• 한국수산과학회지
• /
• 제39권5호
• /
• pp.398-403
• /
• 2006

Gonad development and the gametogenic cycle of pen shells, Atrina pectinata, collected from November 2004 to October 2005 in the coastal waters of Jangheung, Jeollanam-do, Korea were investigated histologically. The clams are dioecious. The gonads consist of a number of gametogenic follicles. The sex ratio (Female:male) was 1:1.2. The gonad index (GI) reached a maximum in May and a minimum in July. The condition index (CI) reached a maximum in April and a minimum in June. The gonadosomatic index (GSI), GI and CI all increased with gonad development. The gametogenic cycle of the clam could be divided into five stages: the degenerative/inactive (August to October), early active (November to March), late active (December to April), ripe (May to June) and spent (June to July) stage.

• Animal cells and systems
• /
• 제5권1호
• /
• pp.37-44
• /
• 2001

Gonadal development, reproductive cycle, gonad index, meat weight rate, and first sexual maturity of the top shell, Omphalius rusticus were Investigated monthly by histological observations. Specimens were collected from the west coast of Korea during the period from January to December in 1999. O. rusticus is dioecious and oviparous. The gonad is widely situated on the surface of the digestive g1and located in the posterior spiral meat part in the shell. The ovary and the testis were composed of a number of oogenic follicles and several spermatogenic follicles, respectively. Ripe oocytes were approximately 120-130 $\mu$m in diameter. The meat weight rate peaked in June (27.7%), and then rapidly decreased in September (19.5%). Monthly changes in the gonad index in both sexes reached the maximum in June, and then sharply decreased in September. Percentages of first sexual maturity of female and male snails ranging from 9.0 to 9.9 mm in shell heights were 58.3% and 54.5%, respectively, and 100% in those over 11.0 mm in both sexes participated in reproduction. Reproductive cycle of this species can be categorized into five successive stages: in females, early active (October to April), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to January): in males, early active (November to March), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to December). Gonadal development, gametogenesis, reproductive cycle, and spawning were closely related to the seawater temperature.

• 한국어류학회지
• /
• 제6권2호
• /
• pp.206-221
• /
• 1994

산란기 직전의 산천어, Oncorhynchus masou 2배체와 유도 3배체를 대상으로 체장과 체중 및 형태측정을 실시하였다. 체중, 내장괴 제거 체중, 체장, dressing 비, 비만도, 생식소 무게와 생식소 지수, 복강두께 및 내장괴 무게와 내장괴 지수가 조사되었으며 체둘레 측정이 등지느러미, 배지느러미 및 등지느러미의 각 종단면에서 이루어졌다. 종단면 면적과 2가지 복강두께 형질이 등지느러미, 배지느러미 및 뒷지느러미의 종단면에서 조사되었으며 아울러 각 종단면에서의 높이, 전체높이, 폭, 3가지 체형질과 9가지 종단절단형질이 조사되었다. 2배체의 체장과 체중은 유도 3배체와 비교시 크게 나타났으며 dressing 비, 생식소 무게, 생식소지수, 내장괴 지수 및 간 지수 역시 2배체가 유도 3배체 보다 크게 나타났다. 반면 유도 3배체는 2 배체에 비해 가슴지느러미 및 등지느러미 종단면에서의 1가지 복강두께 형질과 일부 종단형질에서 높은 치를 나타내었다. 2배체에 비해 유도 3배체의 이러한 형질특성은 유도 3배체 자체의 불임에 기인된 것으로 산란기 직전 유도 3배체의 경제적 가치성을 시사한다고 할 수 있다.

• 한국패류학회지
• /
• 제18권2호
• /
• pp.67-76
• /
• 2002

1997년 7월부터 1998년 6월까지 제주도 함덕리 조간대에서 매월 채집한 흑백배말 (Cellana nigrolineata) 의 생식세포형성과정, 생식주기, 월별 난경 조성 및 생식소지수를 조사하였다. 생식소는 내장낭 내면, 복부 앞쪽에 위치하며, 성숙시기에 정소는 유백색을 난소는 짙은 갈색을 띠고 있다. 생식소지수는 수온이 상승하는 5월부터 서서히 증가하기 시작하여 8월에 최고 값을 나타냈다. 이후 9월에 감소하기 시작하여 8월에 비교적 낮은 값을 유지하였다. 생식주기는 생식소의 월별변화와 난모세포의 크기에 따라 회복기 (11-4월), 활성기 (3-6월), 완숙기 (5-10월) 그리고 방출기 (8-12월)로 구분되었으며, 주 산란기는 9-10월로, 연 1회의 산란시기를 갖는다. 흑백배발은 자웅이체로서 성전환 개체나 자웅동체의 개체는 없었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제15권5호
• /
• pp.740-744
• /
• 2002

The relationship of gonad weight and liver weight with body weight of six fish species viz; Catla catla, Labeo rohita, Cirrhina mrigala, Hypophthlamichthys molitrix, Ctenopharyngodon idella and Cyprinus carpio under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond were examined after a rearing period of one year. The positive relationship between gonad weight and body weight was significant which showed the dependence of gonadal development on body weight in all the six fish species. The currelation coefficients were higher in female fishes. However, the major carps had a much smaller proportional gonadal weight as compared with Chinese carps and a common carp due to their faster growth rate. The overall comparison of six fish species under different experimental treatments revealed that highest liver weight was observed for C. idella closely followed by C. carpio. The maximum correlation value was observed with H. molitrix under the broiler manure. The maximum Gonadosomatic Index (GSI) remained as 32.63 for C. carpio followed by C. idella. The maximum value for Hepatosomatic Index (HSI). remained 1.99 for C. idella followed by C. mrigala.

• Fisheries and Aquatic Sciences
• /
• 제13권2호
• /
• pp.140-149
• /
• 2010

We determined the seasonal gonad maturation in Strongylocentrotus nudus sea urchins inhabiting an artificially enhanced seaweed forest along the Samchuk Coast of Korea from April 2006 to March 2007. A total of 30 sea urchins per month were collected from the study area, and gonadosomatic index (GSI), gonad index (GI), egg diameter, and RNA/DNA variation were measured for each specimen. GSI values of female and male urchins achieved maximums of 17.6 and 17.0, respectively, in June. Based on histological studies, maximum GI values occurred in July (4.6 for females and 4.8 for males). A mean ovarian egg diameter of $73.7\;\pm\;14.2\;{\mu}m$ was measured in August; during the main spawning period in September, mean egg diameter reached a maximum of $74.2\;\pm\;17.8\;{\mu}m$. The RNA/DNA ratio and RNA content for both males and females showed a distinct peak during the ripe stage in July, but another peak occurred in the spring season from March to April, when urchins deposit protein into the nutritive phagocytes of immature gonads prior to gametogenesis. The reproductive cycle of S. nudus is divided into five stages: early active (December-May), late active (March-July), ripe (July-September), spent and degenerative (August-November), and inactive (October-February). Our continuous removal of sea urchins from the study area did not influence the reproductive cycle, as populations quickly recovered, and achieved normal gonad development cycle in the site.

• 한국수산과학회지
• /
• 제37권5호
• /
• pp.385-392
• /
• 2004

Gonadal development, gametogenesis, reproductive cycle, gonad index, and flesh weight rate of the murex shell (Ocenebra japonica) collected from the rocky intertidal zone of Buan-gun, Jeollabuk-do, Korea were investigated by means of histological method from January to December 2002. O. japonica had separate sexes, and was oviparous. The gonad was widely situated on the surface of the digestive gland located in the rear of the spiral flesh part in the shell. The male penis was located near the two tentacles. The ovary was composed of a number of oogenic follicles, and the testis was composed of several spermatogenic tubules. The size of ripe oocyte was approximately $140{\mu}m$ in diameter. The gonad index (GI) began to increase in March $(33.24{\pm}2.33)$ and reached the maximum in June $(47.77{\pm}1.90)$ Thereafter, the values decreased from July $(45.12{\pm}3.60)$ to October $(19.32{\pm}2.91)$. The flesh weight rate (FWR) began to increase in January $(25.93{\pm}1.32)$ and reached the maxium in May $(31.78{\pm}1.09)$ Thereafter, the values decreased from June $(31.50{\pm}0.66)$ to October $(24.09{\pm}1.60)$. The reproductive cycle could be classified into five successive stages: early active (October to April), late active (January to June), ripe (May to September), spawning (July to September) and recovery (September to February). The reproductive cycle was closely related to the seawater temperature.

• Fisheries and Aquatic Sciences
• /
• 제2권2호
• /
• pp.142-148
• /
• 1999

Monthly changes in the gonad index (GI), egg-diameter composition, gonadal development, reproductive cycle of the ark shell, Scapharca subcrenata, were investigated by histological method and morphometric data. This species is dioecious and oviparous. The gonad is located among the subregion of mid-intestinal gland, digestive diverticula and the outer fibromuscular layers compacted by the fibrous connective tissues and muscle fibers. The gonad index sharply increased in May, reached the maximum value in June, and then gradually decreased from July to December. The reproductive cycle of this species can be divided into six successive stages: early active stage (January to May), late active stage (June to July), ripe stage (June to August), partially spawned stage (July to September), degenerative stage (August to December), and resting stage (January to April). S. subcrenata spawns once a year between July and early September, and the main spawning occurred between July and August when the water temperatures were above $20^{\circ}C$. This evidence suggest that timings of maturation and spawning are closely related to water temperatures. Even though the spawning period was once a year, it is assumed that the number of spawning frequencies (broods) may occur more than twice during the spawning season.

• 한국수산과학회지
• /
• 제39권6호
• /
• pp.472-479
• /
• 2006

The sexual maturity and reproductive cycle of the common squid, Todarodes pacificus captured from the East Sea, Korea, between January 2004 and January 2006, were investigated by documenting changes in the gonadosomatic index (GSI), gonad development, and oocyte size frequency distribution. The GSI of females began to increase in July, reached a maximum in August, and then gradually decreased. The GSI of males increased from July to March. Using gonad histological observations, we identified four oocyte developmental stages. The changes in GSI and gonad tissue resulted in the classification of the annual reproductive cycle into the following four successive stages: immature (April to June), growing (June to July), mature (July to August), and ripe and spawning (August to March). According to the oocyte diameter size frequency distribution in the ovary, this species appeared to have asynchronous oocyte development and one spawning time.

• Ocean and Polar Research
• /
• 제40권1호
• /
• pp.15-22
• /
• 2018

In the present study, we investigated temporal variation in the reproductive effort and biochemical contents in adult Manila clam Ruditapes philippinarum at Shi-Heung-Ri beach on the east coast of Jeju Island. Gonad-somatic index (GSI), a ratio of the egg mass to the total biomass determined using ELISA increased dramatically from late May to June (7.1% to 19.5%). In mid-July, GSI dropped to 15.1%, indicating spawning on a small scale during this period. GSI also declined dramatically from late August (15.5%) to September (4.3%), suggesting that massive spawning occurred during this period. A positive correlation was observed between clam size and potential fecundity, while potential fecundity ranged between 1.19-8.40 million eggs/clam. Total proteins and lipids in the tissue increased from late spring to mid-summer, coinciding with an increase in GSI. Protein, lipid and carbohydrate contents in the tissue were lowest in January, indicating that clams were suffering from poor nutritional circumstances, which may be associated with poor food supply from the environment. Monthly increase and/or decrease in the body weight were closely related to gonad maturation and subsequent spawning, which was also linked to temporal changes in the contents of protein, lipid and carbohydrates in the tissue.