• Title/Summary/Keyword: Gonad index

Search Result 127, Processing Time 0.032 seconds

Report on the Annual Reproductive Cycle and Imposex Phenomenon of the Rock-Shell, Thais clavigera in Jeju Port (제주항 내에 서식하는 신복족류 Thais clavigera의 연중 생식주기 및 임포섹스 현상에 관한연구)

  • Yang, Hyun-Sung;Kim, Bong-Kyu;Park, Heung-Sik;Choi, Kwang-Sik
    • The Korean Journal of Malacology
    • /
    • v.26 no.1
    • /
    • pp.97-105
    • /
    • 2010
  • Annual gonad development of the rock shell, Thais clavigera distributed in Jeju Port was investigated over a 12 month period from March 1998 to February 1999. Monthly change in gonad development was examined using histology. Gametogenesis of T. clavigera in the study area initiated as early as in October and fully ripe eggs could be observed from May to July. Percent gonad area (PGA) also increased rapidly from May to July then dropped in August when the water temperature remained $22.6-24.5^{\circ}C$, suggesting that rock shell released their eggs during this period. All female rock shell collected during the course of study exhibited pseudo-penis in the head, indicating that a certain level of imposex had progressed in the study site. Relative penis size index (RPSI), an indicator of level of imposex phenomenon varied 59.5-173.4% and this value was relatively higher than the index reported from elsewhere. It was believed that such imposex phenomenon observed in T. clavigera was caused by endocrine disruption by chemical contaminants such as TBTs released from biocidal paints in the port environment.

Seasonal Variations of Digestive Diverticula in the Scallop, Patinopecten yessoensis (가리비, Patinopecten yessoensis 소화맹낭의 계절변화)

  • Chang, Young-Jin
    • Journal of Aquaculture
    • /
    • v.4 no.1
    • /
    • pp.19-30
    • /
    • 1991
  • The seasonal variations of digestive diverticula in the scallop, Patinopecten yessoensis culturing by sowing method were studied by microscopic observations and individual measuring of the shells collected monthly from Abashiri Bay located in Hokkaido, Japan. Digestive diverticula index revealed the seasonal variations which showed the highest value in May and July, and the lowest value in December through April. The highest number of tubules per $mm^{2}$in the preparation of digestive diverticula was counted in March. But, in September and October the number of tubules decreased to the lowest value. The relationship between gonad index(X) and percent of lipid tubule(Y) as an indicator for the transference of lipid in digestive diverticula into the gonad was expressed by an exponential equation, $Y=145.6X^{-0793}$. It was suggested that the lipid in digestive diverticula showed the seasonal variations might be transferred into the gonad.

  • PDF

Stomach Contents of the Sea Urchins, Anthocidaris crassispina and Hemicentrotus pulcherrimus and Characterization of the Marine Algal Community along the Tongyeong Coast of Korea (통영연안에 서식하는 보라성게(Anthocidaris crassispina)와 말똥성게(Hemicentrotus pulcherrimus)의 위 내용물과 서식지 해조군락)

  • Kim, Nam-Gil;Jang, Jae-Gil
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.45 no.6
    • /
    • pp.686-693
    • /
    • 2012
  • The seaweed community and stomach contents of the dominant herbivorous sea urchins Anthocidaris crassispina and Hemicentrotus pulcherrimus were examined from November 2008 to October 2009, in coastal areas of Tongyeong, Korea. Thirty-five seaweeds including two green, nine brown, and 24 red algae, were found over the study period. Seventeen seaweeds (two green, two brown, and 13 red) and two invertebrates were found in the stomachs of A. crassispina. In H. pulcherrimus, stomach contents were two green, one brown, 11 red seaweeds, and two invertebrates. The shell diameter of A. crassispina and H. pulcherrimus ranged from 22.3 to 62.3 mm and 15.3 to 40.1 mm, respectively. Total body weights ranged from 48.5 to 86.7 g for A. crassispina and from 7.7 to 25.9 g for H. pulcherrimus. The total weight of stomach contents were 5.1 to 25.8 g in A. crassispina and 1.7 to 11.8 g in H. pulcherrimus. The range of gonad weight was 3.6 to 17.0 g in A. crassispina and 0.8 to 4.0 g in H. pulcherrimus. The gonad index (GI) for A. crassispina peaked in July and reached a minimum in December, whereas the GI for H. pulcherrimus was highest in February, and lowest in May.

Sexual Maturation of the Turban Shell, Lunella coronata coreensis (Gastropoda: Turbinidae), on the West Coast of Korea (눈알고둥 (Lunella coronata coreensis)의 성 성숙)

  • LEE Ju Ha
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.33 no.6
    • /
    • pp.533-540
    • /
    • 2000
  • Gonadal development, gametogenesis, reproductive cycle, gonad index, flesh weight rate, and first sexual maturity of the turban shell, Lunella coronata coreensis were investigated by histological observation. The materials used were collected monthly from the rocky intertidal zone of Daehang-ri, Buan-gun, Jeollabuk-do, on the west coast of Korea, from July 1998 to June 1999. Sex of L coronata coreensis was separate. The gonad was widely located in the spirals of the visceral mass buried in the digestive gland. The ovary and testis were composed of a number of oogenic follicles and speymatogenic follicles, respectively. Monthly variations in the gonad index increased from March ($23.86{\pm}3.73$) when the water temperature increased and reached the maximun in July ($49.76{\pm}6.47$). And then, the gonad index sharply decreased in September ($15.58{\pm}2.33$). The flesh weight rate ranged from $25.2{\%}$ to $32.3{\%}$, and its variation showed a similar pattern to the gonad index. Individuals $<5.9 mm$ in shell height could not take part in reproduction in both sexes. Percentages of first sexual maturity of female and male specimens ranging from $7.0{\~}7.9 mm$ in shell heights were $84.6{\%}\;and\;91.7{\%}$, respectively, and $100{\%}$ in those over 8.0 mm in shell height in both sexes took part in reproduction. By studying the monthly changes of the morphological features and sizes of germ cells during gametogenesis in the gonad, the reproductive cycle of this species could be devided into five successive stages: early active (December to April), late active (January to July), ripe (May to August), spawning (July to September), and recovery (September to March). The spawning period of this species was once a year between July and September, and the main spawning occurred in July when the seawater temperature reached above $24.8^{\circ}C$. The fully ripe eggs were $150{\~}160\;{\mu}m$ in diameter.

  • PDF

Reproductive Cycle and First Sexual Maturity of Sinonovacula constricta(Lamarck, 1818)(Bivalvia: Pharidae) in Western Korea

  • Kim, Tae-Hoo;Lee, Ki-Young
    • The Korean Journal of Malacology
    • /
    • v.24 no.2
    • /
    • pp.97-104
    • /
    • 2008
  • The gonad index, reproductive cycle and first sexual maturity of Sinonovacula constricta collected from Simpo, Kimje-gun, Korea were investigated by histological analysis. The gonad index(GI) in both sexes of S. constricta increased from April and reached a maximum in July when the water temperature rapidly increased. And then, the GI values gradually decreased by spawning from August through October. Monthly variations in the GI showed a close relationship with ovarian development. The reproductive cycle in females and males can be classified into five successive stages: early active stage(March to June), late active stage(May to July), ripe stage(July to September), partially spawned stage(August to October), spent/inactive stage(October to March). The percentage of first sexual maturations in female and male clams of 50.1-60.0 mm in shell length was over 50%, and for clams over 70.1 mm in shell length, it was 100%. Because harvesting clams < 50.1 mm in shell length could potentially cause a drastic reduction in recruitment, a measure including a prohibitory fishing size should be taken for adequate improved fisheries resource management.

  • PDF

Ultrastructure of Germ Cells during Spermatogenesis and the Reproductive Cycle in Male Meretrix petechialis on the West Coast of Korea

  • Chung, Ee-Yung
    • The Korean Journal of Malacology
    • /
    • v.22 no.2
    • /
    • pp.115-124
    • /
    • 2006
  • Gonad index, spermatogenesis and the reproductive cycle of Meretrix petechialis were investigated by cytological, histological observations. Monthly changes in the gonad index coincides the gonadal development. The morphology of the spermatozoon had a primitive type and is similar to that of other bivalves having a short mid-piece with five to six mitochondria surrounding the centrioles. The morphology of the sperm nucleus type and the acrosome shape of this species were cylindrical type and cap-like shape, respectively. The spermatozoon was approximately 40-45 ${\mu}m$ in length including the sperm nucleus length (about 1.50 ${\mu}m$), acrosome length (0.60 ${\mu}m$) and tail flagellum. The axoneme of the tail flagellum consisted of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail showed 9 + 2 microtubular arrangement. The spawning period was from June to September and the main spawning occurred from July to August when seawater temperatures were higher than $20^{\circ}C$. The reproductive cycle of this species could be categorized into five successive stages: early active stage (February to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to September), and spent/inactive stage (September to February).

  • PDF

Some aspects of the reproductive biology of Synodontis schall from a lotic freshwater in Nigeria

  • Ukpamufo Cyril Olowo;Nkonyeasua Kingsley Egun;Ijeoma Patience Oboh
    • Fisheries and Aquatic Sciences
    • /
    • v.26 no.4
    • /
    • pp.256-267
    • /
    • 2023
  • The suitability of any fish species for successful aquaculture requires basic information on its reproduction and growth. This study investigated some facets of the reproductive biology of Synodontis shall (Mochokidae) from River Siluko in Nigeria. Fish samples were collected forth-nightly for a duration of fourteen (14) months-March 2015 to April, 2016 with the assistance of artisanal fishermen. Fishes were identified using taxonomic guides and standard techniques were used for determination of sex ratio, gonad maturation and fecundity. Linear regression method was used to define the correlation between fecundity and fish length, body weight and ovary weight. Results showed that sex ratio did not indicate a significant divergence (p > 0.05) from the 1 male to 1 female distribution ratio (1:1.41). Gonad morphology revealed paired gonads. Testes and ovaries were classified into four maturity stages: immature, resting, ripening and ripe. Gonadosomatic index ranged from 0.04 to 5.68 (males) and 0.03 to 20.19 (females). Absolute fecundity ranged from 1,014 to 4,520 eggs (mean = 2,592 eggs) and did not correlate significantly (p > 0.05) to ovary weight. This study has contributed to existing data on the biology of freshwater fish species in Nigeria and provided valuable information for fishery management tools in the conservation and utilization of this valuable freshwater fish species.

Feeding Habits and Growth of the Sea Urchin, Strongylocentrotus pulcherrimus (A. Agassiz) Reared in the Laboratory (실험실에서 사육한 말똥성게 Strongylocentrotus pulcherrimus (A. Agassiz)의 식성과 성장)

  • HUR Sung Bum
    • Journal of Aquaculture
    • /
    • v.1 no.2
    • /
    • pp.121-133
    • /
    • 1988
  • Strongylocentrotus pulcherrimus is one of the very important fishery stock in this country since its high demand for raw gonad. Although the demand has been continuously increasing, the natural stock of this species seems to be decreasing. Since fresh macroalgae are not always available, the substitution of terrestrial vegetables for algae as a principal food was examined for the intensive indoor culture of the sea urchin. The results from the studies on selective and non-selective feeding habits and nutritional efficiencies using 13 food stuffs (6 macroalgae, 5 vegetables and 2 animal products) indicate that algae can be substituted with vegetables in sea urchin culture. Although the growth of body weight was the highest when sea urchins were fed Undaria Pinnatifida, the gonad index of the sea urchins fed on spinach, radish leaf and lettuce was higher than that of this brown alga. Considering the different food efficiencies of body and gonad growth, spinach and radish leaf will be adequate during gonad growth season, while lettuce and Chinese cabbage will be suitable for test growth season. In particular, radish leaf, which is usually not eaten by humans, could be highly beneficial and very economical in the sea urchin culture.

  • PDF

Reproductive Ecology of Neptunea(Barbitonia) arthritica cumingii (갈색띠매물고둥, Neptunea(Barbitonia) arthritica cumingii의 번식생태)

  • Kim, Yeon-Ho;Chung, Ee-Yung;Shin, Moon-Seup
    • Development and Reproduction
    • /
    • v.11 no.3
    • /
    • pp.155-165
    • /
    • 2007
  • Gonad index (GI), conditon index, the reproductive cycle with gonadal development of the Neptunea (Barbitonia) arthritica cumingii, were investigated histologically, based on the samples which have been collected from the subtidal zone of Oeyeondo, Boryeong, Korea from January to December, 2006. Neptunea (Barbitonia) arthritica cumingii is dioecious and oviparous. Monthly changes in the gonad index (GI), studied for determination of spawning period, were closely associated with gonad developmental phases. The GI reached a maximum in April, and gradually decreased from May to August due to spawning. The gonadsomatic index and condition index showed similar patterns to gonad developmental phases and the spawning period. The reproductive cycle according to gonad developmental phases of this species can be classified into five successive stages in females and males: in females, early active stage (September to October), late active stage (November to February), ripe stage (February to June), partially spawned stage (May to August) and recovery stage (June to August); in males, the early active stage (September to October), late active stage (November to February), ripe stage (February to June), copulation (April to July), and recovery stage (July to August). Spawning occurred between May to August in females and April to July in males, and spawning peak in females was observed between June and July when the seawater temperature rose to above $19^{\circ}C$. Percentages of first sexual maturity of female and male snails ranging from $50.1{\sim}60.0\;mm$ in shell height were over 50%, and 100% for snails over 60.1 mm in shell height. The sex ratios of females to males were not significantly different from a 1:1 sex ratio.

  • PDF

Gonadal Maturation and Artificial Spawning of the Manila Clam, Ruditapes philippinarum (Bivalvia: Veneridae), in Komso Bay, Korea

  • Chung Ee-Yung;Hur Sung Bum;Hur Young-Baek;Lee Jung Sick
    • Fisheries and Aquatic Sciences
    • /
    • v.4 no.4
    • /
    • pp.208-218
    • /
    • 2001
  • We have investigated the gonad index (GI), gonadal development, reproductive cycle, first sexual maturity, sex ratio, the number of spawned eggs and spawning frequency of the Manila clam, Ruditapes philippinarum. Samples were collected from the intertidal zone of Komso Bay, Korea from January to December in 1999. Monthly changes in the gonad index (GI) and condition index showed a similar pattern in the reproductive cycle. The spawning period was once a year between early June and early October, there was a spawning peak between July and August when seawater temperature was over $20^{\circ}C$. The reproductive cycle of this species can be categorized into five successive stages; early active (February to March), late active (April to May), ripe (April to August), partially spawned (June to October), and spent/inactive stage (August to March). Percentages of first sexual maturity of female and male clams of l5.1-20.0mm in shell length were $56.3\%$ and $60.0\%$, respectively, and $100\%$ for the clams >25. mm. The sex ratio of individuals >15.1 mm in shell length was about 1:1 $(\chi^2= 0.02,\;p>0.05)$. Number of the eggs released from each clam by the induction increased as the size of clam in terms of shell length increased. Mean number of the eggs from the second induction of the spawning was $75.35-84.30\%$ $(average\;79.81\%)$ of the number of the eggs released in the first spawning. Our data indicated that R. philippinarum in Komso Bay has one major spawning peak with over two minor spawning, and the interval of each spawning was estimated to be approximately 15-17 (average 16.5) days.

  • PDF