Study On Artificial Breeding Technology Of Mastacembelus Armatus In Hainan

The tire track eel(Mastacembelus armatus)is delicious and nutritious,with high market economy value and development prospects.In recent years,due to overfishing and environmental degradation,the population resources of wild tire track eel have decreased sharply.Various regions have accelerated the research on the protection of germplasm resources and artificial breeding techniques.Based on the understanding of the reproductive biology of the tire track eel in Hainan,this study carried out research on artificial breeding techniques,in order to establish a large-scale breeding technology system for large locusts in Hainan.The main research results are as follows:Through sampling and researching the wild population of tire track eel in Hainan,the stable and countable traits of the number of dorsal spines and vertebrae can be determined as the classification of the tire track eel,and the most significant physical indicators of the weight of the tire track eel in Hainan are found.Body length(BL)and liver weight(LW),the relationship is BW=-1.98.198+9.608 BL+16.834 LW,these two indicators can provide reference for broodstock selection and pedigree breeding in the breeding of tire track eel in Hainan.On the comparable traits,the body length/1-2(X1),body length/7-8(X2),full length/body length(X3)and body length/6-7(X4)were selected.The weight-based regression equation of the tire track eel in the Longzhou River Basin:BW=-6392.903+256.392Xi-79.840X2+5394.003X3-83.928X4,which can be used as a basis for judging the population of the tire track eel in Hainan.The above studies have different results in the selected physical signs and screening results from the morphological findings of the populations of the tire track eel in other regions.The effects of feed type,water temperature,feeding mode and flow stimulation on the growth and gonad development of tire track eel in Hainan were studied.The tamed bait suitable for different sizes of wild the tire track was determined:≥50g The suitable bait for juvenile the tire track eel is red worm,the suitable bait for 50-120g tire track eel is yellow mealworm,the suitable bait for≤120g tire track eel is barley worm;the optimum growth temperature for tire track eel broodstock in Hainan is 26-29℃ The monthly weight gain ratio can reach 41.87%,and the gonad development is also the most rapid;the daily food intake of the tire track eel can reach 4%of the body weight.The best feeding method is to feed the fish body weight 1%every morning,and the feeding amount at noon.1.4%,the amount of feeding in the evening is 2.4%;the optimal water flow for growth and gonadal development of the tire track eel is 50mL/s,and the monthly weight gain ratio can reach 41.74%under the stimulation of the water flow.The histological study of the ovary at different developmental stages of the adult female of the tire track eel was carried out.It was found that the surface ovary of the stage Ⅲ ovary was obvious,and the egg diameter was about 600 μm.The volume of the ovary in the Ⅳ stage increased and the egg gradually became yellow,and the egg diameter was about 1200 μm.The ovary volume in the Ⅴ phase was further increased,the egg became bright yellow,and the egg diameter was about 2000 μm.The ovary in the VI stage began to shrink,the appearance was flesh-colored,and the egg diameter was about 1000 μm.The effects of different oxytocin and their combinations on the artificial reproduction rate and fertilization rate of tire track eel in Hainan were studied.The best artificial oxytocin was to inject two mixed liquids of LHRH-A2(10ug/kg)and DOM(10mg/kg).The first dose was 60%of the total dose,and the remaining dose was injected after 12 hours,and the male dose was halved.Under this condition,the female individual of the tire track eel can achieve a yield of 90%,the fertilization rate is 79.3%,and the average ovulation rate is 894.According to the cultivation density,water temperature and feeding method of seedlings,the suitable breeding conditions for the tire track eel seedlings in Hainan were:for the freshly hatched seedlings of about 5 days,the suitable density was 1000-1500 tails/m2.The growth ratio is 162.6%,and the survival rate is 90%;the suitable water temperature at this stage is 25℃;for the seedlings after hatching 30,the suitable feeding method is to feed four times at different times every day,and the monthly weight gain ratio can reach 93.88%.This paper studies and improves the whole process of artificial breeding of tire track eel in Hainan,and provides scientific basis for large-scale cultivation of tire track eel in Hainan.