전자저널 > 전자저널 > Studies on the Gonadal Development and Gametogenesis of the Granulated Ark, Tegillarca granosa (Linne)

Studies on the Gonadal Development and Gametogenesis of the Granulated Ark, Tegillarca granosa (Linne)

Ju Ha Lee

School of Life Science, College of Natural Science and Engineering, Jeonju University, Jeonju 560-759, Korea

Although granulated ark, Tegillarca granosa is one of the important aquatic resources eaten by human beings, the basic biological studies on this species are still not too well known. Therefore the present paper deals with the histological studies on the gonadal development, gametogenesis, and reproductive cycle of the T. granosa as the basic biological studies. The materials were monthly collected at the costal area of Beolkyo, Chollanam-Do, southern coast of Korea for one year from January 1995 to February 1996. T. granosa is dioecious and oviparous. The gonads are situated from the connective tissues surrounded midintestinal gland in visceral cavity to the muscle layers of foot. Undifferentiated mesenchymal tissues and eosinophilic granular cells are abundantly distributed in the follicles of the gonads in the early active stage. With the further development of the gonads, these tissues and cells gradually disappear. Therefore they could be considered as a kind of nutritive materials. On the bases of the gonadal development, gametogenesis, histo-differentiation, and cytological characteristics, the reproductive cycle of the species may be divided into five successive stages: early active, late active, ripe, partially spent, and spent/inactive. The spawning occurs from late June at about 20℃ in the seawater temperature, but the main spawning occurs from July to August at about 23 to 24℃ in the temperature. The ripe oocytes are about 50 to 60 ㎛ in diameter. The early active stage is rather long period (January to May) compared to other stages, the spent/inactive stage is also rather long period (September to April of the next year) compared to other stages. While late active (May to July), ripe (June to August), and partially spent stages (June to August) are rather short period compared to above the two stages. The monthly changes of the fatness coefficient closely correlate with the gonadal development, reproductive cycle, and the seawater temparature. Hermaphroditism was found one among the 433 individuals examined.

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