Nghiên cứu đặc điểm sinh học và khả năng nhân giống cá ong căng terapon jarbua (forsskal, 1775) vùng ven biển thừa thiên huế tt tiếng anh

HUE UNIVERSITY COLLEGE OF EDUCATION LE THI NHU PHUONG RESEARCHING ON BIOLOGICAL CHARACTERISTICS AND PROPAGATION ABILITY OF Terapon jarbua (Forsskål, 1775) IN COASTAL AREAS OF THUA THIEN HUE THESIS SUMMARY HUE, 2019 The work was completed at THE COLLEGE OF EDUCATION, HUE UNIVERSITY Science instructors: Assoc Prof Dr Vo Van Phu Assoc Prof Dr Nguyen Quang Linh Reviewer 1: Reviewer 2: Reviewer 3: The thesis was defended at the Council of thesis assessment of Hue University: Council held at: Le Loi Street, Hue City, Thua Thien Hue Province, at… on … /… /201… The thesis can be further referred at: National Library Center for Information and Library of College of Education, Hue University INTRODUCTION Thua Thien Hue, a coastal province in the Central region of Vietnam, has over 127 kilometer - length coastline, continental shelf of the East Sea and large lagoon system, and diverse ecosystems which are inhabitations of so many aquatic species The lagoon system and coastal area of Thua Thien Hue have many values in terms of socio-economy, cultural history, especially of ecology, environment and biodiversity Seafoods such as fish, crab, shrimp, molluscs, acquatic plants are all essential resources for high economic value of exports Developing aquaculture and fishery in the area appropriately plays a critical role in contributing to the development of Thua Thien Hue province's socio-economy Marine-orgin Terapon Jarbua (Forsskål, 1775) belongs to the family of Teraponidae and locates in set of Perciformes entered the lagoon and estuarine and coastal areas In many recent years, natural resouces in the estuarine and coastal areas are being over-fished and not put in master plan that have been leading to serious ecological consequences such as destroying the habitat of many species, declining biodiversity and reducing the benefits of valuable - exploited objects, specially Terapon jarbua Prior to the demading of aquaculture and management of the benefits of T Jarbua in coastal and lagoon areas of Thua Thien Hue, intensive research on the biological characteristics and fertility of the T jarbua to proceed to artificial breed production that aims to be proactive in providing stable and quality breed sources for aquaculturists, contributing to species conservation and development Hence, we choosed this topic research: "Researching on biological characteristics and propagation ability of Terapon Jarbua (Forsskål, 1775) in coastal area of Thua Thien Hue." 1 Necessary of the research Through the first steps of surveying the recent researches on T Jarbua’s family in generally and on T Jarbua both worldwide and in Vietnam in particular, as well as exploiting and fishing T Jarbua in Vietnam, the research topic was selected for these following reasons: - In the world, the studies of the family of T Jarbua in generally and of T Jarbua in particular mainly focused on biological characteristics, distribution and its habitat - Some studies of T Jarbua in Vietnam mainly focus on description, distribution, some biological characteristics, there has not been any study focused on artificial reproduction - T Jarbua is considered to have many prospects for growing in the lagoon area of Thien Thien Hue because of its good resistance, energy, commercial value, high nutritional value, and being flavored by many people However, aquaculture of T Jarbua has not been developed as its potential prospect because of shortage of breeding source, and especially, artificial produced breeds to supply large quantities for demanding Hence, the study of biological characteristics and breeding capacity of T Jarbua has contributed to the aquaculture in Thua Thien Hue province Research objectives - Comprehending and identifying the biological characteristics of the T Jarbua in the coastal area of Thua Thien Hue - Exploring the propagation ability of T Jarbua: testing some appropriate kinds of sex hormones, sexual stimulants to exalt reproduction of T Jarbua, researching on the growth of T Jarbua alevin and on technical methods to grow breeds from the alevin period to fingerlings Research contents - Researching the biological characteristics of T Jarbua: characteristics of growth, nutrition and reproduction - Using the different sex hormones and sexual stimulants to axalt T Jarbua in the process of artificial reproduction and the growth of T Jarbuas'embryo - Researching to rear the T Jarbua from alevin stage to breeding stage in distinctive levels of salinity and kinds of food - Building up process of breeding T Jarbua The scientific and practical significances of the subject - Aspects of science: + This thesis is to contribute to providing complete data on the biological characteristics of T Jarbua +The reseach is to ascertain some types and doses of sex stimulants, stimulants for artificial breeding in T Jarbua Techniques to grow breeds from the alevin stage to fingerling stage and to breedings - Practical aspects: The conclusions about the biology and techniques of the production of T Jarbua breeds will be an important source of documents for the improvement and development of the production of breedings and growing breeds, to proactively supply breeds for aquaculture, diversifying objects and aquaculture models, contributing to sustainable development of aquaculture in coastal areas Contribution of dissertation - For the first time, providing basic and complete documents on biological characteristics, especially reproductive characteristics of Terapon jarbua in coastal areas of Thua Thien Hue province - Providing artificial breeding process of Terapon jarbua to breed proactively in problem of fish cultivation in coastal areas of Thua Thien Hue The layout of the thesis In addition to the appendix, the thesis is presented in 109 pages, the layout includes the following sections: Preface Content: Three chapters Chapter 1: Document overview Chapter 2: Subject, location, time and methods of reseaching Chapter 3: Result and conclusion Summary and suggestion References Appendix Chapter THE DOCUMENT OVERVIEW Teraponidae family in worldwide has about 52 species in 16 varieties Their contribution is mainly in the coastal areas of the Indian Ocean and the Western Pacific Some documents show that studies of T Jarbua mainly focused biological characteristics, distribution and its habitats Especially, the correlation between length and weight of Terapon jarbua has been studied by many authors in India, Taiwan, Thailand, and Pakistan, etc These studies showed that the fishes grew rapidly in length in early period while in the post period fish increased rapidly in weight, along with common adaptability of many tropical coastal fishes The studies on nutrition of T jarbua have many views depending on the natural conditions of each studying area but they all confirmed that the large-size fish group has a wider food spectrum than the small-size one Studies on characteristics of reproductive biology of T jarbua concentrated on developmental period of gonads, absolute reproductive capacity, relative reproductive capacity, GSI coefficient and breeding season Through studies, it can be seen that the reproductive capacity of T jarbua is relatively high, the breeding season is mainly in the period of Spring - Summer In Vietnam, Teraponidae family is recorded with species, varieties, mainly distributed in estuaries and coastal areas The studies on Teraponidae family mainly focused on classification and biological characteristics (anatomy, growth, development, nutrition, reproduction, ) In a number of domestic studies on classification and ecology, species of Teraponidae family are identified as commercial fish It can be seen that Teraponidae family has a few species In the most areas, two common species are T jarbua, T theraps According to the above studies, it can be seen that the T Jarbua has a wide distribution area and distributed in rivers, estuaries, coastal area and in the saline water area as well In Vietnam, the studies on Teraponidae family and Teraponidae family mainly focused on composition of spieces, identifying Teraponidae family including economic-value fish The research focused mainly in some estuarine, coastal areas The study of biological and ecological characteristics still seems to be still limited, mainly in the central coastal provinces A number of studies on experiments to preserve genes and researches for conservation and sustainable development have been undertaking In general, in Vietnam, studies of artificial reproduction of marine fish are conducted mainly in coastal areas and objects are almost economic-value fishes In order to reproduce artificialy, the authors used sex hormone stimulants such as hypophysis of fish, HCG, LHRHa + Dom, Ovaprim with different doses Currently, there has not been any study specializing in exploration of propagation ability of Terapon jarbua in Vietnam published in prestigious domestic and international magazines Therefore, the study on biological characteristics, exploration of propagation ability of- Terapon jarbua (Forsskål, 1775) is very essential to improve the artificial production process of breeds as well as supplying the breed source for aquaculture in our country Chapter OBJECTS, MATERIALS AND METHODOLOGY 2.1 Objects, period and place of research T Jarbua (Forsskål, 1775) (picture 2.1) is located in classification system of chordata - Phylum: Chordata - Class: Actinopterygii -Order: Perciformes -Family: Teraponidae - Genus : Terapon - Species: Terapon jarbua (Forsskål, 1775) - Common names: Cá Căng, Cá Ong căng or cá Căng cát - English Name: Target Fish or Crescent Perch - Synonyms: Scianena Forsskål, 1775 Holocentrus jarbua Forsskål, 1775 Therapon jarbua Forsskål, 1775 Figure 2.1 Terapon jarbua (Forsskål, 1775) 2.2 Research period The project was carried out from May 2015 to December 2017, in which field surveys and sample collection were conducted in two years from September 2015 to August 2017; The experiments of exploring the artifical reproduction in Terapon jarbua was conducted simultaneously with sampling and using the previous data of the State-level scientific topic of Genetic Fund by Assoc Dr Nguyen Quang Linh chaired, and the author was a member 2.3 Research place 2.3.1 Location of collecting specimens Throughout the study areas, we selected 10 locations for collecting but Tam Giang lagoon and Hai bridge area has complex habitats, so there were research sites selected In the coastal area of Thua Thien Hue, we placed the study sites about kilometers from the shoreline, that was about 20 meters of the average depth, suitable for near-shore fishing vessels, the experimental specimens were fresh and favorable benefit of studying the growth of collected fishes (Figure 2.2) (Source: Google map) Figure 2.2 Locations of collecting the researching specimens 2.3.2 Places for analyzing the research specimens Laboratory of Incubation Center and Technology Transfer Center; Institute of Biotechnology and Department of Biology, University of Science, Hue University 2.3.3 Locations for exploiring breeding capacity Breeding and artificial reproduction experiments were conducted at the Center for Aquaculture Practices and Internship, Research and Development Institute; Huy Son Breeding Farm in Phu Thuan Commune, Phu Vang District, Thua Thien Hue Province 2.4 RESEARCH METHODS 2.4.1 Diagram of the research 2.4.2 Research methods in the field We collected fish specimens by fishing directly with fishermen or buying them at boats, fish stations, markets along the lagoon and along the coastal areas of Thua Thien Hue The collected specimens of Terapon jarbua were fresh to measure weight and length, take scales, anatomy, The total number of collected specimens during the researching period were 720 Collecting specimens for the growth research: processed the collected fish as soon as they were fresh, measured body-length index (L and L0) and weighed scales (W and W0) of the fishes Collecting of specimens for nutrition research: fish-specimens were operated on as soon as they were alive to observe the intestines and had been on surgery to take food in the digestive tracts Then, shaping the food in 4% formol liquid or 70O alcohol liquid We defined the food composition of T Jarbua in each month in the year and in fish size groups Collecting of specimens for reproduction research: collected fish specimens were on anatomy to determine the weight and periods of sexual maturity of T Jarbua gonads about morphology following a 6-step scale of K.A Kisisevits (1923), then fixed in Bouin liquid and making specimens used in researching the cytology of gonads of T Jarbua 2.4.3 Research methods in Laborary room (Lab): 2.4.3.1 About the criteria of mornology classification Measuring classification criteria based on Pravdin‟s guide papers of researching on fish (1973) 2.4.3.2 Research on growth Determining the length-weight correlation: The length-weight correlation of the T Jarbua was indicated by the growth equation of Berverton - Holt (1956): W  a  Lb Determining age: Using scales to determine the age of the T Jarbua Growth rate: Using the method of Rosa Lee (1920) to determine the level of length growth of T Jarbua with the formula: V (1) Lt  t  L  a   a V The growth equation of Von Bertalanffy (1952):  k t t -Length: Lt  L 1  e      - Weight: Wt  W 1  e k t t0     2.4.3.3 Research on nutrition Ascertaining components of feeding: food was separated from in-research fishes‟ guts and stomaches in diferent size groups Observing under the microscope or magnifier loupe double eye glasses Drew observed specimens of food in used glasses‟s slide in order to classify morphology of each group (taxon) and categorized into groups Nutrition spectrum analysis: ascertaining nutrition spectrum of T jarbua by using the method of Mass spectrometry of Biswas (1993) Ascertaining the intensity of catching grey of fish: relying on the stomach capacity in gastrointestinal tract of fishes to evaluate the intencity of catching grey Stomach capacity was measured by the satiety level of research subjects Confirming the satiety of stomach and guts in scale of five (from level to 4) of Lebedev Ascertaining the coefficient of fat: using Fulton‟s methods (1902) and Clark (1928) to confine Terepon jarbua’s coefficient of fat 2.4.3.4 Research on reproduction Researching reproduction of research subjects was conducted by using common methods of Fish Physiology using in laboratory (Lab) of Pravdin (1973), Sharech (1990), Micheal King (1995) and Quentin Bon (2008) b equation is 8.6 mm That was the size of the fish at the beginning of the formation of scales Rosa Lee (1920)‟s the „back calculating‟ equation of Terapon jarbua growth process could be written: Lt  ( L  8, 6) Vt  8, V The equation of length and weight growth according to Von Bertalanffy takes the form: Lt  346,08.[1  e0,426.(t 0,323) ] The parameters showed that T jarbua could reach a maximum weight of 1,132.0 g, corresponding to a maximum length of 346.08 mm 3.1.2 Nutrition characteristics 3.1.2.1 Food ingredients The analytical results showed that the composition of T Jarbua was quite diverse, including 28 types of food belonging to different aquatic groups and organic residue humus Among them, the predominant was types of Arthropoda (accounting for 21.43%), followed by Silica (accounting for 17.86%), Annelida and Vertebrate fauna with the ratio of 14.29%, Cyanobacteria and Mollusca occupy 10.71%, organic residue humus accounted for 3.57% 3.1.2.2 Intensity to catching prey 3.1.2.2.1 Intensity of catching prey over time From the obtained results, comments could be made: T Jarbuas catched prey over months of the year but with different intensity In March and May that was the most possitive intensity In the dry season, fish catches more actively than the rainy season This could be related to water temperature and nutrient requirements for sexual maturity 3.1.2.2.2 Together with the gonad development T Jarbua's gonad developed through stages Every stage of development of the gonads was related to the process of nutrient accumulation, energy This could be shown in relation of the satiety of the fish and the development of each stage of sex maturity 3.1.2.2.3 To age group The research results on the intensity of feeding of fish by each age group showed that fish stomach and intestines in five age groups have different levels of satiety (table 3.12) This proved that the fishes catched aggressively (digestive tubes were full of food) From fish in the age group of 0+ to 2+, the intensity increased along 12 with age level, more aggressively than ones in age groups + and 4+ In each age group, the intensity was also different (expressed at different levels of satiety) Right from the age of 0+ stage T jarbua fish had been shown to be quite aggressive prey species, showing that up to 4.2% of fish were at level and 1.1% at level 3.1.2.3 Coefficients of fat of T Jarbua It could be seen that the Coefficients of fat following Fulton's formula was always bigger than Clark's formula This showed that the internal organs' weight (digestive tract, gonads, food) of T Jarbua was quite large The commercial value of fish depends on the fatness of each age group Therefore, it was possible to base on the fat coefficient to determine the appropriate age for fishing to achieve high product quality 3.1.3 Charateristics of reproduction 3.1.3.1 The period of development of auxocyte Research on the organization structure of the fish 's gonads in accordance with Xakun O.F.'s and Buskaia N.A (1968)'s theories [41] We found that there were four stages of found process of egg cell (ovum) of T Jarbua: the synthesis stage of nucleus, the stage of phospholipid and protein growth, the stage of nutrition growth and the sexual maturity stage The process of developing male reproductive cells also underwent stages: reproduction stage, growth stage, formation stage and maturity stage 3.1.3.2 Development stages of the gonads According to point of view of Kiselavis K.A (1923); Xakun O.F and Buskaia N.A (1968), we used external morphological characteristics to divide the developmental stages of the gonads of T Jarbua and combined with analysis of the organization structure of the fish's male gonads to divide the process of male gonad development and female ovary of T Jarbua into stages 3.1.3.3 Age of sexual maturity T Jarbua in the coastal area of Thua Thien Hue were early sexual matured, fish in the age 1+ group could have sex to join oviparity Aged 2+ to 3+ groups were the main groups involved in oviparity during the breeding season 3.1.3.4 Fertility Relative reproduction of T Jarbua in Thua Thien Hue fluctuated not much compared to length and weight in different age 13 groups, from 967 - 999 eggs / g, averaging 982 eggs / g Similar to the study of Tsu-Chan Miu and cs(1990), when studying the absolute fertility of T Jarbua in Taiwan ranged from 37,083- 480,400 eggs (average 145,816), the relative fertility of the fish ranged from 334 1,258 (520) eggs / g It could be seen in the wild that T Jarbua had a relatively large fertility If they were not over-fished, the ability of repopulation of T Jarbua in the coastal area of Thua Thien Hue would be high and capable of repopulation 3.2 THE BREEDING CAPACITY TEST IN TERAPON JARBUA 3.2.1 Stimulation of reproduction and hatching of T Jarbua 3.2.1.1 Growing sexual maturity of T Jarbua 3.2.1.1.1 Environmental factors The fluctuation of the factors of temperature, salinity, dissolved oxygen, pH in the growing process were in the permitted level and favorable for the development of T Jarbua 3.2.1.1.2 The sexual mature of the T Jarbua in growing process a) Influence of the environment on the sexual maturity of T Jarbua The result of g in different environments showed that the rate of sexually maturing fish in both experiments increased gradually and reached the highest level in the 5th month The rate of maturity of male fish was higher than female one For seawater-environment experiments, the rate of sexual maturity reached 57.1% (female) and 65.7% (male fish) lower than that in lagoon environment was 68.6% (female) and 71.4% (male) Thus, growing in seawater and lagoon environment both gained good results of the development of gonads of T Jarbua The lagoon environment had a higher maturity rate, but not significantly This result showed that the possibility to grow sexual maturity of T Jarbua successfully to serve the production of artificial breeds b) Effect of feeding types on the ability of sexual maturity of T Jarbua The result of rearing sexual maturity after months, the rate of sexually maturing in experiments increased gradually and reached the highest level in the 5th month For the experiments feeding fish with mixed food (50% trash fish + 50% squid), the rate of sexual maturity reached 68.6% (females) and 71.4% (males); while the experiments with 100% trash fish feeding the rate was 51.4% (female) and 62.9% (male) In each month of growing, the rate of female- sexual maturing in the experiments fed trash fish was lower 14 than of the mixed feed experiments From the above-mentioned results of the maturity growth, it could be confirmed that T Jarbua was able to be normal sexual maturity in seawater fishponds, in lagoon environment with food source including trash fish or 50% trash fishes and 50% squids 3.2.1.2 Stimulating T Jarbua's reproduction 3.2.1.2.1 Influence of LRH-A3 concentration on some reproduction indicators of T jarbua Thus, the appropriate concentration of LRH-A3 to stimulate T Jarbua's reproduction gave the best results in terms of duration, fertility, fertilization rate and hatching rate of eggs was 70 μg / kg + mg / kg DOM The used dose of LRH-A3 for T Jarbua to get the success was higher than the used dose for Rachycentron canadum (20 and 30µg / kg) and lower than the dose for M planiceps 100 µg / kg female) 3.2.1.2.2 Influences of HCG concentration on some reproductive parameters of T.jarbua We could see that the concentration of HCG only affected the effect time (the higher the concentration, the shorter the duration of effect) but it did not change the results of fertilization rate and hatching rate of the T Jarbua The dose of HCG used in artificially reproduction of T jarbua was similar to that of R canadum (250 750 UI / kg female), lower than white M planiceps (1,500 UI / kg female) and Lates calcarifer (4,500 UI / kg female) Hereby,we can see that the using of different reproductive stimulants also gave results, some stimulants effectively on some piece may not effective on others Therefore, in artificial reproduction of fish, it was depended on the subject and the specific conditions; the type, dosage and method of injecting of the appropriate stimulants should be used to bring about high effects in artificial reproduction From the research results in the experiment of stimulating artificial reproduction in fish, it can be concluded that in order to get the best result in stimulating artificial reproduction, the LRH-A3 with the dose of 70 μg / kg + mg / kg DOM or HCG with the dose of 750 UI / kg female could be used 15 3.2.1.2.3 The development of the T jarbua’s embryo a inseminated eggs (x40) b two cells(30 muinutes) (x40) c cells (1 hour) (x40) d cells(1hour 30 munites) (x40) e 32 cells (2 hour 30 munites ) (x40) f Embryo 64 cells (3 hours) (x40) g Blastocyst (5 hours 40 minutes) (x40) h Nerve embryos (10 hours) (x40) i Hatching embryo (14 hours 40) (x100) k Newly hatched Alevin (14h50) (x40) Figure 3.2 The development stages of fish embryo 16 The time of T Jarbua's embryo development ranged about 14 to 16 hours, with an average of 14 hours and 50 minutes in water temperature of 28.0OC to 29.5 OC and pH from 8.3 to 8.4 Newly hatched fish were nourished by yolk and after about - days, the fish would use all yolk and started feeding with external food 3.2.2 Techniques to grow the Alevins to fingerlings 3.2.2.1 Factors of invironment The temperature in duration of growing varied in the range of 26 - 31OC, in which the average temperature ranged from 26.5 ± 2.8, the temperature during the experiment was favorable for growth and development During the experiment, dissolved oxygen content (DO) ranged from 4.5 - 5.6 mg /l, averaging at 5.2-5.4 mg /l It could be seen that DO in hatching ponds was suitable for the development of the experimental fish 3.2.2.2 The influence of types of food on the survival rate of T Jarbua from the alevin stage to fingerlings stage After 15 days of rearing, the survival rate of fish from experiments was quite low, ranging from 1.03% - 4.48% (Table 3.1) The highest survival rate in experiments number (Nanochloropsis oculata + Rotifer) was 4.48%, followed by experiments number (Nanochloropsis oculata + Nauplius of artemia) reaching 3.23% and lowest was experiments number (Nanochloropsis oculata + industrial feeds) 1.03 % Especially in the experiments number 4, alevins died simultaneously after days with industrial feeds Results of variance analysis showed that there was a statistically significant difference among experiments (p