To develope seaweed transplantation method to reduce grazing pressure by Anthocidaris crassispina, seaweed biomass and number of sea urchin were examined after 2 days from Ecklonia cava transplantation by four ways (three floating rope methods and seaweed transplantation block method). Three floating rope methods were different in the seaweed rope connection to fixation block rope; direct connection, polypropylene rope connection, and stainless wire connection. About twenty sea urchins were found on the seaweed cultivation rope connected directly to fixation block rope and on transplantation block. However no sea urchin was found for 2 days on the seaweed cultivation ropes connected by stainless wire and polypropylene rope. After 2 days from seaweed transplantation, biomass of E. cava was maximal with 992.61 ± 78 g m-1 in wet weight on stainless wire connection method and minimal in seaweed transplantation block method with 121.85 ± 71.67 g m-1. Before transplanting 42 Ecklonia cava plants were on one meter of cultivation rope and 41 plants on the cultivation rope connected with stainless wire to fixation block but five plants were remained on the transplantation block after 2 days. In conclusion, the best transplantation method of E. cava in this study to reduce grazing pressure of sea urchin was a floating rope method connected stainless wire to fixation block.

The gonadosomatic index (GSI), gonadal development and changes in hormones in plasma level of the indoor cultured grunt (Hapalogenys nitens) were investigated by histological study from August 2011 to October 2012. The GSI showed similar trends with gonad developmental stages during the culture periods. Changes in plasma level of estradiol-17β of female H. nitens reached the highest value before the spawning period, and seasonal changes in plasma level of estradiol-17β were similar in trends of oocyte developments and GSI changes. Testosterone levels of male H. nitens reached the highest value before and after the spent stage. Ovarian developmental stages of H. nitens could be classified into early growing stage, late growing stage, mature stage, ripe and spawning stage, recovery and resting stage. The testicular developmental stages could be divided into growing stage, mature stage, ripe and spent stage, and recovery and resting stage.

Ultrastructural studies of oocyte degeneration in the oocyte, and the functions of follicle cells during oocyte degeneration are described to clarify the reproductive mechanism on oocyte degeneration of Mactra chinensis using cytological methods. Commonly, the follicle cells are attached to the oocyte. Follicle cells play an important role in oocyte degeneration. In particular, the functions of follicle cells during oocyte degeneration are associated with phagocytosis and the intracellular digestion of products. In this study, morphologically similar degenerated phagosomes (various lysosomes), which were observed in the degenerated oocytes, appeared in the follicle cells. After the spawning of the oocytes, the follicle cells were involved in oocyte degeneration through phagocytosis by phagolysosomes. Therefore, it can be assumed that follicle cells reabsorb phagosomes from degenerated oocytes. In this study, the presence of lipid granules, which occurred from degenerating yolk granules, gradually increased in degenerating oocytes. The function of follicle cells can accumulate reserves of lipid granules and glycogen in the cytoplasm, which can be employed by the vitellogenic oocyte. Based on observations of follicle cells attached to degenerating oocytes after spawning, the follicle cells of this species are involved in the lysosomal induction of oocyte degeneration for the reabsorption of phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves.

Guppy has become a model organism for studying behavioral traits such as courtship and mate choice, as well as for understanding ecogeographic adaptation. Unfortunately, studying the early development of live bearers is more complicated than that of oviparous species, due to the inaccessibility of developing embryos for experimental manipulation. Ulrike et al. showed that the embryos could not be cultured for the entire period of their embryonic development. To optimize conditions embryo in vitro culture we established system for varying the concentration of fetal bovine serum in the medium impact on the embryonic development of in vitro embryos. For in vitro culture, embryos were incubated in 8 ml of sterile embryo medium (L-15 [Leibovitz] medium, supplemented with 5, 10, 15, and 20% fetal bovine serum respectively, 20 units/ml penicillin, and 200 mg/ml streptomycin) in a dark incubator at 25℃. Our study found that in 5% of FBS of the medium, embryos can be maintained until the middle-eyed. In 10% and 15% embryos can be maintained constant development; some of them can be fed; however, in 15% it is faster than 10%. And although in 20% of FBS can sustain rapid development of early stage, but ultimately died. According to our experimental data, both 10% and 15% FBS in medium can be used for in vitro culture, the slowly development in 10% FBS appears to be more conducive to observation.

본 연구는 수컷 살조개 Protothaca (Notochione) yessoensis의 정자 형성 과정 중 생식세포들의 분화와 성숙정자의 미세구조 특징에 관한 몇 가지 특징을 투과전자현미경 관찰에 의해 조사하였다. 본 종의 정자형태는 원시형(primitive type)으로, 이매패강, 이치아강(Heterodonta)에 속하는 다른 종들과 유사하다. 생식세포에 인접하여 연결되어 있는 보조세포들은 생식세포들의 발달을 위해 영양공급에 관여한다. 본 종의 정자의 핵형은 긴 원통형이며 첨체의 형태는 모자모양이다. 정자는 길이가 대략 46～50 ㎛이며, 길다란 정핵(길이 약 2.44 ㎛)과, 첨체(길이 0.45 ㎛), 그리고 미부 편모(약 42～46 ㎛)로 이루어져 있다. 미부 편모의 악소님(axoneme)은 9+2 구조를 나타낸다. 첨체소포의 특징으로써 basal ring의 기저부 위에서 측면부위는 전자밀도가 불투명한 부위를 나타내나, 첨체소포의 앞쪽 정단부위는 전자밀도가 비교적 투명한 부위로 나타나는 특징을 보인다. 이것이 이치아강에 속하는 백합과와 또 다른 여러 과들에 속하는 종들의 정자들이 갖는 첨체소포의 공통특징이다. 따라서 이치아강이 갖는 이들 첨체소포가 갖는 공통특징은 분류의 key 또는 중요한 도구로써 계통․분류를 위해 사용될 수 있다. 정자 중편에 있는 미토콘드리아 수는 4개로 이치아강 내에서 백합과의 3종을 제외한 모든 종들과 다른 과들의 종들에서 공통으로 나타나고 있는데, 예외로, 개조개, 백합, 가무락조개 만은 중편의 미토콘드리아가 5개로 이루어져 있다. 미토콘드리아 수는 과나 또는 상과 수준에서 종들의 분류학적 분석을 할 경우, 분류 key 또는 중요한 도구로 사용될 수 있다.