• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.122-128
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• 2014

The present study was performed to examine the contraction and relaxation responses of the smooth muscles, and search for antimicrobial and antioxidant activities in the tissues, of the starfish Asterina pectinifera. Frozen samples were extracted with distilled water containing 1% acetic acid. Extracts from all tissues showed potent antimicrobial activity against Escherichia coli D31. Relatively high levels of antimicrobial activity were also detected in the body extracts. Liver, tube feet, and body extracts caused contraction responses in the dorsal retractor muscles (DRM) of the starfish. In contrast, all tissues examined exhibited contractile activity in the esophagus of squid Todarodes pacificus. In addition, liver and gonad extracts caused contraction responses upon application to the intestine of the puffer fish Takifugu pardalis. Relaxation effects on the DRM of starfish were identified in most of the extracts, while no relaxant activity was detected in body extracts. Extracts from all tissues examined also exhibited antioxidant activities. The results of this study suggest that starfish are a potential source of novel bioactive compounds.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.48-54
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• 2017

The ecological characteristics of Pseudoblennius cottoides were investigated off Dolsan Island, Yeosu, Korea, from June to December, 2001. Their habitats were the reef zone and surrounding embankment which was covered with seaweeds. Their range of total length (TL) was 6.10-8.40 cm (n=15), and the individuals (over 8.10 cm) of them accounted for in June. It was 8.60-15.7 cm (n=67), and the individuals 11.1-12.0 cm in TL accounted for in October, 2001. The female to male sex ratio was 1:0.48 (n=185). The gonads were in the shape of a rod and the ovaries were large in size. In June, the histology of the seminiferous tubules was observed. In August, the testicles appeared. In October, spermatocyte was observed in the testes, and ovaries were observed in relation to circumference popularity and oocyte.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.36-42
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• 2020

The maturation and spawning of white crocker Pennahia argentatus were investigated using samples collected in the Southern Sea of Korea from January to December 2018. We analysed monthly changes in maturity stage, gonad-osomatic index (GSI), total length (TL) at 50% group maturity. The spawning period was May to July. Fecundity varied between 71,627 and 888,041 eggs. The relationship between the fecundity and TL of the fish was expressd in the fecundity equation as F=0.2198TL^4.2784 (r²=0.8423). The percentage of sexually mature females estimated from a logistic function was over 50% for the size group 19.33 cm (total length, TL).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.581-585
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• 1985

This study was carried out with blue mussels at Otsuchi Bay in Japan from August 1981 to May 1982, in order to investigate the effect of the parasitic pea crab (Pinnotheres pholadis) on the reproductive capacity of host blue mussels (Mytilus edulis galloprovincialis). The results show that pea crabs delay gonad development of host mussels about one month and lower their fatness rate by intercepting nutrients. The parasitization with pea crabs is thought not to prevent spawning activity itself, but to reduce the number of germ cell resulting in the reduced space of gonads.

• Environmental Analysis Health and Toxicology
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• v.25 no.4
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• pp.287-294
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• 2010

Objectives : The aim of this study was to verify the intersexuality of Crassostrea gigas and Ruditapes philippinarum in southern coastal waters of Korea. Methods : Specimens of Crassostrea gigas (n=363) were collected from six areas of Tongyeong, Geoje and Yeosu. Ruditapes philippinarum (n=221) was collected from five areas of Yeosu. The sex ratio and intersexuality were determined after observing gonad preparations. Results : The rate of intersexuality in Crassostrea gigas was 16.25%, with females (24.79%; n=30/121) exhibiting a higher rate than males (11.98%; n=29/242). The rate of intersexuality in Ruditapes philippinarum was 24.43%, with females (37.76%; n=37/98) exhibiting a higher rate than males (13.82%; n=17/123). Conclusions : The results of this study suggest that intersexuality is induced by aquatic pollutants such as endocrine disrupting chemicals (EDCs).

• Development and Reproduction
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• v.18 no.1
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• pp.51-56
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• 2014

This study describes the developmental process of gonads in chameleon goby, Tridentiger trigonocephalus from the stage of hatching to 100 days after hatching (DAH). Based on histological observation, the primordial germ cells were observed in mesentery between mesonephric duct and gut at 15 DAH (total length, TL: $6.8{\pm}0.2mm$). At 20 DAH (TL: $7.9{\pm}0.1mm$), the primordial gonad began to protrude into peritoneal cavity and developed between mesonephric duct and gut. Initial ovarian differentiation was identified by the presence of ovarian cavity and oogonia in the gonads at 55 DAH (TL: $21.1{\pm}1.3mm$). Testicular differentiation started at 65 DAH (TL: $23.7{\pm}0.9mm$) with appearance of spermatogonial cells in the gonads. These findings indicate that sex differentiation in T. trigonocephalus occurs earlier in females than males, suggesting that this species can be classified as an undifferentiated gonochorist.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2001.02a
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• pp.46-49
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• 2001

R. Philippinarum is dioecious and oviparous. In the early vitellogenic oocyte, the Golgi apparatus and mitochondria present in the perinuclear region are involved in the formation of lipid droplets and in lipid granule formation. In the late vitellogenic oocyte, the endoplasmic reticulum, mitochondria in the cytoplasm are involved in the formation of proteid yolk granules. At this time, exogenous lipid granular substance and glycogen particles in the germinal epithelium are passed into the ooplasm of oocyte through the microvilli of the vitelline envelope. Ripe oocytes are about 55-60 $\mu$ m in diameter. The spawning period was once a year between early June and early October, and the main spawning occurred between July and August when seawater temperature was approximately 20 C. The reproductive cycle of this species can be categorized into five successive stages: early active stage (February to March), late active stage (April to May), ripe stage (April to August), partially spawned stage (June to October), and spent/inactive stage (August to March). Gonad developmental phases by histological qualitative analysis showed similar results with those of quantitative image analysis.

• Development and Reproduction
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• v.5 no.1
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• pp.9-16
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• 2001

Biogenic monoamines are divided into three categories; catecholamines(dopamine, norepinephrine, and epinephrine), indoleamine(serotonin and melatonin) and histamine. Among them, serotonin has been intensively studied by many researchers with a broad spectrum of biomedical interests. A concise overview of serotonin-related topics such as biosynthetic pathway, receptor subtypes, and roles in reproduction will be provided. In particular, serotonergic efffect on the regulation of hypothalamus-pituitary-gonad hormonal axis and sexual behaviors will be emphasized. Though our Knowledge on the biological roles and its clinical applications are still limited, these topics are quite promising subjects which will be helpful for improving our 'quality of life' in near future.

• Development and Reproduction
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• v.24 no.2
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• pp.79-88
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• 2020

This study was carried out to obtain information on the developmental biology and the management of biological resources of the abalone Haliotis gigantea in Korea. The sex ratio (female:male) in the present study was 1:1.7 and the proportion of females was 36.6% (n=106/290). Their gonadal structures displayed definitive seasonal changes which were similar in pattern to the changes in the gonad index (GI). The GI showed a pattern of definitive seasonal changes in both males and females it was high in the fall and low in the spring. The reproductive cycle could be categorized into the following six stages: inactive, early active, late active, ripe, spent, and degenerative stage. Based on the monthly changes in GI and stages of gonadal development, October to November was determined to be the main spawning period for H. gigantea on Jeju Island, Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.1
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• pp.27-34
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• 2006

Sexual maturation and reproductive cycle of the bat star Asterina pectinifera were investigated by histological method. Specimens were collected monthly in Donghwari, Gosunggun, Korea from January 2004 to February 2005. The bat star was dioecious. The gonads are composed of a number of gametogenic follicles. The gonadosomatic index (GSI) of female and male were reached the maximum in July (5.72, 4.54) and the minimum in December (0.89) and January, February (0.51), and the gonad index (GI) of female and male were reached the maximum in July (3.53, 3.91) and the minimum in August (0.95) and October to December (1.0), respectively. The main spawning was from August to September. The reproductive cycle of the bat star could be divided into five stages: in the female, inactive (November-February), early active (January February), late active (March-June), ripe (July), spent and degenerative (August-November) and in the male, inactive (November-February), early active (January-March), late active (April-June), ripe (July), spent and degenerative (August-October), respectively.