DOCSLIB.ORG

Artificial Japanese Glass Eel (Anguilla Japonica) Production in Korea the Mature Stage Between 10 and 20 Years

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Artificial Japanese Glass Eel (Anguilla Japonica) Production in Korea the Mature Stage Between 10 and 20 Years Manufacturing & Packaging Artificial Japanese Glass Eel (Anguilla japonica) Production in Korea the mature stage between 10 and 20 years. Marine habitat, Abstract but metamorphosis commences in freshwater. Freshwater eels are very valuable fish species, principally in Asian and European countries. Over 97% of worldwide eel Japanese eel, Anguilla japonica, is a very important cultured production is based on farming of the European eel, Anguilla species in East Asia due to its high market value, desirable anguilla and the Japanese eel, Anguilla japonica. Eel farming taste and recent supply shortage (Ren et al., 2007). Five major is a capture-based aquaculture activity. It is based on the producers of this species are China, Japan, Korea, Malaysia practice of collecting juvenile eels from the wild and on- and Taiwan. The eel aquaculture industry in these countries growing in captivity to marketable size using aquaculture has been growing, e.g. in Korea its production increased from techniques. Due to their complex life cycle, research efforts 2739 tons in 2000 to 6766 tons in 2009 (Son et al., 2011). Eel have not yet managed to produce glass eels on a commercial culture has depended on natural captured Japanese glass scale. After a series of efforts, Korea made a breakthrough by eels, and the highest amount of fishing reached 160 tons (15 producing two Japanese glass eels in 2012. Several other tons in Korea) in East Asia in 2006. Recently, the amount of phenomenal pieces of research were conducted to produce Japanese glass eel fishing has been gradually decreased and the artificial Japanese glass eel, as well as to develop the the value reached 15 tons (one ton in Korea) in East Asia, complete package for eel aquaculture in Korea. 2013. Environmental variation, overfishing, climatic changes, pollution and infections with the swim bladder parasite Introduction (Anguillicoloides crassus) and/or eel viruses have been The family Anguillidae, commonly referred to as freshwater implicated as causes for the current decline in the Japanese fish, is composed of at 16 species and three subspecies, all in glass eel population (Tsukamoto, 2009). the genus Anguilla (Tsukamoto, 2009). Anguilla species are distributed throughout tropical and temperate waters, expect for the Eastern Pacific and South Atlantic (Aoyama et al., 1999). The various life stages of all Anguilla species are harvested and traded on a global scale for farming and consumption. As catadromous fish, they migrate from rivers and inland bodies of water to the oceans to breed, and then the young return to freshwater. For all Anguilla species, the life cycle is essentially the same (Fig. 1). The limited and inconsistent availability of wild broodstock Japanese eel, as well as early survival rate decreasing in culture of the tropical Japanese glass eel (Luo et al., 2013) and the protection or import regulation of Japanese glass eel resources (Crook et al., 2013) over the last decades, increased the requirement for artificial eel production in captivity. Artificial eel production has been studied since the 1960s, Leptocephalus: The oceanic pelagic larval eel, which migrates and Yamamoto and Yamauchi first succeeded in producing from the spawning area to the continental shelf. Narrow, Japanese eel larvae in 1974 from eggs obtained from deep-bodied, shaped like a willow leaf. Glass eel: Small, hormone-treated eels, and Yamauchi et al. (1976) succeeded transparent juvenile eel formed by metamorphosis of in rearing pre-leptocephalus for two weeks. In 2002, the leptocephalus. Metamorphisis occurs at sea, perhaps near the National Research Foundation of Korea (Korea Research edge of the continental shelf. They are not fully pigmented Foundation) approved the national project on “NRF-2002- juveniles. Marine and estuarine habitat. Elvers: Fully 005-F00002” through the Feeds and Foods Nutrition Research pigmented juvenile eel, with a total length under 30 cm and Center (FFNRC) as the priority research institute at Pukyong less than five years old. Predominantly freshwater habitat. National University, Busan, Korea. This project was the first Yellow eel: Eel residing in continental waters, with a size official Korean Government Support Project almost from generally over 30 cm long and more than five years of age. 2002 to 2004. FFNRC successfully produced the artificially This stage typically lasts several years. Predominantly matured male and female broodstock Japanese eel and freshwater habitat. Silver eel: A sexually maturing eel, fertilised eggs in 2003. This research fund was terminated in migrating to the oceanic spawning area. They usually reach 2004, and the National Fisheries Research and Development Institute (NFRDI) continued this research in 2006 with fund 78 International Animal Health Journal Volume 2 Issue 3 Manufacturing & Packaging research from FFNRC, successfully hatching two Japanese glass eels in 2012. Artificial production technology of Japanese eels has improved markedly in Korea, and further studies are necessary to obtain high quality and mass production of Japanese eel eggs. Additionally, artificial reproduction of the European eel, Anguilla anguilla (Palstra et al., 2005), the New Zealand longfin eel, Anguilla dieffenbachia and the shortfin eel, Anguilla australis (Lockman and Young, 2000) have been attempted with a number of research groups. Research on Japanese eel reproduction is complicated, because broodstock eels stop feeding when silvering in nature. For example, Chow et al. (2010) found that Japanese eels caught in the spawning area had not been eating in the marine phase of the migration. Also in captivity, feeding is terminated after transfer to saltwater prior to induction of maturation. Moreover, it is also clear that the availability of an optimal diet is identified as a crucial factor for the sexual maturation and reproduction of the Japanese eel. For Japanese eels, all the qualitative and quantitative Fig. 1. Life cycle of eel (Gissurardottir, 2006) requirements for reproduction have to be met from their body reserves, highlighting the importance of pre-spawning nutrition. Delivering more information Fix-a-Form® multi-page labels, the clever application allowing more information on your product. For further information and for samples contact: t: 01284 701381 e: [email protected] www.dennybros.com Manufacturing & Packaging Summary of Research and Development of Japanese Eels Ginneken VJT and van den Thillart GEEJM. 2005. Artificial (A. japonica) in Korea maturation and reproduction of European silver eel: Recent nutrition studies have contributed further to a better Development of oocytes during final maturation. knowledge of the requirements of proteins, lipids, vitamins Aquaculture 249, 533-547. and additives for the maturation process in the Japanese eel. • Ren T, Koshio S, Ishikawa M, Yokoyama S, Micheal FR, It was shown that the optimum dietary protein (44.3%), P/E Uyan O and Tung HT. 2007. Influence of dietary vitamin ratio (24.1 mg protein/kJ), linolenic acid (LNA, 0.35~0.5%), C and bovine lactoferrin on blood chemistry and non- linoleic acid (LA, 0.5~0.65%), vitamin E (21.2 mg/kg), vitamin specific immune responses of Japanese eel, Anguilla C (41.1 to 43.9 mg/kg) in juvenile and (410.8 to 911.8 mg kg- japonica. Aquaculture 267, 31-37. 1) in broodstock, as well as additives such as quartz porphyry • Son MH, Kim KW, Kim KD and Kim SK. 2011. State of (0.7%), BAISM (0.5%) and propolis (0.25-0.5%) levels could aquacul¬ture management for optimal rearing of eel, be essential for maintenance of normal growth, physiological Anguilla japonica. Korean Journal of Fisheries and function and overall health. Still our knowledge on the Aquatic Science 44, 359-365. reproduction of Japanese eels remains limited. However, our • Tsukamoto K, Aoyama J and Miller MJ. 2009. Present previous studies have shown that final maturation in silver status of the Japanese eel: resources and recent research. female and male Japanese eels could be induced by weekly American Fisheries Society Symposium 58, 21-35. injections of salmon pituitary extract (SPE) and human chorionic gonadotropin (HCG), respectively. Also, our results indicated that artificial maturation by hormone treatment Dr. Erfan Shahkar, Nutritionist, Blue Aqua was successful only during the spring to summer seasons in International Pte Ltd. After finished his Master of seawater with low temperatures (10ºC). These results will Science on Fish Nutrition, Department of Natural provide valuable information for elevation of the artificial Resources Science, University of Lahijan, Iran. He maturation and reproduction coefficient in the Japanese eel. continue studied and finish his Ph.D. in the same major from Department of Marine Bio-Materials Future Perspectives: and Aquaculture, Pukyong National University, 1. Emphasis on nutrition of broodstock eels South Korea. Dr. Erfan recently join Blue Aqua International Pte 1.1. Cost-effective rearing process Ltd. on July, 2015 as Nutritionist. His expertise in Fish nutrition 2. Domesticate broodstock in captivity will help all farmers on the problem for highest benefit for the 3. Feed development for larvae Aquaculture. 4. New feed development for larvae E-mail: [email protected] 5. Rearing larvae in captivity 6. Selective breeding for better growth and survival 7. Disease prevention (e.g. vaccine development) Hyeon Ho Yun, Ph.D., Fisheries Science at 8. Conservation of eel resources in the wild Pukyong National University (PKNU). Current position, Researcher (Ph.D) at Department of Fisheries Biology/Feeds and References Foods Nutrition Research Center (FFNRC) Pukyong • Aoyama J, Mochioka N, Otake T, Ishikawa S, Kawakami Y, National University (PKNU). Castle P, Nishida M and Tsukamoto K. 1999. Distribution Email: [email protected] and dispersal of anguillid leptocephali in the western Pacific Ocean revealed by molecular analysis. Marine Ecology 188, 193-200. Dr. Rungtiwa Piamtongkam is now working • Chow S, Kurogi H, Katayama S, Ambe D, Okazaki M, as Regulatory affairs and technical support for Watanabe T, Ichikawa T, Kodama M, Aoyama J, Shinoda Blue Aqua International Pte., Ltd. after finished A, Watanabe S, Tsukamoto K, Miyazaki S, Kimura S, B.Sc.
Load more

Recommended publications
  • Artificial Completion of the Japanese Eel, , Life Cycle: Challenge to Mass
    水研センター研報，第35号，111－117，平成24年 Bull. Fish. Res. Agen. No. 35, 111-117, 2012 111 Artificial Completion of the Japanese Eel, Anguilla japonica, Life Cycle: Challenge to Mass Production ＊1 ＊1 ＊2 ＊1 Yoshitsugu MASUDA , Hitoshi IMAIZUMI , Kentaro ODA , Hiroshi HASHIMOTO , ＊3 ＊4 Hironori USUKI , and Kazuhisa TERUYA Abstract：Current eel culture depends entirely on glass eels captured from the wild. How- ever, in recent decades, eel populations have declined. Thus, establishment of the technol- ogy for producing sustainable supplies of eel seeds is required. To achieve that end, selec- tive breeding and mass production of glass eels is necessary. This year, we were successful in closing the Japanese eel life cycle. However, we have not as yet established techniques for mass production of glass eels because of various technical difficulties. In this paper, we describe the significance of closing the eel life cycle and the challenges that need to be over- come in order to develop a system of glass eel mass production. Key words：ell culture, glass ell production, ell life cycle, Anguilla japonica The mysterious life cycle of eels has attracted maintained the availability of eels to consumers many researchers. For a long time, no one could at reasonable prices. However, current eel culture find eel eggs or larvae in the habitats where the depends entirely on glass eels captured from the adults were found; such as rivers, ponds, coastal wild. A decrease in the availability of glass eels waters. Early in the 20th century, Schmidt (1922) and increase in demand for eels in the marketplace conducted numerous expeditions and discovered will inevitably lead both to increased prices and that the spawning area for both the European eel decreased natural eel stocks.
    [Show full text]
  • TESIS DE DOCTORADO Desarrollo De Herramientas Moleculares Para Su Aplicación En La Mejora De La Trazabilidad De Los Alimentos Fátima C
    TESIS DE DOCTORADO Desarrollo de herramientas moleculares para su aplicación en la mejora de la trazabilidad de los alimentos Fátima C. Lago Soriano 2017 Desarrollo de herramientas moleculares para para moleculares Desarrollo de herramientas : DO Fátima Soriano Lago C. TESIS DOCTORA DE la los trazabilidad de alimentos aplicaciónla su mejora de en 2017 Escuela Internacional de Doctorado Fátima C. Lago Soriano TESIS DE DOCTORADO DESARROLLO DE HERRAMIENTAS MOLECULARES PARA SU APLICACIÓN EN LA MEJORA DE LA TRAZABILIDAD DE LOS ALIMENTOS Dirigida por los Doctores: Montserrat Espiñeira Fernández Juan Manuel Vieites Baptista de Sousa Página 1 de 153 AGRADECIMIENTOS Cuando una etapa llega a su fin, es cuando por fin puedes mirar a atrás, respirar profundamente, y acordarte de aquellos que te acompañaron. Del mismo modo, es difícil entender los agradecimientos de una tesis hasta que pones el punto y final. Es en este momento cuando se puede percibir la gratitud que sientes a todas las personas que han estado presentes durante esa etapa, ya bien sea codo a codo o simplemente trayéndote un café calentito en el momento preciso. Pero también es cierto que, entre toda esa gente que ha estado ahí, hay pocas caras que se dibujan clara e intensamente en mi cabeza. En primerísimo lugar, me gustaría dar las gracias de una manera muy especial a Montse por muchos, muchísimos motivos: por darme cariño y amistad desde el día en que nos conocimos; porque a lo largo de esta década hemos compartido muchísimos momentos alegres, acompañados de risas y carcajadas, pero también los más tristes de mi vida, inundados de lágrimas y angustia; por estar ahí para lo que sea, para todo, y tener siempre tendida su mano amiga; por escucharme una y otra vez, sin cansarse, y aconsejarme sabiamente; por confiar en mí y guiarme, no solo durante el desarrollo de esta tesis, sino también en mi formación y día a día; por su eterna paciencia;… y, sobre todo, por poner en mi vida al “morenocho”, ese pequeño loquito tímido que me comería a besos.
    [Show full text]
  • American Eel Julia Beaty University of Maine
    The University of Maine DigitalCommons@UMaine Maine Sea Grant Publications Maine Sea Grant 2014 Fisheries Now: American Eel Julia Beaty University of Maine Follow this and additional works at: https://digitalcommons.library.umaine.edu/seagrant_pub Part of the Aquaculture and Fisheries Commons Repository Citation Beaty, Julia, "Fisheries Now: American Eel" (2014). Maine Sea Grant Publications. 74. https://digitalcommons.library.umaine.edu/seagrant_pub/74 This Article is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Maine Sea Grant Publications by an authorized administrator of DigitalCommons@UMaine. For more information, please contact [email protected]. (http://www.downeastfisheriestrail.org) American eel Fisheries Now: American eel By Julia Beaty Reviewed by Dan Kircheis, Fred Kircheis, James McCleave Watch “Harvester perspectives on alewives, blueback herring, and American eels in Downeast Maine (http://www.seagrant.umaine.edu/oral­histories­alewife­eel)” oral history video series. A complex life cycle The American eel is the only species in the Gulf of Maine that spends most of its life in fresh water but spawns at sea (a life cycle known as catadromy). American eels are born in the Sargasso Sea, a large area of the Atlantic Ocean south of Bermuda and east of the Bahamas. American eel larvae (known as leptocephali) are transported by ocean currents for nearly a year until they reach the east coast of North America. As they near the coast, leptocephali metamorphose into an early juvenile stage known as a glass eel. The timing of the arrival (http://www.downeastfisheriestrail.org/wp­ of glass eels along the coast of Downeast Maine is content/uploads/2014/11/eels_now_01.png) driven by water temperature and usually takes Elvers caught in the Union River in Ellsworth, Maine in 2011.
    [Show full text]
  • Crazy & Ambitious
    CRAZY & AMBITIOUS CONFERENCE 2017 8-10 MAY 2017, WELLINGTON, NEW ZEALAND Conference Handbook & Book of Abstracts CRAZY & AMBITIOUS NOT YOUR USUAL NATIONAL MEETING 8-10 MAY 2017 / TE PAPA, WELLINGTON New Zealand’s Biological Heritage Ngā Koiora Tuku Iho National Science Challenge Wifi Password: events Name: CRAZY & AMBITIOUS CONFERENCE 2017 8-10 MAY 2017, WELLINGTON, NEW ZEALAND We are very grateful for the support of our Conference Sponsors and Challenge Parties. CHALLENGE HOST AND CONFERENCE PARTNER CONFERENCE SPONSORS CHALLENGE PARTIES PAGE 2 CRAZY & AMBITIOUS CONFERENCE 2017 8-10 MAY 2017, WELLINGTON, NEW ZEALAND Welcome Nau mai, nau mai, nau mai: ki te hui ‘Pōrangi me te Awhero’ o Te Wero Pūtaiao mo Ngā koiora tuku iho i konei i Te Papa i roto i Te Whanganui-a-Tara. Welcome to the ‘Crazy and Ambitious’ conference of the New Zealand’s Biological Heritage National Science Challenge here at Te Papa in Wellington! This is our first national meeting, and we always wanted to try something different. Our vision is to host a gathering that is ‘not your usual science conference’ – rather, a mix of perspectives from the wider Challenge communuty: scientists, community groups and NGOs, primary industry, politicians, and all our Challenge Parties. The conference programme reflects strong involvement of Māori: scientists, communities, and the private sector. We’re also lucky to host the first visit of our International Science Advisory Panel and other Contents international speakers: their global perspectives will bring another dimension again to the programme. All our speakers have been asked Sponsors ............................................2 to put forward their big, bold and unusal (crazy and ambitious!) ideas over the next three days.
    [Show full text]
  • A Checklist of the Parasites of Eels (Anguilla Spp.) (Anguilliformes: Anguillidae) in Japan (1915-2007)
    J. Grad. Sch. Biosp. Sci. Hiroshima Univ. (2007), 46：91～121 REVIEW A Checklist of the Parasites of Eels (Anguilla spp.) (Anguilliformes: Anguillidae) in Japan (1915-2007) 1） 1） 2） Kazuya Nagasawa , Tetsuya Umino and Kouki Mizuno 1）Graduate School of Biosphere Science, Hiroshima University 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan 2）Ehime Prefectural Uwajima Fishery High School 1-2-20 Meirin, Uwajima, Ehime 798-0068, Japan Abstract Information on the protistan and metazoan parasites of three species of eels, the Japanese eel Anguilla japonica, the giant mottled eel A. marmorata and the European eel A. anguilla, in Japan is summarized in the Parasite-Host List and Host-Parasite lists, based on the literature published for 93 years between 1915 and 2007. Both A. japonica and A. marmorata are native to Japan, whereas A. anguilla is an introduced species from Europe. The parasites, including 44 named species and those not identified to species level, are listed by higher taxon as follows: Sarcomastigophora (no named species), Ciliophora (6), Microspora (1), Myxozoa (6), Trematoda (7), Monogenea (7), Cestoda (3), Nematoda (7), Acanthocephala (4), Hirudinida (2), and Copepoda (1). For each taxon of parasite, the following information is given: its currently recognized scientific name, any original combination, synonym(s), or other previous identification used for the parasite occurring in eels; habitat (freshwater, brackish, or marine); site(s) of infection within or on the host; known geographical distribution in Japanese waters; and the published source of each locality record. Of the 44 named species of parasites, 43 are from A.
    [Show full text]
  • What Goes Wrong During Early Development of Artificially
    animals Article What Goes Wrong during Early Development of Artificially Reproduced European Eel Anguilla anguilla? Clues from the Larval Transcriptome and Gene Expression Patterns Pauline Jéhannet 1, Arjan P. Palstra 1,*, Leon T. N. Heinsbroek 2, Leo Kruijt 1, Ron P. Dirks 3, William Swinkels 4 and Hans Komen 1 1 Animal Breeding and Genomics, Wageningen University & Research, 6708 PB Wageningen, The Netherlands; [email protected] (P.J.); [email protected] (L.K.); [email protected] (H.K.) 2 Wageningen Eel Reproduction Experts B.V., 3708 AB Wageningen, The Netherlands; [email protected] 3 Future Genomics Technologies B.V., 2333 BE Leiden, The Netherlands; [email protected] 4 DUPAN Foundation, 6708 WH Wageningen, The Netherlands; [email protected] * Correspondence: [email protected] Simple Summary: Closing the life cycle of the European eel in captivity is urgently needed to gain perspective for the commercial production of juvenile glass eels. Larvae are produced weekly at our facilities, but large variations in larval mortality are observed during the first week after hatching. Although much effort has been devoted to investigating ways to prevent early larval mortality, it remains unclear what the causes are. The aim of this study was to perform a transcriptomic study Citation: Jéhannet, P.; Palstra, A.P.; on European eel larvae in order to identify genes and physiological pathways that are differentially Heinsbroek, L.T.N.; Kruijt, L.; Dirks, regulated in the comparison of larvae from batches that did not survive for longer than three days R.P.; Swinkels, W.; Komen, H. What vs. larvae from batches that survived for at least a week up to 22 days after hatching (non-viable Goes Wrong during Early vs.
    [Show full text]
  • Reviewing the Trade in Glass Eels Anguilla Spp. Report by Hiromi Shiraishi
    Reviewing the trade in glass eels Anguilla spp. Report by Hiromi Shiraishi Anguilla et al Anguilla AnguillaA. anguilla et al Anguilla anguilla Anguilla A. japonica A. rostrata Anguilla anguilla Anguillaet al et al A. japonicaA. rostrata et al A. anguilla Anguilla A. anguilla Anguilla et alet al Anguilla et al. TRAFFIC Bulletin TRAFFIC Bulletin 32(1) 5 MAY 2020 FINAL.indd 13 05/05/2020 12:55:01 S H O R T R E P O R T East Asia and other Customs data Anguilla Anguilla Anguilla Anguilla A. japonica A. rostrata) A. bicolor A. australis A. reinhardtii A. mossambica Anguilla Information released regarding Informal Consultation on International Cooperation for Conservation and Management of Japanese Eel Stock and Other Relevant Eel Species European Eel Anguilla anguilla American Eel Anguilla rostrata TRAFFIC Bulletin TRAFFIC Bulletin 32(1) 5 MAY 2020 FINAL.indd 14 05/05/2020 12:55:01 S H O R T R E P O R T Customs Code Commodity China 0301.92.10.10 Live eel fry of Marbled Eel Anguilla marmorata 0301.92.10.20 Live eel fry of European Eel Anguilla anguilla 0301.92.10.90 Live eel fry, other Anguilla spp. 0301.92.90.10 Live eels, other than fry of Anguilla marmorata 0301.92.90.20 Live eels, other than fry of Anguilla anguilla 0301.92.90.90 Live eels, other than fry of other Anguilla spp. Japan 0301.92.10.0 Live eel fry “Anguilla spp.” (only used for imports) 0301.92.20.0 Live eels, other than fry of Anguilla spp.
    [Show full text]
  • Fish Health Newsletter
    Fish Health Newsletter American Fisheries Society/Fish Health Section Volume 31 Number 1 January 2003 In this issue: Announcements…………………………………………………………………....Page 1 Meetings and Workshops …………………………………………………………Page 4 FHS Nominations……..…………………….……………………………………..Page 6 Evidences of two clonal lineages within the emerging fish pathogen Pseudomonas anguilliseptica by serological and genetic techniques……..……………………...Page 8 Differential Diagnosis: SVCV vs. KHV in Koi ………………………..……...….Page 9 Announcements: Ana Baya will be representing the Fish Health Section at the Midyear Governing Board Meeting of the American Fisheries Society, to be held March 6-8, 2003. New Book Releases from AFS: Sustaining North American Salmon: Perspectives Across Regions and Disciplines U.S. and Canadian fisheries professionals from multiple disciplines examine the history, current knowledge, and research needs of fisheries stakeholders, managers, and policy makers regarding salmon ecology, policy, and management in North America. This book offers a greater understanding of the complexity and repercussions of salmon management, currently a controversial issue between Canada and the United States. Information needs from biological, social, and economic perspectives are identified, enabling managers and policy makers to develop an action agenda to acquire and utilize this information. This excellent reference for the management of salmon presents a synthesis of the history, ecology, sociology, economics, politics/institutions, and the future of one of the most economically
    [Show full text]
  • Catching Eels in Pacific Island Countries and Territories
    World aquaculture production CATCHING EELS IN PACIFIC of freshwater eels has increased over the past decade and about ISLAND COUNTRIES AND 233,000 t were harvested in 2000, with a value of USD 978 TERRITORIES million (FAO 2002). The artifi- cial propagation of eels has not yet been achieved commercially. Introduction For aquaculture, glass eels or Satya Nandlal, elvers must be caught from the The eel is a fascinating creature Aquaculture Officer, wild for stocking in culture and has long been studied in Secretariat of the Pacific facilities. The increasing world- great detail. Reports indicate Community wide demand for eels and the ([email protected]) that since the time of the ancient overexploitation of many eel Greeks, people have wondered fisheries present an opportunity where eels came from and Eels are consistently fished for eel culture. Pacific Island where they spawned. Eels have because of their accessibility and countries offer a good environ- been considered a gourmet del- market demand. According to ment in which to culture eels, as icacy for thousands of years in the United Nations Food and they grow rapidly in tropical cli- many parts of the world. Agriculture Organization (FAO), mates, preferring a temperature there has been a global decline range of 23–28° C, and a pH Eels are found in marine, brack- in the eel catch, from a peak of range of 7.0–8.0. In ideal condi- ish and fresh waters worldwide 18,600 t in 1994 to 12,700 tonnes tions they grow to marketable and reports suggest there are in 2000 (Europe 5300 t; Asia size (150–200 g) in 10 to 20 15–19 species in total, with 2400 t; Oceania 1600 t; North months, although their growth about 10 species in tropical America 1100 t).
    [Show full text]
  • Ages of the Giant Mottled Eel Anguilla Marmorata Recruited at the Northern Luzon Island, the Philippines Between 2009 and 2011
    Coastal Marine Science 39(1): 1–4, 2016 Ages of the giant mottled eel Anguilla marmorata recruited at the northern Luzon Island, the Philippines between 2009 and 2011 Sho Nakazato1, Takuya Minagawa1, Fumiaki Shirotori1, Akira Shinoda2, Jun Aoyama3 and Tatsuki Yoshinaga1* 1 School of Marine Biosciences, Kitasato University, Kanagawa 252–0373, Japan 2 Department of Biology, Tokyo Medical University, Tokyo 160–8402, Japan 3 Atmosphere and Ocean Research Institute, the University of Tokyo, Chiba 277–8564, Japan * E-mail: [email protected] Received 17 April 2015; Accepted 7 May 2015 Abstract― To accumulate information on the larval transportation of the freshwater eels in the North Pacific, we examined the ages of the giant mottled eel Anguilla marmorata recruited at the northern Philippines. The glass eel specimens analyzed were collected at the river mouth of the Cagayan River in the Luzon Island in January 2009, November 2011 and November 2012, and the daily increment rings of the otoliths were observed to determine the ages at recruitment (n=14). There was no significant dif- ference in the ages at recruitment among the 2009- (147.0 ± 24.4 days; 126–182), 2011- (145.2 ± 17.3; 122–161) and 2012-groups (136.0 ± 11.1; 122–145), and were in the range of those in the previous studies at the same place. Further efforts to accumulate in- formation on the ages at recruitment at various localities and timings will be important to comprehensively understand the early life history of A. marmorata in the North Pacific. Key words: Anguilla marmorata, freshwater eel, giant mottled eel, glass eel, otolith, Philippines Introduction moto et al.
    [Show full text]
  • The Hidden Truth About Eel Procurement in Japan a Survey Of
    Greenpeace Japan Briefing Paper, June 4, 2018 The Hidden Truth About Eel Procurement in Japan A Survey of Processed Eel Product (Kabayaki) Sourcing by Major Retailers I. Background Four species of eel are being used as ingredients for eel products known as kabayaki (grilled eel) consumed in Japan, including the Japanese eel, European eel, American eel, and shortfin eel. Three of these (Japanese, European, and American) are designated as endangered species on the IUCN Red List of Threatened Species.1 International trade in the European eel, which is listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), has been regulated since 2009, so any imports or exports require specific permission.2 The European Union (EU) has banned exports of European eel since 2011. 3 Many factors are threatening eels, but besides the deterioration of rivers and other habitats and changes in the marine environment, a major suspected factor is declining populations due to fishing.4 As a part of its activities to protect marine ecosystems, Greenpeace Japan has been working since 2013 to study the procurement policies and awareness of supermarkets and other major Japanese retailers in relation to eel, which is still being widely consumed in Japan even though it is designated an endangered species. As an ingredient for kabayaki, eel is known to be at high risk of involving illegal, unreported, and unregulated (IUU) fishing. This survey was carried out to shed light on the handling of and procurement policies for eel products (kabayaki), the transparency of the supply chain, and areas of concern in eel procurement.
    [Show full text]
  • Leptocephalus of Anguilla Japonica Found in the Waters South of Taiwan
    Japanese Journal of Ichthyology 魚 類 学 雑 誌 Vol.22,No.2 1975 22巻2号1975年 Leptocephalus of Anguilla japonica Found length,collected at 21•‹01.4'N,121•‹00.8'E(KH- 73-2,Station 30-8,ca.2200 m in depth,Fig.2) in the Waters South of Taiwan on March 7,1973(21:07•`21:40)by horizontal tow of the larva net,4 m in diameter,in 75m Osame Tabeta and Toru Takai wire length and 69•‹wire angle at ship speed 1.5 (Received January 21,1975) knots.Towing depth 30m or less. Leptocephali of the Japanese eel Anguilla Water temperatures recorded with BT are japonica Temminck and Schlegel have been re- shown in Fig.3.The present larva was found ported by Matsui et al.(1968),Tanaka(1975) together with the leptocephali of Congridae(12, and Tabeta and Takai(1975)from the waters specimens),Nettastomidae(2)and Nemichthyi- south of Taiwan and of the Okinawa Islands. dae(1).In this station,9 tows were made by Recently,Yamamoto et al.(1974;1975;1975) the same larva net,2 tows by the larva net of described the spawned eggs and yolk-sac larvae 1.5m in diameter and 1 tow by the net of 1.6 m of the Japanese eel obtained by artificial insemi- in diameter at the surface and middle layer,but nation. no other specimens of anguillid leptocephali or At the beginning of March 1973,an anguillid elvers were obtained. leptocephalus,measuring 52.0mm in total Measurements in mm:Total length 52.0, length,was collected in the waters south of standard length 51.0,head 4.8,snout 1.0,eye Taiwan by the R/V Hakuho-maru,Ocean Re- 1.0,upper jaw 1.8,postorbital 2.8,pectoral 1.4, search Institute,University of Tokyo,in the preanal 22.8,predorsal 20.3,ano-dorsal 2.5, course of the first research cruise for the biolog- depth just before eye 1.9,depth at pectoral base ical study of larval stages of the Japanese eel.
    [Show full text]