• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.103-109
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• 1970

The results of this work concerning the growth of the mussel, Mytilus edulis cultured by the hanging method in Koje Bay are as follows: The major spawning time is confined to the period from March to April. The mean growth of the mussel is indicated by the following formula; $$Y\;=\;1.508+0.659X-0.0559X^{2}+0.00367X^3$$ The major growing seasons are June and October The variance varied in proportion to the growth of the mussel, and each ranged, in shell height, from $1.25\~2.75\;to\;2.25\~4.25$ (mean:1.60 to 2.78)cm, $2.25\~5.25(3.00)cm,\;2.25\~7.75(4.83)cm,\;2.25\~7.75(5.05)cm\;and\;2.25\~8.25(5.95)cm$, and the variance were $0.278\~0.230$, 0.368, 0.701, 1.053 and 1.209, respectively. On the other hand, the variances differed in proportion to the growth of the mussel. The average length of the mussel life was about eighteen months. The mussels growing on the hanging line for arrestation undergo seasonal vicissitudes, and the mussels which fall off, mass into countless numbers during the period from August to October and finally disappear completely in November. The dimensions of the largest mussel are as follows: The shell height : 9.48cm The shell length: 4.49cm The shell breath : 3.55cm The shell weight : 22.05g The weight of the soft parts 19.25g The relative growth of the mussel is indicated as follows: Relationship between the shell height and the shell length: Y =0.486X+0.334 Relationship between the shell height and the shell breadth: Y = 0.359X+0.107 Relationship between the weight of the soft part and the shell weight: Y = 0.882X+0.901 Relationship between the shell height and the weight of the soft part: $$Y\;=\;0.02828X^{2.90518}$$

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.869-874
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• 1998

A feeding trial was carried out to investigate the optimum density of juvenile abalone (Haliotis discus hannai) fed the formulated diet or macroalgae ( Undaria). Abalone with initial average shell length of 8.41 mm were stocked into three replicate tanks at four different densities of 1430, 2860, 4290, and 5720 individual/$m^2$ for 15 weeks. The formulated diet produced higher body weight and shell growth, soft body weight and survival rate than Undaria in abalone. Abalone fed the formulated diet have significantly (P<0,05) higher lipid and ash, and lower moisture and protein in soft body. Higher density resulted in lower growth and survival (P<0.05). Whereas shell growth, survival rate and weight gain were not significantly (P>0.05) different within the abalone stocked at stocking densities of 1430 and 2860 individual/$m^2$ in each diet group. Body composition of abalone was not affected by increasing density. These study indicate that the number of abalone (shell length ranges of between 8 mm and 17 mm) below 2860 individual/$m^2$ were predicted to effective density in the indoor tank culture system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.375-379
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• 1986

A culture experiment of the ark shell, Anadara broughtonii, one of the edible clams, was carried out in Yoja Bay located at the south ern coast of Korea to find the state of growth and any problems which influence them. Seed shells at an average length of 2.5cm and a weight of 2.5g were planted on bottom mud with a density 20 to 40 shells per square meter on March 10 and 11, 1982. Shell length, shell height, shell breadth, meat weight (wet weight), and total weight for six months from August 1982 to February 1983 were measured to find their state of growth. At the same time, the survival rate was investigated during the whole culture period through December 1983 when they were harvested. Growth, on the whole, was fast when water temperature was high. For a year, an average shell length and total weight attained to 6.1 cm and 63.0g respectively and meat weight was gained to 19.5g. It showed that the state of growth was favourable. Shell shape became round from the oval ana meat weight increase was faster than shell growth as time goes by regardless of water temperature while both shells and total weight increased faster during high temperature. A month after seed shells were planted, about $30\%$ of them was dead and a high mortality, say $5\%\;to\;8\%$ per month, was kept till September. It dropped to around $2\%$ aften divers eliminated starfish, Asterias spp., in August. Thereafter, the rate maintained through December. In all, the final survival rate was about $10\%$ at the time of harvest in December 1983. It was caused mainly by starfish predation. Therefore, a best way for satisifactory culture is seemed to find a way to get rid of the starfish.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.71-78
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• 2001

Age and growth of the pen shell, Atrina (Servatrina) pectinata japonica, on the west coast of Korea were studied based on 701 samples caught in April 1995 to March 1996. The results are summarized as follows: the relationship between shell height and ring radius in each ring group was expressed as a regression line. Therefore, it could be recognized that there is a correspondence in the formation of each ring. Based on the monthly variation of the marginal index (MI') of the shell, it was assumed that the ring of this species was formed once a year during the period of June to July. The relationship between shell height (SH) and total weight (TW) were expressed by the following equation TW = 5.906$\times$10/$^{-3}$SH$^{3.844}$. Shell length (SL) and shell height were highly correlated according to the following equation SL = 0.5277 SH +0.0934. The shell height-shell width (SW) relation was expressed by the following equation SW = 0.2681 SH -1.3757. Growth curves for shell height and total weight fitted to the von Bertalanffy's equation were expressed as: SHt=30.99(1-e-$^{-0.3212(t+0.9653)}$, TWt=657.94(1-e-$^{-0.3212(t+0.9653}$)$^{3.3844}$.

• Journal of Preventive Medicine and Public Health
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• v.22 no.1 s.25
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• pp.14-24
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• 1989

현재 중국에는 55개의 소수민족이 있으며, 그 인구총수는 6,700만을 초과한다. 중국정부는 특히 70년대 후반서부터 소수민족에 대한 일연의 보호정책을 쓰고 있으며 다수민족인 한족에 대하여 엄격히 실시하는 1가구 1자녀 정책에서도 소수민족을 제외하고 있다. 이에 따라 소수민족의 증가는 현저하게 늘었다. 그러나 전반적인 인구학적특성으로 보면 소수민족은 아직 후진성을 면하지 못하고 있다. 조선족이라고 일컫는 재중 우리교포는 한족을 포함하여 중국내 어느 민족과 비교하여도 인구학적으로 독특한 위치를 차지하는 경우가 많다. 예를 들어 인구증가율은 가장 낮으며 어느민족보다 앞서서 1970년대 중반에 이미 대치수준 이하의 출생률에 도달한 것으로 믿어지고 있다(Han 등, 1988). 문맹률은 최하이며 대학수업율은 최고로 높다(장(張), 1984). 사망률은 전소수민족중 가장 낮고 평균 수명은 가장 길다(Dowdle, 1984). 이렇게 재중 조선족은 인구학적으로 가장 선진적이기 때문에 1자녀 정책에 대한 수용 준비가 다른 민족보다 앞서 있다고 할 수 있겠다. 물론 조선족은 소수민족에 속하기 때문에 1자녀정책에 구애될 필요가 전혀 없다. 따라서 조선족 가정에서 1자녀만을 낳겠다는 서약을 하여 이른바 '독생자녀증'을 영수하면 이것은 한족의 경우와 달리 자율의사에 따른 것이라 할 수 있을 것이다. 이 논문에서는 다음 두가지를 다루기로 하겠다. 즉, 조선족이 인구학적으로 보아 딴 민족에 비하여 어떤 위치에 있으며, 또 중국의 중요인구정책인 1가정 1자녀제에 어떻게 반응하고 독생자녀증을 어떻게 수용하느냐 하는 것이다. 이 밖에 중국의 대소수민족 인구정책의 앞날에 대하여도 약간의 전망을 하여볼까 한다.스와 여기에 사용되는 신호 방식을 논의하고 있다. 그 외에도 전광 통신망 운용에 필요한 라우팅 및 파장할당 방법과 OXC를 이용한 그물형 망에서의 보호 및 복구에 대한 연구도 활발히 진행되고 있다.rotene 보충군에 비하여 유의적으로 높았으며 retinyl acetat와 B-carotene 보충군 사이에는 유의적인 차이가 없었다.3.17%로 가장 양호하였으나, 양파망과 염화비닐판을 수직으로 놓은 것은 각각 1.52%와 1.61%로 비교적 저조하였다. 수정 후 40일째부터 90일째까지 측정한 부착치패의 경과 일수에 따른 각장의 성장은 $SL=184.44e^{0.0335X}(r^2=0.9861)$의 회귀직선식으로서 나타났다. 중간육성 시험에서 수심별 성장을 분석한 결과, 비단가리비 치패는 저층보다 표층이 각장 5.92mm, 전중량 6.07g 정도 더 빨리 성장하였다. 시간으로 하여 l 주 44 시간을 기준으로 측정하면 통상질환관리 18.56시간, 지역사회 보건관리 5.67 시간, 모자보건 및 가족계획 5.52 시간, 사업 운영관리 및 지도 4.10시간, 지역사회 조직 및 개발 3.05 시간, 보건정보체계 개발 및 수집 2.94 시간, 사업계획 수립 2.89시간의 순으로 나타났다. 5) 보건진료원의 업무영역별 수행 소요시간의 상판판계를 살펴보면 지역사펴 조직 및 개발을 위 해 소요한 시간은 사엽계획 수립 소요시간 및 보건정 보체계 관리 소요시간과 순상관관계를, 사업 계획 수립 소요시간은 지역사회 보건관리, 모자보건 및 가족계획 관리 소요시간 및 보건정보체제 관리 소요시간과 순상관관계를 나타냈다. 또한 통상질환관리 소요시간은 지역 사회 조직 및 개발, 사업계획 수립, 지역사회 보건관리와 모자보건

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.501-508
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• 1987

Gonadal development, the annual reproductive cycle and the first sexual maturity of hen clam, Mactra chinensis were studied histologically. Sexuality of the species was dioecious. The gonads were irregularly arranged from the subregion of mid-intestinal 91an4 in visceral cavity to the reticular connective tissue of the foot. The ripe eggs were about $50-60\;{\mu}m$ in diameter, and they were surrounded by gelatinous membrane. The spawning period was from May to September when the water temperature ranged $18.5-27.0^{\circ}C$, with the peak in June and July. The annual reproductive cycle of Mactra chinensis could be classified into five successive stages; multiplicative, growing, mature, spent, and degenerative and resting. The monthly changes of the fatness coefficient closely correlated with the annual reproductive cycle. Percentages of the first sexual maturity of female and male clams were over $50\%$ among those individuals ranging from 3.5 to 3.9cm, and $100\%$ in those over 5.0cm in shell length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.253-262
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• 1990

Hardened seed oysters which inhabit the Hansan Bay of Korea and Hiroshima Bay of Japan were cultured at the oyster farm of Nino island near Hiroshima from June, 1972. to June, 1973. The present experiment investigated monthly increment of shell height, shell length, meat weight, moisture, fatness and gonad development of the seed oysters. Environmental factors were also checked to know ecology of the oysters. The oyster farm of Nino island near Hiroshima city showed high water temperautre and low salinity com-paring with the oyster farm of Hansan Bay. Korea. Shell height and shell ten求h of the hardened seed oyster of Hansan Bay grew faster than those of Hiroshima Bay, especially in oyster meat weight. Histological observation on gonads showed little difference in developmental process between the two localities from June through December, 1972, whereas the hardened seed oyster from Hansan Bay has grown rapidly in the development of gonad after February, 1973. It can be concluded that in the viewpoint of seed oysters productivity the hardened seed oyster from Hansan Bay is more effective than that of Hiroshima Bay comparing in seed growth, fatness and developmental process of gonad.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.234-241
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• 1975

Reproductive cycle of Haliotis discus hannai Ino was studied based on the samples which were collected in Yeosu area from January, 1973 to December, 1974. Particular emphasis was paid on the seasonal variation of gonad maturity factor, coefficieot of gonad maturity, fatnesss, and relationship of gonad weight to growth of the abalone. seasonal fluctuation of water temperature and induction of artificial spawnings were also checked. The abalone of this area spawns twice a year: spring spawning(early May-late July) and Autumn spawning(early September-late November). peak spawning occurs from late May to middle of June for spring spawning: it occurs from late September to early November for Autumn spawning. Gonad maturity factor was closely related to the spawning seasons. For the spring spawning Gonad maturity factor reached to its maximum value as 18.84 in April; for the Autumn spawning it reached to its maximum value as 22.65 in September. Annual minimum value was 12.65 in January. Annual maximum values of coefficient of gonad maturity were 44.10 in May and 49.05 in September and the annual minimum was 10.09 in January. Fatnesswas highest in July as 0.221 and it was lowest in October as 0.1058. Ratios of shell length to gonad weight were formulated as follows : $$In\;September\;GW=0.000003710SL^{3.7860}$$ $$In\;January\;GW=0.000021198SL^{2.8564}$$ $$Annual\;mean\;GW=0.00000005013SL^{4.2273}$$ Relations of total weight to gonad weight were formulated as follows : In September GW=0.1918TW-4.9231 In January GW=0.0992TW-0.1759 Annual maan GW=0.1568UW-3.5256.

• The Korean Journal of Malacology
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• v.20 no.2
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• pp.121-124
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• 2004

Water temperature tolerance of spats of the Manila clam, Ruditapes philippinarum was investigated in the different temperature groups, 15, 20, 25, 30 and 35$^{\circ}C$. The survival rates of the groups were 99.7%, 91.0%, 88.7%, 73.3% and 0%, respectively (p < 0.05). When the temperature of the water decreased from 15$^{\circ}C$ to 5$^{\circ}C$, the survival of spats was higher than when the temperature increased. The growth and survival of spats were investigated in different types of bottom substrates in the tanks. The spats grew the best in the polyvinyl plates, the average shell length was 3.9 ${\pm}$ 0.4 mm. In the FRP tank bottom and sand bottom, the average shell lengths of spats were 3.6 ${\pm}$ 0.3 mm and 3.2 ${\pm}$ 0.3 mm, respectively. The best survival of spats cultured in the FRP tank bottom (22.9 g) and in the polyvinyl plates (20.6 g) (p < 0.05).

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.19-31
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• 2021

We investigated the distribution characteristics of mussels (Mytilus coruscus) growing in the Geomundo sea area by water depth. The research was also conducted to identify the surrounding benthic organisms. Mussels showed high density and low obesity in low water depths. The lower the density, the higher the obesity level appeared in deeper water. The morphological characteristics also appeared to increase as the water depth deepened. In addition, the shell length and total weight were more strongly correlated at a depth of 12 m than at 2 m. The total weight by the growth of the shell length and shell height was affected by the water depth. The analysis showed that the density and biomass of the algae inhabiting the surroundings decreased somewhat as the water depth increased. In benthic animals, the number of mussels tended to decrease slightly at the point where oysters dominated, at a depth of 2 m. Conversely, the number of oysters tended to decrease in deeper water dominated by mussels. Thus, the spatial competition between oysters and mussels was affected by the water depth. Also, mussels did not appear in areas where large algae flourished, suggesting that the survival of mussels was affected by the presence or absence of large algae.