• Animal cells and systems
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• v.16 no.2
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• pp.162-171
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• 2012

We investigated food webs of a $Salix$ $subfragilis$-dominated wetland in the Janghang wetland in the Hangang estuary, which is very close to the Demilitarized Zone, along the west coast of Korea. Our study focused on understanding sesarmine crab ($Sesarma$ $dehaani$)-related food webs in a $S.$ $subfragilis$ forest. For our study, we used carbon and nitrogen stable isotopes and fatty acid biomarkers. We collected samples of plants, animals, and detrital sediment from four quadrats ($5{\times}5m^2$) set in the $S.$ $subfragilis$ community. Samples were collected from September 2006 to June 2009, except during the winter hibernation period of $S.$ $dehaani$. In the wet season, the sediment showed relatively high ${\delta}^{13}C$ and low ${\delta}^{15}N$ signatures compared with relatively low ${\delta}13C$ and high ${\delta}15N$ signatures in the dry season. Mature $S.$ $dehaani$ appeared to feed on fresh leaves and other carbon sources, such as immature individuals or fish, in addition to detrital sediment, which appeared to be the main carbon source for immature crabs. Principal component analysis of fatty acid biomarkers of $S.$ $dehaani$ showed a clear difference between immature individuals (10-30 mm) and mature ones (larger than 30 mm), indicating that the main food source for immature crabs was detrital sediment, whereas mature crabs foraged plants in addition to consuming detrital sediment. On the basis of our results from stable isotope and fatty acid analyses, mature $S.$ $dehaani$ appeared to feed on detrital sediment and fresh leaves of $S.$ $subfragilis$ in summer in addition to engaging in cannibalism of immature individuals.

• Korean Journal of Plant Taxonomy
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• v.43 no.2
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• pp.128-138
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• 2013

The conservation status of an endemic perennial herb, Hanabusaya asiatica (Nakai) Nakai (Campanulaceae) was determined by applying the IUCN risk assessment criteria from our field study and available specimen data. Also, the GIS technology was used to develop a species distribution map to calculate the extent of occurrence (EOO) and area of occupancy (AOO) for the taxon. After two years of continuous field studies, 269 mature individuals were found in four localities in 2011, while 216 mature individuals were confirmed in three localities in 2012. Based on the following data, such as EOO (2,742 $km^2$), AOO (76 $km^2$) and estimated population size of mature individuals, the taxon, which is known as 20 localities in Korean peninsula, is evaluated as the category of Endangered (EN). A major difficulty in application of IUCN criteria to Korean rare plants were the lack of essential biological information and understanding the correct knowledge of the IUCN criteria in previous Korean studies. Sound conclusions regarding the conservation status of individual species require more intensive population studies, observations, and applying IUCN assessment procedures correctly.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.493-503
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• 2015

This study analyzed how spatial distribution of Himantormia lugubris is affected by the microenvironment in the Antarctic Specially Protected Area (ASPA) No. 171 located in the Barton Peninsula of King George Island that belongs to the maritime Antarctic. In order to determine the population structure of H. lugubris growing in Baekje Hill within ASPA No. 171, we counted the individuals of different size groups after dividing the population into 5 growth stages according to mean diameter as follows: ≤ 1 cm, 1-3 cm, 3-5 cm, 5-10 cm, and ≥ 10 cm. The count of H. lugubris individuals in each growth stage was converted into its percentage with respect to the entire population, which yielded the finding that stages 1 through 5 accounted for 32.8%, 25.3%, 15.9%, 22.5%, and 3.5%, respectively. This suggests that the population of H. lugubris in ASPA No. 171 has a stable reverse J-shaped population structure, with the younger individuals outnumbering mature ones. The mean density of H. lugubris was 17.6/0.25 m², mean canopy cover 13.3%, and the mean dry weight 37.8 g/0.25 m². It began to produce spore in the sizes over 3 cm, and most individuals measuring 5-10 cm were adults with sexually mature apothecia. The spatial distribution of H. lugubris was highly heterogeneous. The major factors influencing its distribution and performance were found to be the period covered by snow, wind direction, moisture, size of the substrate, and canopy cover of Usnea spp. Based on these factors, we constructed a prediction model for estimating the spatial distribution of H. lugubris. Conclusively, the major factors for the spatial distribution of H. lugubris were snow, wind, substrate and the competition with Usnea spp. These results are important for understanding of the distribution in the maritime Antarctic and evolution of H. lugubris that claims a unique life history and ecological niche.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.162-167
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• 2010

Ecological characteristics of Orthrias nudus from the Eoron Stream, Gangwon-do, Korea were investigated from January to December 2009. O. nudus inhabits mainly riffles of the upstream and mid-upstream stretches of Eoron Stream, which were composed of boulder and cobble bottoms. The current velocities in these habitats were 0.42~1.34 m/sec and depths were 15~46 cm. The sex ratio of female to male was 1 : 0.98. It is presumed that the spawning season is from April to June when water temperatures were $15{\sim}19.2^{\circ}C$. Sexually mature individuals appeared to be over one year of age. Frequency analysis of total length indicated that the group 58~99 mm in total length is represented by one-year-old individuals, and the group over 100 mm by two-year-old individuals. The average number of eggs in the ovaries was estimated as 4,119 per mature female. Stomach contents of O. nudus were composed of aquatic insects such as Ephemeroptera, Trichoptera and Diptera.

• American Studies
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• v.43 no.1
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• pp.83-97
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• 2020

"Behind a Mask" (1866) marks the new direction of Louisa May Alcott's artistic and personal life. Her European trip solidified her identity as a mature woman, most importantly as a mature American woman, one whose independence from Victorian stereotypes would, from now on, make her fortune and fame. Her sensational stories, especially "Behind a Mask," would tell truths that readers recognized but had rarely seen written. These truths would free them, and the author herself, to explore their talents as individuals. Henceforth, Alcott would embody the successful American artistic entrepreneur as one who shed the European domination of false titles and inherited wealth. These motifs of the transnational connection pervade the story, in the form of images and likenesses. Just as Alcott would soon, in two years, reach astonishing financial success with the publication of Little Women, her meteoric ascent parallels America's rise to power in the world's economy, which came about with almost alarming speed after the conclusion of the American Civil War.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.245-250
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• 2005

The maturity and spawning of Pacific cod, Gadus macrocephalus, was studied using samples caught by gillnets in the East Sea from January to December 2003. Monthly changes of maturity observed with the naked eyes for females showed that maturing Pacific cod appeared from August, and their numbers increased to $83\%\;and\;100\%$ in November and December, respectively. In January, mature and spawning Pacific cod were observed for the first time and composed over $40\%$ of the population. In February, the proportion of spawning individuals increased to over $50\%$, however, the mature individuals decreased to less than $10\%$. In March, mature fish were not found, and all were in an immature (spent) or spawning state. From April to July all fish remained in immature condition. The males maintained this trend with the females, whereas, mature males appeared from November to March. Monthly changes in the gonadosomatic index (GSI) of females and males showed higher values both in January and February and declined sharply in March. The lower value remained until October and then began to increase from November for the female population. For the males, however, this value remained lower until August, and then began to increase from September, and showed higher values in October through December than in January and February. These results indicated that the spawning season of Pacific cod was from December to March, and the main spawning season was from January to February, and the period of the spawning season was longer for males than the females. The diameter of the matured oocytes was 0.80-1.10 mm with a single mode of 0.95 mm. Fecundity was 1,300,000-9,400,000 in total length of 65-95 cm and the relationship between the total length (TL, cm) and fecundity (Fc) was Fc= $180,248\timesTL-10,883,638$. The total length at first maturity was observed at 57 cm for females and 47 cm for males. The size at $50\%$ group maturity was estimated to be 63.9 cm for females and 56.0 cm for males.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.189-201
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• 1995

In order to clarify regeneration processes and mechanisms of the disturbed Pinus densiflora forest, responses of Pinus densiflora to gap formed by disturbance were analysed by growth of saplings and mature and growth equations were obtained from branch growth of mature trees and height growth of saplings, and age distribution of saplings and young trees recruited within gap was analysed in relation to gap age. Height growth of saplings within gaps was accelerated after gap formation. Such abrupt increases of growth of saplings after the gap formation might be resulted in the difference of growth of saplings between gap and non-gap areas. In fact, height and diameter of saplings in the central part of gap were larger than those of saplings in marginal parts of gap and non-gap area. However, density of saplings was not different in both parts. In addition, growth of annual rings of mature trees bordering on gap also increased after gap formation. Branch growth of mature trees bodering on gap was 6.3 - 6.5 cm /year and the mean radius of gaps created by death of only one canopy tree was about 3 m. Therefore, for those gaps to be closed by branch growth it will take 46 years. Growth of saplings within gap showed exponential equation. Fifty years will be required for the saplings to enter the forest canopy by the exponential growth equation. Therefore, gap created by only one tree might be closed by branch growth of surrounding canopy trees in advance of being done by height growth of saplings. But gaps created by death of trees more than 2 will be closed by the growth of saplings. Among the regenerating saplings and young trees within gaps, individuals established in advance of gap formation were more than those established after the gap formation. From these results, it was assumed that the disturbed Pinus densiflora forests in these sites were regenerated by height growth of saplings recruited in advance of gap formation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.5
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• pp.410-418
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• 2006

Sexual maturity and growth characteristics of Octopus minor were investigated in 796 individuals from mud flats in Goorori, Muan-Goon, Korea. Gonadosomatic index (GSI) peaked between June and July in females and between November and January in males. The discrepancy in the index peaks between females and males might result from the earlier sexual maturation of males. The sex ratio was biased toward females (68%) in April and toward males (78%) in September, although the differences were not significant (p>0.05). In females, about 50% of individuals with a mantle length of 70.6 mm were sexually mature versus 100% of individuals with mantle lengths over 80 mm. In females, fecundity was also related to size, ranging from 44 eggs in individuals with a mantle length of 54 mm to 179 eggs in the female with a mantle length of 100.5 mm. The relationship between mantle length (ML) an body weight (BW) was BW=0.008 ML$^{2.2797}$ (n=389, r$^2$=0.83, p<0.01) in males and BW=0.029 ML$^{2.2797}$ (n=407, r$^2$=0.74, p<0.01) in females. Analysis of co-variation showed that the difference in the slopes of the two regression lines was significant (p<0.01). Analysis of mantle length-frequency for each month revealed 1 to 3 normal distribution modes. The growth parameters obtained by fitting the modal progression to the seasonalized von Bertalanffy growth function (VBGF) were ML$\infty$= 112.38 mm, K=1.9, C=0.90, and WP=0.1. The results indicate that the seasonal growth oscillation of the stock is very strong and winter is the season when growth is the slowest.

• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.84-91
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• 2018

The study about maturity and spawning of Korean Mandarin fish, Siniperca scherzeri collected using the set net and gill net in Soyangho Lake from April to November 2014 was conducted. The number of individuals was 401 (female: 204, male: 197). The total length of females ranged from 113 mm to 365 mm and that of males was from 140 mm to 342 mm. The water temperature in May which is the start of spawning season indicated about $15^{\circ}C$ and gradually increased to July ($26^{\circ}C$). Gonadosomatic index (GSI) of females indicated 2.3%, 4.6% and 3.1%, respectively, in May to July. Males' value showed the similar pattern recording 8.0%, 6.6% and 4.5% in the same time. According to histological observations of gonadal tissue, the most of female in May had the gonadal tissue of maturing and mature stage. And the ovary of June was mostly in the stage of ripe and spawning and a number of individuals in July was recovery stage. In the case of male, a number of males in May showed in the stage of mature. The testis of June showed that mature sperm was releasing. And the testis of July was mostly in recovery stage. The total length at 50% group maturity was estimated 245.16 mm. As shown in the above, the main spawning period of S. scherzeri was May to June.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.132-138
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• 1997

In order to obtain the basic information for seedling production of surf clam, Spisula sachalinensis, annual reproductive cycle was investigated from March 1994 to May 1995. S. sachalinensis was dioecious. The gonads are located between the digestive diverticula and muscle tissue of the foot. The condition factor was reached its maximum (0.19) in June, and then decreased to 0.16 in July. In November, the value was the lowest and then increased slowly. The age and minimum size for sexual maturation were 2 years old and about 50 mm in shell length, respectively. However, less than $10\%$ of sexually undifferentiated individuals were larger than 80 mm in shell length. On the other hand, the size of mature oocytes was ranged to $50\~60{\mu}m$ in diameter and testis-ova was observed in testis of the mature stage. Annual reproductive cycle could be classified into five successive stages : multiplicative (October to January), growing (February to April), mature (April to June), spawning (June and July) and degenerative and resting (August and September) stages.