• Title/Summary/Keyword: Length at maturity

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Maturity and Spawning of White Croaker Pennahia argentatus in the Southern Sea of Korea (한국 남해안에 서식하는 보구치(Pennahia argentatus)의 성숙과 산란)

  • Jeon, Bok-Soon;Choi, Jung-Hwa;Im, Yang-Jae;Lee, Hae-Won;Kim, Jae Won
    • 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=0.2198TL4.2784 (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).

Variation of Major Characters in Soybean Varieties II. Effects of Day Length (대두품종의 주요특성 변이 II. 일장조건의 영향)

  • 이성춘;최경구;김진호;장영남
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.35 no.1
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    • pp.10-15
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    • 1990
  • These experiments were conducted to investigate the effect of day length on some chracteristics and seed weight in the soybean cultivars. Those were classified into three type's of seed weight with delaying seeding date in the previous paper. Flowering was delayed as the longer day length was employed. When the length became longer. the number of leaves at flowering greatly length of main stem and the number of nodes at maturity greatly increased. The seed weight decreased when the day length was longer than 14 hours. Negative correlation was obtained between seed weight and day length. There was negative correlation between seed weight and the number of days required to flowering, and length of main stem and the number of nodes at maturity. Type I cultivars decreased in seed weight when the day length was longer than 16 hours, but this trend was found to be clear with type II cultivars. Type III cultivars decreased in seed weight with increasing the day length.

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Maturity and Spawning of Pacific Cod (Gadus macrocephalus) in the East Sea (한국 동해안 대구(Gadus macerocephalus)의 성숙과 산란)

  • LEE Chae Sung;HUR Young Hee;LEE Jeong Young;KIM Wan Ki;HONG Sung Hyun;HWANG Sean Jae;CHOI Soo Ha
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.38 no.4
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    • pp.245-250
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    • 2005
  • The maturity and spawning of Pacific cod, Gadus macrocephalus, was studied using samples caught by gillnets in the East Sea from January to December 2003. Monthly changes of maturity observed with the naked eyes for females showed that maturing Pacific cod appeared from August, and their numbers increased to $83\%\;and\;100\%$ in November and December, respectively. In January, mature and spawning Pacific cod were observed for the first time and composed over $40\%$ of the population. In February, the proportion of spawning individuals increased to over $50\%$, however, the mature individuals decreased to less than $10\%$. In March, mature fish were not found, and all were in an immature (spent) or spawning state. From April to July all fish remained in immature condition. The males maintained this trend with the females, whereas, mature males appeared from November to March. Monthly changes in the gonadosomatic index (GSI) of females and males showed higher values both in January and February and declined sharply in March. The lower value remained until October and then began to increase from November for the female population. For the males, however, this value remained lower until August, and then began to increase from September, and showed higher values in October through December than in January and February. These results indicated that the spawning season of Pacific cod was from December to March, and the main spawning season was from January to February, and the period of the spawning season was longer for males than the females. The diameter of the matured oocytes was 0.80-1.10 mm with a single mode of 0.95 mm. Fecundity was 1,300,000-9,400,000 in total length of 65-95 cm and the relationship between the total length (TL, cm) and fecundity (Fc) was Fc= $180,248\timesTL-10,883,638$. The total length at first maturity was observed at 57 cm for females and 47 cm for males. The size at $50\%$ group maturity was estimated to be 63.9 cm for females and 56.0 cm for males.

Maturity and Spawning of Sebastes thompsoni in the Coastal Waters off Ulleungdo, Korea (울릉도 연안에 서식하는 불볼락(Sebastes thompsoni)의 성숙과 산란)

  • Yang, Jae Hyeong;Lee, Jae Bong;Lee, Hae Won;Cha, Hyung Kee;Kim, So Ra;Heo, Yo Won
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.3
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    • pp.404-409
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    • 2016
  • We investigated the maturation and spawning of Sebastes thompsoni in the coastal waters off Ulleungdo, based on samples collected by gill net from March 2013 to February 2014. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity, and total length (TL) at 50% group maturity. The average TLs of female and male S. thompsoni were 22.6 cm and 22.5 cm, respectively. The main parturition period of females was during March and April. The GSI of females began to increase in January, and reached a maximum in March. The GSI of male reached a maximum between January and February. The spawning period of males was shorter than that of females. The egg diameter during gestation stage was 1.4±2.1 mm. The TL of females at 50% group maturity was 22.3 cm.

Maturity and Spawning of Brown croaker Miichthys miiuy in the South-western Water of Korea (한국 서남해 민어(Miichthys miiuy)의 성숙과 산란)

  • Lee, Seung Hwan;Chung, Sangdeok;Kim, Yeong Hye;Yoo, Joon Taek
    • Korean Journal of Ichthyology
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    • v.29 no.2
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    • pp.109-116
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    • 2017
  • We investigated maturation and spawning of Miichthys miiuy in the south-western water of Korea, based on samples collected by stow net from August 2015 to December 2016. We analysed monthly changes in maturity stage, gonadosomatic index (GSI), total length (TL) at 50% group maturity. The spawning period was August to October. We estimated the TL at 50% group maturity as 54.8 cm for females and 49.0 cm for males.

Maturity and spawning of the pointhead flounder, Hippoglossoides pinetorum in the coastal waters off Gangwon-do, East Sea (동해 강원도 연안 용가자미, Hippoglossoides pinetorum의 성숙과 산란)

  • YANG, Jae-Hyeong;CHO, Jung-Hyun;KIM, Jong-Bin;PARK, Jeong-Ho;LEE, Soo-Jeong;YOON, Byoung-Sun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.54 no.4
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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.

Sexual Group Maturity and Main Spawning Period of Glyptocephalus stelleri (Teleostei: Pleuronectidae) (기름가자미 Glyptocephalus stelleri의 군성숙도와 주 산란기)

  • Shin, So Ryung;Kim, Hyeon Jin;Oh, Han Young;Lee, Jung Sick;Song, Hyejin;Kim, Jae Won
    • Journal of Marine Life Science
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    • v.7 no.1
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    • pp.37-44
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    • 2022
  • This study was performed to obtain information on the sex ratio, size at sexual group maturity, and main spawning period of Glyptocephalus stelleri. The sex ratio (female: male) was 1:0.54 (n=189:103, 64.7% female), and the frequency of females in the population tended to increase with total length. The oocyte development pattern was group synchronous development, in which oocyte groups at different stages were identified within the same ovary. The total length at 50% sexual group maturity was analyzed using a logistic regression model, and was determined to be 28.51 (female) and 30.49 cm (male). The gonadosomatic index (GSI) displayed the highest values in April (female) and March (male), and the main spawning period being in April to May.

Length-based stock assessment of the pacific yellowtail emperor in the Southern Sulawesi, Indonesia

  • I Nyoman Suyasa;Alifah Fitam Rakhma Sari;Siska Agustina;Rian Prasetia;Ratna Suharti;Toni Ruchimat;Budy Wiryawan;Irfan Yulianto
    • Fisheries and Aquatic Sciences
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    • v.26 no.3
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    • pp.216-223
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    • 2023
  • Pacific yellowtail emperor, Lethrinus atkinsoni Seale, 1910, is one of the most targeted reef fish species in Southern Sulawesi, Indonesia. Therefore, assessing its stock is important to understand the condition of the population, providing valuable inputs for sustainable fisheries management in the area. Here we assess the stock condition of L. atkinsoni in Southern Sulawesi, Indonesia, using the length-based spawning potential ratio model. A total of 4,887 individuals were collected from commercially small-scale fishers from January to October 2022. The total length, sex, and gonad maturity of the individuals were examined. We observed that the fish length ranged from 10.5 to 39.5 cm, with an average length of 23.3 cm. The sex ratio was equal (1:1.2) between male and female individuals. Length at first maturity and length at first capture were 23.4 and 19.6 cm, respectively. In addition, we observed a growth coefficient of 0.45/year, with an asymptotic length of 41.14 cm and natural mortality of 0.6/year. Based on these life history parameters, we observed the spawning potential ratio (SPR) value of 12%, indicating an unsustainable fishery level (SPR of < 30%). Further concerns related to the sustainability of the species and strategy to rebuild stock of the L. atkinsoni in Southern Sulawesi are of utmost importance.

Length-weight relationships and reproductive biology of commercially important fishes from Ribb Reservoir, Ethiopia

  • Agumassie Tesfahun Asres;Sale Alebachew;Negesse Kebtieneh
    • Fisheries and Aquatic Sciences
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    • v.26 no.5
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    • pp.318-335
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    • 2023
  • It is important to understand the biological aspects of fish for fishing management. This study was conducted from February through October 2021. A total of 1,629 fishes were collected using different fishing gears. The length-weight relationship is a power curve for all fishes and showed a significant (r2 > 0.8). All fishes revealed a negative allometric growth pattern except Labeobarbus intermedius. Oreochromis niloticus (1.714 ± 0.009) was found in better condition than other fish species (analysis of variance [ANOVA], p < 0.05). The length at maturity was 24.0 cm and 25.4 cm total length (TL), 28.9 cm and 28.2 cm fork length, and 53.2 cm and 57.5 cm TL for females and males of O. niloticus, L. intermedius and Clarias gariepinus, respectively. Fecundity was ranged between 100-947 eggs/g with absolute fecundity (AF) of 468-3,832 eggs, 200-1,000 eggs/g with AF of 2,752-136,420 eggs, and 505-900 eggs/g with AF of 2,000-6,404 eggs for O. niloticus, C. gariepinus, and L. intermedius, respectively. Their respective mean fecundity was 1,490 ± 91, 23,330 ± 5,070, and 3,096 ± 273 eggs, respectively. Mean fecundity revealed a significant variation between size classes and species (ANOVA, p < 0.05). The fecundity length and fecundity-body weight relationships except (O. niloticus) of fishes were curvilinear while the gonad weight (GW)-fecundity relationship was linear for all fish species. The fecundity was moderately associated with increasing length than body weight, and GW for all fishes (r2 > 0.6). In conclusion, a tangible management setup is required to sustain the use of fish in the reservoir.

Maturity and Spawning of Snailfish, Liparis ochotensis (Schmidt), in the East Sea

  • Yang, Jae-Hyeong;Lee, Sung-Il;Yoon, Sang-Chul;Kim, Jong-Bin;Chun, Young-Yull
    • Fisheries and Aquatic Sciences
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    • v.13 no.4
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    • pp.332-339
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    • 2010
  • Maturity and spawning of the snailfish, Liparis ochotensis was investigated based on samples collected by gill net in the East Sea of Korea from December 2008 to December 2009. The average total length of L. ochotensis was 63.4 cm and 64.1 cm for females and males, respectively. Gonadosomatic index (GSI) began to increase in July, reaching a maximum in November, then began to decrease in December. Monthly changes in the GSI values of L. ochotensis were similar for females and males. Annual reproductive cycle of this species can be divided into five successive stages in females: early growing stage (May), late growing stage (June to July), mature stage (August to September), ripe and spent stage (September to December), and recovery and resting stage (January to April). Males show four successive stages; growing stage (May to July), mature stage (August to September), ripe and spent stage (September to December), and recovery and resting stage (January to April). Relationship between total length (TL) and fecundity (F) was F=$0.00003TL^{4.002}$ ($R^2$ = 0.703), and F increased with TL. Total length at 50% group maturity was estimated to be 55.8 cm. Our findings suggest that the spawning period takes place from September to December, with the main spawning period occurring from October to December.