A Preliminary Study of larvacean in Taiwan
Date Issued
2015
Date
2015
Author(s)
Huang, Shih-Jung
Abstract
Anguilla japonica is an important economic species, while the problem of nutrition source after hatching always evokes everyone''s attention. In previous studies had found larvacean houses existence in the leptocephalus gut (Otake et al., 1993). However, in Taiwan no one has tried to collect live larvacean for rearing.This report is the first time about the living larvacea collection and breeding attempts in our lab. The results show that we can collect Oikopleura dioica or the other larvacean by hand along the coast. We collected larvacean at night by flash light, and further retain in the homemade rotation tank to enhance the larvacean’s survival rate from 7% up to 50% when transport the animal,and began to cultivate after one to three days. Under 20℃after fertilization the embryo undergoes rapid cleavage cycles and the tailbud stage hatches from the chorion 207.5 minutes postfertilization. During the tadpole stages the tail became longer and longer and organogenesis occurs.At metamorphosis, 385 minutes postfertilization, the tail shifts from a linear posteriorly directed orientation relative to the trunk to a more orthogonal position, with the end of the tail lying in the same direction as the mouth. Immediately following tailshift, the first house is inflated. The relationship of embryonic development of Oikopleura dioica and temperature by linear regression analysis is y = -8.6099x + 323.12, R2 = 0.6117 (N = 10) .Both directions of water entering and feces discharging are different from the previous studies in observation about the house. During the Experiment we used camera, optical microscope and electronic eyepiece to record Oikopleura dioica’s .larvacean has a simplified anatomical organization, remains transparent throughout an exceptionally short life cycle of less than 1 week and exhibit high variable fecundity. By using histological method to observe the ovary development of coenocyst. Growing oocytes defined a selective kinase environment in the common coenocyst cytoplasm. Vitellogenesis preceded the timing of oocyte selection among excess germ line nuclei. This unique feature enables late adjustment of oocyte number in accordance with the cytoplasmic volume of the germline cyst accumulated during vitellogenesis. Through current equipment and methods,we can bred at least five serial generations by artificial insemination.The relationship between larvacean (houses) and eel larvae, needs further research.
Subjects
Oikopleura dioica
coenocyst
culture
insemination
Type
thesis
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