• Title/Summary/Keyword: SPAWNING SEASON

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A study on resource utilization and management of chub mackerel, Scomber japonicus consider to proximate composition (영양성분을 고려한 고등어, Scomber japonicus 자원 이용과 관리 방안)

  • OH, Taeg-Yun;SHIM, Kil-Bo;SEO, Young-Il;KWON, Dae-Hyun;KANG, Su-kyung;LIM, Chi-Won
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.52 no.2
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    • pp.130-140
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    • 2016
  • This study analyzed annual catch trend during 45 years and monthly catch of the least 10 years (2005~2014) for chub mackerel caught in the Korean coastal waters. To determine fishing status of chub mackerel, fork length measurements were conducted at least twice every week for 100 individuals randomly selected at the Busan Cooperative Fish Market from January of 2012 to December of 2014; and biological characteristics and proximate composition (moisture, protein, fat, ash) were analyzed by length class (I~IV) on a monthly basis from January to December of 2014. Monthly catch trend showed low level below 5,000 mt from February to July, whereas high level above 15,000 mt from October to December. For the period between 2012 and 2014, annual average catch proportion of juvenile were relatively high at 68.1%, 53.1% and 53.2% from January to April, before spawning season, while those were low at 21.5%, 20.7% and 29.12% from June to November. As for the change in the proximate composition per 100 g of muscle, protein and ash did not change much by seasons and length class, whereas fat and moisture contents showed large fluctuations and complementary relationship between the two factors. Regardless of length class, monthly average fat content, containing Omega-3, showed the lowest at 7.18 g in April and highest at 19.27 g in December, which exhibited 2.6 times difference from one another. Regardless of fishing seasons, fat content by length class were 19.06 g for the class I and 6.43 g for the class IV, which showed three times difference. Fat contents of the class I were high at 26.97 g and 27.19 g in November and December, while low at 8.37 g and 9.99 g in April and May. Especially, fat contents from January to May were 5.0 g, which was the lowest. Therefore, it is expected that consumer could indirectly contribute fisheries management through their understanding and wise consumption based on fishing status and fluctuation of proximate composition.

Gonadal Development and Sex Steroid Hormone Levels of the Yellowfin Goby Acahthogobius flavimanus (문절망둑(Acanthogobius flavimanus)의 생식소 발달과 혈중 성 스테로이드호르몬 농도 변화)

  • PARK Myoung Hee;HWANG In Joon;KIM Dae Jung;LEE Young Don;KIM Hyung Bae;BAEK Hea Ja
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.38 no.5
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    • pp.309-315
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    • 2005
  • Changes of sex steroid hormones in the plasma of yellowfin goby, Acanthogobius flavimanus were investigated in relation to the gonadosomatic index (GSI), the hepatosomatic index (HSI) and gonadal development. The GSI in females rose rapidly in November and remained high from December to May $(7.26\pm0.89­6.62\pm0.02)$. The Male's GSI also increased gradually from November and was highest in May $(0.16\pm0.08)$. The HSI in both sexes was in reverse correlation with the GSI, and the HSI was low during the spawning season (February-May). In females, the $estradiol-17{\beta}\;(E_2)$ level increased during vitellogenesis (November and December) and reached its maximum $(8.13\pm2.87 ng/mL)$ at the maturing period, in January. $17{\alpha},\;20{\beta}$-dihydroxy-4-pregnen-3-one$(17{\alpha}20{\beta}OHP)$ gradually increased from October $(0.063{\pm}0.02ng/mL)$ to March $(0.16{\pm}0.02ng/mL)$ and increased rapidly in May. The level of testosterone (T) showed a similar tendency of $E_2$. In males, T increased gradually during spermatogenesis from September to December $(0.14{\pm}0.06­0.26{\pm}0.10ng/mL)$ and peaked in January $(0.36{\pm}0.29 ng/mL)$ when the spermatozoa filled the testis. 11-KT also rose markedly in January and then decreased. On the other hand, $17{\alpha}29{\beta}OHP$ in males did not show any clear tendencies.

Water temperature assessment on the small ecological stream under climate change (기후변화에 따른 소하천에서의 수온 모의연구)

  • Park, Jung Sool;Kim, Sam Eun;Kwak, Jaewon;Kim, Jungwook;Kim, Hung Soo
    • Journal of Wetlands Research
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    • v.18 no.3
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    • pp.313-323
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    • 2016
  • Water temperature affects physical and biological processes in ecologies on river system and is important conditions for growth rate and spawning of fish species. The objective of this study is to compare models for water temperature during the summer season for the Fourchue River (St-Alexandre-de-Kamouraska, Quebec, Canada). For this, three different models, which are CEQUEAU, Auto-regressive Moving Average with eXogenous input and Nonlinear Autoregressive with eXogenous input, were applied and compared. Also, future water temperature in the Fourchue river were simulated and analyzed its result based on the CMIP5 climate models, RCP 2.6, 4.5, 8.5 climate change scenarios. As the result of the study, the water temperature in the Fourchue river are actually changed and median water temperature will increase $0.2{\sim}0.7^{\circ}C$ in June and could decrease by $0.2{\sim}1.1^{\circ}C$ in September. Also, the UILT ($24.9^{\circ}C$) for brook trout are also likely to occurred for several days.

Seasonal variation in species composition of catch by a coastal beam trawl in Jinhae Bay and Jinju Bay, Korea (진해만과 진주만에서 새우조망으로 어획된 수산자원의 계절변동)

  • Song, Mi-Young;Kim, Joo Il;Kim, Sung Tae;Lee, Jong Hee;Lee, Jae Bong
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.4
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    • pp.428-444
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    • 2012
  • The species composition and seasonal variation of fisheries resources in Jinhae bay and Jinju bay, were studied using shrimp beam trawl through a year of 2010. During the study period, a total of 117 species were collected in Jinhae bay. Species included were 63 species in Pisces and 24 in Crustacea. And a total of 106 species were collected in Jinju bay. Species included were 57 species in Pisces and 31 in Crustacea. The dominant species were Zoarces gilli, Crangon hakodatei and Oratosquilla oratoria in Jinhae bay, and Crangon hakodatei, Leiognathus nuchalis and Charybdis bimaculata in Jinju bay. The samples were mainly grouped according to the location and season on the SOM. Group 1 with sample sites in Jinju bay, was characterized by high values of Parapenaeopsis tenella, Leiognathus nuchalis and Hexagrammos otakii. Group 2 with sample sites in April, were dominant Crangon hakodatei and Luidia quinaria. The samples in Group 3 were high values of Charybdis bimaculata and Pleuronichthys cornutus. Group 4 with sample sites in Jinhae bay, was characterized by high densities of Zoarces gilli and Pholis fangi. The dominant species, Crangon hakodatei, were catched egg-bearing females until June. Zoarces gilli and Leiognathus nuchalis were presented small size individuals during study period. It represented that study area is an important role in spawning and nursery ground for fisheries resources.

Control Method of Habitat Density of Limnoperna fortunei in the Enclosed Facility of Water Supply Pipeline (폐쇄공간 송수관로내 민물담치의 서식밀도 조절방법)

  • Shin, Jae-Ki;Chong, Sun-A;Noh, Joonwoo;Kim, Youngsung;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • v.47 no.3
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    • pp.219-224
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    • 2014
  • This study was conduct to the reduction and elimination of Limnoperna fortunei that problem in the facilities and water supply pipeline is done to review proposals for the controls. In order to effectively removal the larva and the adult of that, chlorination and being used to an existing method is to be commended. The water temperature of Limnoperna fortunei spawning season was ranged 16 to $17^{\circ}C$ during May to early November. A chlorination of this period is appropriate in order to control a larva. However, existing in the attached young and old shell at the same time consistently been deemed to apply, because it must be taken into account. The range of concentration of chlorination to control the biomass for Limnoperna fortunei was from 0.5 to 1.0 ppm. Proliferation attached to the mitigation or appropriate technology to solve the domestic situation the priorities of the choice of a more urgent. Also, the monitoring of water temperature and larva will constantly to be done. And development of larva monitoring method as well as after chlorine treatment is effective analysis needed. Finally, we are expecting to good use in validating the results presented in this study.

Experimental Studies on the Mechanism of Reproductive Cycle in the Bluegill, Lepomis macrochirus (파랑볼우럭, Lepomis macrochirus의 생식기구에 관한 실험적 연구)

  • LEE Taek Yuil;Kim Sunng Yeon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.20 no.6
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    • pp.489-500
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    • 1987
  • Annual reproductive cycle of Bluegill, Lepomis macrochirus (RAFINESQUE) were studied in the natural population. Based on these informations, reproductive mechanism of the fish including activation, degeneration and remature were examined under the controlled conditions of temperature and photoperioe. In the natural populations, gonads began to grow with the temperature increase in March ana matured in June, and spawning occurred in July. With the onset of the shorter day-length and the maximum temperature condition in August, the gonads began to degenerate. Resting stage was continued during winter season. In the laboratory-reared population, activation of the gonads was initiated by the complex environmental factors including higher temperature$(>15^{\circ}C)$ and longer photoperiod $(>14L)$. For the maturation, photoperiod of more than 14 hours was critical. Under this condition higher temperature was the only compensative factor. Regeneration of the gonads was induced by higher temperature$(>25^{\circ}C)$ and the shorter photoperiod accelerated the regenerative processes. Even from the resting stage the gonads can be induced to matured stage by the longer photoperiod $(>15L)$. Based on these observations, the reproductive rhythm of this fish is supposed to be artificially controlled.

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Reproductive Ecology of the Freshwater Melania Snail, Semisulcospira coreana (v. Martens) in Bukhan River (북한강 참다슬기, Semisulcospira coreana (v. Martens) 의 번식생태)

  • Kim, Dae-Hee;Bang, In-Chul;Lee, Wan-Ok;Baek, Jae-Min
    • The Korean Journal of Malacology
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    • v.28 no.2
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    • pp.175-185
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    • 2012
  • To clarify reproductive ecology of the melania snail Semisulcospira coreana (v. Martens, 1886) in Bukhan River, gonad development, fatness, gonad index, sex ratio, first sexual maturity of population, monthly change of larvae number and developmental stages in brood pouches were investigated by six identification methods. As maturation progrsses, the sex of the snali can be distinguishable easily by color:: the ovary being blue-green and testis light yellow. The sex ratio of female to male individuals over 13.95 mm shell height was significantly different from 1:1 (${\chi}^2$ = 38.45, p < 0.05). The sex ratio of female to male individuals changed drastically according to the season, Based on the monthly variations of fatness, gonad index and histological analysis, spawning occurred twice a year (spring and autumn) and the mean size of matured eggs was $450{\mu}m$ in diameter. The monthly change of larval number in brood pouch showed also two distinct peaks in March and September during the year. The average number of larvae in brood pouches was 286 - 862 individuals. In this study, the number of larvae in the brood pouches were a minimum in December and a maximum in March (975 larvae). The biological minimum size (the size at 50% of group sexual maturity) of the melania snail was 13.95 mm in shell height in females and males. All females over 15 mm in shell height possesed brood pouches.

ECOLOGICAL STUDIES ON THE PROPAGATION OF SAXIDOMUS PURPURATUS(SOWERBY) (개 조개 Saxidomus purpuratus(SOWERBY)의 증식에 관한 생태학적 연구)

  • KIM An Young
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.4 no.3_4
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    • pp.92-98
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    • 1971
  • With Saxidomus Purpuratus which were sampled near Yungdo, in the harbor of Pusan during the period from September 1967 to October 1968, the author investigated the maturity against seasonal change of water temperature; and shell length, height and width against live weight, respectively, and the reciprocal correlations of shell length, height and width, as well. The maturity, concerned deeply with tile developing procedure of gonad, is dependent on the change in water temperature. The value of maturity becomes higher from March to May, but in August with high temperature the value decreases temporarily. During the main spawning season from the late August to the middle of October, the value shows the peak throughout a year. After the period, it has decreased until January when the water temperature is below $10^{\circ}C$ The equations of shell length against live weight for male($W=0.4749L^{2.62307}$)and for female ($W=0.3438L^{2.77993}$) shell height against live weight ($W=0.3221L^{3.06661}$), and shell width against live weight ($W=3.5868L^{2.46646}$), show non-straight lines respectively. On the other hand, th: equations of shell length against shell height Y=0.818x+0.292 (r=0.958), shell length against shell width Y=0.520x+0.200 (r=0.799) and shell height against shell width Y=0.499x+0.516 (r=0.773) show straight lines, respectively.

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Age and Growth of Small Yellow Croaker, Larimichthys polyactis in the South Sea of Korea (한국 남해 참조기의 연령과 성장)

  • Kim, Yeong Hye;Lee, Sun Kil;Lee, Jae Bong;Lee, Dong Woo;Kim, Young Seop
    • Korean Journal of Ichthyology
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    • v.18 no.1
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    • pp.45-54
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    • 2006
  • Age and growth of the small yellow croaker, Larimichthys polyactis were estimated using right sagittal otoliths of 506 fish specimens from March to December, 2002 and from January to February, 2005 in the South Sea, part of the East China Sea of Korea. Examination of outer margins of the otolith showed that the opaque zone was formed once a year. Marginal increment of the otolith formed annual rings from May and June at the beginning of spawning season. In the relationship between total length and body weight, a multiplicative error structure was assumed because variability in growth increased as a function of the length, and the estimated equation was $BW=0.0044TL^{3.2502}$ ($R^2=0.97$). The relative growth as body weight at total length has significant difference between females and males (P<0.05). For describing growth of the small yellow croaker, Larimichthys polyactis a von Bertalanffy growth model was adopted. The von Bertalanffy growth curve had an additive error structure and the growth parameters estimated from non-linear regression were $L_{\infty}=33.88cm$, K=0.20/year and $t_0=-2.39year$. Growth at age of males and females shows no significant difference (P>0.05). Most examined fish were 1, 2 and 3 years old, although the oldest fish were 7 old for males and 8 for females.

Age and Growth of Epinephelus akaara in the South Western Sea of Korea (한반도 서남 연안 붉바리(Epinephelus akaara)의 연령과 성장)

  • Lee, Tae-Won;Lee, Chang-Gyu
    • Korean Journal of Ichthyology
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    • v.8 no.2
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    • pp.16-22
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    • 1996
  • Age and growth of Epinephelus akaara were determined using samples collected from the south western sea of Korea. Thin - sectioned otoliths showed relatively well defined annuli when examined under dark - field microscope. Because the fish do not feed at the temperature under $10^{\circ}C$, the annuli in otoliths are considered to be formed during the period between December and April. Considering that the peak spawning season is July, the first annulus must have been formed in 0.5 year after birth. The oldest fish examined was 9 years old, and the largest one was 47cm. The body length(L, cm) was linearly related to the otolith radius (R, ${\mu}m$) : L= - 2.84+7.01 R. Back-calculated lengths for each age using the relationship between body and otolith size were well adjusted to the Von Bertalanffy growth curve : $L_t$=55.5[1-exp{-0.162(t+0.128)}]. Using relationship between length and weight ($W_t$=0.00608$L^{3.21}$), growth in weight was expressed by Wt=2409(1-exp{-0.162(t+0.128)}]$^{3.21}$.

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