• Korean Journal of Ichthyology
• /
• v.29 no.3
• /
• pp.197-204
• /
• 2017

Life history of the Siberian stone loach, Orthrias toni, were investigated using samples collected from Buk Stream, Goseong-gun, Gangwon-do, Korea. Growth was rapid between April and October when water temperature exceeded $10^{\circ}C$, but growth almost stopped from November-March when water temperature was below $10^{\circ}C$. Age groups for O. toni estimated by frequency distribution of total length in spawning season (May) indicated the 60~81 mm is 1-year old, the 82~99 mm group is 2-years old, the 100~119 mm is 3-years old, and the 120~140 mm is more than 4-years old. Total length range by sex was similar, and sex ratio (♂/♀) was 0.73. Spawning season according to the gonadosomatic index (GSI) was May with water temperature $14{\sim}17^{\circ}C$, and almost all fish were mature after one year old. Fecundity increased rapidly with age with an average of $4,460{\pm}3,302$ ($mean{\pm}SD$). Size of mature eggs was $0.87{\pm}0.03mm$ in diameter irrespective of age.

• The Korean Journal of Malacology
• /
• v.30 no.4
• /
• pp.437-441
• /
• 2014

One specimen of Argonauta argo belonging to the family Argonautidae, was collected Songjeong, southeastern coastal water of Korea on July 12, 2010. The specimen, a mature female of 76 mm mantle length and 97 mm shell length. The number of ribs are 56 in shell. The shell is distinct between the arm I's. The I arm has expanded, hemi-discoidal web to which the distal part is fused together. The funnel is large and exceeds the base of arm IV. The arms formula is IV > $II{\fallingdotseq}III$ > I. The specimen was female. Fecundity was 155,203 eggs. This species is pelagic octopus and important prey item of dolphin.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.33 no.2
• /
• pp.92-95
• /
• 2016

The black soldier fly is economically important because its prepupae are used as feed for many animals, including fish and swine. In Korea, black-soldier-fly farms have attempted to increase annual breeding and mass egg production for use in animal feed, as well as the decomposition of organic waste. Such efforts require an understanding of optimal mating and oviposition techniques. Specifically, adult densities and cage size may both improve the efficiency of mass egg production. Our study used four sizes of nylon cages ($1.0{\times}1.0{\times}2.5m$, $1.5{\times}1.5{\times}2.5m$, $2.0{\times}2.0{\times}2.5m$, $2.5{\times}2.5{\times}2.5m$) and three density treatments (4 kg, 8 kg, and 10 kg of pupae) to investigate optimal habitat size and adult density. We found that cage size (independent of density) did not significantly influence female fecundity (number of egg clutches and egg weight), whereas higher densities increased egg number and weight regardless of cage size. Thus, we recommend manipulating adult density to enhance productivity in commercial black-soldier-fly farming. However, we also propose further detailed research to develop methods that account for seasonal changes and environmental conditions, as climatic variables (temperature, sunlight) likely influence female fecundity as well.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.1
• /
• pp.48-55
• /
• 2009

The gonad maturation and spawning of blue crab, Portunus trituberculatus (Miers, 1876) using samples caught by trammer net in the western coast of Korea from January to December. The gonadosomatic index (GSI) showed the highest value of 15.0 in June and lowest value of 1.29 in August. Hepatosomatic index (HSI) showed the lowest in the spawning season from June to July. Thereafter, from August the value started to increase to 5.77 in December, showing an adverse trend against GSI. In the histological studies of the female reproductive organ, the gonad filled with primary oocytes from January to February and secondary oocytes in May. The female gonads mature from June, and mature and immature groups could be distinguished from December to February or March. In August, female developed another cycle of gonad development, showing new primary oocytes in the gonads again. Some of female crabs had receptaculum filled with already active sperm cells in it from March to May. In the time of August to September, almost all the females had the sperm sacs in the receptaculum. From the result, the coupling period estimated from August to September. Total RNA and DNA values of the crabs were highest in May (2.51, $0.57{\mu}g/mg$). The DNA value remained unchanged except for the value in May ($0.09-0.13{\mu}g/mg$). while RNA value was lowest in January ($1.08{\mu}g/mg$). The RAN/DNA ratio was the lowest (6.23%) in May and highest (18.05%) in July. The value of correlations coefficient between body weight and fecundity of the crabs was higher that of between carapace width and fecundity.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.4 no.1
• /
• pp.23-30
• /
• 2002

The general and specific combining abilities and hybrid vigour of seven polyvoltine breeds [BL24, BL62, BL6S, BL67, BL68, BL69, and Pure Mysore (PM)] with five bivoltine breeds (NB4D2, CSR2, CSR5, CSR18 and CSR19) were evaluated in a line ${times}$ tester design by analysing six quantitative traits viz., fecundity, yield 110,000 larvae both by number and weight, cocoon weight, shell weight and cocoon shell ratio. ANOVA estimates showed significant effects for all the traits indicating the role of both additive and non- additive gene actions. Estimation of GCA revealed that the breed BL67 exhibited significant positive effects toy all the six traits followed by BL68 for four important economic traits viz., fecundity, cocoon weight, shell weight and cocoon shell ratio. Among testers, CSR5 showed significant GCA effects for five traits whereas CSR2 exhibited for shell weight and shell ratio. Three hybrids viz., BL67${times}$ NB4D2, BL67 ${times}$CSR5 and BL67${times}$ CSR19 excelled in four quantitative traits for SCA. Majority of the hybrids expressed positive hybrid vigour for cocoon yield/10,000 larvae by weight, cocoon weight and shell weight. Four hybrids namely PM ${times}$ NB4D2, BL67 ${times}$NB4D2, BL67${times}$ CSR5 and BL67${times}$ CSR19 manifesting positive hybrid vigour for five economic traits were adjudicated as best Heterotic hybrids and recommended for commercial exploitation to increase the silk yield.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.6
• /
• pp.737-742
• /
• 2004

Garole, a prolific small sized sheep breed of West Bengal, was introduced in the Mutton project of the Institute in 1997 to explore the possibility of incorporating fecundity gene(s) into monotocus Malpura sheep of Rajasthan. Results of reproduction and production traits in respect of Garole${\times}$Malpura (G${\times}$M) half-breds have been obtained. Of 35 lambing obtained so far from the ewes of Garole${\times}$Malpura, 45.71% were twin lambing, whereas, Malpura sheep produced mostly single lamb except 2.55% twin lambing on an average. Other reproduction traits in G${\times}$M ewes such as lambing rate, litter size at birth and weaning were considerably improved over Malpura ewes. Results revealed that the fecundity genes responsible for increasing ovulation rate and litter size have been incorporated in to the G${\times}$M genotype and it might prove a valuable germ plasm towards evolving a new prolific strain of sheep. Interestingly, survivability of G${\times}$M half-breds was almost at par with the local Malpura sheep in harsh climatic conditions of semi-arid tropics. The body weights at different ages of G${\times}$M half-breds were on little lower side compared to contemporary Malpura lambs. Average kilogram of lambs weaned/ewe lambed in Malpura and G${\times}$M genetic group was 11.86 and 11.07 kg respectively. In view of minimizing the differences in body weights and kg of lambs weaned/ewe lambed between the two genetic groups, G${\times}$M ewes has to be backcrossed with Malpura rams to raise the inheritance of latter up to 75% level. However, further research is needed to reach on certain conclusions regarding net returns from such crosses.

• Journal of Animal Reproduction and Biotechnology
• /
• v.35 no.2
• /
• pp.149-154
• /
• 2020

The aim of the current study was to compare the effects of season and breed on the reproductive performance of male and female sheep using 12 rams and 318 ewes of Assaf and Awassi breeds under the seasonal environmental condition of United Arab Emirates for two years. The blood level of testosterone hormone was measured monthly. Semen was collected twice a month from each male using artificial vagina and evaluated for volume, motility, livability, abnormality and concentration. The scrotal circumference and thickness as well as the left testicular length, width, height and volume were measured at one-month intervals. The level of testosterone in Assaf breed was significantly higher in autumn than winter and summer. The scrotal circumference and thickness as well as the left testicular length were significantly higher in Assaf breed than Awassi breed. While, left testicular width and volume were significantly higher in Awassi breed than Assaf breed. Scrotal circumference which was higher in spring and summer than in autumn and winter season in both breeds. The SCC of semen was significantly higher in autumn than in other seasons in both breeds. The sperm abnormality was significantly higher in summer than other seasons in both breeds. The livability was significantly lower in summer in both breeds. Fecundity and prolificacy were significantly higher in Assaf than Awassi breed during autumn season. Assaf breed showed the superior reproductive performance in the autumn season when compared with Awassi breed in the same season and other seasons. The Assaf breed tolerated the climatic conditions in UAE and kept the litter size of 1.72 in comparison to Awassi breed which showed litter size of 1.09. in conclusion, the results showed the superiority of Assaf over Awassi breed and offer a good model of breeding with increased fecundity and prolificacy specially in autumn season.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.40 no.2
• /
• pp.79-83
• /
• 2007

The maturation and spawning of Shuttles hoppfish Periophthalmus modestus were studied from April to October, 2005 in the mud flat of Suncheon Bay, Korea. The specimens ranged in body length (BL) from 1.5 to 8.4 cm. The gonadosomatic index (GSI) of females was highest in May and decreased until September. The hepatosomatic index (HSI) and fatness index of females were high in April and then decreased to a nadir in July. The data indicate that the spawning season was from April to September. There was no significant difference in the ratio of females to males $(X^2-test,\;p>0.01)$. Over 50% of the females over 5 cm in BL were sexually mature. Fecundity ranged from 1,664 to 13,428. The relationship between fecundity (F) and body length (BL) of the fish was expressed as $F=0.026BL^{2.8638}\;(R^2=0.79)$. The first spawning length was 4.5 cm BL.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.3
• /
• pp.261-265
• /
• 1985

Limanda yokohamae was studied on its growth, age at maturity, fecundity and survivorship, based on the specimens off the southeastern coast of Korea from December 1983 to November 1984. The total lengths at the formation of annulus on the otolith were back-calculated. The age at the first reproduction is 2yrs in both sexes. Fecundity was estimated to be $121{\times}10^3{\sim}429{\times}10^3$. Annual survival rate is 0.435 in female and 0.335 in male.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.6
• /
• pp.835-842
• /
• 2013

Flathead flounder Hippoglossoides dubius is a commercially important fish in the coastal waters of Gangwon Province, which is its spawning ground and breeding habitat. A total of 1,669 gonads were sampled monthly from February 2011 to May 2013 to investigate ecological characteristics, such as variations in maturation and spawning by gonad index, visual maturity stage, histological observations and oocyte diameter. Males were numerically dominant over females in the fishing grounds year round. The spawning season was from January to April, and the peak was from February to March. Oocyte number as a measure of fecundity was between 27,372 and 915,209 eggs with a length range of 26.0-48.7 cm TL, while the largest oocyte grew to 0.9-1.4mm in egg diameter during its spawning season. The relationship between fecundity and total length was $F=0.0016TL^{5.2539}$. The smallest mature lengths of the females and males were 28.4 and 22.6 cm respectively, and the 50% mature lengths of females and males were 32.9, 26.9 cm respectively.