• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.331-340
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• 1992

A study on the spawning and fecundity of anchovy, Engraulis japonica, in the southern waters of Korea was carried out on the basis of data collected from gonad examination during March-september, 1991. Spawning period showed that length class in the range of 9-12cm fork length occurred during May-July, whereas adults above 12cm from March to September. In comparison with the oocyte compositions of the ovary of anchovy adult caught at sunrise and sunset, together with variation of the gonad weight and sex ratio of the fish sampled during time between 14:00 and 21:00, considering that the oocyte more than 600um in diameter existed much in the samples from sunset compared with that from sunrise, as well as a decreasing trend in the gonad weight and proportion of female of anchovy taken around sunset, spawning was estimated to occur mainly after sunset. The proportion of the adult with a pronounced peak above 600um in oocyte composition was estimated to be about $20\%$ of the spawning population. Fecundity was estimated to the range of about 23,000-315,000 with batch fecundity of 1,857-8,223 and specific batch fecundity of $438\pm146$.

• Fisheries and Aquatic Sciences
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• v.23 no.6
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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.

• Journal of Aquaculture
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• v.17 no.1
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• pp.30-38
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• 2004

To estimate the spawning period the annual change of gonadosomatic index (GSI) were examined from January 2000 to December 2001. Fecundity, spawning frequency and egg diameter were measured by ocular observation. Germ cell differentiation during gametogenesis, the reproductive cycle and the first sexual maturity of greenling Hexagrammos otakii were observed under light microscopy from January to December, 2000. GSI began to increase in August and reached the maximum in November when ovary was getting mature. The reproductive cycle of H. otakii can be divided into five successive stages in females: early growing stage (July), late growing stage (July to August), mature stage (September to October), ripe and spent stage (September to December), and recovery and resting stage (December to June). Males showed four successive stages : growing (June to August), mature (August to October), ripe and spent (September to December), and recovery and resting stage (December to May). According to the frequency distributions of egg diameter in spawning season, H. otakii could be one of polycyclic species spawning 2 times or more during one spawning season. Number of total eggs and mature eggs in the absolute fecundity were related to the standard length and body weight, respectively. Number of total eggs and mature eggs in relative fecundity were also proportional to the standard length, but rather these numbers decreased with body weight. Percentages of first sexual maturity of females and males in greenling were over 50% from 19.1 to 21.1cm in length, and 100% for fish over 25.1cm in length. Therefore, both sexes are ready to reproduce after one year old.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.129-137
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• 2010

Four major agricultural insect pests, Bemisia tabaci, Myzus persicae, Plutella xylostella and Tetranychus urticae, were irradiated with 30, 50, 70, or 100 Gy electron-beam. Longevity, egg hatching, emergence, and fecundity of the test insects were measured. Hatchability of B. tabaci, P. xylostella and T. urticae declined with increasing irradiation doses, and all B. tabaci and T. urticae eggs were dead at 100 Gy. When eggs of B. tabaci, P. xylostella and T. urticae were irradiated, hatch was inhibited. B. tabaci adults grown from 70 Gy irradiated eggs did not lay eggs. Fecundity of P. xylostella from the 100 Gy irradiated eggs decreased. When B. tabaci, P. xylostella, M. persicae and T. urticae nymphs/larvae were irradiated, the results were similar as those of the hatched eggs. When P. xylostella pupae were irradiated with 100 Gy, fecundity of emerged adults decreased and no eggs hatched. When B. tabaci, P. xylostella, M. persicae and T. urticae adults were irradiated with 70 and 100 Gy, fecundity decreased and egg hatch of B. tabaci was inhibited. However, the longevity of adults did not change and electron-beam irradiation of all developmental stages had no effect on the longevity of adults.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.52-57
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• 1996

This experiment was carried out to evaluate the effect of sublethal doses of BPMC, etofenprox,and buprofezin on N. lugens. and its predator C. lividipennis. Buprofezin was found to be the most toxic to N. lugens and the most safe to C. lividipennis among the three insecticides, based on LD50 values. Selective toxicity index calculated by dividing LDSo value of C. lividipennis by that of N. lugens indicated that buprofezin was very safe to C. lividipennis, showing selective toxicity of 2703.3. Longevity and fecundity of N. lugens treated with LDIU and LDm of buprofezin and BPMC were not significantly different with those of untreated brown planthoppers. However, egg hatchability' of N. lugens was greatly reduced when treated with LDm of buprofezin, having the highest inhibition rate of 17.7%. Hatchability of eggs from insects treated with BPMC was similar to that of control. The oviposited peak of treated hoppers appeared late as compared to the untreated which showed the peak at early part of the ovipositional period. The longevity and fecundity of C. lividipennis treated with BPMC were significantly reduced as compared with the untreated. Etofenprox also induced fecundity reduction when treated with LDlo, and LDm. However, C. lividipennis treated with sublethal doses of buprofezin showed no redution in logevity and fecundity. From these results, it may be said that buprofezin can be used to control brown planthopper without disrupting of C. lividipennis population in the rice field.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.58-65
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• 1996

This experiment was carried out to evaluate the effect of sublethal doses of BPMC, etofenprox, and buprofezin on N. lugens. and its predator C. lividipennis. Buprofezin was found to be the most toxic to N. lugens and the most safe to C. lividipennis among the three insecticides, based on LD50 values. Selective toxicity index calculated by dividing LDSo value of C. lividipennis by that of N. lugens indicated that buprofezin was very safe to C. lividipennis, showing selective toxicity of 2703.3. Longevity and fecundity of N. lugens treated with LDIU and LDm of buprofezin and BPMC were not significantly different with those of untreated brown planthoppers. However, egg hatchability' of N. lugens was greatly reduced when treated with LDm of buprofezin, having the highest inhibition rate of 17.7%. Hatchability of eggs from insects treated with BPMC was similar to that of control. The oviposited peak of treated hoppers appeared late as compared to the untreated which showed the peak at early part of the ovipositional period. The longevity and fecundity of C. lividipennis treated with BPMC were significantly reduced as compared with the untreated. Etofenprox also induced fecundity reduction when treated with LDlo, and LDm. However, C. lividipennis treated with sublethal doses of buprofezin showed no redution in logevity and fecundity. From these results, it may be said that buprofezin can be used to control brown planthopper without disrupting of C. lividipennis population in the rice field.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.101-106
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• 2007

We investigated the maturity and spawning of black edged sculpin, Gymnocanthus herzensteini caught by gillnet in the East Sea from March 2003 to February, 2004. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), gonad weight (GW), egg diameter, fecundity, total length at 50% group maturity and sex ratio. The spawning period was December to February. The fecundity ranged form 8,814 eggs at 14.7 cm (TL) to 25,560 eggs at 24.4 cm (TL). The relationship between total length (TL) and fecundity (F) was $F=285.11TL^{1.4092}$ ($R^2$ =0.571) and fecundity increased with total length. The total length at 50% group maturity was estimated to be 15.25 cm. The sex ratio was 60 for female and 40 for male, where the female population was seen to be slightly predominant. For sex ratio by length class, male was a little predominant in small size, but female was 90% more than 24 cm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.115-122
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• 2012

Frequency distribution of carapace width, relative growth, sex ratio and fecundity of blue crab Portunus trituberculatus in Younggwang adjacent water were investigated. A total number of individuals collected for this study were 658(Males : 305 and females : 353). Water temperature and salinity of the study areas varied from 5.9 to $27.3^{\circ}C$ and 28.1 to 31.6 psu, respectively. The carapace length-width and carapace width-weight relationship was calculated and the equations obtained are; For males; CL = 1.3652CW + 22.495($R^2$=0.741), $TW=0.0068CW^{2.4001}$($R^2$=0.749), For females; CL = 1.3073 CW + 25.684($R^2$=0.791), $TW=0.0061CW^{2.4231}$($R^2$=0.801). The sex ratios(Males : females) for blue crab were 0.86 : 1. The value of correlations coefficient between total weight and fecundity of the blue crabs was higher that of between carapace width and fecundity.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.126-132
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• 2012

Two different feed(bran and swine feed) effect was tested on development of Tenebrio molitor at $25{\pm}5^{\circ}C$, $65{\pm}10%RH$. There was no significant feed effect on larval developmental periods(80.0 ~ 83.7 days), pupal length (18.1 ~ 18.7 mm) and fecundity(44.3 ~ 55.3 eggs) during first two days. However, fecundity was significantly affected by the pupal weight(P < 0.05), such that the number of eggs 172.3, 191.2, 215.0 gradually increased as pupal weight rose from 0.12 g, 0.15 g to 0.18 g, respectively. During the first two weeks of oviposition was 51.8%, which gradually decreased for further days. Longevity was $27.1{\pm}6.9$, $30.1{\pm}7.8$, $27.4{\pm}8.5$ days with increasing pupal weight of 0.12, 0.15, 0.18 g, respectively. Larval densities of 100, 300, 500 and 700 individuals reared in the container ($16{\times}21.5{\times}7cm$) resulted 67.9% of the T. molitor pupation during first three weeks. Pupal weight was decreased $146.9{\pm}6.5$, $142.1{\pm}8.3$, $122.0{\pm}9.6$, $118.5{\pm}5.2mg$ when it was reared at different larval densities of 100, 300, 500 and 700 individuals, respectively in size of($16{\times}21.5{\times}7cm$) rearing container.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.449-462
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• 2021

We analyzed the effects of temperature on the survival, development, and reproduction of the non-diapause Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae). A 16:8 h light:dark photoperiod was supplied to the non-diapause stages of O. furnacalis. The insects were raised on an artificial diet at seven constant temperatures between 15 and 35℃ for immature stages, and eight temperatures between 13 and 33℃ for the adult stage. The survival rate of eggs exceeded 70% at all temperatures, whereas survival of larvae was as low as 7.4% at 15℃. The developmental periods of the immature stages decreased with increasing temperature, but the larval period did not decrease further at 35℃. The pupal weight increased with increasing temperature, but the female weight decreased at 35℃. Variations with different last larval instars within the colonies at different temperatures were observed. Adults produced offspring at all tested temperatures. Adult longevity and the pre-oviposition and oviposition periods decreased with increasing temperature, but the pre-oviposition period increased at 33℃. Total fecundity exceeded 400 viable eggs at 22℃ and 31℃. The mean daily fecundity during the oviposition period and the mean daily fecundity on the day of oviposition increased with increasing temperature, but decreased at 33℃. Daily fecundity sharply increased at earlier adult ages and slowly decreased thereafter. The simulated oviposition frequency was greatest at 22℃. The lower developmental threshold temperatures were estimated to be the lowest at 9.7℃ for the first instar larva and the highest at 14.7℃ for the 5th to last instar larval stage, using a linear model.