Maturity and spawning of the pointhead flounder, Hippoglossoides pinetorum were investigated on the basis of samples collected in the coastal waters off Gangwon-do, East Sea from January 2012 to December 2013. The average total length of H. pinetorum was 25.0 cm and 21.9 cm for females and males, respectively. The spawning period was from May to July according to monthly changes gonadosomatic index (GSI) and maturity stages. The spawning period in Gangwon-do was delayed relatively to that in Gyeongbuk-do. The mature egg diameter ranged between 300-700 ㎛. The relationship between TL and fecundity (F) was F = 63.574 TL - 1471.3 (R2=0.7603), that is, the larger total length, the more fecundity H. pinetorum had. We estimated that the TLs at 50% group maturity were 25.6 cm for females and 19.9 cm for males. The spawning ecology by sea area should be considered efficient resource management for H. pinetorum. Furthermore, it is necessary to study more on the relationships among growth, maturity and water temperature variations in the East Sea.
The age and growth of Pleurogrammus azonus in the coastal of Gangwon-do, East Sea were determined, from monthly samples of commercial catches, caught by the gill net and set net fishery from January to December in 2008. Gonadosomatic index (GSI) began to increase in September, and reached the maximum between November and December. After spawning GSI began to decrease from January. The annuli of P. azonus are formed once a year, with the boundary between opaque and translucent zones forming from December to January. The relationships between fork length (FL) and body weight (BW) were BW = 0.005 FL3.240(R2 = 0.963) for females and BW = 0.006 FL3.238(R2 = 0.946) for males. The FLs at annuli formation in otoliths were back-calculated from the otolith-length relationship and were adjusted to von Bertalanffy growth curves to FLt = 70.54 (1–exp(-0.099(t+1.188))) for females and FLt = 51.87 (1–exp(-0.135(t+1.697))) for males. Until the age of 3 years, males grew faster than females; however, from the age of 4 years, females grew faster than males. In the future, we want to study the relationship between early growth and water temperature changes in the East Sea
This present study investigated characteristics of distribution and community structure of macrobenthic invertebrates through the survey of commercial Danish seine fisheries from 2011 to 2013. In this study, a total of 28 species were sampled with a mean density of 32,568 ind./km2 and mean biomass of 1,649.5 kg/km2. The dominant species, comprising over 1.0% of the total number of individuals, were Chionoecetes opilio (11,203 ind./km2, 34.4%), Pandalus eous (9,247 ind./km2, 28.4%), Ophiuridae spp. (5,750 ind./km2, 17.7%), Argis lar (2,631 ind./km2, 8.1%), Neocrangon communis (994 ind./km2, 3.1%), Berryteuthis magister (612 ind./km2, 1.9%), Sepiola birostrata (499 ind./km2, 1.5%) and Strongylocentrotidae sp. (424 ind./km2, 1.3%). The dominant species, in terms of biomass, comprising over 1.0% of the total biomass, were C. opilio (1,167.2 kg/km2, 70.8%), B. magister (130.3 kg/km2, 7.9%), P. eous (102.4 kg/km2, 6.2%), Ophiuridae spp. (84.6 kg/km2, 5.1%), Enteroctopus dofleini (45.5 kg/km2, 2.8%), A. lar (35.7 kg/km2, 2.2%), Strongylocentrotidae sp. (25.0 kg/km2, 1.5%) and S. birostrata (22.1 kg/km2, 1.3%). Among them, S. birostrata, E. dofleini, Strongylocentrotidae sp. and Ophiuridae spp. were higher abundance and biomass in the shallow water (<200 meters in depth), whereas C. opilio, P. eous, A. lar, N. communis and B. magister were higher in the deep water (301 ~ 500 meters in depth).As the results of cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on the Bray-Curtis similarity of fourth root transformed data for number of species and individuals, the macrobenthic invertebrates community by Danish seine survey was divided into two groups of station in the shallow water (<200 meters in depth, Group A) and the deep water (201 ~ 500 meters in depth, Group B). The major individual-dominant species was S. birostrata, Ophiuridae spp. and immature C. opilio in group A. But Group B was P. eous, A. lar, B. magister and mature C. opilio.
The distribution of eggs and larvae of mackerel, Scomber japonicus was examined in the coast of Jeju island, Korea in spring from April to May in 2013 and May to June in 2014. In the monthly variations of mean abundances, as a whole, mackerel eggs were observed abundantly in April, 2013, and mackerel larvae were observed abundantly in June, 2014. Especially, high densities over 5,000 ind./1,000 m3 of mean eggs abundances were observed in the eastern part of Jeju Island where is water temperature was over 18℃. It can be inferred that these areas were major spawning grounds of mackerel around Jeju island, and that it may be caused by influences of the Tsushima warm current.
Marine macroalgal community structure of subtidal zones were examined at eight study sites, Jeju, Korea, from March to June 2010. A total of 182 species were identified, including 22 green, 37 brown and 123 red algae. Of them, 15 species were observed at all the study sites. Species richness of seaweeds was maximal at Seongsan with 112 species and minimal at Sinheung with 44 species. Average seaweed biomass was 735.24 g wet wt. m-2 and ranged from 165.82 g wet wt. m-2 at Sinheung to 1,160.43 g wet wt. m-2 at Bomok. Articulated coralline algae were dominant occupying 27.05% (198.92 g wet wt. m-2) of total biomass for the eight study sites in Jeju Island. Subdominant species were Ecklonia cava and Codium coactum, comprising 26.62% (195.72 g wet wt. m-2) and 8.42% (61.91 g wet wt. m-2), respectively. Vertical distribution of subtidal seaweeds in terms of biomass showed from E. cava Colpomenia sinuosa - Codium coactum Ecklonia kurome Undaria pinnatifida - Cladophora wrightiana - Peyssonnelia capensis in the subtital zone between 5~15 m depth level.
방사성폐기물의 처리와 관리는 원자력을 이용하는 국가들이 반드시 해결해야 하는 중요한 문제이다. 오늘날 동 사안에 대 해서는 극소수의 국가들만이 실질적인 진척이 있으며, 그 중 프랑스의 관련 정책이 대표적인 성공 사례로 평가되고 있다. 한국의 경우에 있어서도 방사성폐기물의 관리에 대한 적절한 정책의 준비가 필요하며, 이에 프랑스 법제화 접근법을 적용 하자는 제안들이 있다. 동 연구는 그 적용성 검토를 위해 방사성폐기물의 관리와 관련된 두 나라의 기술 현황 및 사회정책 적 지표를 비교하였으며, 자원 재활용과 사회적 수용성 증진 전략 측면에서 프랑스식 법제화 모델을 반영하는 것이 바람직 하다고 판단한다.
To examine species composition, abundance and biomass of fishes in the northwestern East Sea of Russian EEZ, trawl survey were conducted at 31 sampling stations from 2006 to 2008. Also, trawl survey were conducted at 21 sampling stations in the southwestern East Sea of Korean EEZ from 2006 to 2008. A total of 67 fishes were collected in the northwestern East Sea of Russian EEZ, a total of 39 fishes were collected in the southwestern East Sea of Korean EEZ. Among them, a total of 53 fishes were collected in the northwestern East Sea of Russian EEZ only, and a total of 25 fishes were collected in the southwestern East Sea of Korean EEZ only. Mean abundance per area which caught by trawl survey in the northwestern East Sea ranged from a high of 116,478 inds./km2 in 2008 to a low of 19,737 inds./km2 in 2006. And mean abundance per area in the southwestern East Sea ranged from a high of 89,129 inds./km2 in 2006 to a low of 8,234 inds./km2 in 2008. Mean biomass per area which caught by trawl survey in the northwestern East Sea ranged from a high of 11,333 kg/km2 in 2008 to a low of 2,439 kg/km2 in 2006. And mean biomass per area in the southwestern East Sea ranged from a high of 6,273 kg/km2 in 2006 to a low of 1,062 kg/km2 in 2008. Cluster analysis, based on a Bray–Curtis similarity matrix of fourth root transformed data of number of species and individuals per area, showed division into three different groups by depth in the northwestern and southwestern East Sea.
This study was performed to estimate biomass and provide management guidance through population ecological characteristics, including growth parameters, instantaneous coefficients of natural and fishing mortalities, and age at first capture of the starry flounder, Platichthys stellatus and olive flounder, Paralichthys olivaceus of Korea. For describing growth of this species, a von Bertalanffy growth model was adopted. The von Bertalanffy growth parameters estimated from a non-linear regression for starry flounder were L∞=48.25 cm, K=0.16/yr, and t0=-1.48, respectively and those for olive flounder were L∞=86.46 cm, K=0.26/yr, and t0=-0.29, respectively. Biomass of Platichthys stellatus was estimated by direct biomass estimation method was 2.6 M/T, that was estimated by indirect method was 13.4 M/Tt. Those of Paralichthys olivaceus were estimated as 10.1 M/T, 19.3 M/T, respectively. An yield per recruit analysis showed that the current yield per recruit on Platichthys stellatus was about 48.2 g with F=0.646/yr and the age at first capture (tc) 1.35yr, that on Paralichthys olivaceus was about 167.6 g with F=1.121/yr and the age at first capture (tc) 1yr.
The age and growth of rabbit fish, Siganus fuscescens were investigated from samples monthly collected in the coast of Jeju island, Korea from February to December 2012. Ages were determined from annuli in otoliths, and annuli were formed in one or two months immediately after spawning once a year. Also, main spawning period was estimated between July and August, thus rings were considered as annual marks. The von Bertalanffy growth equations estimated from a non-linear regression method were Lt=37.24 (1-e-0.33(t + 1.24)) (R2=0.92) for female and Lt=31.44(1-e-0.45(t + 1.23)) (R2=0.90) for male, and the growth between female and male was different.
Maturity and spawning of the giant Pacific octopus, Octopus dofleini was investigated based on the samples collected in the coast of Gangwondo, East Sea, from January to December in 2009. Individuals of mature stage had a higher occurrence rate from February toMay, and gonadosomatic index (GSI) also showed a higher value from February toMay than the other months. For that reason, the spawning period was estimated from February to May with the main spawning period from March to May. The total number of eggs in the fecundity (F) ranged from 9,045 in 11.0 kg (TW) to 148,682 in 16.5 kg (TW), which was proportional to total weight (TW), and the relationship between total weight and fecundity was F=0.185×TW2.238 (R2=0.389). The total weight at 50% group maturity (TW0.5) of female was estimated to be 12.2 kg.
This study investigated purplish Washington clam, Saxidomus purpuratus on its gonadal development, reproductive cycle and shell length (age) at 50% female group maturity from January to December 2011 in Jinhae Bay, Korea. This species is dioecious. The gonad index (GI) began to increase in January, reached the maximum value in May and to decrease in June, reached the minimum value in September then to increase slowly in October again. The reproductive cycle of the clams can be divided into five successive stages: the early active stage (Ea, from February to March), the late active stage (La, from January to March and October to December), the ripe stage (R, from January to May), the spawning stage (S, from June to December) and the degenerative and inactive stage (Ia, from January to February and November to December). The spawning periods were from June to December and the main spawning periods were from July to October. The shell length at 50% female group maturity (SL50) was estimated to be 63.6 mm, which can be converted as sexual maturity age of 2.2 year.
The annual and monthly fluctuation in the species composition and the catch abundance of dominant species were analyzed using the daily sales slip catch data by a set net in the offshore waters off Dolsan Island in Yeosu from March 2004 to December 2011. Mean catch from 2004 to 2011 is 372M/T and the maximum and the minimum catch are 526 M/T in 2005 and 27 2M/T in 2009, respectively. The dominant species were Engraulis japonicus mainly in spring and Scomberomorous niphonius in Autumn and therefore the set net catch that is dominated by S. niphonius's catch was much higher in autumn than in spring. Through comparative analyses for the environmental factors to the annual catch fluctuation, it is revealed that the water temperature variation affected the recruitment property of S. niphonius to the fishing ground but the effect of typhoon on the catch fluctuation was not distinct. Furthermore, the big blooming event of jellyfish, particularly Nemopilema nomurai, that occurred in 2009 showed a tendency of faster appearance and later extinction until December. The occurring characteristic of N. nomurai became a direct cause that brought about the lowest total catch in 2009 since the dominant species catch of the set net fishery was concentrated mostly in Autumn.
Distribution pattern and fishing conditions of sandfish, Arctoscopus japonicus in the East Sae were explored using catch and catch per unit effort (CPUE) by eastern sea Danish seine and coastal gill net fisheries from 2004 to 2008. A. japonicus was one of major target species for the eastern sea Danish seine and coastal gill net fisheries in the East Sea, which were caught from April to October for the eastern Danish seine, and from October to December for the coastal gill net, respectively. In recent, the distribution and centroid of fishing ground moved northward, as seawater temperature increased. The species spawned in the coastal areas of Gangwon, northern East Sea, during winter, started to move to deeper water after spawning from spring, extended widely from Gangwon to Ulsan, southern East Sea, during summer, and migrated back to the spawning ground off Gangwon during autumn.
In this study, energy budget was estimated to produce an efficient artificial seed. And it needs to enhance fisheries productivity of sandfish, A. japonicus. In order to estimate energy budget of the sandfish, A. japonicus juvenile fed on nonriched Artemia nauplii (NA) and the enriched Artemia nauplii (EA), of sandfish were reared at constant condition of seawater temperature of natural temperature (NT) and heated temperature (HT). During the reared period, energy used by the reared juveniles were calculated from estimates of data on ingestion, growth, oxygen consumption, nitrogen excretion and energy content. Energy budget of NT-NA, NT-EA, HT-NA and HT-EA were represented as 100C=66.49G+21.28M+0.78F+1.44U, 100C=67.54G+21.40M+9.39F+1.67U, 100C=66.86G+22.66M+8.01F+2.47U and 100C=67.06G+22.96M+7.70F+2.28U. The assimilation efficiency estimated NT-NA, NT-EA, HT-NA and HTEA were represented as 87.78%, 88.94%, 89.52% and 90.02%. Gross growth efficiency estimated NT-NA, NT-EA, HT-NA and HT-EA were represented as 66.49%, 67.54%, 66.86% and 67.06%. Net growth efficiency estimated NT-NA, NT-EA, HT-NA and HT-EA were represented as 75.75%, 75.94%, 74.68% and 74.49%. In this results, two ways could be considered to produce an efficient artificial seed of sandfish. To hasten the growth of sandfish juvenile, heated seawater (HT) and enriched Artemia nauplii (EA) should be inputted to reared condition. And to increase the energy efficiency, natural seawater (NT) and enriched Artemia nauplii (EA) should be inputted to reared condition.
To develop the artificial spawning seaweeds of the sandfish, Arctoscopus japonicus, the effects by the material type of artificial spawning seaweeds were investigated at Dongsan port in Gangwon-do from December 2006 to March 2007. Sargassum fulvellum, S. horneri, rope and net were used as materials for artificial spawning seaweeds, and the most effective thing among them was S. fulvellum. A. japonicus began to attach the egg mass to artificial spawning seaweeds when sea temperature dropped below 10℃ in December, spawned heavily when it was around 8℃ in January, and completed the behavior when it started to increase over 10℃ in February. The hatching period of eggs was estimated to be about 60 days. The middle position in artificial spawning seaweed had the highest number of egg masses and the diameter of the egg mass ranged from 25mm to 62mm. Based on the result for the effects, the artificial spawning seaweeds of A. japonicus were developed and it is possible to use them to form seaweed forests or spawning grounds of other species.
ZnO thin film was grown on a sapphire single crystal substrate by plasma assisted molecular beamepitaxy. In addition to near band edge (NBE) emissions, both blue and green luminescences are also observedtogether. The PL intensity of the blue luminescence (BL) range from 2.7 to 2.9eV increased as the amountof activated oxygen increased, but green luminescence (GL) was weakly observed at about 2.4eV without muchchange in intensity. This result is quite unlike previous studies in which BL and GL were regarded as thetransition between shallow donor levels such as oxygen vacancy and interstitial zinc. Based on the transitionlevel and formation energy of the ZnO intrinsic defects predicted through the first principle calculation, whichemploys density functional approximation (DFA) revised by local density approximation (LDA) and the LDA+Uapproach, the green and blue luminescence are nearly coincident with the transition from the conduction bandto zinc vacancies of V2-Zn and V-Zn, respectively.
LPE방법을 이용하여 InP기판 상에 GaAs이종접합 박막을 최초로 성장하였으며 제반 성장조건들이 박막특성에 미치는 영향을 NDIC광학현미경, SEM, TEM 및 DCXRD 등을 이용하여 조사하였다. 적정 LPE성장온도는 720˚C(냉각속도 0.5˚C/min.)이었으며 성장된 GaAs 박막의 표면형상은 융액 균질화 처리 시 기판을 InP cover웨이퍼로 보호한 경우가 In/InP 융액으로 보호한 경우에 비해 현저히 개선되었다. 박막 성장 시 Ga성장융액 내에 0.005wt% 정도의 Se을 첨가함으로서 기판의 열융해(meltback)현상이 억제되었고 박막의 표면 거칠기도 현저히 개선되었다. 미세 격자가 식각된 InP기판 상에 성장된 GaAs 박막의 DCXRD측정결과 미세 격자 패턴이 없는 기판 위에 성장된 시료보다 결정성이 더욱 향상되었으며 이는 TEM 관찰결과 GaAs/InP계면에서 생성된 전위들 중 일부가 상호반응에 의하여 미세격자 영역 내에 국한되기 때문으로 판단되었다.
Contaminated water from abandoned mines, non-sanitary landfills, and tunnel excavation flows into rivers via groundwater. These sources of contamination contain significant heavy metals and are discharged without treatment. As contaminated water flows into the river, water quality decreases. Furthermore, water that flows into rivers also contaminates the soil. This causes problems for both the environment and society. However, it is difficult to place water treatment plants at each source of contamination because of problems related to economics, site security, etc. The author has selected permeable reactive barriers (PRBs) to solve these problems. The aim of this study is to develop eco-friendly technology for reuse of waste. In this study, three reacting media were used. The first reacting medium was zero-valent iron (ZVI). ZVI can be used as a PRB and is effective at removing heavy metals. The second medium was steel-making slag. It is suitable for removal of heavy metals because its components include lime and iron oxide. The final reacting medium was bark. The bark is the outer layer of a tree, and consists of dead tree trunk tissue. The chemical structure of bark includes carboxyl and hydroxyl moieties that combine well with heavy metals. In this study, the materials to be removed were heavy metals including arsenic, cadmium, copper, lead, zinc, and nickel. The experiment was carried out for two months using two pilot scale PRBs. ZVI and steel-making slag were placed on the front of the two pilot scale PRBs under the same conditions. Activated carbon and bark were placed on the end of each device. After two months, the experiment showed efficient removal of arsenic and lead. It is possible to reduce the generation of waste by removing heavy metals with waste materials like bark.