• Title/Summary/Keyword: SPAWNING SEASON

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Age and Growth of the Mudskipper, Scartelaos gigas(Perciformes, Gobiidae) from Korea

  • Park, Kyeong-Dong;Kim, Jin-Koo;Chang, Dae-Soo;Kim, Joo-Il;Oh, Chul-Woong
    • Animal cells and systems
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    • v.12 no.4
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    • pp.305-311
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    • 2008
  • Age and growth of the mudskipper, Scartelaos gigas were investigated using the second actinost bone of the pectoral girdle, based on an analysis of 560 individuals collected from the mud flats in south west Korea. Specimens were collected semimonthly from March to September of 2003. Actinost and ring radii of each ring group showed a direct one-to-one relationship, with ring radius increasing in tandem with actinost radius. Monthly change in the marginal indices showed that ring formation occurred between May and July(mainly June), being supported by the monthly change in the gonadosomatic(highest in June) and hepatosomatic(lowest in July) indices. Because the species has not been found since November, when air temperature was less than about $10^{\circ}C$, it is thought to enter to hibernation. Therefore, it was suggested that the two new actinost rings may appear a year: one during the spawning season(May-July) and another during hibernation(since November). Although the growth of S. gigas must be limited to short periods each year from March to April and from August to October, its growth rate was considerably fast. The von Bertalanffy growth parameters of S. gigas were $TL_{\infty}$=179.36 mm, K=0.78 $year^{-1}$, $t_0$=-0.7762, and age-length key were $TL_1$=134.3 mm, $TL_2$=158.6 mm, $TL_3$=169.1 mm, $TL_4$=175.0 mm.

Age and Growth of Largehead Hairtail Trichiurus lepturus in the East China Sea (동중국해에 분포하는 갈치(Trichiurus lepturus)의 연령과 성장)

  • Kim, Yeong-Hye;Yoo, Joon-Taek;Lee, Eun-Hui;Oh, Taeg-Yun;Lee, Dong-Woo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.44 no.6
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    • pp.695-700
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    • 2011
  • Age, growth, and maturity of Trichiurus lepturus were estimated based on right-handed sagittal otoliths belonging to 1,031 fish collected from January to December 2007 in the East China Sea. The outer margins of the otolith were examined and showed that an opaque zone was formed once per year. Marginal increments in otoliths formed as annual rings between June and August, at the beginning of the spawning season. Fish growth was expressed by the von Bertalanffy growth equation, as follows: $L_t=494.0$ ($1-e^{-0.2453(t+-0.4822)}$) for females and $L_t=330.4$ ($1-e^{-0.4292(t+0.7513)}$) for males, where $L_t$ is the total length in mm and t is age in years. The growth rates of males and females were significantly different (P<0.05).The age composition ranged mostly between ages 2 and 4, and the oldest individuals were 4 years old in males and 6 years old in females. Finally, the age composition of largehead hairtail was compared with data from the 1970s and is discussed in the context of environmental changes.

Assessment of Influx Efficiency at By-Pass Fishway Using Two-Dimensional Physical Habitat Simulation Model -Focused on Zacco Platypus- (인공하도식 어도에서 2차원 물리서식처 모형을 이용한 어류 유입 효율 평가 -피라미를 대상으로-)

  • Baek, Kyong Oh;Park, Ji Hyun;Kim, Young Do
    • Journal of Korea Water Resources Association
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    • v.46 no.6
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    • pp.629-642
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    • 2013
  • In this study, the efficiency of the by-pass fishway installed at Kangjung-Goryong Weir in Nakdong River was assessed by using River2D which is a two-dimensional physical habitat simulation model. The model was calibrated and validated through the measured water elevation. The assessment was performed according to flow condition such as flood, normal, and low flow. Especially the low flow condition was focused on because the target fish, Zacco Platypus, have moved frequently up and downstream at the spawning season from April to June. From simulation results, it can be deduced that the influx efficiency and the passage efficiency of the fishway in the low flow is higher than that in the flood and normal flow due to occurrence of proper velocity at fishway entrance.

Morphometrical Differences between Diploid and Induced Triploid Cherry Salmon, Oncorhynchus masou (산천어, Oncorhynchus masou 2배체와 유도 3배체의 형태학적 차이)

  • Park, In-Seok;Zhang, Chang-Ik
    • Korean Journal of Ichthyology
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    • v.6 no.2
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    • pp.206-221
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    • 1994
  • Morphometrical data for diploid and induced triploid cherry salmon, Oncorhynchus masou were analyzed prior to the spawning season to compare their commercial values. The following traits were measured with the diploids and induced triploids : ungutted and gutted body weight; body length; dressing percentage; condition factor; gonad weight and gonad index; belly thickness; viscera weight; viscera index; body circumference at the pelvic, dorsal and anal fins; area of the cross sections at the pelvic and dorsal fins; two belly thickness traits measured on each cross section; total height, height and width of each cross section; three body shape traits; and nine cross section shape traits. Body length and body weight of diploids were larger than those of induced triploids and dressing percentage, gonad weight, gonad index, viscera index, and liver index were also larger in diploids. However, induced triploids showed higher values in one belly thickness trait and some section shapes than diploids. Differences in body traits were due to the sterility of induced triploids. Therefore, induced triploid cherry salmon appears to have greater potentials for the commercial values than their diploids.

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Shell Height Frequency using of Age and Growth of Blood Cockle, Tegillarca granosa (Linnaeus) in Yeoja Bay, Southern Coast of Korea (각고조성을 이용한 남해안 여자만 꼬막의 연령과 성장)

  • Chang, Dae-Soo;Moon, Tae-Seok;Jung, Min-Min
    • The Korean Journal of Malacology
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    • v.22 no.2
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    • pp.135-141
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    • 2006
  • This paper describes relative age and growth pattern of the blood cockle, Tegillarca granosa (Linnaeus) in Yeoja Bay, southern coast of Korea. The young shell of blood cockle that spawned from July to August reached 5.60 mm $({\pm}\;1.07)$ in shell height in October. Slow growing season was estimated to be from October to the next May with water temperature under $23^{\circ}C$. With warm water temperature in July to September, the growth was fast. The young shells reached 29 percentage of asymptotic shell height 11-15 months after spawning. Growth was estimated by von Bertalanffy growth function as follows. $I_t(sh_t)=46.1317\;(1-e^{-0.4997(t-0.5828)})$.

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Age and Growth of the Stone Flounder Rareius Bocolortus in Approaches to Kyongyolto of Yellow Sea Korea (한국 서해안 격열비열도 근해산 동가자미의 연령과 성장)

  • 박종수
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.2
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    • pp.121-126
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    • 1995
  • Age and growth of stone flounder kareius bicolortus in approaches to Kyongyolbiyolto of Yellow sea were studied by otolith reading of 248 fishes from September 1992 to August 1993. Examination of the ourter margins of the otoliths showed that th hyaline zone as annulus was formed once a year and that its formation was completed at the end of the spawning season(Jan. to Feb.). Growth of the fish was expressed by the von Bertalanffy's equation as Lt=313.7[1-exp{-0.463(t+0.0704)}] for males and Lt=478.6[1-exp{-0.286(t-0.1619)}] for females, where Lt is body length in mm and It is age in years. It was found that growth of males and females differs, with the females showing a higher growth than the males. Growth in body weight was also examined. The oldest fish were seven years old for males and females.

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A Study of Growth and Age Structure for Chub Mackerel, Scomber japonicus Caught by a Large Purse Seine in the Korean Waters (한국 주변해역에서 대형선망으로 어획한 고등어(Scomber japonicus)의 성장과 연령구조 연구)

  • Jung, Kyung-Mi;Kim, Heeyong;Kang, Sukyung
    • Korean Journal of Ichthyology
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    • v.33 no.2
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    • pp.64-73
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    • 2021
  • We examined the growth and age structure for chub mackerel caught by a large purseseine in the Korean waters from January to December 2015. A total of 459 specimens were used for otolith analysis, ranging from 19.6 cm to 46.0 cm in fork length. Translucent zone was regarded as an annual mark, and age was counted using the information of the number of translucent zone, capture date, edge type of the otolith and nominal birthdate of 1 January. Annuli in otoliths were mainly formed in May, coinciding with the spawning season. Estimated ages were 0~6 years, and the von Bertalanffy growth models were not significantly different between male and female. Sex-combined growth model was obtained as FLt=39.3×{1-exp[-0.90×(t+0.033)]}. Among the chub mackerel caught in 2015, the age 2 group had the highest proportion (30.9%), and the age 0 to 2 group accounted for 88.5% of the total catch.

Effects of the Dietary Inclusion of Pollock Oil on the Quality of Eggs and Larvae of Walleye Pollock Gadus chalcogrammus (명태(Gadus chalcogrammus) 친어 사료내 명태유 첨가가 수정란과 자어 품질에 미치는 효과)

  • Han, Gyeong Sik;Choi, Jin;Byun, Soon-Gyu;Lim, Hyun Jeong;Kim, Hee Sung;Lee, Sang-Min
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.53 no.6
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    • pp.894-899
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    • 2020
  • This study investigated the effects of inclusion of pollock oil (PO) in the diet of broodstock on the egg and larval quality of Walleye Pollock Gadus chalcogrammus. The experimental diet comprised of semi-moist pellets prepared either with or without PO (control; Con). The fish assigned to each diet were fed to visual satiation (two meals per day) for 12 weeks. Eggs spawned from both groups of fish were sampled during the spawning season (three months) and the egg and larval quality was determined. Total egg volume, fertilization, and hatchability of eggs from the PO group were higher than those of the Con group. Fatty acid composition of fertilized eggs was not affected by the experimental diet. Oleic acid, eicosapentaenoic acid, and docosahexaenoic acid content in larvae of the PO group was higher than that in larvae of the Con group. These results demonstrate the beneficial effects of including PO in the broodstock diet of Walleye Pollock, specifically on the quality of the eggs (total egg volume, fertilization, and hatchability) and larvae (fatty acid composition).

Beso (Varicorhinus beso Rüppell, 1836) biological parameters to establish management measures in the Geray Reservoir (Ethiopia)

  • Yirga Enawgaw;Asnaku Bazezew;Ayalew Sisay;Solomon Wagaw;Assefa Wosnie
    • Fisheries and Aquatic Sciences
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    • v.27 no.4
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    • pp.231-239
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    • 2024
  • Geray Reservoir is home to some fish species including Varicorhinus beso, Cyprinus carpio, Carasius carasius, Oreochromis niloticus, and Tilapia randelli. The V. beso is among the top fish-farming species for the reservoir. However, this data on total fish catch showed that the fish population is declining as a result of overexploitation of the stock. The purpose of this study was to set some management measures for the Geray reservoir using some biometric data on the most commonly caught fish-V. beso. A total of 170 fish samples (102 females and 68 males) ranging from 21 to 40.2 cm in total length (TL) and 94.6 to 618.4 g in total weight (TW) were gathered between October 2022 and May 2022 using a cast net with a mesh size of 6 cm. Nonetheless, it is thought that the sampling period is sufficient because the fish were spawning more during the month when the data was collected because of the high concentration of nutrients during that time. The overall male-to-female sex ratio in the population was 1:1.5, which differed considerably from the real ratio of 1:1 (x2 = 6.8; p < 0.01). V. beso in the Geray reservoir exhibited virtually an isometric growth (b = 3) considering the length-weight relationships of males (TW = 0.0122TL2.993) and females (TW = 0.0114TL3.0139). The V. beso had an absolute fecundity (AF) of 2,190 to 11,265 eggs. AF was significantly correlated with TL, TW, and gonad weight (p < 0.01). V. beso's reproductive season peaked between November and May, with the gonadosomatic index ranging from 0.02 to 20.12 for females and 0.03 to 5.67 for males. The average V. beso condition factors for both sexes were higher than 1, indicating that the fish in the reservoir had properly developed, which may be the result of favorable habitat conditions.

Ecological Guidelines for Creation of Eco-washland (생태 천변저류지의 생태학적 조성계획기준)

  • Chun, Seung-Hoon;Choi, Jun-Gil;Yoo, Jeong-Chil
    • Journal of Wetlands Research
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    • v.10 no.1
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    • pp.39-47
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    • 2008
  • An eco-washland is increasingly getting attentions as a new alternative plan for management of water resources because of role as flooding control and ecological park without social and ecological side effects. However, there is a lack of study regarding technological development and ecological guidelines to create eco-washland. This study was carried out to suggest ecological guidelines necessary for engineering process to create eco-washland. A study site was the lower reach of Seokjang stream connecting to Yimjin river, a candidate of new eco-washland, and Kumsa area in Namhan river was selected as a reference site. The analysis of ecological characteristics focused on vegetation, fishes, and birds. Major vegetation communities, composed of dominant species such as Salix koreensis, Salix gracylistyla, Miscanthus sacchariflorus, Phragmites communis, etc., formed physical conditions along with other land uses including open water, sandbar, cultivated land, etc. Dominant species of fishes were some species belonging to Cyprinidae and Acheilognathinae, and in case of birds Anser albifrons, Anas platyrhychos, Anas poecilorhyncha belonging to waterbirds and Paradoxornis webbinanus dependent to forest edge were dominantly distributed. The results showed that complex wetland types associated with partially deep water and upland was the optimal eco-hydrological condition of washland. Cyprinidae and Acheilognathinae in case of fish and Egretta spp. (spring season) and Anas spp. (winter season) in case of bird were selected as target species for the these wetland types. Finally, a detail planning criteria to create habitats of these target species were discussed in terms of spawning, breeding, feeding, resting, refuge, nesting, etc.

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