Nghiên cứu xây dựng qui trình sản xuất giống nhân tạo cá rô biển (lobotes surinamensis bloch, 1790) tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING NHA TRANG UNIVERSITY oo0oo - NGO VINH HANH RESEARH ON ARTIFICIAL SEED PRODUCTION OF TRIPLETAIL (LOBOTES SURINAMENSIS BLOCH, 1790) Major: Aquaculture Major code: 9620301 SUMMARY OF DOCTORAL THESIS Khanh Hoa – 2019 Research was accomplished at Nha Trang University Supervisors: Dr Pham Anh Tuan Dr Le Anh Tuan Referee 1: Associate Prof PhD Ton That Chat Referee 2: PhD Truong Ha Phuong Referee 3: Associate Prof PhD Vu Ngoc Ut The thesis was defended at the committee of doctorate thesis examiners of University in Nha Trang University at ………………… The thesis can be found at: ………………………………………… ………………………………………… KEY FINDINGS The thesis project is the first study on reproductive characteristics and technological solutions to artificial propagation of tripletail fish (Lobotes surinamensis Bloch 1790) in Vietnam Through the research, some reproductive traits of tripletail fish in the culture condition are identified, including: reproductive season occurs naturally from August to September annually; the first maturation age of the male and female is 0+ and 1+, respectively; the absolute fecundity ranges between 6,840,787 and 12,294,400 eggs per female whose total body weight is from 3.7 to 5.7 kg each; the relative fecundity ranges from 1,849 to 2,542 eggs per gram of female body weight (average = 2,306±283 eggs per gram of female body weight) In this study, suitable technical parameters were identified to develop the artificial fish propagation protocols for tripletail fish, such as: using fresh cuttle-fish as broodstock food results in the best performance in maturation, fertilization, hatching and fish larval rates, and survival rate of fish larvae at the age of days after hatching; using LHRH-a with dosage of 20µg+2mg DOM per kg of female body weight results in the best performance; the optimal incubation density is between 1,500 and 2,000 fertilized eggs per litter of sea-water; using a combination of live micro-algae, rotifers and copepods as fish larvae’s food results in the highest survival rate; the tripletail fish larvae which are reared with the density of 30 individuals per litter and at the salinity between 25 and 30 ppt have higher growth and survival rate Ph.D Student Ngo Vinh Hanh LIST OF PUBLICATION AND CONFERENCE Ngo Vinh Hanh, Nguyen Huu Ninh, 2016 Research on nursing of Tripletail (Lobotes surinamensis Bloch, 1790) Science and Technology Journal of Agriculture and Rural Development, pp 93-98 Ngo Vinh Hanh, Nguyen Huu Ninh, 2015 Research on reproductive characteristics of Tripletail (Lobotes surinamensis Bloch, 1790) under artificial condition Science and Technology Journal of Agriculture and Rural Development, pp 65-70 INTRODUCTION Tripletail (Lobotes surinamensis Bloch, 1790) is a very potential aquaculture species due to its rapid growth and high meat quality (Jason, 2011) The tripletail is natural distribution in coastal and offshore areas from North to South of Vietnam Cage culture of this species is very popular in coastal areas including Quang Ninh, Hai Phong provinces In order to develop tripletail for aquaculture, source of fingerling is main limited, this issue is not only for tripletail but also for other marine species in Vietnam Therefore, it is necessary to study artificial propagation of tripletail (Lobotes surinamensis Bloch, 1790) Aims of study: Establishment of procedure for artificial propagation of tripletail Main activities of the study: Study on reproductive characteristics of tripletail in captive condition Study on broodstock management and husbandry Study on induce breeding Study on nursing from larvae to fry and fingerling Scientific and practical application of the study: For scientific: The research results provide scientific data for artificial seed production of tripletail In addition, the achieved results are also reference for other valuable marine fish species of similar biological characteristics For practical: Building up procedure for artificial seed production of tripletail that contribute to diversify marine aquaculture fish species and preserve natural resources New findings: In Vietnam, this is the first study on biological characteristics, factors effect to growth, breeding, embryo development and nursing that provide scientific and practical knowledge for building up procedure of artificial propagation of tripletail (Lobotes surinamensis Bloch, 1790) CHAPTER LITERATURE REVIEW 1.1 Some biological characteristics of tripletail Tripletail (Lobotes surinamensis Bloch, 1790) is also called blackfish, Atlantic tripletail of the Perciformes family, Lobotidae family In the world they are distributed from the tropics to the subtropics In Vietnam, tripletail is distributed from North to South, from estuaries to estuaries (Pham Thuoc, 2007) Tripletail has a variety of shapes ranging from yellowish brown to dark brown with faint spots and mottled spots Tripletail, which spawns several times during a breeding season, mainly spawns in three months (June to August) Tripletail male reach sexual maturity at age 0+, female at age 1+ Tripletail feeds are crustaceans in the bottom water body and small fish, which can reach 19.2 kg body weight 1.2 Marine fish seed production technology in the world and Vietnam In the world: The thesis has provided an overview of the development of marine fish fry production in the world through references of FAO (2005, 2006), Rimmer (2008), Hong and Zhang (2003), Liao (1969), Liao et Takeuchi (2001), Nguyen Dinh Mao and Le Anh Tuan (2007), Shields (2001), Lee and Ostrowski (2001), Faulk and Holt, (2005) To better understand the nutritional requirement of broodstock and larvae in marine fish seed production, the thesis research have been referred from studies of Fernández-Palacios (1995, 1998, 2011), Brooks Kjorsvik et al (1990), Brooks et al (1997), De Silva Sena (2006), Azeddine et al (2009), Understanding the mechanism of action of environmental parameters as well as hormones in promoting sexual maturation and stimulating spawning in fish is very important, allowing us to formulate strategies better seed production or possibly improved breeding techniques by synthetic hormones or artificial extracts The thesis referred from studies of Weirich and Riley (2007), Bui Minh Tam et al (2008); Cerdá et al (1994), Tucker (2000); Ho et al (2005), Main et al (2007), Ngo Vĩnh Hạnh (2007), Pham Quoc Hung and Nguyen Tuong Anh (2011), In Vietnam In 1990s, many studies on artificial seed production and growout of marine species were conducted in Vietnam through the reports of Dao Manh Son (1998), Truong Si Ky (2006), Do Van Khuong (2001), Le Xan et al (2003, 2005), Nguyen Dich Thanh (2008), Research on artificial seed reproduction of tripletail In the world, there are two researches on artificial seed production of tripletail reported by Franks et al (2005) and Jason et al (2011) Up to present, there have been no research study on artificial seed reproduction of tripletail in Vietnam although some studies have been reported on morphological characteristics CHAPTER MATERIALS AND METHODS 2.1 Subjects, time and place of study 2.1.1 Research objects: Tripletail (Lobotes surinamensis Bloch, 1790) 2.1.2 Study period: Time of study is from 2012 to 2015 2.1.3 Study sites: National Marine Breeding Center, Cat Ba, Hai Phong 2.2 Materials and methods 2.2.1 Materials Tripletail (Lobotes surinamensis Bloch, 1790) broodstock were wild-caught and selected on farms in Quang Ninh, Hai Phong provinces The number of collected breeder is 150 individuals with an average weight of about 3.0kg 2.2.2 Methods 2.2.2.1 Study on reproductive characteristics of tripletail in captive conditions The project has used 110 individuals to raise and study on maturity index from July 2012 to June 2015 Broodstock were cultured in cages (3×3×3m), 10-12 cm/individual in length, 15 individual/m3 in stocking density Samples of 3-5 brooders were collected monthly to examine general reproductive characteristics such as maturity, size of first mature fish, maturity index These samples were also used to study on histology of gonad development Age at first maturity: The age at first reproductive male was observed base on fish that was produced artificially in 2011, 2012 and grow-out in cages in Cat Ba, Hai Phong 2.2.2.2 Study on broodstock management and husbandry in cage Tripletail broodstock management are divided into two stages: 1) Pre-maturation culture starts from October to end of April with feeding rate 3-5% of body weight; 2) Maturation culture starts at early May with feeding rate 2-2.5% of body weight Experiment for feeds trial of broodstock husbandry: Treatment 1: Feeding 100% trash fish Treatment 2: Feeding 50% trash fish + 50% fresh squid Treatment 3: Feeding 100% fresh squid 2.2.2.3 Study to induce spawning using hormones Experimental design of using hormones to induce spawning as follows: LHRH-A 10µg + 2mg DOM Expe rime nt Expe rime nt 20µg + 2mg DOM 20µg + 2mg Expe rime nt Expe Cá rime nuôi vỗ nt 1ở TN1 Expe Cá rime nuôi vỗ nt 2ở TN2 30µg + 2mg DOM 30µg + 2mg Expe Cá rime nuôi vỗ nt 3ở TN3 Expe rime nt Expe rime nt Expe rime nt Parameters measured: Spawning rate, fertilization rate, hatching rate, time effect of drug (spawning) - Effect of temperature in incubation: Experiment was set up with hatching temperatures: 230C, 260C, 290C, 320C - Effect of salinity in incubation: Experiment was set up with hatching salinity: 15‰, 20‰, 25‰, 30‰, 35 ‰ - Effect of density in incubation: Experiment was set up with incubation density: 1,500, 2,000, 2,500 eggs / liter 2.2.2.4 Study on nursing from larvae to fry and fingerling (5-6 cm/fish) • Nursing from larvae to fry Experiment 1: Trial of some feeds for nursing Treatment 1: Fresh algae + Rotifer + Copepoda Treatment 2: Algae + Rotifer + Artemia Treatment 3: Algae + Rotifer + pellet feed Experiment 2: Study on the effect of stocking density and salinity on growth and survival rates Experimental design as follows: 20‰ 30 ind./L 40 ind./L 25‰ 50 ind./L 3030 con/lít ind./L 4040 con/lít ind./L 30‰ 5050 con/lít ind./L 30 ind./L 40 ind./L • Nursing from fry to fingerlings (5-6 cm/fish) The treatments of stocking densities were 200, 400, 600 and 800 individuals/m3, using pellet feed (Inver, Thailand) with protein content ≥56%, lipid ≥9% 2.2.2.5 Data calculation - Coefficient of maturation: Wtsd × 100 K (%) = -Wo Where: K is the maturity coefficient (%) Wtsd is the gonad weight Wo is the weight of fish without intact - Relative and absolute spawning capacity: 10 50 ind./L Table 3.3 Effects of hormone doses and food for breeder on time (hour) of hormone influence Hormone doses LHRH-A LHRH-A LHRH-A 10 µg + 20 µg + 30 µg + 2mg 2mg 2mg DOM 100% trash fish Diets 50% trash fish+50% squid 100% squid Mean DOM DOM a 40.17a 40.94X 43.12b 40.00a 40.17a 41.11X 43.17b 39.83a 40.33a 41.11X 43.06B 39.89A 40.22A ±0.248* 42.83 b Mean 39.83 Mean values with different letters differed significantly (p