Summary of biology doctoral thesis: Nematode species component in some perciformes fishes in coastal regions of Viet Nam

Thesis 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.

MINISTRY OF EDUCATION

AND TRAINING

VIETNAM ACADEMY OF 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 nematodes, to human and animal health constitute are an important problems The infections are not only caused health deficiency or disability of humans and animals 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 nematode 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

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

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)

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

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)

6

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

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)

8

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

in host

Prevalence (%)

Intensity (Min-

PHYLUM NEMATODA POTTS, 1932

Class Enoplea Inglis, 1983

Order Trichinellida Hall, 1916

Familly Capillariidae Railliet, 1915

Genus Capillaria Zeder, 1800

1 Capillaria sp Decapterus maruadsi Stomuch 11,43 1-12 x

Seriola dumerili Stomuch 22,73 1-5 x PHYLUM NEMATODA POTTS, 1932

Class Chromadorea Inglis, 1983

Order Rhabditida Chitwood, 1933

Familly Anisakidae Skrjabin & Karokhin, 1945

Genus Anisakis Dujardin, 1845

2

Anisakis typica *

(Diesing, 1860)

Baylis, 1920

Decapterus macarellus Cavity 19,35 1-9 x

Megalaspis cordyla Cavity 5,88 1-3 x

Priacanthus hamrur Cavity 33,89 1-18 x

Pristipomoides filamentosus Cavity 30 1-2 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

Lutjanus vitta Intestin 50 1-14 x x x x x

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

Selar crumenophthalmus Cavity 17,39 1-14 x x x

Siganus canaliculatus Intestin 5/5 23-100 x

10

Trichiurus lepturus Cavity 27,85 3-24 x x

4 Contracaecum sp

Acanthopagrus latus Cavity 40 1-12 x

Alepes kleinii Cavity 8,55 1-8 x x x x x

Eleutheronema tetradactylum Cavity 10,20 2-12 x x x

Epinephelus amblycephalus Cavity 19,30 1-6 x x x x x

Gerres filamentosus Cavity 31,75 5-27 x x

Larimichthys croceus Cavity 2,86 4 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

7

H aduncum

Rudolphi, 1802

Alepes kleinii Intestin 7,69 1-7 x x x x x

Carangoides malabaricus Intestin 27,40 1-11 x x x

Cephalopholis miniata Intestin 3/5 1-3 x

Epinephelus retouti Intestin 7,14 1 x

Evynnis cardinalis Intestin 58,06 1-6 x 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

Sillago Aeolus Intestin 6,67 2 x

Terapon jarbua Intestin 18,47 1-6 x x x x

8

H chorinemi

(Parukhin, 1966)

Bruce & Cannon, 1989

Nemipterus hexodon ** Intestin 37,14 4-17 x

Upeneus sulphureus ** Intestin 86,36 1-18 x

Upeneus tragula ** Intestin 14,63 1-23 x

Nemipterus marginatus Intestin 6/8 2-24 X

Parupeneus macronemus Intestin 6,67 6 X

Upeneus moluccensis Intestin 26,67 2-7 x

12

Upeneus tragula Intestin 24,39 4-18 x x x x

Genus Raphidascaris Railliet & Henry, 1915

12 Raphidascaris

acus* Bloch, 1779

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

Carangoides malabaricus Intestin 16,44 2-7 x x x x x

Coryphaena hippurus Intestin 1/5 3 x

Dcapterus maruadsi Intestin 48,57 1-128 x x x

Decapterus macarellus Intestin 51,61 1-13 x 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

Priacanthus macracanthus Intestin 10 2 x

Rastrelliger brachysoma Intestin 12,35 1-8 x x

Selar crumenophthalmus Intestin 13,04 3-23 x x

Sphyraena jello Intestin 9,43 1-5 x x

13 Raphidascaris sp

Alepes kleinii Intestin 8,55 1-11 x x x x 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

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

Lutjanus russelli Intestin 3,92 1;3 x

Parastromateus niger Intestin 6,67 2-8 x

14

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

14 R nipponensis*

Yamaguti, 1941

Dactyloptena orientalis

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

17 Ascarophis sp

Sargocentron melanospilos **

18 A moraveci Ha et

al., 2011

Scatophagus argus Stom 5,80 1-8 x x

Nibea albiflora Stom 22,45 2-17 x x

Genus Spinitectus Fourment, 1883