breeding programs that will serve to scale-up and improve their production in terms of quantity and quality.

Nutrition: The cost of feeding in aquaculture production is around 40-70% of total production cost. New species in aquaculture are fed with available diets designed for other species, which may constraint their growth performance and general condition. For this reason, it is important to develop species-specific feeds that consider the nutritional requirements of each species at different stages of development and that can improve their performance (e.g. FCR, growth rate), quality (e.g. morphology, fillet yield and product composition, and egg viability) and health condition (e.g. prevention of metabolic disorders). To achieve this goal, DIVERSIFY will establish the unknown nutritional requirements of several macro- and micronutrients and dietary energy needs for most of the species considered in the proposal. In addition, in order to fit larval needs, specific live prey enrichment products will be developed. Development of specific formulated feeds, live prey enrichment products and feeding protocols will result in new products that may be commercialized worldwide.

Growth and husbandry: A larval and juvenile rearing system is a complex environment, with numerous factors influencing larval development and performance, as well as behavior and survival. These factors can be environmental (light intensity, temperature, salinity, tank color, water current), nutritional (feed composition and availability, feeding frequency), social (fish density) and genetic. For species such as meagre, pikeperch, grey mullet and Atlantic halibut, improvements in terms of fish growth and husbandry will be addressed to refine the existing protocols (e.g. weaning schedule), procedures and facilities (e.g. semi-intensive and intensive rearing procedures, cage culture, RAS and flow-through systems) in order to solve existing bottlenecks (e.g., large size dispersion and high variable growth rates in the case of meagre, high cannibalism rates in pikeperch, low survival and larval quality in halibut and grey mullet). In contrast, emphasis will be given to developing new species-specific larval rearing protocols in the case of greater amberjack and wreckfish, since these are species with important knowledge gaps in these areas. This approach will increase our knowledge on the development of fish larvae in greater amberjack, wreckfish, Atlantic halibut, grey mullet and pikeperch that will serve to synchronize the state of development of the fish under different rearing conditions with the new or existing rearing technology. Finally, the output of these tasks will be the development and refining of rearing protocols for selected species that will result in the improvement of current practices, and an increase in production yields.

Health: Fish health is a key trait to be optimized in cultured fish. The effect of the developmental stage, rearing conditions and nutrition on the capacity to modulate specific immune responses will help predict vaccine responsiveness and fish health. DIVERSIFY will characterize the immune system of meagre and greater amberjack to identify key immune molecules as potential markers of immune system development, and induction of antiviral and antibacterial responses in preparation for vaccine development for disease management. In addition, potential solutions for specific bacterial infections and parasitoses will be investigated, providing means to prevent and/or minimize these issues at an industrial scale.
Also related, transport of live animals across large distances and introduction of allochthonous species to new geographic regions is a continual source of introduced and emerging diseases, and potentially zoonotic ones as well. A primary goal of this project - the improved efficiency of fish culture for the food sector - means that autochthonous species can be produced locally and reduce market drives for other aquatic species, and thereby eliminate the risks associated with the introduction of allochthonous species for cultivation that may do harm to local species diversity in the region of introduction. While preventing emerging or introduced aquatic diseases is not a goal or the focus of this project, it is an added positive impact that may have on the sector.

Sustainability: Sustainability of aquaculture production has a strong uphold in DIVERSIFY and has been considered from different points of view, most of them already mentioned above. To summarize, these concerns have been addressed by i) supporting the growth and expansion of the sector based on different production systems that can be regarded as more sustainable (cage culture – no competition with land resources; RAS- ecologically friendly, with efficient use of water; extensive pond-lagoon culture, with very low environmental effects and in some cases even contributing to the restoration of ecosystems – e.g., abandoned “Salinas”/salt marshes); ii) introduction of a herbivorous fish into the aquaculture sector, with positive influence in the environment where it is cultured (improving sediment quality, avoiding oxygen depletion and reducing ammonia levels) and requiring low or close to none input from marine-based feedstuffs; iii) an important focus of the proposal resides on the determination of species-specific dietary requirements, including the investigation of more sustainable ingredients, as well as feeding behaviour, which will result in less waste of diets and nutrients into the environment; iv) research will be conducted that will hopefully enable anticipated potential disease problems to have veterinary solutions prepared in time and, finally, v) considering consumer requirements, including changes in societal and ethnic demands, to enable a market-orientated growth of the aquaculture sector. Altogether, these factors will ensure a sustainable growth and expansion of aquaculture within the EU and EEA member states.

So, overall, the main expected impact of DIVERSIFY will be the identification of the most appropriate new/emerging fish candidates for the future growth of the European marine and inland aquaculture and the improvement of production technologies for the selected species. Furthermore, DIVERSIFY is expected to have also a significant impact on removing bottlenecks in markets and consumer's perception and preferences. This will be achieved through identification of innovative opportunities for growth of the industry and increase of the EU consumption of aquaculture products through diversification of products and marketing approaches directed to improve consumer perception of aquaculture and develop new markets. Such an integrated combination of biological, technological and socioeconomic activities will lead to a reduction in the dependence of the EU on imports from third countries of questionable, at times, production, health, environmental and social standards.

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