• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.848-849
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• 2005

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.370-374
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• 2015

Pacific herring Clupea pallasii eggs were attached to the gill net in Korean coastal waters off Busan. To conservation and management the eggs attached to the gill net, we followed the natural hatching in coastal waters from five days after fertilization to the hatching finished, where the temperature was $9^{\circ}C$. The diameter of fertilized eggs was 1.24-1.55 mm (n= 50), and had a segmented pale yellow yolk, no oil globule. Natural hatching had started by 10 days after fertilization. Mass hatching occurred around 11-12 days after fertilization, most of eggs separated from the gill net. Therefore, when the Pacific herring eggs attached in gill net, should be natural hatching-induced in coastal waters during 12-14 days.

• Environmental Analysis Health and Toxicology
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• v.20 no.1
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• pp.57-65
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• 2005

Effects of five polycyclic aromatic hydrocarbon (PAHs) constituents (naphthalene, fluorine, fluoranthene, benzo(a)pyrene, pyrene) on fertilization and early development of sea urchin egg, sperm and fertilized egg were investigated. The eggs, sperm and fertilized eggs were exposed to several concentrations of PAHs (1, 10, 100, 1000 and 10000㎍/L). The rate of fertilization and hatching decreased when the eggs and sperm were exposed to aqueous solution of PAHs. Also, Exposure of fertilized eggs with each PAHs did decrease survival and hatching rate. Concentration-dependent toxic effects on the rate of fertilization, hatching, survival and abnormality in A. crassispina were observed following exposure to PAHs (1, 10, 100, 1000 and 10000㎍/L). These data show that PAHs exposure decreased in fertilization success of sea urchin egg and sperm and producted abnormal embryo. It is plausible to suggest that PAHs had the potential to significantly reduce coastal recruitment of sea urchin.

• Plant Disease and Agriculture
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• v.1 no.1
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• pp.14-18
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• 1995

This study was carried out to investigate effect of transplanting method, environmental factor, and fertilizing level on occurrence of Pseudomonas glumae in south-west coastal area of Chonnam province. Occurrence in filed began after heading and increased gradually during 3-4 weeks. Occurrence of this disease was great at daily minimum temperature of 23-$25^{\circ}C$ and series of rainfall during early and mid. August Degree of infection by fertilization of nitrogen and by transplanting fertilizing level of 50% than standard fertilization of nitrogen and by transplanting method was greater machine-transplanting than hand-transplanting. Rate of degradation was 6.5% in case of 10% of infected panicle, 14.5% in 30%, 22% in 50% and 35.9% in 70%. We can reduce occurrence of this disease by sawing non -infected seed and balanced fertilizing in cultural practice and applying oryza 4kg/a in early transplanting or Kasugamin EC and Allta in heading stage.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.158-158
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• 2003

Bioassays using gametes of sea urchins are widely used in ecotoxicological assessments of marine environments. Since most of sea urchin species in Korean coastal water spawn from spring to autumn, bioassay with them during the winter is impossible. In the course of developing standard methods for bioassays with Korean species, we found a winter-spawning starfish, Asterias amurensis, Since reproductive mode of asteroids is similar to echinoids, the bioassay protocol for sea urchins could be applied similarly to the starfish. Here, we tested and determined several conditions for the acceptability of bioassay with A. amurensis. The least required time for formation of fertilization membrane of fertilized eggs to be easily distinguished from unfertilized ones was 60 min. The threshold of sperm to egg ratio that could make acceptable fertilization rates in controls was 3000. The allowed time for manipulation of sperm after dilution in seawater was at most 3 hr. The optimal exposure time of sperms when the response against toxicant solution was relatively stable was in the range of 20-60 min. The tolerance range of sperms to the salinity of test solution was 26-38 psu. The sensitivity of A. amurensis sperm was intermediate among marine organisms commonly used in aquatic toxicity tests. The sperm bioassay with A. amurensis can be satisfactorily applied to toxicity assessments of marine environments.

• 한국해양학회지
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• v.28 no.2
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• pp.79-85
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• 1993

The final biomass yields of 16 marine phytoplankton clones were measured in media with different levels of iron and phosphorus concentrations. The biomass yields of oceanic clones were either only slightly limited or not limited by iron, and those of coastal clones were severely limited by iron in all photogenetic groups other than cyanobacteria. By contrast oceanic cyanobacteria clones as well as coastal clones required higher iron concentrations: minimum concentrations of iron addition for detectable growth of the Synchronous species were estimated to fall between $10^{-9}{\;}and{\;}10^{-8}{\;}M$. Not only the habitat differences (oceanic-coastal trends) but also the photogenetic differences of the oceanic phytoplankton species in the response to the iron enrichments deserve very careful attention before ocean iron fertilization.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.2
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• pp.98-104
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• 2004

Early development and metamorphosis of the ascidian (Halocynthia hilgendorfi ritteri) were investigated from fertilized egg. The samples were collected in the coastal waters of Yongdam, northwest of Jeju Island in November 2002. H. hilgendorfi ritteri was solitary ascidian and produced spheral eggs with egg size ranging from $0.33\pm0.01\;mm.$ On the outer surface of the vitelline coat are attached many follicle cells. At $21.0\pm0.5^{\circ}C$ of water temperature, first cleavage took place in about 1.5 hrs after fertilization, and gastrulation followed in about 12.5 hrs. The formation of tailbud embryos and free swimming larvae were observed 13.3 hrs and 20.5 hrs after fertilization, respectively. The size of newly hatched tadpole larva was 1.30-1.45 mm, the larva swam for 2 hrs to 14 hrs. At 4 hrs after hatching, the palpi were lost and tail absorption began with an abrupt rupture of the anterior end of the notochord. At 17-18 hrs after hatching, tail completely absorption and remained trunk. The coniform adhesive papilla began protrusion at 30 hrs after hatching. The oral and atrial siphon formed at 6-7 days after settlement. At 17-18 days after settlement, metamorphosed the larvae developed into protoascidian of which the external morphology was similar to their adult.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.43-50
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• 2020

The aim of this study is toxicity assessment using two types of sea urchins (H. pulcherrimus, M. nudus) that can representative primary consumers in potential coastal environments pollutants, Zinc undecylenate (ZU), which is used for various purposes, such as pharmaceutical agents and anti-bacterial and anti-fungi. The Fertilization rate and normal embryogenesis rate of H. pulcherrimus and M. nudus were concentration-dependent decreased. Besides, EC₅₀ of fertilization rate with H. pulcherrimus and M. nudus were 11.27 mgl^-1 and 1.48 mgl^-1, and EC₅₀ of normal embryogenesis were 0.94 mgl^-1 and 3.78 mgl^-1. NOEC of normal embryogenesis were 0.20 and 0.78 mgl^-1, respectively. In addition, to find the safety criteria of the ZU on the marine environment. PNEC value was 0.0094 mgl^-1, calculated using the toxicity values of two species of sea urchin derived from this study and the acute toxicity results of the coastal area through literature research. The above results will be used as basic data for establishing environmental protection strategies for marine environmental pollutants.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.80-87
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• 2021

In this study, the toxic effects of PFOA and PFOS potassium salt on Mesocentrotus nudus using 10 min-fertilization rate and 48 h-normal embryogenesis were confirmed through the calculation of toxicity values such as Non-observed effective concentration, Low-observed effective concentration, and 50% of effective concentration. The case of 10 min-fertilization rate and 48 h-normal embryogenesis showed the concentration-dependent reduction pattern when exposed to PFOA and PFOS potassium salt, in tested concentration, respectively. The EC50 values of 10 min-fertilization rates for PFOA and PFOS potassium salt were 1346.43 mg/l and 536.18 mg/l, respectively, and the EC50 values of 48 h-normal embryogenesis were 42.67 mg/l and 17.81 mg/l, respectively. Both toxicity test methods showed high toxicity sensitivity to PFOS potassium salt. Recent studies have shown that the concentration of PFOA and PFOS in the marine environment has continuously decreased, and it is not enough to show acute toxicity to sea urchin. However, PFOA and PFOS have a very long half-life and can accumulate throughout the life of marine life, so it is still observed at a high concentration in shellfish. Therefore, a study on chronic toxicity through the whole-life cycle of marine organisms in coastal environments should be needed.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.1
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• pp.35-42
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• 2011

Behaviour habitats of sailfin sandfish, Arctoscopus japonicus, one of the stock recovery species of Korea, were investigated when they were approaching toward the eastern coastal waters of Korea during spawning season. Underwater surveys were conducted in December, 2009 at Jug-island, Goseong, Gangwon-province to observe the behaviour of sailfin sandfish by underwater video camera and underwater camera, and the body characteristics of sailfin sandfish caught by gillnet were measured. It was observed that the species generally move in school but a few of individuals go out of the school to approach and dig into the sand bottom. Eggs of sailfin sandfish were shown in many cases to be attached to seaweed like Sargassum fulvellum and Zostera mairna. The females maintain its body in horizon and shake the body to breed eggs. It was also observed that the males spray sperm on the eggs attached on seaweed. Sailfin sandfish is assumed to make diurnal migration by moving to the shallow coast at night for spawning and fertilization, and moving out to the offshore at sunrise.