ABSTRACT
Some major Singaporean koi breeders specialized in koi dealing (i.e. the mono-culture koi farms) were all founded by hobbyists. They turned their interests into money-making ventures while keeping in touch with the koi-collecting community, global distributors and even Japanese breeders. A few enterprising Singaporean koi farmers have also built up their own internal networks within Southeast Asia. Many Singapore koi dealers import Japanese young koi fries and then rear them until they are a saleable size. Most Singaporean koi dealers and hobbyists consider Japan as the progenitor and ultimate authority on all things kois and regard their stocks and breeds as the benchmark of standards. Therefore, some Singaporean koi farmers try to emulate Japanese breeding methodologies with some localized adaptations. For Singaporean enthusiasts, kois are equated with images of Japan and Japanese-ness. Because imported kois are considered premium and a major highlight of the ornamental fish shows, therefore keeping koi imports alive in optimal condition is important as it is a major draw in the ornamental fish industry. Precautions are in place when trading in kois, e.g. koi farm visitors must wear farm-allocated shoes to go through disinfectant mats at the entry and exit points. It is a good habit to keep kois originating from different suppliers in different designated tanks and nets to prevent cross-infections.
Keywords: KHV, Singapore, ornamental, Japan, koi
BACKGROUND
Ornamental fish aquaculture in Singapore is situated inland and Singapore has a long history of breeding tropical freshwater fish whose inland freshwater breeders have an almost complete control over oxygen levels as well as chemical, biological, physical and radiological features of a body of water (Tan, 2018). Ornamental fish farms in Singapore are typically farming family-owned and then went into profitable ornamental tropical fish businesses like guppies and discus fishes. Differing from these tropical fish breeders, some major koi breeders like Nippon Koi Farm's Pay Bok Seng started off as specialized koi dealers before breeders while mono-culture koi farms like Max Koi Farm, Zion Koi Farm and Diamond Koi Farm were all founded by enthusiasts turned breeders (Tan, 2018).
There are 275 koi importer/exporters in Singapore (SGFave, 2018) that made Singapore a major re-exporter of kois in Southeast Asia, purchasing 1.3 million carp from Malaysia, 169,000 from Thailand and smaller numbers from China, Taiwan, India, Indonesia and Vietnam in addition to 28,000 high grade fishes from Japan in the 21st century (Kyodo News international Inc., 2004). These kois are typically re-exported to Europe and the US in addition to domestic consumption by an estimated 1,000 hobbyists (Kyodo News international Inc., 2004). By 2014, Singapore with exports pegged at US$69.32 million was nicknamed the "ornamental fish capital of the world", making up nearly 20% of the total global supply (Dey, 2016). It stayed as the main trading hub in Asia in 2016 with more than 30% of the ornamental fish re-exported coming from other countries (including kois) (Dey, 2016).
They converted their hobbies into a business while maintaining close ties (emotively) and socializing with the enthusiast community, global koi distributors/retailers and Japanese breeders/farmers and, within this network, Max (founder of Max Koi Farm) is reputable in the global koi dealer community, including amongst stakeholders in Japan (Tan, 2018). Some Singapore koi farms have built their own Southeast Asian-based networks, e.g. Marugen Koi Farm, a boutique Japanese koi fish farm in Singapore, which has a network of sister branches in Ho Chi Minh (Vietnam) and partners in Kuala Lumpur (Malaysia) (Aquatic Network, 2023).
Singaporean koi farmers mostly double up as dealers, importing Japanese kois, rearing them until they are marketable sizes before retailing/exporting them without engaging in complete aquaculture due to the legal separation of breeding and dealer licenses, and the significant efforts to apply for these two separate licenses (Tan, 2018). Moreover, from at least 2018, koi hobby in Singapore is declining and so paying for a breeder's license becomes less viable (especially when one has to cope with unexpected situations like a disease outbreak that can affect the fishes) (Tan, 2018). In addition, most koi farm sites in Lim Chu Kang have been re-designated for agricultural cultivation by the Agri-Food and Veterinary Authority of Singapore (AVA) (Tan, 2018). Perhaps, in managing any decline in hobbyist trends and also diversifying sources of profits, Nippon Koi Farm had turned to food farming by applying for governmental funding and sponsorship (Tan, 2018).
Koi originated from the Chinese common carp food fish but the colorful ornamental pond-based pet-fish Nishikigoi variety is cultivated in Japan, specifically from Niigata Prefecture, that was first bred for food but its blue variety was adapted for ornamental purposes about 200 years ago (Tan, 2018). While the vocabulary of 'koi' refers to the ornamental fish, ‘koi’ in Japanese refers to the edible carp, more specifically ‘magoi’ (Tan, 2018). In rare, niched specialty sashimi stores, kois are even served raw as sashimi, something less usual in Japan since marine fishes are preferred for the dish of sashimi. Japanese farmers often consulted with their officials for advice on the koi business while officials work with farmers in their scientific breeding experiments (Tan, 2018).
In contemporary Japan, most high-quality breeds come from Niigata Prefecture (a place well-known for both kois and rice agriculture) with other countries like China producing their own stocks of kois. Unlike Singapore koi farmers, many Niigata koi farmers had been engaged in the business for minimally two generations and some of them export rice simultaneously while most of them do koi export businesses (up to 80% of overall sales) (Tan, 2018). Generationally cultivated reputation is important in this industry. Retailers and hobbyists are often reminded that tracing the history of their supplying farm/s will provide more reliable guarantee of their stock (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Therefore, most Singaporean koi dealers (and enthusiasts) in Singapore regard Japan as the authority on koi cultivation and the community attributes premium to the origin, stock and breed of the fish while the more adventurous amongst them attempt to imitate breeding techniques with modifications for local conditions (Tan, 2018). Due to koi culture’s close ties with Japanese culture, the industry presents an ambiguous identity for some local sociologists, as kois are very much intertwined with the Singaporean ornamental fish industry but, at the same time, conjure up specific images of Japan and Japanese-ness for the enthusiasts (Tan, 2018).
The community of koi enthusiasts is very important to the industry as the very genesis of koi aquaculture in Singapore lies in ornamental fish hobbyists and many of them reared other species before turning to koi as a hobby (Tan, 2018). In building up relations with the community of enthusiasts, Max Koi Farm organizes competitions premises, as well as culling young kois that are deemed unsuitable in terms of quality to ensure quality control for the hobbyist-customers (Tan, 2018). Similarly, another Singaporean koi farm Marugen provides hand-selected quality imported Japanese Kois and Tamasabas (Japanese Goldfishes) from leading Japanese breeders in Japan to supply koi and goldfish hobbyists in Singapore, Malaysia, Vietnam and Asian markets like Sri Lanka and Myanmar (Aquatic Network, 2023).
Reputation is very important in the business as there are still much to learn about KHV and other diseases so retailers and customers are advised to acquire their kois from clean, disease-free sources with a good track record as healthy-looking koi can still be carriers undetectable by diagnostics (Agri-Food and Veterinary Authority of Singapore AVA, 2011). Latent or KHV carriers are considered the greatest threat to the ornamental koi industry (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Japan is considered by Singaporean koi enthusiasts to be the nucleus of koi breeding and rearing techniques and koi retailers like Singapore Max Koi Farm noted that their boss "spends over four months in Japan and makes at least ten trips. A commitment that has allowed him special access to top koi breeders, testing growing techniques, experimenting with nutrition in koi feed, developing in [-] depth [sic] knowledge of various bloodlines" (Tan, 2018).
Most hard-core enthusiasts regard the Niigata fishes as the best in the industry. Japanese koi evaluators and judges defined the benchmarks of the ideal koi according to body shape, pattern, skin quality, etc. and Singaporean hobbyists try to decipher/interpret these criteria from the winning koi entries and determine the traits of a champion fish while comparing them with previous winners in the past (Tan, 2018). The genetics of prized kois are treated with great care. Premium fishes also go through tests to ensure they are disease-free. Koi-testing of valuable broodstock and prized kois utilizes a 3 – 5 mL blood sample to understand if the originating farms were exposed to KHV in the past (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Singapore-style koi cultivation has the tendency of rearing imported adult kois rather than breeding them from the mating stage, even though Singapore’s Primary Productions Department (PPD) had publicly revealed Singapore’s success in induced koi spawning (Tan, 2018). There are exceptions to this convention. Marugen Fish Farm also focuses on breeding first generation Japanese koi fish from Japan by importing quality oyagois (parent kois), and then sell the off-springs to domestic as well as overseas customers in Europe, Malaysia, Vietnam, Myanmar, Cambodia and Sri Lanka (Aquatic Network, 2023).
HIGH VALUE-ADDED PRODUCTS
The fact that kois are large fishes for aquariums and tanks means that they are usually reared in ponds, which needs space. Some argue that koi pets may denote some form of socioeconomic class status because having a pond to breed them in land-scarce Singapore would denote affordability of land or space while, in terms of breed, hard-core koi enthusiasts do not place locally-bred koi on the same pedestal as the Japan-imposed ones (Tan, 2018). For hard-core hobbyists in Singapore, there may also be additional financial burden to pay to upkeep the kois. For example, the water conditions in Niigata and Singapore differ in that there is no winter season in the tropics. Because English language-translated manuals in Singapore mentioned the breeding condition of leaving kois in deep ponds during winter, there is an assumption that kois need to be exposed to deep Niigata-standard snowfall so Singaporean hobbyists even installed cooling units for their ponds/tanks (Tan, 2018). For some of these unfortunate kois owners, Singapore’s wild sea otters would sometimes also slip into these ponds and consume some of the kois, resulting in lost investments on prized kois.
With this hobbyist valuation in mind, it becomes crucial that, since imported kois are valuable, keeping koi alive and in optimal condition for sale is needed to maintain Singapore’s middleman role in koi import/export trade is crucial, particularly since koi is a major draw in the ornamental fish industry (Tan, 2018). Koi farm visitors wearing specific farm-designated shoes passing through disinfectant mats at the entry and exit points of each section of the farm conform to the mantra that prevention is better than cure as the cost of disinfectant tools is minute compared to the cost of stocks lost to diseases (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
The translocation of non-native koi to Singapore introduces it to a new tropical environment, interactions with local hobbyists, domestic farmers, and local water conditions with its own set of microscopic entities, different from the conditions of its original temperate region of Niigata Japan. All these factors result in variations between Japanese-bred kois and their Singaporean counterparts in the areas of colour, growth speed (Tan, 2018).
KOI HERPESVIRUS (KHV) PATHOGEN
Global logistics processes for moving the kois from Japan to Singapore and their final export destinations are exposed to microorganisms, pathogens and other invisible agents so specialized aqua-cultural scientific knowhow is required to keep the kois in good condition to prevent infections (Tan, 2018). Therefore, simple rules must be followed. It is a good practice for kois from different suppliers to be placed in different tanks and nets to prevent infections (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
In the 21st century, scientists have carried out experiments to test why there had been cases of mass mortalities of carps and kois worldwide. Kois experimentally infected with the wild-type KHV produce the highly-infectious Koi herpesvirus (KHV) pathogen that led to a highly virulent disease in ornamental koi and common carp, resulting in mass mortalities globally (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Within local spaces modified for rearing kois that tries to imitate Japan’s natural environs, kois are also exposed to microscopic microbial from domestic sources, Japan and other countries, so rearing non-domestic kois opened up the potential for biological risk that need to be contained as well (Tan, 2018). There are additional difficulties in testing for these pathogens and microorganisms when it comes to fishes. Serology-based tests like Enzyme linked immunosorbent assays (ELISA) are commonly utilized for virus detections in humans and animals, but not commonly used for fishes due to the reliance of their immune response on environmental temperature (Agri-Food and Veterinary Authority of Singapore AVA, 2011). However, at the same time, some opined importantly that, once the animals are infected with known disease and symptoms developed, ELISA can be a good and sensitive tool. Indeed, according to this view, amino-acid-based ELISA nor nucleic acid-based PCR are not applicable to microorganism identification. Compared to PCR, ELISA is the commonly used tools featured by its cheap, quick, and sensitivity.
Koi diseases such as the Koi Herpes Virus (KHV) made known in 2000 through English language-translated information (along with other parasites) and the medication, quarantine procedures and observation techniques needed to deal with it; translation often became necessary for experts outside Japan to understand these items (Tan, 2018). It was discovered that, placing the koi at permissive water temperatures before testing, improves copy numbers of the virus and helps with detection rates but it is not feasible in the ornamental fish trade where fast test results are needed (Agri-Food and Veterinary Authority of Singapore AVA, 2011). The origins of the KHV disease were scientifically traced back to its first emergence in America and Israel and attempts to study how it was different from other carp diseases resulted in the development of a rather innovative diagnostic tool that can differentiate KHV from other diseases (Tan, 2018).
Early research focused on detecting live viruses in infected fishes but there were challenges in isolating the virus on cell lines (Agri-Food and Veterinary Authority of Singapore AVA, 2011). Overcoming this challenge resulted in the development of real-time polymerase chain reaction (PCR) which could detect the virus from just 5 KHV genomic copies in sampled organs compared to the 100 – 1,000 KHV genomic copies needed in conventional kits (Agri-Food and Veterinary Authority of Singapore AVA, 2011). Experts indicated that real-time PCR is a way to detect expression levels of RNA, by transforming RNA into DNA to amplify detection signals. The PCR option is a blessing for the industry. Even the molecular diagnostic methodology which are precise and sensitive have limitations when it comes to detecting KHV in latently-infected kois, especially due to the dilution of the KHV viral antigen in a large sample volume/pool size (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Physical signs exhibited by kois like swimming erratically, lack of skin color or even death as a result of microscopic disease-causing agents, can trigger customs and/or other industry stakeholders to prevent arrival of such infected fishes to stop/contain the disease from entering Singapore, given the importance of the ornamental fish industry within the aquaculture community (Tan, 2018). Sick fingerling kois may also exhibit “Skinny fingerling with pin head” symptoms (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
KHV is a serious disease for kois and can potentially hurt any koi aquaculture industry so it has motivated researchers to understand the disease more and KHV is specifically named because of the targeted way in which it infects kois and the common carp (such as the grass carp) (Tan, 2018). Lethal KHV has the potential to destroy big populations of kois and can impact on fish farm communities that depend on ornamental koi cultivation or common or grass carp food fish (Tan, 2018). Treatment for afflicted kois include change of water to remove all bad conditions affecting the fish, testing the organism or water to determine the ailment and then interpretations of results for additional remedy (Tan, 2018).
CONCLUSION
The koi component of the ornamental fish aquaculture in Singapore created a special link with a particular genre of fish that originated from Japan. Today, its import/export into and from Singapore is managed by specialized koi farms that are driven by re-export businesses as well as domestic hobbyists. The kois imported from Japan represent the pinnacle of quality, aesthetics and value for hard-core enthusiasts. At the same time, the challenges faced by both koi farms as well as hobbyists is avoiding infectious diseases like koi herpesvirus and rearing kois in land-scarce Singapore.
REFERENCES
Agri-Food and Veterinary Authority of Singapore (AVA). Challenges posed by Koi herpesvirus (KHV). Ornamental Fish Newsletter Vol. 2 Iss. 3. September 2011. Retrieved from https://www.sfa.gov.sg/docs/default-source/publication/industry-publicat..., pp. 7-8
Aquatic Network. Marugen Fish Farm in Singapore. Aquatic Network. 2023. Retrieved from https://www.aquanet.com/singapore/singapore/aquaculture-aquaponics/marug...
Dey, VK. The Global Trade in Ornamental Fish. April 2016. Retrieved from https://www.bassleer.com/ornamentalfishexporters/wp-content/uploads/site...
Kyodo News International Inc. FOCUS: Koi virus sends chill over Singapore koi hotels. 6 January 2004. Retrived from https://www.thefreelibrary.com/FOCUS%3A+Koi+virus+sends+chill+over+Singa...
SGFave. Import Export Of Japanese Koi In Singapore - Business Directory. 2018. Retrieved from https://www.sgfave.com/s/import-export-of-japanese-koi
Tan, Delfinn Sweimay. The history of Koi aquaculture in Singapore from 1965 to the present : translating translocated scientific knowledge from Japan into biosecurity. Singapore: Nanyang Technological University. 2018.
The Development of Singapore’s Koi Aquaculture
ABSTRACT
Some major Singaporean koi breeders specialized in koi dealing (i.e. the mono-culture koi farms) were all founded by hobbyists. They turned their interests into money-making ventures while keeping in touch with the koi-collecting community, global distributors and even Japanese breeders. A few enterprising Singaporean koi farmers have also built up their own internal networks within Southeast Asia. Many Singapore koi dealers import Japanese young koi fries and then rear them until they are a saleable size. Most Singaporean koi dealers and hobbyists consider Japan as the progenitor and ultimate authority on all things kois and regard their stocks and breeds as the benchmark of standards. Therefore, some Singaporean koi farmers try to emulate Japanese breeding methodologies with some localized adaptations. For Singaporean enthusiasts, kois are equated with images of Japan and Japanese-ness. Because imported kois are considered premium and a major highlight of the ornamental fish shows, therefore keeping koi imports alive in optimal condition is important as it is a major draw in the ornamental fish industry. Precautions are in place when trading in kois, e.g. koi farm visitors must wear farm-allocated shoes to go through disinfectant mats at the entry and exit points. It is a good habit to keep kois originating from different suppliers in different designated tanks and nets to prevent cross-infections.
Keywords: KHV, Singapore, ornamental, Japan, koi
BACKGROUND
Ornamental fish aquaculture in Singapore is situated inland and Singapore has a long history of breeding tropical freshwater fish whose inland freshwater breeders have an almost complete control over oxygen levels as well as chemical, biological, physical and radiological features of a body of water (Tan, 2018). Ornamental fish farms in Singapore are typically farming family-owned and then went into profitable ornamental tropical fish businesses like guppies and discus fishes. Differing from these tropical fish breeders, some major koi breeders like Nippon Koi Farm's Pay Bok Seng started off as specialized koi dealers before breeders while mono-culture koi farms like Max Koi Farm, Zion Koi Farm and Diamond Koi Farm were all founded by enthusiasts turned breeders (Tan, 2018).
There are 275 koi importer/exporters in Singapore (SGFave, 2018) that made Singapore a major re-exporter of kois in Southeast Asia, purchasing 1.3 million carp from Malaysia, 169,000 from Thailand and smaller numbers from China, Taiwan, India, Indonesia and Vietnam in addition to 28,000 high grade fishes from Japan in the 21st century (Kyodo News international Inc., 2004). These kois are typically re-exported to Europe and the US in addition to domestic consumption by an estimated 1,000 hobbyists (Kyodo News international Inc., 2004). By 2014, Singapore with exports pegged at US$69.32 million was nicknamed the "ornamental fish capital of the world", making up nearly 20% of the total global supply (Dey, 2016). It stayed as the main trading hub in Asia in 2016 with more than 30% of the ornamental fish re-exported coming from other countries (including kois) (Dey, 2016).
They converted their hobbies into a business while maintaining close ties (emotively) and socializing with the enthusiast community, global koi distributors/retailers and Japanese breeders/farmers and, within this network, Max (founder of Max Koi Farm) is reputable in the global koi dealer community, including amongst stakeholders in Japan (Tan, 2018). Some Singapore koi farms have built their own Southeast Asian-based networks, e.g. Marugen Koi Farm, a boutique Japanese koi fish farm in Singapore, which has a network of sister branches in Ho Chi Minh (Vietnam) and partners in Kuala Lumpur (Malaysia) (Aquatic Network, 2023).
Singaporean koi farmers mostly double up as dealers, importing Japanese kois, rearing them until they are marketable sizes before retailing/exporting them without engaging in complete aquaculture due to the legal separation of breeding and dealer licenses, and the significant efforts to apply for these two separate licenses (Tan, 2018). Moreover, from at least 2018, koi hobby in Singapore is declining and so paying for a breeder's license becomes less viable (especially when one has to cope with unexpected situations like a disease outbreak that can affect the fishes) (Tan, 2018). In addition, most koi farm sites in Lim Chu Kang have been re-designated for agricultural cultivation by the Agri-Food and Veterinary Authority of Singapore (AVA) (Tan, 2018). Perhaps, in managing any decline in hobbyist trends and also diversifying sources of profits, Nippon Koi Farm had turned to food farming by applying for governmental funding and sponsorship (Tan, 2018).
Koi originated from the Chinese common carp food fish but the colorful ornamental pond-based pet-fish Nishikigoi variety is cultivated in Japan, specifically from Niigata Prefecture, that was first bred for food but its blue variety was adapted for ornamental purposes about 200 years ago (Tan, 2018). While the vocabulary of 'koi' refers to the ornamental fish, ‘koi’ in Japanese refers to the edible carp, more specifically ‘magoi’ (Tan, 2018). In rare, niched specialty sashimi stores, kois are even served raw as sashimi, something less usual in Japan since marine fishes are preferred for the dish of sashimi. Japanese farmers often consulted with their officials for advice on the koi business while officials work with farmers in their scientific breeding experiments (Tan, 2018).
In contemporary Japan, most high-quality breeds come from Niigata Prefecture (a place well-known for both kois and rice agriculture) with other countries like China producing their own stocks of kois. Unlike Singapore koi farmers, many Niigata koi farmers had been engaged in the business for minimally two generations and some of them export rice simultaneously while most of them do koi export businesses (up to 80% of overall sales) (Tan, 2018). Generationally cultivated reputation is important in this industry. Retailers and hobbyists are often reminded that tracing the history of their supplying farm/s will provide more reliable guarantee of their stock (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Therefore, most Singaporean koi dealers (and enthusiasts) in Singapore regard Japan as the authority on koi cultivation and the community attributes premium to the origin, stock and breed of the fish while the more adventurous amongst them attempt to imitate breeding techniques with modifications for local conditions (Tan, 2018). Due to koi culture’s close ties with Japanese culture, the industry presents an ambiguous identity for some local sociologists, as kois are very much intertwined with the Singaporean ornamental fish industry but, at the same time, conjure up specific images of Japan and Japanese-ness for the enthusiasts (Tan, 2018).
The community of koi enthusiasts is very important to the industry as the very genesis of koi aquaculture in Singapore lies in ornamental fish hobbyists and many of them reared other species before turning to koi as a hobby (Tan, 2018). In building up relations with the community of enthusiasts, Max Koi Farm organizes competitions premises, as well as culling young kois that are deemed unsuitable in terms of quality to ensure quality control for the hobbyist-customers (Tan, 2018). Similarly, another Singaporean koi farm Marugen provides hand-selected quality imported Japanese Kois and Tamasabas (Japanese Goldfishes) from leading Japanese breeders in Japan to supply koi and goldfish hobbyists in Singapore, Malaysia, Vietnam and Asian markets like Sri Lanka and Myanmar (Aquatic Network, 2023).
Reputation is very important in the business as there are still much to learn about KHV and other diseases so retailers and customers are advised to acquire their kois from clean, disease-free sources with a good track record as healthy-looking koi can still be carriers undetectable by diagnostics (Agri-Food and Veterinary Authority of Singapore AVA, 2011). Latent or KHV carriers are considered the greatest threat to the ornamental koi industry (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Japan is considered by Singaporean koi enthusiasts to be the nucleus of koi breeding and rearing techniques and koi retailers like Singapore Max Koi Farm noted that their boss "spends over four months in Japan and makes at least ten trips. A commitment that has allowed him special access to top koi breeders, testing growing techniques, experimenting with nutrition in koi feed, developing in [-] depth [sic] knowledge of various bloodlines" (Tan, 2018).
Most hard-core enthusiasts regard the Niigata fishes as the best in the industry. Japanese koi evaluators and judges defined the benchmarks of the ideal koi according to body shape, pattern, skin quality, etc. and Singaporean hobbyists try to decipher/interpret these criteria from the winning koi entries and determine the traits of a champion fish while comparing them with previous winners in the past (Tan, 2018). The genetics of prized kois are treated with great care. Premium fishes also go through tests to ensure they are disease-free. Koi-testing of valuable broodstock and prized kois utilizes a 3 – 5 mL blood sample to understand if the originating farms were exposed to KHV in the past (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Singapore-style koi cultivation has the tendency of rearing imported adult kois rather than breeding them from the mating stage, even though Singapore’s Primary Productions Department (PPD) had publicly revealed Singapore’s success in induced koi spawning (Tan, 2018). There are exceptions to this convention. Marugen Fish Farm also focuses on breeding first generation Japanese koi fish from Japan by importing quality oyagois (parent kois), and then sell the off-springs to domestic as well as overseas customers in Europe, Malaysia, Vietnam, Myanmar, Cambodia and Sri Lanka (Aquatic Network, 2023).
HIGH VALUE-ADDED PRODUCTS
The fact that kois are large fishes for aquariums and tanks means that they are usually reared in ponds, which needs space. Some argue that koi pets may denote some form of socioeconomic class status because having a pond to breed them in land-scarce Singapore would denote affordability of land or space while, in terms of breed, hard-core koi enthusiasts do not place locally-bred koi on the same pedestal as the Japan-imposed ones (Tan, 2018). For hard-core hobbyists in Singapore, there may also be additional financial burden to pay to upkeep the kois. For example, the water conditions in Niigata and Singapore differ in that there is no winter season in the tropics. Because English language-translated manuals in Singapore mentioned the breeding condition of leaving kois in deep ponds during winter, there is an assumption that kois need to be exposed to deep Niigata-standard snowfall so Singaporean hobbyists even installed cooling units for their ponds/tanks (Tan, 2018). For some of these unfortunate kois owners, Singapore’s wild sea otters would sometimes also slip into these ponds and consume some of the kois, resulting in lost investments on prized kois.
With this hobbyist valuation in mind, it becomes crucial that, since imported kois are valuable, keeping koi alive and in optimal condition for sale is needed to maintain Singapore’s middleman role in koi import/export trade is crucial, particularly since koi is a major draw in the ornamental fish industry (Tan, 2018). Koi farm visitors wearing specific farm-designated shoes passing through disinfectant mats at the entry and exit points of each section of the farm conform to the mantra that prevention is better than cure as the cost of disinfectant tools is minute compared to the cost of stocks lost to diseases (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
The translocation of non-native koi to Singapore introduces it to a new tropical environment, interactions with local hobbyists, domestic farmers, and local water conditions with its own set of microscopic entities, different from the conditions of its original temperate region of Niigata Japan. All these factors result in variations between Japanese-bred kois and their Singaporean counterparts in the areas of colour, growth speed (Tan, 2018).
KOI HERPESVIRUS (KHV) PATHOGEN
Global logistics processes for moving the kois from Japan to Singapore and their final export destinations are exposed to microorganisms, pathogens and other invisible agents so specialized aqua-cultural scientific knowhow is required to keep the kois in good condition to prevent infections (Tan, 2018). Therefore, simple rules must be followed. It is a good practice for kois from different suppliers to be placed in different tanks and nets to prevent infections (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
In the 21st century, scientists have carried out experiments to test why there had been cases of mass mortalities of carps and kois worldwide. Kois experimentally infected with the wild-type KHV produce the highly-infectious Koi herpesvirus (KHV) pathogen that led to a highly virulent disease in ornamental koi and common carp, resulting in mass mortalities globally (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Within local spaces modified for rearing kois that tries to imitate Japan’s natural environs, kois are also exposed to microscopic microbial from domestic sources, Japan and other countries, so rearing non-domestic kois opened up the potential for biological risk that need to be contained as well (Tan, 2018). There are additional difficulties in testing for these pathogens and microorganisms when it comes to fishes. Serology-based tests like Enzyme linked immunosorbent assays (ELISA) are commonly utilized for virus detections in humans and animals, but not commonly used for fishes due to the reliance of their immune response on environmental temperature (Agri-Food and Veterinary Authority of Singapore AVA, 2011). However, at the same time, some opined importantly that, once the animals are infected with known disease and symptoms developed, ELISA can be a good and sensitive tool. Indeed, according to this view, amino-acid-based ELISA nor nucleic acid-based PCR are not applicable to microorganism identification. Compared to PCR, ELISA is the commonly used tools featured by its cheap, quick, and sensitivity.
Koi diseases such as the Koi Herpes Virus (KHV) made known in 2000 through English language-translated information (along with other parasites) and the medication, quarantine procedures and observation techniques needed to deal with it; translation often became necessary for experts outside Japan to understand these items (Tan, 2018). It was discovered that, placing the koi at permissive water temperatures before testing, improves copy numbers of the virus and helps with detection rates but it is not feasible in the ornamental fish trade where fast test results are needed (Agri-Food and Veterinary Authority of Singapore AVA, 2011). The origins of the KHV disease were scientifically traced back to its first emergence in America and Israel and attempts to study how it was different from other carp diseases resulted in the development of a rather innovative diagnostic tool that can differentiate KHV from other diseases (Tan, 2018).
Early research focused on detecting live viruses in infected fishes but there were challenges in isolating the virus on cell lines (Agri-Food and Veterinary Authority of Singapore AVA, 2011). Overcoming this challenge resulted in the development of real-time polymerase chain reaction (PCR) which could detect the virus from just 5 KHV genomic copies in sampled organs compared to the 100 – 1,000 KHV genomic copies needed in conventional kits (Agri-Food and Veterinary Authority of Singapore AVA, 2011). Experts indicated that real-time PCR is a way to detect expression levels of RNA, by transforming RNA into DNA to amplify detection signals. The PCR option is a blessing for the industry. Even the molecular diagnostic methodology which are precise and sensitive have limitations when it comes to detecting KHV in latently-infected kois, especially due to the dilution of the KHV viral antigen in a large sample volume/pool size (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
Physical signs exhibited by kois like swimming erratically, lack of skin color or even death as a result of microscopic disease-causing agents, can trigger customs and/or other industry stakeholders to prevent arrival of such infected fishes to stop/contain the disease from entering Singapore, given the importance of the ornamental fish industry within the aquaculture community (Tan, 2018). Sick fingerling kois may also exhibit “Skinny fingerling with pin head” symptoms (Agri-Food and Veterinary Authority of Singapore AVA, 2011).
KHV is a serious disease for kois and can potentially hurt any koi aquaculture industry so it has motivated researchers to understand the disease more and KHV is specifically named because of the targeted way in which it infects kois and the common carp (such as the grass carp) (Tan, 2018). Lethal KHV has the potential to destroy big populations of kois and can impact on fish farm communities that depend on ornamental koi cultivation or common or grass carp food fish (Tan, 2018). Treatment for afflicted kois include change of water to remove all bad conditions affecting the fish, testing the organism or water to determine the ailment and then interpretations of results for additional remedy (Tan, 2018).
CONCLUSION
The koi component of the ornamental fish aquaculture in Singapore created a special link with a particular genre of fish that originated from Japan. Today, its import/export into and from Singapore is managed by specialized koi farms that are driven by re-export businesses as well as domestic hobbyists. The kois imported from Japan represent the pinnacle of quality, aesthetics and value for hard-core enthusiasts. At the same time, the challenges faced by both koi farms as well as hobbyists is avoiding infectious diseases like koi herpesvirus and rearing kois in land-scarce Singapore.
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