MINISTRY OF EDUCATION VIETNAM ACADEMY OF AND TRAINING SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY ------

HOANG VAN HIEN

NEMATODE SPECIES COMPONENT IN SOME PERCIFORMES FISHES IN COASTAL REGIONS OF VIET NAM

Major: Parasitology

Code: 9 42 01 05

SUMMARY OF BIOLOGY DOCTORAL THESIS

HA NOI - 2019 The thesis is completed at:

GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY

VIETNAM ACADEMI OF SCIENCE AND TECHNOLOGY

Supervisors:

1: Ass. Prof. Dr. Ha Duy Ngo

2: Dr. Nguyen Van Duc

Reviewer 1: ......

Reviewer 2: ......

Reviewer 3: ......

The dorteral thesis will be defended at the Evaluation Committee of:

GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY

Time: Date...... month...... 2019

The thesis can be found at:

- The library of Graduate University Science and Technology

- National Library of Vietnam

INTRODUCTION

1. THE THESIS NECESSARY The risks of fish parasites, especially , to human and health constitute are an important problems. The infections are not only caused health deficiency or disability of humans and but also reduce productivity and profitability of aquacultute, increase economic burden due to the costs for disease treatment and prevention. Although parasitic deseases caused many harmfulness, they have received little attention from scientists, managements. Our study of the composition of the parasitic nematodes in marine fishes in the off Vietnam is urgently needed. The survey’s results are not only provide the information about the fauna of fish’s nematoda, the relation between hosts-parasites, but also assess the the potential risks for human consumption. 2. OBJECTIVES To have the knowleadge of the fauna from Perciformes fishes in the sea off Vietnam. 3. THE RESEARCH CONTENTS * To study and build the systematic of nematode fauna from Perciformes fishes in the off Vietnam. * To describe the morphological features of some selected nematode species. * To know the current status of nematode infections (prevalence, intensity of infection) in some Perciformes fish species (Perciformes) in the off Vietnam. 1

4. THE SCIENTIFIC AND PRACTICE SIGNIFICANCE OF THE THESIS - Providing the composition and the distribution of the parasitic nematodes from Perciformes fishes in the off Vietnam,, including a new records of host species. Especially,, 19 nematode species were found and described for the first time in Vietnam. - Providing the morphological data (measurement, drawings and images, classification system) of all nematode species which were collected in this study. - Contributing the data of parasitic nematodes for the book "Fauna of Vietnam: Parasitic roundworm in Vietnamese marine fishes" later. 5. THE THESIS STRUCTURE The thesis consists of 150 pages, in which: Introduction 2 pages; Literature review 20 pages; Materials and research methods 13 pages; Results and Discussions 104 pages; Conclusion and Suggestions 1 page. The published works, which are related to the thesis 1 page; References 9 pages, include 13 documents in Vietnamese and 81 documents in the foreign languages. The thesis has 11 tables, 47 figures and illustrations, diagrams and 16 appendix pages. I. Chapter 1. OVERVIEW 1.1. Basic characters of parasitic nematodes: General morphological features, biological characters, life cycle of nematodes, the distribution and harmfull effects of nematodes were provided.

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1.2. Summary of the parasitic roundworm classification system: The outline of the nematode classification system in the World and Vietnam were summarized. 1.3. Some basic characters of the Vietnamese marine fish fauna, including the Perciformes order: General characters of marine fish fauna in Vietnam, especially fishes belong to Perciformes order were mentioned. 1.4. The studying situation of parasitic nematodes in marine fishes. 1.4.1. Research on parasitic nematodes in marine fishes in the Western Pacific region Research on parasitic helminths in marine animals has been conducted since the late 19th century, but it was received more attention by scientists from the miStole of the 20th century. Particularly, the data of nematode fauna from the Western Pacific region has been avaiable about three late decades.

Wu (1927) had the first report of parasitic nematode from marine fish in the off China, the author described one nematode species Paraleptus scyllii from sharkes Chiloscyllium plagiosum in Taiwan sea . Up to 1965, Chinese scientists continued to investigate the parasite fauna from marine fishesin this region. In 2011, Peng et al. listed a total of 90 species of nematodes belonging to 31 genera, 13 families, 9 supperfamilies, 3 orders and 2 subclasses in marine fishes in China. However, this list already included all species (19 nematode spcies) which were found by scientists from Vietnam and the former Soviet Union in the East Sea of Vietnam (South China Sea).

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Arthur et al. (1997) listed 201 parasitic species in Philippine fishes, including 20 species of nematoda. In this list has presented of Capillaria philippinensis, which can infecting to human. In Thailand, Purivirojkul (2004) found 11 nematode species from marine fishes. Jakob et al. (2006) identified 38 helminthic species in marine fish in Java Island, Indonesia; including 5 nematoda species. Akhtar et al. (2006) recorded 7 families, 9 subfamilies, 23 genera and 71 species of nematoda from fishes in the off Pakistan. Later, Kazmi et al. (2013) listed 90 nematode species in whole country. In Japan, studies on parasitic helminths in marine fish were early carried out, e.g. Layman (1930)found the species Capillaria helenae. Recently, Nagasawa et al. (2007) identified 7 nematode species of 7 genera. Arthur et al. (2015) has recorded 24 species of nematode parasites in fish in the off Malaysia. Almost species were identified to genus. 1.4.2. The studying situation of parasitic nematode from marine fishes in Vietnam. Research on the system of the parasitic helminth from marine fishes in Vietnam has only been carried out after 1960. The Russian scientists autopsied 1,118 individuals of 53 fish species, 16 families from the off East Sea. Among them, 888 individuals of 44 species belong to Perciformes. The authors

4 have discovered and described 42 new species, including one species of Nematoda. Le Van Hoa et al. (1972), the first Vietnamese parasitologists, described 2 new Bulbocephalus species from Thread finfish. Hà Duy Ngọ et al. (2009) found 2 nematode species genera Capillaria and Anisakis in the off Ha Long, Quang Ninh Province. Vo The Dung (2010) detected 54 parasitic species from the grouper Epinephelus spp. in the off Nha Trang, Khanh Hoa province, including 34 identified species and 20 other unidentified species. Especially, 8 nematode species were listed. Nguyen Van Ha (2011) described a new species Ascarophis moraveci from 3 fish species in the off Ha Long, Quang Ninh province. Dang Nguyen Anh Tuan et al. (2015) recorded a species Camallanus sp. from Parupeneus spp. in off Nha Trang, Khanh Hoa province. Chapter 2. MATERIALS AND METHODS 2.1. Subjects, sites and time of the study 2.1.1. Subjects of the study Subjects of this study were parasitic nematodes that collected on from Perciformes marine fishes. . 2.1. 2. Time of the study: from 10/2014 to 12/2017 2.1.3. Places of study: Nine provinces of 3 coastal regions in Vietnam (Figure 1)

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Figure 1: Study sites 2.2. Study methods Nematode specimens were collected by using a “comprehensive examination” method of Skrjabin (1928). Samples were fixed, and made slides by using a method of De Grisse (1969). Morphological characters of nematodes were 6 studied by using photographic scanning of electron microscope (SEM) (Fagerholm , 1982) or by light microscope (Olympus CH40); all characters were drawings with the aid of camera lucida and then were redrawn using Adobe Illustrator CS6. All measurements are also given. Larval samples were examined by using molecular . All nematode specimens are preserved and stored at the Department of Parasitology, Institute of Ecology and Biological Resources. The references which most using for identification of nematodes are listed below: - Systema helminthum, Volume III, part I - The nematodes of vertebrates (Yamaguti, 1961). - Keys to the Nematode Parasites of Vertebrates (Anderson et al., 2009). - Systematic position and phylogeny. In Lee D. L. (Eds), The biology of nematodes (De Ley et al., 2002). - A new system for Nematoda: combining morphological characters with molecular trees, and translating clades into ranks and taxa In Nematology Monographs and Perspectives (De Ley et al., 2004). - Trichinelloid nematodes parasitic in cold-blooded vertebrates (Moravec, 2001). - Metazoan parasites of Salmonid fishes of Europe (Moravec, 2004). The fish hosts were identified by morphological method, using the references below: Fauna of Vietnam, episode 17; 19 (Sea bass); FAO species identification guide for fishery purposes; Database of fishes (www.fishbase.org).

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Chapter 3. RESULTS 3.1. The composition of parasitic nematodes from Sea bass fishes in the off Vietnam. A total of 7951 individuals of nematoda, including 2717 adults and 5234 larvae, were collected from 3735 individuals of 129 species, 38 families of the Perciformes in the off Vietnam. Thirdty sevennematode species belonging to 2 classes, 2 order, 9 families and 21 genera were identified, including, 24 species have been identified at species level, 13 species have been identified at genus level. Especially, 19 species were the first time found in Vietnam, and one species Cucullanus(Cucullanus) sp. could be a new species. 26 fish species are recorded as new hosts for the nematode fauna. The results are shown in Table 3.1: Table 3.1: Composition of parasitic nematode species in some fish species of the Sea bass in Vietnam coastal waters Site Intensity Prevalence No. Nematoda Host (fishes) in (Min- (%) QN HP NĐ NA QB TTH KH KG BL host Max) PHYLUM NEMATODA POTTS, 1932 Class Enoplea Inglis, 1983 Order Trichinellida Hall, 1916 Familly Capillariidae Railliet, 1915 Genus Capillaria Zeder, 1800 Decapterus maruadsi Stomuch 11,43 1-12 x 1 Capillaria sp. Seriola dumerili Stomuch 22,73 1-5 x PHYLUM NEMATODA POTTS, 1932 Class Inglis, 1983 Order Chitwood, 1933

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Familly Anisakidae Skrjabin & Karokhin, 1945 Genus Anisakis Dujardin, 1845 Carangoides malabaricus Cavity 4,11 1-5 x Decapterus macarellus Cavity 19,35 1-9 x Lutjanus johnii Cavity 4,17 1;3 x * Anisakis typica Megalaspis cordyla Cavity 5,88 1-3 x 2 (Diesing, 1860) Baylis, 1920 Priacanthus hamrur Cavity 33,89 1-18 x Pristipomoides filamentosus Cavity 30 1-2 x Sargocentron rubrum Cavity 1/8 2 x Trichiurus lepturus Cavity 16,46 1-5 x x Genus Contracaecum Railliet & Henry, 1912 Alectis ciliaris Cavity 5,56 1;2 x x Atropus atropus Intestin 10,34 3-14 x x Scomberoides commersonianus Intestin 12 2-7 x Contracaecum Dentex tumifrons Intestin 50 4-27 x osculatum* 3 Lutjanus vitta Intestin 50 1-14 x x x x x (Rudolphi, 1802) Baylis, 1920 Otolithes ruber Intestin 12,24 2-12 x x Penhania argentata Cavity 34,48 2-8 x Rastrelliger brachysoma Cavity 7,41 3-8 x x x Sarda orientalis Intestin 10 1 x Selar crumenophthalmus Cavity 17,39 1-14 x x x Siganus canaliculatus Intestin 5/5 23-100 x

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Trichiurus lepturus Cavity 27,85 3-24 x x Acanthopagrus latus Cavity 40 1-12 x Alepes kleinii Cavity 8,55 1-8 x x x x x Carangoides hedlandensis Cavity 90 5-52 x Eleutheronema tetradactylum Cavity 10,20 2-12 x x x Epinephelus amblycephalus Cavity 19,30 1-6 x x x x x 4 Contracaecum sp. Epinephelus areolatus Cavity 37,50 1-3 x Gerres filamentosus Cavity 31,75 5-27 x x Gerres oyena Cavity 20,34 1-15 x x x Jhonius belangerii Cavity 5,77 6-31 x x Larimichthys croceus Cavity 2,86 4 x Polynemus melanochir Cavity 20 1;9 x Genus Terranova Leiper & Atkinson, 1914 5 Terranova sp*. Siganus fuscescens Intestin 0,85 2 x Genus Goezia Zeder, 1800 6 Goezia sp*. Eleutheronema tetradactylum ** Stomuch 6,12 1-5 x Familly Raphidascarididae Hartwich, 1954 Genus Hysterothylacium Ward & Magath, 1917 Alepes kleinii Intestin 7,69 1-7 x x x x x H. aduncum Carangoides malabaricus Intestin 27,40 1-11 x x x 7 Rudolphi, 1802 Cephalopholis miniata Intestin 3/5 1-3 x

Dentex tumifrons Intestin 40 4-30 x

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Epinephelus retouti Intestin 7,14 1 x Evynnis cardinalis Intestin 58,06 1-6 x x Lutjanus russelli Intestin 1,96 5 x Nemipterus japonicus Intestin 21,21 1-12 x Otolithes ruber Intestin 8,16 3-7 x x x Pomadasys maculatus Intestin 1,67 2 x Priacanthus macracanthus Intestin 20 1-2 x Sargocentron rubrum Intestin 2/8 3;7 x Siganus virgatus Intestin 2,86 1 x Sillago Aeolus Intestin 6,67 2 x Terapon jarbua Intestin 18,47 1-6 x x x x ** H. chorinemi Nemipterus hexodon Intestin 37,14 4-17 x 8 (Parukhin, 1966) Upeneus sulphureus ** Intestin 86,36 1-18 x Bruce & Cannon, 1989 Upeneus tragula ** Intestin 14,63 1-23 x H. fabri* (Rudolphi, 1819) 9 Uranoscopus oligolepis Stomuch 58,82 1-40 x Deardorff & Overstreet, 1980 H. longilabrum* 10 Siganus fuscescens Intestin 41,53 5-148 x x x x x x x x x Li, Liu & Zhang, 2012 Nemipterus marginatus Intestin 6/8 2-24 X 11 Hysterothylacium sp. Parupeneus macronemus Intestin 6,67 6 X Upeneus moluccensis Intestin 26,67 2-7 x 11

Upeneus tragula Intestin 24,39 4-18 x x x x Genus Raphidascaris Railliet & Henry, 1915 Acanthocepola limbata Intestin 20 1;2 x Acanthopagrus berda Intestin 4,11 1-4 x x Acautrogobius canius Intestin 30,77 1-6 x x Argyrosomus japonicus Intestin 13,33 1-20 x Ariomma indicum Intestin 10,53 1;2 x x Atropus atropus Intestin 20,69 1-12 x x Bostrychus sinensis Intestin 20 1;4 x Butis butis Intestin 21,74 2-11 x x Carangoides malabaricus Intestin 16,44 2-7 x x x x x Raphidascaris Coryphaena hippurus Intestin 1/5 3 x 12 acus* Bloch, 1779 Dcapterus maruadsi Intestin 48,57 1-128 x x x Decapterus macarellus Intestin 51,61 1-13 x x Eubleekeria jonesi Intestin 53,33 4-28 x Glossogobius giuris Intestin 20 1-7 x x Leiognathus equulus Intestin 10,14 1-12 x x Megalaspis cordyla Intestin 1,47 4 x x Nemipterus bathybius Intestin 46,67 1-21 x x Nemipterus japonicus Intestin 21,21 2-18 x x Otolithes ruber Intestin 12,24 2-7 x x Pampus chinensis Intestin 11,11 2-7 x x

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Priacanthus macracanthus Intestin 10 2 x Rastrelliger brachysoma Intestin 12,35 1-8 x x Selar crumenophthalmus Intestin 13,04 3-23 x x Sillago sihama Intestin 6,25 1-3 x Sphyraena jello Intestin 9,43 1-5 x x Alepes kleinii Intestin 8,55 1-11 x x x x x Atule mate Intestin 6,67 4 x Chorineruus lasaus Intestin 24,53 1-10 x Diagramma pictum Intestin 10 3;7 x x Drepane punctate Intestin 11,11 2;3 x Epinephelus epistictus Intestin 100 2-4 x Epinephelus fasciatus Intestin 10 3 x x Gazza minuta Intestin 30 1-4 13 Raphidascaris sp. Gerres limbatus Intestin 5,48 2-13 x x Leiognathus splendens Intestin 4 5;17 x x Leiognathus equulus Intestin 5,79 2-17 x x Lethrinus lentjan Intestin 20 5;12 x Lutjanus johnii Intestin 8,33 2-7 x Lutjanus russelli Intestin 3,92 1;3 x Megalaspis cordyla Intestin 1,47 5 x Parastromateus niger Intestin 6,67 2-8 x Platax teira Intestin 33,33 2-8 x

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Pterocaesio chrysozona Intestin 23,08 1-12 x Scomberoides commersonianus Intestin 8 2;9 x x Selaroides leptolepis Intestin 61,90 4-27 x Trachinotus baillonii Intestin 5 7 x Genus Raphidascaroides Yamaguti, 1941 R. nipponensis* Dactyloptena orientalis x 14 Intestin 6,67 1 Yamaguti, 1941 ** Familly Ascarididae Baird, 1853 Genus Porrocaecum Railliet & Henry, 1915 15 Porrocaecum sp. Nimepterus Japonicus ** Intestin 3,03 7-12 x Familly Quimperiidae (Gendre, 1928) Baylis, 1930 Genus Haplonema Ward & Magath, 1917 16 Haplonema sp*. Terapon jarbua ** Intestin 1,27 1;3 x x Familly Cystidicolidae Skrjabin, 1946 Genus Ascarophis Van Beneden, 1871 Sargocentron Stom 2/8 5;9 x melanospilos ** 17 Ascarophis sp. Epinephelus retouti ** Stom 7,14 1 x Dentex tumifrons ** Stom 20 2;3 x A. moraveci Ha et Scatophagus argus Stom 5,80 1-8 x x 18 al., 2011 Nibea albiflora Stom 22,45 2-17 x x Genus Spinitectus Fourment, 1883

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** S. echenei Coryphaena hippurus Intestin 3/5 2-9 x 19 Parukhin, 1967 Auxis thazard ** Stomuch 15,52 1-5 x Genus Prospinitectus Petter, 1979 Prospinitectus 20 mollis (Mamaev, Auxis thazard Stomuch 10,34 2-5 x x 1968) Petter, 1979 Familly Philometridae Baylis & Daubney, 1926 Genus Buckleyella Rasheed, 1963 B. buckleyi 21 Jhonius carouna** Intestin 6 1-7 x Rasheed, 1963 Genus Philometra Costa, 1845 P. scieanae* Pennahia argentata Intestin 10,34 1-5 x 22 Yamaguti, 1941 Priacanthus hamrur ** Intestin 15,25 1-28 x Genus Philometroides Yamaguti, 1935 P. atropi (Parukhin, 1966) Scomberoides 23 Intestin 4 1 x Moravec & commersonianus ** Ergens, 1970 Familly Camallanidae Railliet et Henry, 1915 Genus Camallanus Railliet & Henry, 1915 Camallanus Carangoides malabaricus Intestin 5,48 4-9 x 24 carangis Olsen, 1954 Atule mate ** Stomuch 13,33 2;5 x 25 Camallanus sp. Jhonius carouna ** Intestin 7 2-5 x

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Nemipterus hexodon ** Intestin 14,29 1-8 x Genus Procamallanus Baylis, 1923 P. annulatus* Yamaguti, 26 Siganus guttatus ** Stomuch 11,76 1;1 x 1955 P. laeviconchus* Wedl, 27 Siganus virgatus ** Stomuch 2,86 2 x 1862 Genus Procamallanus Baylis, 1923 Subgenus Procamallanus (Spirocamallanus) Olsen, 1952 P. (Spirocamallanus) 28 spiralis* Baylis, Leiognathus splendens ** Intestin 8 4-22 x 1923

P.(Spirocamallanus) ** guttatusi Lateolabrax japonicus Intestin 16 3-8 x 29 Andrade-Salas,

Pineda-Lopez et Epinephelus retouti ** Intestin 7,14 7 x Garcia-Magana, 1994 P.( Spirocamallanus) 30 pereirai* Otolithes ruber Intestin 4,08 1-15 x Annereaux, 1946 P.( Spirocamallanus) dussumieri* 31 Jhonius carouna ** Intestin 6 1-8 x x Bilqees, Khanum & Jehan, 1971 Cephalopholis miniata Intestin 2/5 2;4 x 32 P.(Spirocamallanus) sp.* Lethrinus miniatus Intestin 18,18 3;3 x

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Familly Cucullanidae Cobbold, 1864 Genus Cucullanus Muller, 1777 C.heterochrous 33 Scatophagus argus ** Stomuch 10,14 3-21 x Rudolphi, 1802 Pomadasys maculatus ** Intestin 1,67 3 x C.rastrelligeri* Sargocentron melanospilos ** Intestin 3/8 1-37 x 34 Thanapon Y., Moravec ** F., Chalobol W., 2011 Sargocentron rubrum Intestin 1/8 4 x Siganus fuscescens ** Intestin 3,39 1-11 x Cucullanus x x 35 (Truttaedacnitis) Nibea albiflora ** Intestin 24,49 2-13 Truttae* Fabricius, 1794 Cucullanus x x 36 Jhonius carouna Intestin 10 2-14 (Cucullanus)*** sp. Genus Dichelyne Jagerskiold, 1902 37 Dichelyne sp. Jhonius belangerii ** Intestin 11,54 3-12 x

Note: * Nematode species was the first recorded in Vietnam; ** New host species; *** Maybe a new nematode species.

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3.2. The Classification of nematodes from Perciformes fishes in the off Vietnam. - General characters of 2 classes, 2 orders, 9 familly and 21 genera of nematodes in this study were provided. - 37 nematode species from Perciformes fishes were described. Other relevant issues of the described species were also commented, e.g. historical and differentiating characters, the different characters from the original description of the species and other close species in the common genus. - Providing a classification key for some nematode species which were collected in this study. - Using both molecular and morphological techniques to identify Anisakis typica. 3.3. The prevalence and intensity of nematode infection from Perciformes fishes in the off Vietnam. 3.3.1. The prevalence of nematode infection by fish families There are 32 out of 38 fish families infected with nematodes; other 6 families have no infection .

Figure 3.38: The prevalence of nematode infection by fish families 3.3.2. The prevalence of nematode infection by fish species A total of 3735 individuals of 129 fish species were examined. There were 825 individuals of 89 species infected by nematodes, and thecommon infection was 22.09%.

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3.3.3. The prevalence of nematode infection from Perciformes fishes by coastal regions in Vietnam. + The prevalence of nematode infection by fish families at each coastal region (number families of infected fish / number families of examined fish examinations at each coastal region).

Figure 3.39: The prevalence of nematode infection by fish families in different coastal regions + The infection rate of nematodes by fish species (number of infected fishes/ number of each examined fish species in different coastal regions).

Figure 3.40: The infection rate of nematodes by fish species in different coastal regions in Vietnam 19

+ The infection rate of nematodes in different coastal regions in Vietnam (Number of infected fishes / number of examined fishes in each coastal regions).

Figure 3.41: The infection rate of nematodes in different coastal regions + The percentage of examined fishes in each coastal regions (Number of examined fishes in each coastal region / A total of examined fishes in this study)

Figure 3.42: The percentage of examined fishes by regions + The infection rate of nematodes by regions (Number of infected fishes in each region / a total of examined fishes) 20

Figure 3.43: The infection rate of nematodes by the coastal regions 3.3.4. The intensity of nematode infection from Perciformes fishes in the off Vietnam The intensity of nematode infection has a large range of variability among fish families as well as fish species and even among individuals of each species, e.g. Oysters 1-128 worms / fish. 3.4. Several character of nematode fauna from Perciformes The researches on parasitic nematodes from marine fishes have are great importance because marine fish products have increaasingly contributed to total aquaculture production. So, the knowleadge of nematode fauna from marine fishes will help exporters to control the risks of “fishborne zoonotic nematodes” of their products.. However, researchs on nematode fauna were less received attend of scientists and managers in Vietnam. In this study, 37 nematode species were found in whole country. Among them, the number of nematode species in the Northern, Central and Southern coastal region were 15, 26, and 11, respectively (Figure 3.44). The diversity of nematode fauna in the Central coastal region is highest, and lowest in the Southern coastal region.

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Figure 3.44: The number of nematode species collected in the seas

Figure 3.45 : Characteristics of nematode distribution in Vietnamese waters 22

Figure 3.46: The number of host of nematodes Regarding to host-parasite relationship, 19 out of 37 (51,35%) nematode species parasitize in only one host species; 18 (48,65%) remained species have 2 or more hosts species (Figure 3.46).

Figure 3.47: The number of nematode species in their host(s) Among 89 infected fish species, 51 (57,30%) species were infected by only 1 nematode species. Similarly, the number of fish species infecting by 2, 3, 4 nematode species were 26 (29,21%), 9 (10,11%), and 3 (3,38%), respectively. 23

CONCLUSIONS AND RECOMMENDATIONS CONCLUSIONS 1. The study 3735 individuals of 129 fish species, 38 families of Perciformes has identified Thirdty seven nematode species belonging to 2 classes, 2 orders, 9 familly and 21 genera were identified, including 24 species have been identified at species level, 13 species have been identified at genus level . Especially, 19 species were the first time found in Vietnam, 26 fish species are recorded as new hosts for the nematode fauna. 2. The specialization of nematodes in their hosts (Perciformes) is quite high, e.g. 19 (51.35%) nematode species were foundfrom 1 fish species, 18 (48,65%) remained species have 2 or more hosts species. 3. The proportion of nematode species in their order, family, genus (18.5 species / 1 order; 4.11 species / 1 family; 1.76 species / 1 genus). The highest proportion is found in Rhabditida (97.30%, 36 species). Contrarily, the lowest proportion is found in Trichinellida (2.70%, 1 species). 4. 37 (100%) nematode species were found from bottom- dwelling fishes while only 7 (18.92%) were found from fish living in surface of the water. 5. The prevalence of common nematode is 22.09%, the intensity of infection is 1 - 148 worms/fish with a total of 7951 nematodes, including 2717 adult nematodes and 5234 larvae nematodes. RECOMMENDATIONS 1. Thirteen unidentified nematode species should be collected more samples for comparing morphological characters and molecular analyzing. 2. This study should be expanded to provide more data of nematodes in different fish orders and updating the knowleadge of nematode fauna from marine fishes in the off Vietnam. 24

LIST OF PUBLICATIONS 1. Hoang Van Hien, Nguyen Van Ha, Ha Duy Ngo, Nguyen Van Duc, Primary research on parasitic nematodes in some coastal marine fish of Quang Binh province, Vietnam Journal of Agricultural Sciences, 2017, 15 (11), 1529-1538. 2. Hoang Van Hien, Ha Duy Ngo, Nguyen Van Ha, Nguyen Van Duc, Research on parasitic nematodes in some coastal marine fish of Khanh Hoa province, Science and Technology Journal of Agriculture & Rural Development, 2018, 14, 70-77. 3. Hoang Van Hien, Ha Duy Ngo, Nguyen Van Ha, Nguyen Van Duc, Bui Thi Dung, Investigation on nematode species composition of perciformes in coastal reigion Hai Phong province, Publishing House for Science and Technology, 2017, 170-175. 4. Hoang Van Hien, Bui Thi Dung, Ha Duy Ngo, Nguyen Van Ha, Nguyen Van Duc, A Preliminary investigation on nematode species composition of the snake eels (Ophichthidae: Pisodonophis) in coastal reigion Nam Dinh province, Publishing House for Science and Technology, 2015, 126-132.