• Fisheries and Aquatic Sciences
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• 제23권6호
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• pp.16.1-16.10
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• 2020

This study was conducted in Lake Hayq between January and December 2018. The objectives of this study were to determine the growth, condition, sex ratio, fecundity, length at first sexual maturity (L₅₀), and spawning seasons of common carp (Cyprinus carpio). Monthly fish samples of C. carpio were collected using gillnets of stretched mesh sizes of 4, 6, 7, 8, 10, and 13 cm and beach seines of mesh size of 6 cm. Immediately after the fish were captured, total length (TL) and total weight (TW) for each individual were measured in centimeters and grams, respectively, and their relationship was determined using power function. Length at first maturity (L₅₀) was determined for both males and females using the logistic regression model. The spawning season was determined from the frequency of mature gonads and variation of gonadosomatic index (GSI) values of both males and females. Fecundity was analyzed from 67 mature female specimens. The length and weight relationship of C. carpio was TW = 0.015TL^2.93 for females and TW = 0.018TL^2.87 for males that indicate negative allometric growth in both cases. The mean Fulton condition factor (C_F) was 1.23 ± 0.013 for females and 1.21 ± 0.011 for males. The value of C_F in both cases was > 1 that shows both sexes are in good condition. Among the total 1055 C. carpio collected from Lake Hayq, 459 (43.5%) were females and 596 (56.5%) were males. The chi-square test showed that there was a significant deviation between male and female numbers from 1:1 ratio (χ²= 22, df = 11, P > 0.05) within sampling months. The length at first sexual maturity (L₅₀) for females and males were 21.5 and 17.5 cm, respectively. Males mature at smaller sizes than females. The spawning season of C. carpio was extended from February to April, and the peak spawning season for both sexes was in April. The average absolute fecundity was 28,100 ± 17,462. C. carpio is currently the commercially important fish while Nile tilapia fishery has declined in Lake Hayq. Therefore, this baseline data on growth, condition, and reproductive biology of common carp will be essential to understand the status of the population of carp and design appropriate management systems for the fish stock of Lake Hayq, Ethiopia, and adjacent countries.

• 한국수산과학회지
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• 제37권6호
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• pp.478-484
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• 2004

On 11 June 1991, eggs from the brood stock of small yellow croaker (Larimichthys polyactis) were artificially fertilized using the standard dry method and were hatched. Each of the fertilized eggs (1.1-1.2 mm in diameter) had an oil globule and was transparent and buoyant. The fertilized eggs hatched in a range of water temperatures $(17.5-20.3^{\circ}C)$ 44 hrs after fertilization. The total lengths of the newly hatched larvae were 3.1-3.3 mm, and these hatchlings had 31 myotomes (10+21). Melanophores and yellow-brown chromatophores were concentrated on the head, at the ventral part of the yolk, and in the middle of the tail. Four days after hatching, the larvae completely absorbed the yolk and became flexions of 5.1-5.5 mm in total length. Fifteen days after hatching, one spine (the anterior tip of the maxillary) appeared in the upper jaw and three spines developed at the upper parts of the eyes and on the posterior part of the head. At this stage, the larvae were approximately 8.3 mm long. Thirty-nine days after hatching, juveniles (1.9-3.4 mm in total length) had a pointed tail fin. By 66 days after hatching, the juvenile fish (about 4.0-6.5 mm in total length) were similar to adult fish in body shape. The larvae of L. polyactis could be distinguished from those of L. croacea by two distinct characteristics: the large number of vertebrae (28-29), and a relatively small bony ridge on the occipital region of the head.

• 대한지역사회영양학회지
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• 제20권1호
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• pp.11-20
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• 2015

Objectives: The purpose of this study was to examine mothers' eating behavior and salty taste and its relationship to their preschool children's eating behaviors. Methods: This survey was conducted by self-report after getting permission from sixty one mothers who had preschool children. The questionnaire was focused on mothers' salty test and salt-related eating behavior of both mothers and their preschool children. Results: Comparison of eating behavior score between mother and their preschoolers showed that mothers' score was lower than their preschoolers' one. Salty foods with high preference and intake frequency by mothers and preschoolers were 'salted dry fish, stock fish' and 'soup, stew, noodle soup'. In addition, there were strong positive correlations between preference and intake frequency on most of the salty food items. Intake of Ramen soup was significantly different (p < 0.001) between the two groups. Preschoolers ate less ramen soup compared to their mothers. Conclusions: Overall results showed that preschoolers' dietary behavior was better than the mothers' one. However, preschoolers' dietary behavior was significantly influenced by their mothers. Therefore, mothers should have an appropriate eating behavior in order to have a positive influence on their children's eating habits. In addition, the results suggested that proper nutrition education is needed for mothers of preschool children.

• 한국양식학회지
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• 제20권4호
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• pp.219-225
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• 2007

본 연구는 양식산 뱀장어 Anguilla japonica의 인위적인 성성숙 처리시기와 번식률과의 상호 관련성을 확인하기 위해 5월(봄)부터 익년 1월(겨울)까지 각 계절별로 수행되었다. 실험어의 인공 성성숙 유도를 위해 암컷($400{\sim}600\;g$) 뱀장어에 salmon pituitary extraction (SPE, 20 mg/fish/week)를 매주 복강에 주사하여 인위적인 성성숙을 유도하였다. 호르몬 처리 $8{\sim}13$주 이후 대부분의 개체들은 난황형성이 완료되었고, $17{\alpha}$, $20{\beta}-dihydroxyprogesteron$ (DHP, $2\;{\mu}g/g$ body weight)를 주사하여 배란을 유도하였다. 수컷 뱀장어($200{\sim}350\;g$)는 human chronic gonadotropin (HCG, 1 IU/g body weight/week)을 매주 복강에 주사하여 정자형성 및 배정을 유도하였고, 이후 상기의 개체들에 대해 자연산란에 의한 수정 및 인공수정을 병행하였다. 배란율, 부상률, 수정률 및 부화율을 포함한 계절별 번식률에 있어서 봄과 여름($5{\sim}7$월)에 인공성성숙을 유도한 실험구가 다른 계절에 비해 높았다. 산란수와 부화 유생수 및 부화유생의 생존일수는 번식률과 유사한 경향을 나타내었다. 본 연구결과, 양식산 뱀장어에 있어서 호르몬 처리에 의한 인공성성숙유도의 시기는 자연계에서 주산란시기인 봄과 여름철이 적합함을 나타내고 있다. 따라서, 양식산 뱀장어의 적절한 인공성성숙시기는 배란율, 부상률, 수정률 및 부화율을 포함한 번식률에 의해 결정할 수 있다.

• 한국수산과학회지
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• 제22권5호
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• pp.306-316
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• 1989

우리나라 근해에서 어획되는 병어류의 어획물에 혼재된 "병어"와 "덕대"의 혼획비를 조사하고, 그중에서 양적으로 월등히 많은 것으로 확인된 덕대를 대상으로 실측 조사된 체급별 체장조성과 어체조사자료를 기초로 하여 자원해석을 실시하고 자원관리방안을 검토하였다. 병어류의 어획물중에서 덕대의 혼획비율은 중양비로써 $60\~70\%$를 차지하는 것으로 밝혀졌으며, 어획물의 체장조성은 FL 15 cm를 중심으로 한 단일 mode로 구성되고 체장조성의 연변동은 거의 없었으며, 연령조성은 1세어가 $41\~46\%$를 차지하며 다음으로 많은 조성비를 차지하는 것은 0세어로 나타났다. 현재의 자원특성치는 다음과 같이 추정되었다. 자연사망계수(M) : 0.6 어획사망계수(F) : 0.924($1986\~1988$년 값의 평균) 어장가입년령($t_r$) : 0.19 어획개시년령($t_c$) : 0.49 0세어의 어장가입률(Q) : 0.29 가입당어획이론에 의하여 이루어진 자원진단결과 어획개시연령과 어획사망의 두 가지 기준에서 볼 때 덕대의 현재 자원상태는 적정수준이하에 있으며, 어획강도의 조절에 의한 어획량증가효과는 거의 없으므로 최선의 관리방법은 어획강도의 조절보다 어획개시년령을 현재의 0.49로 부터 1.5세 부근까지 높이는 것으로 판단되었다.

• 한국해양공학회지
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• 제17권2호
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• pp.8-13
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• 2003

Soil, ground water, and sea bed are exposed to a continuous accumulation of polluted materials, causing serious environmental damage. It has been reported that such pollution causes a massive mortality of fish stock in rivers due to the resuspension of toxic chemicals, occurring during strong wind conditions. Therefore, it becomes apparent that there is an immediate demand for the restoration treatment of polluted river bed (or sea bed) sediment layers. Pollution levels of major rivers and ports, such as Paldang, Kyungan rivers, and Masan port, are becoming of great public concern, and are posing a serious environmental threat. In particular, the pollution of the Shi-hwa river has become a nation wide issue for the last few years. In spite of such public concern, the pollution levels of such rivers or ports are worsening everyday. In this study, an environmentally sound engineering package is introduced that helps to restore the polluted river bed or sea bed sediments. This engineering package consists of a suction facility, followed by a series of mechanical, chemical, and biological treatment units. The suction facility is designed to minimize secondary pollution that occurs from the resuspension of toxic materials during suction. The sea bed cleaning engineering package is designed to be installed on the top of a floating barge. Such a combination of environmental plant and shipbuilding technology provides a cost-effective solution, minimizing the transportation between suction and treatment facilities.

• 수산해양기술연구
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• 제55권4호
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• pp.363-371
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• 2019

Thousands of demersal fishes inhabit in the waters around Korea and most of them are overexploited. One of reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the Danish seine fishery from 1960s to 2010s. Gross tonnage was decreased stably, but the horse power was increased annually. The length of ground rope, warp and hand rope was somewhat longer, but changed a little. Color fish finder was utilized from the mid-1960s and positioning system was used five years later. A hydraulic line hauler were introduced in the mid-1980s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting researchers. Therefore, the relative fishing power index in the Danish seine fishery increased stably from 1.0 in 1970 to 1.0 in 1980, to 1.2 in 1990, to 1.3 in 2000 and to 1.3 in 2010. The results are expected to contribute to reasonable fisheries stock management.

• 한국식품위생안전성학회지
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• 제27권3호
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• pp.285-289
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• 2012

In this study, the veridical efficacy of an aquatic disinfectant tablet composed to calcium hypochlorite against red sea bream iridovirus (RBIV). A veridical efficacy was determined with the viability of RBIV contacted with the disinfectant in viral stock cultured in fat head minnow cell line. An aquatic disinfectant tablet and RBIV were reacted on the distilled water (DW), hard water (HW) or organic matter suspension (OM) condition. On DW and HW condition, RBIV was inactivated with 25,000 fold dilutions of an aquatic disinfectant tablet. With the investigation of the antiviral effect of the disinfectant on OM condition, RBIV was inactivated on 22,000 fold dilutions of an aquatic disinfectant tablet. As an aquatic disinfectant tablet possesses veridical efficacy against RBIV, the disinfectant solution can be used to limit the spread of cultured marine fish viral disease.

• 분석과학
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• 제36권5호
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• pp.205-215
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• 2023

In the present study, an analytical method was proposed for detecting trifluralin in aquatic products at trace concentrations. The method employed QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) as the sample preparation and measurement, respectively. The effect of the aqueous phase volume used in the QuEChERS was demonstrated, and the ratio of 10:10 (mL) between water and acetonitrile phase was used for 5 g of sample. Besides, dSPE using C18 and primary-secondary amine (PSA) was applied to remove the potential interferences from the food matrices, indicating no remarkable analyte loss. The linear range was built up from 0.50 ㎍ L^-1 to 3.0 ㎍ L^-1 (R² = 0.9993). Other criteria, i.e., repeatability (RSD_r = 0.86-1.96 %), reproducibility (RSD_R = 1.09-2.01 %), and recovery (over 90 %), were in accordance with Appendix F of AOAC (2016) for method performance. Although no trifluralin was detected for the commercial samples (fish, shrimp, and breaded shrimp), the spiked samples performed favorable recoveries and precision.

• 한국양식학회지
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• 제21권4호
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• pp.304-308
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• 2008

MS-222 농도별로 자연산 및 양식산 감성돔 치어의 마취효과를 비교하면 수온 $22^{\circ}C$ 고수온구가 $12^{\circ}C$의 저수온구에 비해 마취 및 회복시간이 빨랐으며, 수온 $12^{\circ}C$의 저수온에서는 자연산이 양식산에 비하여 마취 및 회복이 빨랐다. MS-222 100 ppm 농도에서 침지시간별 회복 조사에서도 $22^{\circ}C$ 실험구가 $12^{\circ}C$의 저수온 실험구에 비해 회복시간이 빨랐으며, 수온 $12^{\circ}C$의 동일 수온에서의 자연산과 양식산 치어를 비교했을 시에는 자연산 치어가 양식산 치어에 비해 마취후 회복이 빨랐다. MS-222 100 ppm에 3분간 침지후 공기중 노출시간에 따른 회복시간 조사 결과도 마찬가지로 $22^{\circ}C$ 실험구가 $12^{\circ}C$의 저수온에 비해 회복시간이 빨랐으며, 수온 $12^{\circ}C$에서는 자연산 치어가 양식산 치어에 비해 회복이 다소 빨랐다. 그러나 공기중에 노출시간이 15분 이상인 경우에 $12^{\circ}C$의 저수온 실험 구에서 수온 $22^{\circ}C$의 고수온구에 비해 회복이 빨랐다. 수온 $12^{\circ}C$에서는 자연산이 양식산 치어에 비해 회복이 빨랐다. 따라서 자연산 감성돔 치어가 양식산 치어에 비하여 마취 및 공기중 노출 내성이 강함을 알 수 있었다.