• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.263-269
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• 2023

This study aims to contribute to the research on resource recovery for the rapidly declining population of Liparis tanakae by observing the larval development process and the morphology of juveniles based on their growth. Natural spawning eggs collected in Yeosu were used for observing the process of egg development and larval morphology. The water temperature during the rearing process was maintained at 12.3~13.5℃ (average 12.7℃). The fertilized eggs had an egg diameter ranging from 1.57 to 1.79 mm (average 1.71 mm) and were spherical and adhesive. Within 4 hours 35 minutes after fertilization, they reached the two-cell stage, and after 74 hours 10 minutes, the formation of the yolk sac began. At 106 hours post-fertilization, a caudal fin appeared at the tail tip. Hatching began at 526 hours, and the larvae developed with the yolk sac positioned just behind the eyes. The newly hatched larvae had both the mouth and anus open. Melanophores appeared inside the lower jaw and around the tail on the third day after hatching. By the 16th day after hatching, most of the yolk was absorbed, and melanophores were visible in the head region. Finally, on the 63rd day after hatching, the head region significantly developed, and the body shape and mouth were similar to those of an adult fish, signifying the transition to the juvenile stage. This study will serve as valuable data for aquaculture techniques related to the conservation and restoration of fish species based on the hatching and juvenile morphology of Liparis tanakae.

• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.27-32
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• 2013

Damage of tea bagworms, Eumeta minuscula was observed for the first time from grape leaves of grape (varieties: Cambell Early and M.B.A.) from a vinery at Gumho-up, Gyeongsan, Gyeongbuk on 31 August, 2012. Activity of insecticides [Bacillus thuringiensis var. kurstaki (serotype IIIa, IIIb) WP, chlorantraniliprole 5% GP, methoxyfenozide 21% SC, spinetoram 5% GP, and spinosad 10% GP] was tested on fourth instar larvae of Eumeta minuscula in laboratory. Mortality of 4th instar of Eumeta minuscula was higher when treated with spinosad 10% WG (88.7%) and spinetoram 5% WG (67.7%) sprayed with field recommended concentration using a home sprayer in laboratory. Mortality decreased as the concentration decreased, however leaf damage rate was significantly different between the one-fourth rate and the control. Spinetoram 5% WG and spinosad 10% WG showed 63.7 and 55.7% respectively mortality of fourth instar Eumeta minuscula in field. Though these two insecticides could be used for the control of bagworms on grape, a more effective insecticide needs to be found.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.46-51
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• 1999

Age, hatching date and growth in length of juvenile Limanda yokohamae were determined by analysis of microstructure in otoliths. Monthly samples were collected by a beach seine in the shallow water off Gaduk-do from January to December, 1998. The juveniles were collected between February and April. Mean total length was $22.6{\pm}1.77\;mm$ ($\pm$SD) in February, $23.6{\pm}3.86\;mm$ in March, and $38.2{\pm}8.38\;mm$ in April. The core of otoliths ranged from 18 to $21\;{\mu}m$ in diameter and the growth increments were deposited concentrically from the hatching mark. The secondary growth layer began to appear at the 48 to 56-th increment. It indicates that L. yokohamae larvae may be completed the metamorphosis at this time of ca. 52 d after hatching, and moved into the shallow water for demersal stage. The hatching date calculated from the number of daily increments was between late November and early January, showing a peak in December. The total length (L, mm) was related to otolith radius (R, ${\mu}m$); L=0.055 R+5.81 ($r^2=0.88$). The growth in total length was represented by the Gompertz growth curve; $L_t=3.39e^{4.51(1-e^{-0.0067t})}$ ($r^2=0.81$). Daily growth rate was 0.35 mm/d at the age of 70 d and increased up to 0.55 mm/d at the age of 120 d.

• Korean Journal of Ichthyology
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• v.5 no.1
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• pp.53-67
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• 1993

In December of 1989 and 1990, matured adults of chum salmon were collected from Namdae-chun River in Yangyang-gun, Kangwon-do, Korea. Artificial insemination was made at captured locations. The fertilized eggs were hatched in trough incubators and the larvae were reared in laboratories of the Yangyang Fisheries Institute and the Korea Ocean Research and Development Institute. The fertilized eggs of this species were demersal and separated, and red in color with mean diameter of 7.2mm. The hatching took place from 480 to 531 degree($^{\circ}C$) days after fertilization. The newly hatched alevins were 1.80 to 2.56cm in total length with big yolk and lied on the bottom. In 35 days after hatching, the alevin attained $3.56{\pm}0.12cm$ in total length, and absorbed the yolk completely to become fry with 7 to 11 parr marks on the body. In 3 months after hatching, and the fries became smolt with silvery scales haring 5.67-6.53cm in total length. The early larval developments of chum salmon could be divided into three stages according to the changes in body shapes and length : larval stage before swim up, swim up stage and smolt stage. The growth of snout, trunk and body height to total length were faster than other body parts in swim up stage.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.16-20
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• 2015

The hatchability of the artificially induced hybrid between two groupers (family Serranidae), red spotted grouper (Epinephelus akaara) and brown-marbled grouper (E. fuscoguttatus) that lives in different habit environment was investigated. There was no difference in the required time of each developmental stages after fertilization between hybrid (red spotted grouper ♀ ${\times}$ brown-marbled grouper ♂) and purebred (red spotted grouper ♀${\times}$♂) and required 25.6 hours to hatch at incubated in $25^{\circ}C$, but a noticeable unequal cleavage in cell size was observed in hybrid eggs unlikely to purebred. The hatching rate of fertilized eggs of hybrid was generally low across the four incubate temperatures (22, 25, 28, $31^{\circ}C$) with highest 9.8% in $25^{\circ}C$. This study demonstrated the possibility of artificial hybridization between two groupers, red spotted grouper and brown-marbled grouper, thus preparing the groundwork on developmental characteristics, deformities of hatched larvae and early survival ability for further studies on aquaculture.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.439-442
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• 1996

In this study, we tried to figure out the ecology of Masakimyia pustulae Yukawa et Sunose which attacts evergreen euonymus and results in scenic damage caused by early falling of leaves and may increase the susceptibility for anthrocnose. In addition, we tried to develope a method for the control of the insect to prevent spreading of the damage by use of insecticide. The results obtained from the study were as follows : 1. Masakimyia pustulae emerged from late April to late May at Chuncheon area. Average length of the adult insects was $1.88{\pm}0.43mm$, and the life span of them reached about 11 hours. The sex ratio of the insect was 56 : 44(female : male), and they ovipositied $90{\pm}28$ eggs. The shape of eggs was oval with average length $0.32{\pm}0.013mm$. The length of larvae averaged $1.64{\pm}0.25mm$ and started pupation from mid-March, which took about 40~50 days, although there was variance due to temperature variation in each spring. 2. The 3% powder of carbofuran treatment by burying $200g/m^3$ of the insecticide around the damaged tree during mid-March with additional burying about a week after pupation showed good result for the control of the insect, which resulted in more than 96.2% removal of the insects.

• Journal of Aquaculture
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• v.8 no.4
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• pp.295-306
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• 1995

The present study was performed to produce supermales and superfemales in Oreochromis niloticus by combination of induced sex reversal and diploid gynogenesis. More than $95\%$ of female was obtained by oral administration of $17\beta-estradiol$ (480 mg/kg diet) to the eutheroembryonic larvae of this species. The result of progeny tests with XY pseudofemales showed that incidences of male progeny were ranged from $71.4\%\;to\;73.7\%$. p.opo.lion of male from XY pseudofemale was not significantly different (P>0.05) from that of $\chi^2$ (1:3), but it was significantly different (P<0.01) from that of $\chi^2$(1:1) Gynogenetic diploids were produced by applying cold shocks 3 min after insemination to the eggs of XY pseudofemale sperms were genetically inactivated by ultraviolet rays of 4,050 $erg/mm^2$. Fertilization rates of gynogenetic diploids were not different from that of their controls, however, hatching rates and early survival rates were silghtly lower than those of controls. In the cytogenetic studies, there was no difference in the size of cell and nucleus between the gynogenetic diploids and the controls. At 80 days after hatching, frequencies of gynogenetic male were higher than those of gynogenetic female (P<0.01) in their population.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.319-328
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• 2016

Objectives: Advancements in nanotechnology have led to nanoparticle (NP) use in various fields of medicine. Although the potential of NPs is promising, the lack of documented evidence on the toxicological effects of NPs is concerning. A few studies have documented that homeopathy uses NPs. Unfortunately, very few sound scientific studies have explored the toxic effects of homeopathic drugs. Citing this lack of high-quality scientific evidence, regulatory agencies have been reluctant to endorse homeopathic treatment as an alternative or adjunct treatment. This study aimed to enhance our insight into the impact of commercially-available homeopathic drugs, to study the presence of NPs in those drugs and any deleterious effects they might have, and to determine the distribution pattern of NPs in zebrafish embryos (Danio rerio). Methods: Homeopathic dilutions were studied using high-resolution transmission electron microscopy with selected area electron diffraction (SAED). For the toxicity assessment on Zebrafish, embryos were exposed to a test solution from 4 - 6 hours post-fertilization, and embryos/larvae were assessed up to 5 days post-fertilization (dpf ) for viability and morphology. Toxicity was recorded in terms of mortality, hatching delay, phenotypic defects and metal accumulation. Around 5 dpf was found to be the optimum developmental stage for evaluation. Results: The present study aimed to conclusively prove the presence of NPs in all high dilutions of homeopathic drugs. Embryonic zebrafish were exposed to three homeopathic drugs with two potencies (30CH, 200CH) during early embryogenesis. The resulting morphological and cellular responses were observed. Exposure to these potencies produced no visibly significant malformations, pericardial edema, and mortality and no necrotic and apoptotic cellular death. Conclusion: Our findings clearly demonstrate that no toxic effects were observed for these three homeopathic drugs at the potencies and exposure times used in this study. The embryonic zebrafish model is recommended as a well-established method for rapidly assessing the toxicity of homeopathic drugs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.135-144
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• 1980

The reproductive cycle and the breeding season of the freshwater clam, Anodonta (Sinanodonta) woodiana (Lea) have been investigated by histological examination of the gonadal development under photomicroscopy. The materials were monthly collected from the Nakdong River for one year from September 1979 to August 1980. Sexuality of Anodonta (Sinanodonta) woodiana is dioecious, and the species are ovoviviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of small ovarian sacs, The epithelium of ovarian sac has a function of the germinal epithelium. Oogonia actively proliferate along the germinal epithelium of the ovarian sac, in which young oocytes are growing. The testis is composed of a number of seminiferous tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between the growing oocytes and spermatocytes in the early development stages. With the further development of the ovary and testis these tissues and cells gradually disappear. Then the undifferentiated mesenchymal tissue and granular cells are considered to be related to the growing of the oocytes and spermatocytes. The gonads had function year-round the individuals which have various developmental stages of gonads appearing all the time. Spawning continued year-round except for the period of high temperature of water, during August and September. The peak spawning seasons appeared twice a year between January and March, and between June and July in 1980. Individuals which have trochophore larvae in the marsupium of the adult appeared year-round except September 1579 and August 1980. The rate of individuals which have glochidia in the marsupium was 72.7 percent in May 1980 which was the highest brooding fate.

• 보존과학연구
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• s.21
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• pp.5-55
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• 2000

The cultural properties are damaged by various causes according to the characteristics of material, the condition of preservation, and the period of time. Especially, biodeterioration makes lots of damages in organic properties than inorganic ones. The damages of wooden cultural properties by insects usually are caused by the three orders; Isoptera, Coleoptera, and Hymenoptera. As the result of investigation on the state of 141 buildings of wooden cultural properties in 1999, some of them were damaged by many kinds off actors; wasp, powder post beetle, cigarette beetle, termite, decay, and physical cracking. And it was found that the patterns of damages were related to species-specific habits of insects. There are several methods of pest control for the prevention of wooden cultural properties from damages caused by insects. Those are as follows; physical control, chemical control, biological control, and integrated pest management. When insects and fungi were detected at the wooden buildings, the fumigation is best treatment to stop biodeterioration. And then, wood materials also need to be treated with insecticidal and antiseptic chemicals to avoid a reinfestation, because the fumigant is volatile. The six commercial chemicals which are applied to the insecticidal and antiseptic treatment of wooden cultural properties were purchased to test their abilities. According to the comparative results of efficacy of them in laboratory, chemical D showed excellent efficacy in all items, including antiseptic and termiticidal items. The goal of these pest controls is to protect wooden buildings from insects and microorganisms. The most effective method used currently is chemical control(fumigation, insecticidal and anticeptic chemical treatment), but it has to be treated periodically to control pest effectively. Recently environmentally-friendly control methods such as bait system or biological treatments are replacing traditional barrier treatments using large amounts of chemicals. Especially, termite is a social insect which makes a colony. Although a building with fumigation treatment is safe for a while, once attacked building has a risk of damage by reinfestation of termite. Therefore, to control termites from damaged building, the entire colony including reproductives(queen and king) and larvae around buildings must beeliminated. Bait system can be used as a preventive measure in early detection of them through termites colony monitoring and baiting. It would be the most effective for termite control if bait system would be used together with the chemical controls.