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| | | Seeds and genetic aquaculture resources |
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|  Production is largely derived from land-based freshwater culture systems. These continue to have considerable potential for further expansion, particularly the multiple resource use systems that are integrated with agriculture and irrigation. The marine environment offers resources for aquaculture which remain largely to be explored.A wide variety of animal and plant species are produced through aquaculture: finfish; shrimp, prawns and crabs; clams,oysters and mussels; as well as seaweeds and .other aquatic plantsAquaculture provides about one third, or 40 million metric tonnes, of the annual world fisheries production of 120 million metric tonnes. Half of all aquaculture production is finfish, a quarter is aquatic plants and the remaining quarter is made up of crustacea (such as shrimp, prawns, crabs) and molluscs such as clams, oysters and mussels.The most harvested species in recent years has been the Pacific Oyster (Crassostrea gigas), which grossed 3.4 million metric tonnes in 1998. The Pacific Oyster was the number one aquaculture species in four out of the five years to 1998.A close second is a freshwater fish, the Silver Carp (Hypophthalimichthys molitrix) which contributes more than 3 million metric tonnes per year to world totals. Silver Carp are grown in ponds, mainly in Asia, and eat tiny plankton. In the early 1990s they were the world's leading aquaculture species, until 1994 when the Pacific Oyster took over. Given its higher yield of meat compared to the oyster, it is arguable that the Silver Carp is still the world's most important aquaculture species.Seven out of the ten top species are freshwater finfish and six of those are carps. The other three species figuring in the top ten are molluscs.Carps accounted for nearly half of the 31 million metric tonnes of fish and molluscs produced by farming in 1998. Molluscs also made a major contribution (9.1 million mt) while production of farmed salmon, tilapia and shrimp totaled around 1 million metric tonnes each. Herbivores outnumber carnivores about ten to one in world aquaculture production.The Top Ten Species Produced by Aquaculture (1998)Pacific OysterCrassostrea gigasSilver CarpHypophthalmicthysmolitrixGrass carpCtenopharyngodonidellusCommon CarpCyprinus carpioBighead CarpHypophthalmicthysnobilisJapanese Carpet ShellRuditapesphilippinarumCrucian CarpCarassiuscarassiusYesso ScallopPecten yessoensisNile TilapiaOreochromisniloticusRoho CarpLabeo rohitaThe aquatic plants produced include brown, red and green seaweeds, grown for direct use as food and also for the extraction of alginate and carageenan (agar-agar). Half of the total 1998 production was of just one species, the Japanese Kelp (Laminaria japonicus), 90 percent of which is grown in China.Freshwater fish are the most important aquaculture group by volume and make the greatest contribution to the human food supply. However, some of the minor product groups such as shrimp and marine fish have a disproportionate economic importance because of their high unit value. Farmed freshwater fish, for instance, had an average value of US$1.14 per kg in 1998, while marine fish came in at US$4.35 and crustacea at US$5.90 per kg.Overall most of the major aquaculture product groups exhibited a two- to three-fold growth during the 1990s with some individual species increasing even more. World production of the Chinese River Crab (Eriocheir sinensis), for example, expanded twenty-five fold between 1989 and 1998 (from 5 000 to 123 000 mt). Other notable increases include the Giant Freshwater Prawn (Macrobrachium rosenbergii) with a six-fold growth, the Black Carp (Mytopharyngodon piceus) with a 4-fold growth and the Japanese Carpet Shell (Ruditapes philippinarum) with a 5-fold growth. The sector of high value marine finfish (such as seabass, grouper and mandarin fish) is also experiencing a strong expansion driven by demand in affluent Asian markets, especially for the live product.Whilerecent attention has focused on the adverse impacts of introduced species - also known as alien species and alien genotypes - species introductionsare a valid means to improve production and economic benefit from fisheries and aquaculture.Approximately 17 percent of the world's finfish production is due to alien species. Production of the African cichlid tilapiais much higher in Asia(greater than 700 000 metric tonnes in 1996) than in most areas of Africa(39 245 metric tonnes). Introduced salmonidsin Chilesupport a thriving aquaculture industry that is responsible for approximately 20 percent of the world's farmed salmon and directly employs approximately 30 000 people.Introduced species may have environmental as well as social and economic impacts . Aquatic ecosystems may be affected by the introduced species through predation, competition, mixing of exotic genes, habitat modification and the introduction of pathogens. Human communities may also be impacted through change in fishing patterns due to a newly- established fishery or through changes in land use and resource access when high valued species are introduced into an area.The practice of using species outside their natural range to increase production or profitability can be expected to continue.The issue is not to ban alien species - or to abandon regulation of their movement - but rather to assess associated risks and benefits and then, if appropriate, develop and implement a plan for their responsible use.One mechanism to assist in the responsible use of introduced species is the development of codes of practice such as have been developed by the International Council for the Exploration of the Sea and the European Inland Fishery Advisory Commission.Significant international instruments have recently been established to address the issue of species introductions, such as the Convention on Biological Diversity and the FAO Code of Conduct for Responsible Fisheries. These codes and conventions call for accurate assessments of the risks of using exotic species and are promoting the creation of information sources and an exchange of information on exotic species, their biological and ecological attributes, and potential impacts (both positive and negative). The problem is how to determine the impact of a proposed introduction into complex and dynamic aquatic ecosystems where our information base is often inadequate.Toward this end, FAO Fisheries Department has created the Database on Introductions of Aquatic Species (DIAS) to serve as an important initial summary and registry of introduced species. This database has been incorporated into FishBase, a relational database that contains a variety of information on approximately 20 000 of the world's species of finfish.Genetic resources are the foundation on which species, stocks and genetically-improved strains are based. At the species level, more aquatic animals are being farmed now than ever before. Although the common carp, Cyprinus carpio, and goldfish, Carasius auratus, were domesticated several thousand years ago into a variety of shapes and colours, most of the farmed fish today are very similar to their wild relatives. Improvements in our knowledge of artificial reproduction, reproductive biology, early larval rearing (training series) and basic genetics have recently allowed fish breeders to improve genetically species such as rainbow trout, coho and Atlantic salmon, channel catfish, Nile tilapia, as well as common carp. | | | | The culture of several important species still relies on the collection of brood stock or seed from natural populations. Perhaps the most important group of species whose culture is dependent on natural populations is the marine shrimp Penaeus spp.. Shrimp farming in South and Central America stock production ponds with wild-caught larvae. Hatcheries that produce shrimp larvae exist in Asia and the Americas, but the broodstock are generally collected from the wild. Culturists recognize the problems associated with this harvest of wild resources and are taking steps to domesticate marine shrimp. Other culture systems dependent on wild resources include milkfish in the Philippines, yellow tail in Japan, and eel in Asia and Europe. | | | | However, simply having a domesticated species or genetically improved species is not sufficient to guarantee optimum production from an aquaculture facility. In addition to proper husbandry, i.e. water quality, nutrition, health etc., broodstock must be managed to ensure conservation of genetic resources, to maintain the desirable characters of the farmed species and to avoid problems of inbreeding. | | | | Production is largely derived from land-based freshwater culture systems. These continue to have considerable potential for further expansion, particularly the multiple resource use systems that are integrated with agriculture and irrigation. The marine environment offers resources for aquaculture which remain largely to be explored.A wide variety of animal and plant species are produced through aquaculture: finfish; shrimp, prawns and crabs; clams,oysters and mussels; as well as seaweeds and .other aquatic plantsAquaculture provides about one third, or 40 million metric tonnes, of the annual world fisheries production of 120 million metric tonnes. Half of all aquaculture production is finfish, a quarter is aquatic plants and the remaining quarter is made up of crustacea (such as shrimp, prawns, crabs) and molluscs such as clams, oysters and mussels.The most harvested species in recent years has been the Pacific Oyster (Crassostrea gigas), which grossed 3.4 million metric tonnes in 1998. The Pacific Oyster was the number one aquaculture species in four out of the five years to 1998.A close second is a freshwater fish, the Silver Carp (Hypophthalimichthys molitrix) which contributes more than 3 million metric tonnes per year to world totals. Silver Carp are grown in ponds, mainly in Asia, and eat tiny plankton. In the early 1990s they were the world's leading aquaculture species, until 1994 when the Pacific Oyster took over. Given its higher yield of meat compared to the oyster, it is arguable that the Silver Carp is still the world's most important aquaculture species.Seven out of the ten top species are freshwater finfish and six of those are carps. The other three species figuring in the top ten are molluscs.Carps accounted for nearly half of the 31 million metric tonnes of fish and molluscs produced by farming in 1998. Molluscs also made a major contribution (9.1 million mt) while production of farmed salmon, tilapia and shrimp totaled around 1 million metric tonnes each. Herbivores outnumber carnivores about ten to one in world aquaculture production.The Top Ten Species Produced by Aquaculture (1998)Pacific OysterCrassostrea gigasSilver CarpHypophthalmicthysmolitrixGrass carpCtenopharyngodonidellusCommon CarpCyprinus carpioBighead CarpHypophthalmicthysnobilisJapanese Carpet ShellRuditapesphilippinarumCrucian CarpCarassiuscarassiusYesso ScallopPecten yessoensisNile TilapiaOreochromisniloticusRoho CarpLabeo rohitaThe aquatic plants produced include brown, red and green seaweeds, grown for direct use as food and also for the extraction of alginate and carageenan (agar-agar). Half of the total 1998 production was of just one species, the Japanese Kelp (Laminaria japonicus), 90 percent of which is grown in China.Freshwater fish are the most important aquaculture group by volume and make the greatest contribution to the human food supply. However, some of the minor product groups such as shrimp and marine fish have a disproportionate economic importance because of their high unit value. Farmed freshwater fish, for instance, had an average value of US$1.14 per kg in 1998, while marine fish came in at US$4.35 and crustacea at US$5.90 per kg.Overall most of the major aquaculture product groups exhibited a two- to three-fold growth during the 1990s with some individual species increasing even more. World production of the Chinese River Crab (Eriocheir sinensis), for example, expanded twenty-five fold between 1989 and 1998 (from 5 000 to 123 000 mt). Other notable increases include the Giant Freshwater Prawn (Macrobrachium rosenbergii) with a six-fold growth, the Black Carp (Mytopharyngodon piceus) with a 4-fold growth and the Japanese Carpet Shell (Ruditapes philippinarum) with a 5-fold growth. The sector of high value marine finfish (such as seabass, grouper and mandarin fish) is also experiencing a strong expansion driven by demand in affluent Asian markets, especially for the live product.Whilerecent attention has focused on the adverse impacts of introduced species - also known as alien species and alien genotypes - species introductionsare a valid means to improve production and economic benefit from fisheries and aquaculture.Approximately 17 percent of the world's finfish production is due to alien species. Production of the African cichlid tilapiais much higher in Asia(greater than 700 000 metric tonnes in 1996) than in most areas of Africa(39 245 metric tonnes). Introduced salmonidsin Chilesupport a thriving aquaculture industry that is responsible for approximately 20 percent of the world's farmed salmon and directly employs approximately 30 000 people.Introduced species may have environmental as well as social and economic impacts . Aquatic ecosystems may be affected by the introduced species through predation, competition, mixing of exotic genes, habitat modification and the introduction of pathogens. Human communities may also be impacted through change in fishing patterns due to a newly- established fishery or through changes in land use and resource access when high valued species are introduced into an area.The practice of using species outside their natural range to increase production or profitability can be expected to continue.The issue is not to ban alien species - or to abandon regulation of their movement - but rather to assess associated risks and benefits and then, if appropriate, develop and implement a plan for their responsible use.One mechanism to assist in the responsible use of introduced species is the development of codes of practice such as have been developed by the International Council for the Exploration of the Sea and the European Inland Fishery Advisory Commission.Significant international instruments have recently been established to address the issue of species introductions, such as the Convention on Biological Diversity and the FAO Code of Conduct for Responsible Fisheries. These codes and conventions call for accurate assessments of the risks of using exotic species and are promoting the creation of information sources and an exchange of information on exotic species, their biological and ecological attributes, and potential impacts (both positive and negative). The problem is how to determine the impact of a proposed introduction into complex and dynamic aquatic ecosystems where our information base is often inadequate.Toward this end, FAO Fisheries Department has created the Database on Introductions of Aquatic Species (DIAS) to serve as an important initial summary and registry of introduced species. This database has been incorporated into FishBase, a relational database that contains a variety of information on approximately 20 000 of the world's species of finfish. | | | | |
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