• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.2
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• pp.129-140
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• 2008

This study was performed to estimate biomass and to provide management plan through population ecological characteristics, including growth parameters, survival rate, instantaneous coefficient of natural and fishing mortalities, and age at first capture of hen clam, Mactra chinensis, in the Dong-li self-regulatory community of Busan. The von Bertalanffy growth parameters estimated from a non-linear regression were $SH_{\infty}=86.24mm$, K=0.12/year, and = -1.37year. Survival rate(s) of the hen clam was 0.515. The instantaneous coefficients of natural mortality(M) was estimated to be 0.232/year and fishing mortality(F) 0.432/year for hen clam. The current biomass of the hen clam in the study area was estimated to be 713mt and the acceptable biological catch(ABC) was estimated under various harvest strategies based on $F_{0.1}$ and $F_{40%}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.417-423
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• 1985

In succession to the previous paper, the present study was directed to investigate the nonvolatile organic acids composition in raw and belied-dried products of oyster, sea-mussel, baby clam and hen clam by gas liquid chromatography. The results obtained are summarized as follows : In four kinds of the samples examined, eight kinds of organic acids were identified and determined in oyster, sea-mussel and baby clam, and nine kinds in hen clam. The major organic acids in oyster were pyroglutamic, succinic and malic acid which was $94.2\%$ of total quantity of organic acid, and those in sea-mussel, baby clam and hen clam were succinic and malic acid which were $90.8\%,\;89.7\%\;and\;86.4\%$ of total acids, respectively. The most abundant organic acid in sea-mussel, baby clam and hen clam was succinic acid that was $80.6\%,\;84.9\%\;and\;73.2\%$ in total acids, repectively. And that of oyster was pyroglutamic acid which marked $38.8\%$ in total acids, and the next one was succinc acid marked $34.4\%$. In the total quantity of organic acid, the highest was 913.0 mg/100g in oyster which showed 4.5 times as much as in hen clam, followed by 478.4 mg/100g in sea-mussel, 246.3mg/100g in baby clam, and the least was 201.2 mg/100g in hen clam. The decreasing rate of total quently of organic acids by boiled-dried procersing was the highest in oyster, $54.7\%$, followed by $46.5\%$ in sea-mussel, $37.1\%$ in hen clam and $29.4\%$ in baby clam. The decreasing rate of each organic acid shelved much difference according to the samples examined, in general, great in malic, fumaric and proglutamic acid ana less in succinic, lactic and oxalic acid.

• Journal of Aquaculture
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• v.11 no.2
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• pp.183-191
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• 1998

To substitute fromzed and freeze-dried food for live food in the development of the artificial seedling production of bivalve larvae, the dietary value of live T. suecica was compared with those of freeze-dried T. suecica, frozed T. suecica, live T. suecica (50%)+frozen T. suecica (50%), and live T. suecica (50%)+freeze-dried T. suecica (50%) in the rearing of oyster (Crassotrea gigas) and hen clam (Mactra chinensis) larvae, and manila clam (Tapes philipninarum) spats. Oyster larvae fed live T. suecica showed the highest growth (shell hight $231.9^{\mu}$m) and survival rate (72.6%) and those fed freeze-dried T. suecica showed the lowest growth (shell height $168.9^{\mu}$m) and survival rate (35.3%). However, in the hen clam larvae, there were not significantly different among diet group in growth and survival rate. The small spats of manila clam fed live t. suecica or live T. suecica (50%)+freeze-dried T. suecica (50%) showed higher growth and survival rate than those fed other diet group. In the case of large spats of manila clam, live T. suecica and live T. suecica (50%)+frozen T. suecica (50%) showed better growht. But, survival rates were not different among diet groups. Dietary valuse of frozen and dried T. suecica were different on species and growth stage, and frozen and freeze-dried T. suecica can be partially used as substitute food for T. suecica live T. succica in shellfish hatchery.

• Journal of Korean Home Economics Education Association
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• v.12 no.2
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• pp.47-64
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• 2000

The purpose of this study was to search the calcium and iron rich foods in Korean people. The food sources presented in the current home economics textbooks of middle and high school were investigated. And 40 kinds of calcium and iron rich foods were selected by the quantity in 100g edible portion. one serving size and according to 1997 food supply data. Also 3 major food groups of calcium and iron supply in Korean were identified, and 10 rich foods for each food groups were selected. The results were summarized as follows. 1. The food sources of calcium 1) The food sources of calcium presented in the home economics textbooks of middle and high school are milk and dairy products. small fishes such as anchovy icefish and dried strip and green vegetables etc. 2) The calcium rich foods by 100g edible portion were in order of skim milk powder river snail sesame sea mustard. whole milk powder. snapping turtle loach sea tangle(dried) opossum shrimp and sea lettuce(dried). And the calcium rich foods by the calcium content in one serving were in order of river snail snapping turtle opossum shrimp loach spiny lobster skate skim milk powder small alaska pollack freshwater crab condensed milk whole milk powder skate ray and milk. 3) The 3 major calcium supply food groups in Korean were vegetables fish and shellfishes and milk and dairy products. 4) The calcium supply foods according to the quantity of food supply in 1997 was in order of sea mustard, milk anchovy chinese cabbage soybean skin milk powder laver shrimp welsh onion and maize. The vegetables were the important sources of calcium in Korean. 2. The food sources of iron 1) The food sources of iron which are commonly presented in the textbooks of middle and high school were meat liver egg(egg yolk) and green vegetables etc 2) The iron rich foods on the basis of the iron content in 100g edible portion were in order of surf clam marsh clam laver(dried)( sea lettuce(dried), crayfish pelilla seed little neck clam orient hard clam, venus clam, and freshwater carab. And the iron rich foods by the iron content in one serving were in order of surf clam marsh clam crayfish little neck clam orient hard clam freshwater crab venus clam hen cockle green confertii(fresh) pen shell and spiny lobster. 3) The 3 major iron supply food groups in Korean were cereals an cereal products fishes and shellfishes and vegetables. 4) The iron supply food according to the quantity of food supply in 1997 was in order of soybean sea mustard maize rice meat edible viscera laver wheat flour, pook, red pepper, egg and bovine meat.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.13-18
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• 2001

The relationship between shell length and ring radius in each ring group was expressed as a regression line. Therefore, there is a correspondence in each ring formation. Based on the monthly variation of the marginal index (Ml') of the shell, it is assumed that the ring of this species was formed once a year during the period of August to October, and the main period of the annual ring formation was August through September. The relationship between shell length (SL) and total weight (TW) was expressed by the equation TW = 2.2476 $\times$ 10$^{-5}$ SL$^{3.536}$ ($r^2$= 0.90). Shell length (SL) and shell height (SH; mm) were highly correlated with the equation SH = 0.7545 SL - 0.0145 ($r^2$= 0.93). The shell length (SL)-shell width (SW) relation was expressed by the equation SW = 0.5336 SL- 2.4253 ($r^2$= 0.87). Growth curves for shell length and total weight fitted to the von Bertalanffy's equation were expressed as follows: SL$_{t}$ =60.02[1 - e$^{-0.6458(t-0.3895)}$ ], Twt = 43.63[1 - e$^{0.6458(t-0.3895)}$ ]$^{3.536}$ .

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.541-546
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• 1992

In order to develop low salt fermented hen clam sauce with high stability, the effects of citric acid pretreatment and fermentation temperature were examined. The VBN contents of surf clam sauce treated with citric acid (SCA) were lower than those of control and the same sauces added alcohol at two temperature conditions ($5^{\circ}C$ and room temperature) during fermentation. The maximum $NH_2-N$ contents of control and SCA during fermentation at $5^{\circ}C$ were 501.3 and $618.4{\sim}691.6\;mg/100g$, respectively, and the pH of those showed $5.61{\sim}6.24$ and $2.43{\sim}3.21$. The total creatine contents of control and SCA, respectively, were $36.8{\sim}27.6\;mg/100g$ ranges. As the time of treatment with citric acid was longer, the degradation of ATP, ADP and AMP in the SCA was faster. In the control, the Ala content was $19.6{\sim}23.02%$ and was highest level among all free amino acids. As fermenting term was longer, among the free amino acids, Ala and Gly were large amounts in control and SCA, respectively, and Gly was slowly increased in SCA during fermentation. As the results of organoleptic test, the tastes of SCA showed good score than control.

• 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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.4
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• pp.345-352
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• 2008

A self-regulatory community fisheries management program in Korea is designed to enhance fisheries resources, to protect fishing grounds of self-regulatory communities, and to manage their fisheries resources by their own regulations and knowledge. This study explored an applicable ecosystem-based management plan based on the scientific investigation and analysis. This study suggested objectives, indicators and reference points of the ecosystem-based resource management system which are applicable to selfregulatory community fisheries. The objectives of the management system are to maintain sustainable fisheries production, to maintain optimum fishing intensity, to reduce by-catch, to conserve spawning ground and habitat, to maintain optimum habitat environment, to increase/maintain abundance of prey species, to increase/maintain stock biomass, and to conduct stock enhancement on the basis of scientific assessment. The improved methods for the assessment and management are introduced by demonstrating a self-regulatory fishery which targets on hen clam in Dong-li fishing village in Busan.

• Development and Reproduction
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• v.1 no.2
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• pp.141-156
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• 1997

1992년 1월부터 12월까지 1년간에 걸쳐 전북 군산, 선연리 조하애에서 채집된 개량조개, Mactra chinensis Philippi를 대상으로 생식세포 발달과 생식소 발달양상을 조사하기 위해 토과형 전자현미경으로 미세구조 변활르 관찰하였고, 정확한 산란기를 규명하기 위해 조직학적으로 생식주기를 조사하였다. 개량조개는 장웅이체이다. 난황형성과정은 난모세포의 발달정도에 따라 다르게 나타나고 있다. 전난황형성기 난모세포질 내에서는 핵주변 구여게 골지장치와 수많은 공포들 및 미토콘드리아들이 출현하고 있는데 이들은 차후, 지방적 형성에 관여한다. 난황형성전기 난모세포에서는 지방적 및 지질과립들이 핵막 근처에서 출현하여 피질층쪽으로 분산되는 반면, 같은 발달단계의 난모세포질의 피질구역에서는 피질과립들 (단백질성 난황과립)이 처음으로 생성되어 난황막 근처의 피질층에서 핵주변 구역쪽으로 분산 분포된다. 난황형성후기 난모세포에서는 세포질 내의 골지장치, 공포, 미토콘드리아, 그리고 조면소포체들이 자율합성에 의해 난황과립 형성에 관영하고 있다. 반면, 외인성 물질들인 지질형태의 과립들, 단백질성 물질 및 다량의 글리코겐 입자들이 생식상피 낸에서 출현하고 있는데, 이들 물질이 생식상피에서 난황막 구조물인 미세융모를 통해 난황형성 후기 난모세포의 난질 내로 통과해 들어가는 현상이 관찰되었다. 이와 같은 현상은 난황성성이 일어날 때에 hterosynthesis가 일어나고 있음을 시사한다. 완숙난모세포의 난경은 약 50-60 \mu m이고, 완숙정자 두부의 길이는 대략 3 \mu m이며, 미부의 길이는 약 30 \mu m정도이다. 정자 미부편모의 axoneme은 중앙의 2개의 미세소관(microtubule)과 주변에 위치한 9개의 2중 미세소관 (microtubule)으로 구성되어 있다. 본 종의 산란기는 5월에서 9월 중순에 걸쳐 일어나는데, 주산란시기는 해수수온이 22 \circ C 이상으로 상승하는 6, 7월이다. 따라서 1년에 산란 (번식)시기가 한번 일어나고 있음을 알 수 있다. 생식 주기는 초기활성기 (1-2월), 후기활성기 (2-4월), 완숙기 (4-9월), 산란기 (5-9월) 그리고 퇴화 및 비솰성기 (6-12월)의 연속적인 5단계로 구분할 수 있었다. 재생산에 가담할 수 있는 암, 수개체들의 군성숙도(%)를 조직학적으로 조사한 결과, 각장 3.5-3.9cm 범위의 개체는 55.5%이었고, 5cm 이사인 개체들은 재생산에 100% 참여하였다. 본 종의 암, 수개체들은 만 1년부터 재생산에 가담하는 것으로 추정된다.

• Journal of Life Science
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• v.28 no.12
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• pp.1424-1431
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• 2018

We prepared flocculated detritus-like organic marine snow originating from various organisms by fermentation using microorganisms; this fermented organic material was fed to the leptocephali of the eel (Anguilla japonica) to investigate whether or not such organic matter was an appropriate food source for the larvae. A strain was isolated from a biofloc technology system used to culture fish, and seven types of organic material from hen's egg, eel muscle, tuna muscle, lugworm, shrimp, manila clam, mussel, and sea squirt were fermented using isolated bacteria (Bacillus sp.). The fermented matter did not show any specific form and was larger than $10-20{\mu}m$ but no more than $100{\mu}m$ in size. Four diets (A-D) were prepared using the various fermented products, and the larvae were fed the prepared food from 20 days after hatching. The leptocephali fed the A, B, and C diets survived until 37, 39, and 37 days after hatching, respectively. However, the leptocephali fed the D diet survived for 60 days after hatching. The protein content of each diet was very similar, but the n-3 HUFA concentration in the D diet was approximately twice as high as that of the others.