This study was investigated spawning behavior, structure of egg masses and egg development in Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea. The mating and courtship behavior of A. kurodai occurred in the form of unilateral copulating with chain formation. In chain copulation, only the first animal acted as a female; the second and succeeding animals acted as males (sperm donors) to the animals in front and as females to the animals behind. The fertilized eggs were packaged in capsules that are embedded in jelly to form a cylindrical string called an egg masses. The number of capsule per cm of the egg masses was 55 to 60 capsules and each capsule within the egg masses held 15 to 25 eggs. After spawning, the egg masses were bright yellow or orange in color. This egg masses color not changed until embryos developed into trochophore stage. Thereafter, as embryo developed from trochophore stage to veliger stage the egg masses color became brownish. The fertilized eggs were spherical, with a diameter of approximately 80±1 μm at spawning. At 5 to 6 days after spawning, the embryo developed into trochophore stage and began to rotate within the egg capsule. In the trochophore stage, the precursor of the velum, called the prototroch or prevelum, developed. At 10 days after spawning, the prevelum is transformed into the velum, and the trochophore developed into veliger stage. Between 10 to 15 days after spawning, the veligers broke out of the egg capsule, and hatched as free-swimming larvae.

제주도 성산 연안 지역에 서식하는 오분자기의 생식주기를 조사하기 위하여 2006년 5월부터 2007년 4월까지 채집된 개체를 대상으로 생식소지수와 생식세포 발달단계, 황색 과립세포 출현양상과 생식상피의 형태변화를 조사하였다. 생식소지수(GI)의 월별 변화는 암컷과 수컷 개체 모두 유사한 경향을 보였다. 암컷 GI는 2006년 5월 에서 6~8월 으로 최대값을 보였고, 9월 으로 감소하였다가 10월 증가한 후 2007년 4월까지 낮은 값()을 유지하였다.

Gonadal development and reproductive cycle of Aplysia kurodai inhabiting the coastal waters of Jeju Island, Korea were investigated based on monthly changes of gonadosomatic index, gametogenesis, and developmental phases of ovotestis. A. kurodai was simultaneous hermaphrodite; the ovotestis generally embedded in the posterior dorsal surface of the brownish digestive gland. The ovotestis is composed of a large number of follicles, and both oocytes and sperm are produced in the same follicles. In the sampling periods, the adult A. kurodai population have characteristic of seasonal pattern present during only 10 months. The reproductive cycle can be grouped into the following successive stages in the ovary: inactive (December to February), active (December to April), mature and spawning (April to September). The gonadal development of A. kurodai coincided with rising temperature, and spawning occurred from April to September, when the temperature was high. The histological observations of the ovotestis suggested that this species have a single spawning season that extend over six months.

제주 연안에 서식하는 용치놀래기, 어렝놀래기, 황놀래기, 놀래기를 대상으로 체장에 따른 성 분포와 생식소의 성 특성을 조직학적으로 탐색하여 성 전환 양상을 조사 비교하였다. 용치놀래기, 어렝놀래가, 황놀래기, 놀래기는 자성선숙형 자웅동체어로 조직학적 관찰 결과 정소조직(정자형성부위)이 퇴화기 난소의 전역에 출현하는 혼재형 2에 속하는 어종이었다. 용치놀래기, 황놀래기 그리고 놀래기는 1차 수컷과 2차 수컷이 존재하는 복웅성 어류이고, 조사된 어렝놀래기는

To investigate the variations of physico-chemical factors and microbial population, in ten stations at water region of coastal area of Chagwi-Do, Nutritive salts, water temperature, transparency, suspended solid, salinity, COD, DO, pH, heterotrophic bacteria, coliform group and Vibrio spp. were analysed three times in September, November in 2004 and February in 2005. Heterotrophic bacteria in surface water was 3.5×101～1.16×103 cfu/ml, 1.0×102～5.2×101 cfu/ml, 2.0×101～7.6×101 and bottom water counted 7.0×102～1.0×103 cfu/ml, 1.4×101～2.5×102 cfu/ml, 2.0×102～4.2×101 cfu/ml in September, November in 2004 and February in2005, respectively. The cell number of total coliform bacteria in the surface water amounted to 0～4.3×102 cfu/ml, 0～6.0×101 cfu/ml, 0～1.0×101 cfu/ml and bottom water amounted 0～2.2×102 cfu/ml, 0～5.4×102 cfu/ml, 0～2.0×101 cfu/ml in September, November in 2004 and February in 2005, respectively. As for Vibrio spp., the cell number in the surface water was 1.0×101～2.5×102 cfu/ml, 1.0×101～2.0×101 cfu/ml, 0 cfu/㎖ and bottom water counted 1.0×101～5.2×102 cfu/ml, 0 cfu/㎖, 2.0×101 cfu/ml in September, November in 2004 and February in 2005, respectively.

Eleven wrasse species inhabit the coastal waters of Jeju Island, Korea. They are the target of leisure fishing and are considered good eating. We investigated the distribution of standard length (SL) by sex of wrasse in Jeju coastal waters for Halichores poecilopterus, H. tenuispinis, Pseudolabrus japonicus, and Pteragogus flagellifera. A cross-section of the ovary showed the ovarian cavity and ovarian lamellae containing oocytes. A cross-section of the testis showed many lobules containing spermatogonia and spermatocytes. A cross-section of a gonad undergoing sex reversal showed the regression or reduction of oocytes and some spermatocytes located in the ovarian lamellae. A cross-section of a sex-reversed testis showed the primary structure of the ovary, with spermatocytes distributed in the epithelium of the lamellae, and reformed seminiferous ducts in the basement lamellae. (중략)