© 2005 International Council for the Exploration of the Sea
Worldwide status and perspective on gadoid culture
a Nutreco Aquaculture Research Centre AS PO Box 48, Sjøhagen 3, N-4001 Stavanger, Norway
b Nutreco Aquaculture, Cold Water Marine Species Norway N-4030 Hjelmeland, Norway
*Correspondence to G. Rosenlund: tel: +47 5182 5514; fax: +47 5182 5501. e-mail: grethe.rosenlund{at}nutreco.com.
Currently, Atlantic cod (Gadus morhua) is the primary species being developed for commercial culture, with activities concentrated around the North Atlantic. In addition, closed life cycles have been established for haddock (Melanogrammus aeglefinus), pollock (Pollachius pollachius), and hake (Merluccius australis), but production of these species (in Canada, Spain, and Chile) is rather modest. In the short- to medium-term, Atlantic cod will be the dominant gadoid species in culture, and it is believed that production can reach levels similar to those of farmed salmon within the next 15–20 years. This development is possible because methods for year-round production of juveniles and significant hatchery capacity have been established. Also, there is a demand for farmed cod to fill the gap between increasing market needs and diminishing supply from fisheries. However, challenges must be met if cod farming is to reach its anticipated potential. Juvenile production must become more reliable in terms of survival and quality. For the on-growing phase, the supply of cost-efficient feeds produced from sustainable raw materials is of utmost importance. Consumer markets need to be developed with an emphasis on quality and food safety. Relatively little is known about health management for gadoid species.
Keywords: development, farming, gadoids
Received 13 June 2004; accepted 21 November 2005.
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Introduction |
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 Top Introduction Farming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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Gadoids have a mainly northern circumpolar distribution, although a smaller number of species also are found with a corresponding southern distribution (Nelson, 1984). Atlantic cod (Gadus morhua) has been the most important gadoid species both from an economic and a socio-economic point of view (Kurlansky, 1998) and has provided coastal communities in the north with both food and their principal source of income. In recent years, catches of Atlantic cod have declined dramatically from 3.1 million tons in 1970 to 890 000 tons in 2002 (www.fao.org). The most dramatic reductions have been seen in the northwest Atlantic and North Sea cod fisheries (Tveteraas, 2004).
Cod is still a well-known and popular item on many menus, and farming is the only sustainable way to meet the demand. This paper provides a brief review of current gadoid aquaculture. Although many different gadoid species have been studied with the purpose of farming, only those that have reached some commercial level are included here. Future perspectives for farming of gadoids are discussed.
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Farming of gadoids today |
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TopIntroductionFarming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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Successful culture of salmonids for several decades, coupled with declining fisheries in general, has stimulated the interest for diversification of culture of other species, and of gadoids in particular. With some exceptions, culture of gadoids is found in the main areas of the world's salmon farming industry, namely Norway, the United Kingdom, and on the east coast of the USA and Canada. In addition, smaller operations are active in Iceland, Spain, and Chile (Table 1).
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In the USA and Canada, closed life cycles have been established for both Atlantic cod and haddock (Melanogrammus aeglefinus), but the focus now is on developing cod further. Canada was involved in the development of cod culture prior to the cod moratorium in 1992, but at that time, most on-growing was based on wild-caught juveniles.
Today there are three commercial hatcheries in operation in this area. In 2003, the production of juveniles was about 500 000, but the number is expected to increase significantly in the near future (Fish Farming International, May 2004, pp. 16–17). The total production of market-sized fish was less than 1000 t in 2003 (Table 1).
Diversification into white fish species, based on a local species known as austral hake (Merluccius australis), is also seen as a growth option for the aquaculture industry in Chile. The life cycle has been closed, and a pilot scale hatchery produced 400 000 juveniles in 2003 (Table 1). Plans exist for further commercialization including building of a 3-million-fry capacity commercial hatchery by 2006. However, as in other areas, realization of these plans seems to depend on private investors. In Spain, there is only one commercial company (in Galicia) involved in gadoid culture. It has established a commercial hatchery for pollock (Pollachius pollachius) and on-grows fish in sea netpens. The production is rather modest and reached about 200 000 juveniles and less than 200 t of market-sized fish in 2003. Iceland has one semi-commercial hatchery that produced 250 000 juvenile Atlantic cod in 2003, and an additional 300 000 wild-caught juveniles were grown to market size, reflecting the close collaboration between farming and fisheries sectors with respect to primary processing.
Approximately 15 companies are involved in cod farming. However, because most of this production is based on wild-caught juveniles, it is difficult to get accurate figures of hatchery-based production of market-sized fish.
Atlantic cod is also the main species being commercialized in the United Kingdom, although important developmental work also has been done on haddock. There were two commercial hatcheries in operation in 2003 producing 400 000 juveniles (Table 1), although current production capacity is 10 times higher. The total production of harvest-sized fish in 2003 was close to 100 t. In addition to a lack of juveniles and capital, problems in obtaining licences for cod sea sites have limited the development of cod farming in the United Kingdom, and as a result of these constraints, there is currently only one major on-grower (Fish Farming International, May 2004, pp. 18–19).
Norway has come farthest in developing a cod farming industry, with 16 commercial hatcheries in operation, of which four are pond systems using natural zooplankton. The total production of juveniles (>2 g) was about 4 million in 2003, whereas the total current production capacity is at least 80 million. More than 500 cod farming licences have been issued, corresponding to a total production volume of more than 4 x 106 m3, which translates into a potential annual production capacity of about 300 000 t (Norwegian Seafood Centre, Bergen, Norway). Currently, about 50% of the licences are in use, and the total production of market-sized fish in 2003 was 1500 t. As in the other countries mentioned above, supply of juveniles has limited the growth of the industry, but lack of capital investment in farms resulted in a small oversupply of juveniles in 2003. In Norway, the production of cod juveniles is expected to reach around 90 million, and the corresponding production of market-sized fish may reach more than 200 000 t by 2013 according to analyses done by Kontali Analyse AS (Kristiansund, Norway) and Nutreco (Amersfoort, The Netherlands).
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Perspectives |
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TopIntroductionFarming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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It is anticipated that Atlantic cod will be the dominant species in gadoid farming, but other species may be of more importance locally. By year 2010, it is expected that the total production of gadoids will reach 140–180 000 t (Table 2), of which Norway will produce 50–60% and Canada and the USA about 30%. The development of hake in Chile is more difficult to predict, but the current hatchery situation would suggest a production of 3000–5000 t of hake by 2010 as a realistic estimate. During this period, gadoid culture in Spain will probably remain modest and limited to one species and one company. Norway will continue to lead in expanding the industry because of significant investments from private companies and the very strong and dedicated support from the government to make this a viable industry in the future. Therefore, Norway will serve as an example of how the development of the cod farming industry may occur.
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Why can cod farming be successful now? |
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TopIntroductionFarming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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Great efforts were made 10–15 years ago to develop cod farming (Rosenlund et al., 1993), but for various reasons the commercialization process stopped. Since then, hatchery techniques for other marine species such as sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) have become well-established. The production of these species in Europe increased from 75 million juveniles in 1991 (Stephanis, 1996) to 500 million in 2001 (www.aquamedia.org). More important, the production is fairly reliable and predictable, reflecting the higher level of competence and experience in marine larval rearing leading to good survival. Development of cod hatchery protocols has benefited from this experience.
The change in the structure of the farming industry towards fewer, bigger, and more integrated companies, however, is probably the most important change that will contribute to a rapid development of the cod farming industry.
That is also reflected in the fact that major aquaculture companies now invest in cod farming. This structure allows the same company to have control over all parts of the value chain, from juvenile production to marketing of the processed fish, and it is believed that this value chain approach is a key factor in developing the industry. Previously, there were no formal links between on-growers and the processing, sales, and marketing side. Such links are crucial to ensuring a good flow of product to markets, thus creating better stability in both production and prices.
In contrast to halibut and other flatfish, Atlantic cod and other gadoids can use much of the same equipment used by the salmon farming industry, therefore making it easier and more economical to establish farms for these species.
Also, the fact that cod are already further processed into many different value-added products is a big strength for the developing farming industry. Finally, the interest shown in cod farming by the major aquaculture companies is an important factor in stimulating other stakeholders to become active in this development, including other aquaculture companies, processors and retailers, authorities, R&D institutions, and suppliers of feed, vaccines, and equipment.
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Challenges and R&D needs |
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TopIntroductionFarming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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Realization of the anticipated developments in cod farming, in both Norway and other countries, will depend on strong support from R&D. Husbandry practices related to the feeding of larvae is one important issue requiring further research. Cod larvae have a very high growth potential, and they can reach 1 g in 70–80 days after hatch (Otterlei et al., 1999). They are aggressive feeders and can be cannibalistic (Folkvord and Otteraa, 1993).
The current start-feeding protocols for cod generally include a sequence with rotifers and algae followed by Artemia and co-feeding a dry feed (Olsen et al., 2004) or an early transfer to dry feed directly from rotifers (Nutreco Aquaculture, unpublished).
Under experimental or pilot scale conditions these protocols can produce very good results, but the challenge is to scale up the processes to reduce the cost of juveniles and to ensure a stable and predictable year-round production with at least 20% survival. Thus, optimization of all production components, including live feed production, in both amount and quality, will be crucial.
Larval quality is another important issue. In 2003, a high incidence of deformities in hatchery-reared juveniles was a major problem in the production of cod in Norway. The problem has been related partly to rearing conditions (water current, gas super-saturation, etc.), but nutrition may be a contributing factor (Cahu et al., 2003). Introduction of dry feeds closer to first-feeding will allow more precise studies of larval nutrition and, thus, support further development of larval diets.
There are also considerable gaps in our knowledge of broodstock nutrition (Izquierdo et al., 2001; Watanabe and Vassallo-Agius, 2003), and particularly of how to condition out-of-season stocks for best reproductive performance in terms of quantity and quality of viable offspring (Bromage et al., 2001).
In cod production, the time to reach market size of 3 kg+ should not be more than 24 months from hatch. This target should be achievable, provided that early sexual maturation can be prevented (Ø. Karlsen, IMR, Norway, and G-I. Hemre, NIFES, Norway, pers. comm.). Significant work has been done on cod nutrition (Lie, 1991; Hemre, 1992; Morais et al., 2001; Rosenlund et al., 2004) and good commercial feeds are now available. However, good growing conditions will allow the fish to develop gonads long before they reach market size, and the subsequent weight loss attributable to spawning will extend the production time by at least four months. Photoperiod manipulation can postpone sexual maturation (Ø. Karlsen, pers. comm.), but much work remains to be done to perfect this technology.
Fish farming relies on safe supplies of feeds, and the whole aquaculture industry depends on the development and documentation of a wider range of sustainable raw materials for future cost-efficient feed production. Many relevant protein sources are available, but currently, vegetable proteins are probably the easiest raw materials to develop further. Recently, we found that in contrast to salmon, cod do not develop enteritis when soybean meal is included at high levels in the feed (G-I. Hemre et al., unpublished). This is very promising, given the high dietary protein requirement in cod.
Furthermore, sustainable cod farming also depends on high survival through the on-growing phase. Currently, disease problems in cod culture appear minimal, but it is naïve to believe that this will continue. Thus, future R&D needs include the development of vaccines as well as proper disease management protocols. Also, the likelihood of escapement must be managed through the development of appropriate equipment (for example, non-chewable nets) and management protocols. Some of the traits discussed above (e.g. growth, health, and age of sexual maturation) would be key factors in the development of cod breeding programmes that are now being established in several countries.
Product quality will be a major focal point in cod farming. In general, farmed cod have a much higher fillet yield than wild fish; up to 60% skin-on fillets can be obtained from gutted head-on cod (Nutreco ARC, unpublished), and initial market tests have been very favourable.
However, melanin deposits in the muscle as well as green livers have been reported as quality problems needing attention. Primary processing of farmed cod can employ much of the technology currently in use in the salmon industry, but adaptations will be required to maximize yield and obtain efficient flow through the processing line. Also, methods to monitor and ensure product quality must be established.
Since the fillet yield in cod is modest relative to salmon, it is of utmost importance to develop value-added products, including by-products (livers, heads, etc.). Good traceability is another important quality aspect, which is easier to secure in farmed cod based on a value chain approach production.
However, all efforts to develop a cod farming industry will fail if the products cannot be sold at reasonable prices. Therefore, marketing of fresh cod is the main challenge to maintain a financially healthy industry. Focus on this part of the value chain was lacking during previous attempts to establish cod farming.
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Concluding remarks |
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TopIntroductionFarming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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Gadoid culture is expected to develop rapidly, and mainly in the salmon farming areas, with Atlantic cod as the main species. Worldwide production may reach 150–200 000 t by 2010.
The value chain approach will be a key success factor, but factors such as availability of investment capital, site licences, and support from the authorities will determine the speed of development. It will be important to ensure that R&D activities support this development by addressing challenges related to, for instance, juvenile production, early sexual maturation, sustainable feed raw materials, and disease management. Furthermore, focus on value-added product quality, as well as market development, is crucial to making cod farming a viable industry.
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Acknowledgements |
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Thanks to our colleagues at Nutreco for help in collecting information on production of gadoids in the different areas.
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References |
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TopIntroductionFarming of gadoids todayPerspectivesWhy can cod farming...Challenges and R&D needsConcluding remarksReferences |
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