• Fisheries and Aquatic Sciences
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• 제4권4호
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• pp.208-218
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• 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.

• 한국측량학회지
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• 제31권3호
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• pp.221-228
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• 2013

도시계획이나 상권분석 등의 분야에서, 중심지의 성숙도와 같은 중심지에 대한 평가는 합리적 의사결정을 위해 고려하여야 할 중요한 정보이다. 본 연구에서는 서울시에 대한 2004년과 2009년의 전화번호부 업종 데이터 중 대표적인 소매업종인 소매, 생활서비스, 음식업의 세 업종을 선택하여 중심성 지수와 입지계수를 구했다. 중심성 지수와 세 개의 소매업종에 대한 입지계수로부터 각각 중심지의 성장, 쇠퇴, 성숙을 파악하고 이를 비교, 분석하여 중심지 평가 방법을 제시하였다. 본 연구를 통해 어떤 중심지에 대해서 세 소매업종에 대한 입지계수를 비교하여 성장지역인지, 쇠퇴지역인지, 아니면 성숙지역인지의 여부를 파악할 수 있음을 알 수 있었다. 이러한 중심지의 평가 결과는 상권분석에서 업종의 선택이나 출점 가능 여부 판단과 같은 업무에서 중요한 지표로 매우 유용하게 사용될 수 있을 것이다.

• 한국패류학회지
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• 제23권2호
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• pp.199-208
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• 2007

2006년 1월부터 12월까지 전북 부안군 격포리에서 월별로 채집된 홍합, Mytilus coruscus를 대상으로 생식주기를 조사하였다. 홍합은 자웅이체이며, 난소는 수많은 난소소낭으로 이루어 져 있으며, 정소는 다수의 정소소낭으로 구성되어 있다. 생식소지수 (GI) 와 생식소중량지수 (GSI) 의 월별 변화는 2월에 최고값에 도달한 이후, 4월까지 점차 감소하였으며 GI 값과 GSI 값의 월별 변화는 서로 유사한 경향을 보였다. 비만도지수 (CI) 의 월별 변화는 생식소지수와 생식소중량지수의 변화양상과 유사한 경향을 나타내었다. 따라서 이들 세 가지 지수로부터 홍합의 산란기는 2-4월로 판단된다. 조직학적 조사에 의한 홍합의 산란기는 2-4월이었으며, 주 산란기는 2-3월이었다. 생식주기는 초기활성기 (11-1월), 후기활성기 (11-2월), 완숙기 (12-4월), 부분산란기 (2-4월), 퇴화기 (4-10월), 휴지기 (6-12월) 로 구분되었다. 각고에 따라 홍합의 군성숙도를 조사한 결과, 각고 40.1-50.0 mm인 개체들은 군성숙도 50% 이상 (암컷 71.4%, 수컷 78.9%) 이었고, 각고 50.1 mm 이상인 개체들은 군성숙도 100%이었다. 12개월간 채집한 총 개체들의 성비를 검증한 결과, 암수 성비는 1:1로 유의한 차이를 보이지 않았다 $(x^2\;=\;0.63,\;p\;>\;0.05)$.

• 한국수산과학회지
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• 제53권1호
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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).

• 수산해양기술연구
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• 제50권2호
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• pp.154-161
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• 2014

Maturity and spawning of the giant Pacific octopus, Octopus dofleini was investigated based on the samples collected in the coast of Gangwondo, East Sea, from January to December in 2009. Individuals of mature stage had a higher occurrence rate from February to May, and gonadosomatic index (GSI) also showed a higher value from February to May than the other months. For that reason, the spawning period was estimated from February to May with the main spawning period from March to May. The total number of eggs in the fecundity (F) ranged from 9,045 in 11.0 kg (TW) to 148,682 in 16.5 kg (TW), which was proportional to total weight (TW), and the relationship between total weight and fecundity was $F=0.185{\times}TW^{2.238}$ ($R^2=0.389$). The total weight at 50% group maturity (TW0.5) of female was estimated to be 12.2 kg.

• 한국수산과학회지
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• 제55권5호
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• pp.575-582
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• 2022

This study revealed the reproductive biology of pointhead flounder Cleisthenes pinetorum, in the middle of the West Sea of Korea. We collected samples using gill net and drag net fisheries in coastal waters from January to December 2019. Mmonthly gonodosomatic index and maturity stage results showed that the spawning period was October to December, and the females grew faster than the males. The fecundity ranged from 16,728 to 1,039,616 number of eggs, and the relationship between TL and fecundity (F) was 0.0000003TL^4.7434 (R²=0.4898). The size-frequency distribution of eggs suggested that C. pinetorum spawm once during a spawning period. The length at 50% maturity for females was estimated to be 18.9 cm.

• 한국어류학회지
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• 제35권4호
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• pp.333-339
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• 2023

이번 연구는 인천 연안에 서식하는 쥐노래미(Hexagrammos otakii)의 성비, 성숙체장, 산란기를 구하였다. 암수성비는 1 : 1.2 (n=739 : 906, 전체 개체군의 81.6% 차지)로 암수 출현비율은 통계적 차이를 보이지 않았다. 쥐노래미 암컷의 생식소숙도지수(GSI) 값은 11월에 가장 높았고, 수컷은 10월에 가장 높게 나타났고, 산란기는 10월에서 1월로 추정되었다. 쥐노래미 암컷의 50% 성숙체장은 23.1 cm로 분석되었다.

• 수산해양기술연구
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• 제49권4호
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• pp.449-458
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• 2013

This study investigated purplish Washington clam, Saxidomus purpuratus on its gonadal development, reproductive cycle and shell length (age) at 50% female group maturity from January to December 2011 in Jinhae Bay, Korea. This species is dioecious. The gonad index (GI) began to increase in January, reached the maximum value in May and to decrease in June, reached the minimum value in September then to increase slowly in October again. The reproductive cycle of the clams can be divided into five successive stages: the early active stage (Ea, from February to March), the late active stage (La, from January to March and October to December), the ripe stage (R, from January to May), the spawning stage (S, from June to December) and the degenerative and inactive stage (Ia, from January to February and November to December). The spawning periods were from June to December and the main spawning periods were from July to October. The shell length at 50% female group maturity (SL50) was estimated to be 63.6 mm, which can be converted as sexual maturity age of 2.2 year.

• 한국수산과학회지
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• 제49권3호
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• pp.367-375
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• 2016

Marbled flounder Pseudopleuronectes yokohamae is a commercially important flatfish in the coastal waters of the East Sea off Pohang, Korea. Maturity and spawning dynamics of P. yokohamae were investigated based on samples collected by gill net and long line in the coastal waters off Pohang from January 2013 to December 2014. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity, and total length at 50% group maturity. We found that the spawning period was December to February, wherein fecundity ranged from 55,760 eggs at 20.40 cm total length (TL) to 1,559,007 eggs at 46.6 cm TL. The relationship between TL and fecundity (F) was F = 0.0017 TL^3.5604 (R² = 0.6984), and F increased with increasing TL. We estimated the TL at 50% group maturity as 27.4 cm for female and 23.5 cm for male P. yokohamae, respectively. The results from this research will aid in the development of policies on season and minimum catch length for sustainable production of P. yokohamae. We propose that it is necessary to conduct long-term ecological monitoring for this species because biological properties such as spawning ecology and growth performance are being affected by climate change.

• 수산해양기술연구
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• 제54권4호
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• pp.296-305
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• 2018

Maturity and spawning of the pointhead flounder, Hippoglossoides pinetorum were investigated on the basis of samples collected in the coastal waters off Gangwon-do, East Sea from January 2012 to December 2013. The average total length of H. pinetorum was 25.0 cm and 21.9 cm for females and males, respectively. The spawning period was from May to July according to monthly changes gonadosomatic index (GSI) and maturity stages. The spawning period in Gangwon-do was delayed relatively to that in Gyeongbuk-do. The mature egg diameter ranged between $300-700{\mu}m$. The relationship between TL and fecundity (F) was F = 63.574 TL - 1471.3 ($R^2=0.7603$), that is, the larger total length, the more fecundity H. pinetorum had. We estimated that the TLs at 50% group maturity were 25.6 cm for females and 19.9 cm for males. The spawning ecology by sea area should be considered efficient resource management for H. pinetorum. Furthermore, it is necessary to study more on the relationships among growth, maturity and water temperature variations in the East Sea.