• Korean Journal of Environmental Biology
• /
• v.27 no.3
• /
• pp.297-305
• /
• 2009

The Asian paddle crab, Charybdis japonica (A. Milne-Edwards) is an important fishery resource in Korea. Despite its common occurrence and commercial importance, few studies have been carried out on the life cycle and trophic ecology of these populations inhabiting on the tidal flat. Food habits of C. japonica populations were investigated on the Jangbong tidal flat, Incheon, Korea. Monthly samples were taken using a modified otter trawl from November 1999 to January 2001. Based on the examination of stomach contents from 257 individuals, the frequencies of occurrence and the relative volumes of food items were analysed. As a result, the crustaceans (the brachyura, the cirripedia and the harpacticoid copepoda), the echinoderms (the ophiuroidea) and the molluscs (the cephalopoda Loligo beka, the bivalves Bivalvia unid. and Mytilus galloprovincialis) were important food for this species. To examine ontogenetic shifts in diets, individuals of C. japonica were categorized into 2 different size classes (${\leq}60mm$ and ${\geq}61mm$ in carapace width) representing sexually premature and mature stages. The food items of the small crabs (${\leq}60mm$) were dominated by the crustaceans with the harpacticoid copepods constituting 84.6% of total prey number. The next group was the bivalves and the brachyurans. On the other hand, the large crabs (${\geq}61mm$) mainly feed on the bivalvia (Mytilus galloprovincialis and Bivalvia unid.), the brachyurans (Crab unid.) and occasionally the cephalopods and fishes. The difference in proportions of the main prey items among these two size classes was statistically significant. Therefore, the feeding habits of the portunid crab, C. japonica changed with growth.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.6
• /
• pp.505-513
• /
• 2012

To determine the concentration of trace metals in the tissues of whale from the coastal ocean of Korea, we measured the concentration of trace metals (Cu, Cd, Pb, As, Zn and Hg) in the organs (liver, intestine, muscle, epidermis and blubber) of minke whale entangled from the eastern coast of Korea in 2009. The highest and lowest concentrations of Cu, Cd, Zn, and Hg were found in the liver and blubber, respectively. In contrast, the highest and lowest concentration of As was found in the blubber and muscle, respectively. The accumulation trend of trace metals in the organs of minke whales was in the order Zn > Cu > As > Pb > Hg > Cd. The concentrations of Cu, As and Zn in liver and epidermic were higher in male than in female, whereas the concentrations of Cu and Pb in intestine and muscle were higher in female than in male. The mature individuals of minke whale were much higher Cd in liver, Cd and Hg in muscle, As and Hg in epidermic and blubber, Cd, As and Hg in intestine than immature individuals of minke whale.

• Fisheries and Aquatic Sciences
• /
• v.1 no.1
• /
• pp.82-93
• /
• 1998

Monthly changes of the gonad follicle index (GFI), reproductive cycle, egg-diameter composition, first sexual maturity of the Pacific oyster, Crassostrea gigas, were studied based on the samples which have been collected from the intertidal zone of Poryong west coast of Korea, from January to December, 1996. C. gigas, is dioecious, while a few individuals are alternatively hermaphroditic. Monthly variation of gonad follicle index (GFI) used for determination of spawning period, coincided with the reproductive cycle. GFI increased from April when seawater temperatures gradually increased and reached the maximum in May. And then, GFI sharply decreased from June to September due to spawning. Reproductive cycle of this species can be divided into five successive stages: in females, early active stage (March to April), late active stage (April to May), ripe stage (May to August), partially spawned stage (June to September) and spent/inactive stage (September to February); in males, early active stage (February to March), late active stage (April to May), ripe stage (May to September), partially spawned stage (June to September) and spent/ inactive stage (September to February). The diameter of fully mature eggs are approximately 50um. Spawning occurred from June to September, and two spawning peaks were observed in June and August when the seawater temperature was above $20^{\circ}C$. Percentages of the first sexual maturity of males of 20.1-25.0 mm in shell height were over $50\%$, while those of females of 25.1-30.0 mm in shell height were over $50\%$. All the males of > 30.1 mm and all the females of ^gt; 35.1 mm completed their first sexual maturity. The results suggest that C. gigas has a protandry phenomenon. Sex ratios of 919 oysters observed were 453 females $(49.29\%)$, 429 males $(46.68\%)$, 16 hermaphrodites $(1.74\%)$, and 21 indeterminate individuals $(2.29\%)$. In age class I, sex ratio of males were $64.00\%$, thus, a higher percentage than that of females. It was noted that $64.00\%$ of the young males (age class I) were more functional than females in age class I, but 2-3 year-old oysters showed higher percentage of females. Percentages of hemaphrodites in 2-3 year classes were relatively higher than those in other year classes. Histological pattern of hermaphrodites can be divided into two types: Type I (hermaphrodite having a number of newly formed developing oocytes on the oogenic tissues within a degenerating spermatogenic follicle after discharge of numerous spermatozoa) and Type II (hermaphrodite having two separate follicles in the same gonad).

• Journal of Global Scholars of Marketing Science
• /
• v.15 no.3
• /
• pp.211-231
• /
• 2005

It is important for marketers to understand both individual resistance and group resistance in order to successfully bring innovations into global markets. We suggest that consumers resist innovations as individuals and as members of a group and that they do this in different ways at different stages of decision-making. The individual resistance begins with forms of initial resistance, develops into emergent resistance and mature or belated resistance at the individual level. In addition, personal moral standards can influence decision making in relation to the adoption of innovations. Individual resistance is sometimes accompanied by or evolves into group resistance. We introduce a framework for thinking about consumer resistance to innovations that sees it as a consequence of social identity, which has functions for the individual, the group to which one belongs, and other individuals and groups. Consumers with membership in a certain group try to increase their self-esteem through the process of social comparison. The more consumers strongly identify with and bond with a certain group, the more in-group solidarity and out-group hostility will occur. Out-group hostility gives group members strong resistance toward products and services related to the out-group. Individual resistance and group resistance are threats to marketers and dampen performance. By considering the existence of resistance to innovations and seeking strategies to overcome it, marketers can transform these threat into new opportunities. A better understanding of consumer resistance can complement research on the adoption of innovations and help in the development of a universal model of consumer behavior.

• Korean Journal of Plant Taxonomy
• /
• v.43 no.4
• /
• pp.245-251
• /
• 2013

Paeonia lactiflora is a valuable natural resource for horticulture and traditional Chinese medicine. To propose conservation strategy and future utility of the wild Paeonia lactiflora populations recently found around the Gyeongju National Park, genetic diversity analysis using microsatellite markers were performed. Three populations in and near the Gyeongju N.P. and one population from Jilin, China were analyzed for five microsatellite markers, producing 61 alleles with mean observed heterozygosity($H_o$) of 0.452. $F_{ST}$ value (0.11642) suggested moderate level of genetic differentiation among the populations, and hierarchical AMOVA suggested most of the genetic variation resides within/among the individuals rather than among-population. While AMOVA with $F_{ST}$ suggested lack of genetic differentiation between the regional (Korean vs. Chinese) populations, AMOVA with $R_{ST}$, which incorporates the allele sizes, suggested considerable differentiation between them, but without significant statistical support. STRUCTURE analysis also suggested segregation of regional populations with presence of gene flow among the three Gyeongju N.P. populations. Considering small population size and scarcity of mature individuals, further protection and long-term monitoring are needed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.52 no.4
• /
• pp.372-385
• /
• 2016

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 $32,568ind./km^2$ and mean biomass of $1,649.5kg/km^2$. The dominant species, comprising over 1.0% of the total number of individuals, were Chionoecetes opilio ($11,203ind./km^2$, 34.4%), Pandalus eous ($9,247ind./km^2$, 28.4%), Ophiuridae spp. ($5,750ind./km^2$, 17.7%), Argis lar ($2,631ind./km^2$, 8.1%), Neocrangon communis ($994ind./km^2$, 3.1%), Berryteuthis magister ($612ind./km^2$, 1.9%), Sepiola birostrata ($499ind./km^2$, 1.5%) and Strongylocentrotidae sp. ($424ind./km^2$, 1.3%). The dominant species, in terms of biomass, comprising over 1.0% of the total biomass, were C. opilio ($1,167.2kg/km^2$, 70.8%), B. magister ($130.3kg/km^2$, 7.9%), P. eous ($102.4kg/km^2$, 6.2%), Ophiuridae spp. ($84.6kg/km^2$, 5.1%), Enteroctopus dofleini ($45.5kg/km^2$, 2.8%), A. lar ($35.7kg/km^2$, 2.2%), Strongylocentrotidae sp. ($25.0kg/km^2$, 1.5%) and S. birostrata ($22.1kg/km^2$, 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.

• Korean Journal of Food Science and Technology
• /
• v.46 no.5
• /
• pp.630-635
• /
• 2014

Pine nut oil (PNO) is well known to impart beneficial effects in overweight individuals, but the mechanisms underlying PNO-mediated weight loss remain unclear. To investigate how PNO promotes weight loss, its composition was determined by gas chromatography coupled with mass spectrometry (GC-MS). In addition, the effects of PNO on cytotoxicity, lipid accumulation, expression of lipid metabolism-related biomarkers, and leptin secretion were assessed in 3T3-L1 cells. GC-MS analyses revealed that PNO contains several components, including linoleic acid, oleic acid, palmitic acid, and stearic acid. Moreover, PNO did not have a cytotoxic effect on 3T3-L1 cells. However, it inhibited the expression of peroxisome proliferator-activated receptor (PPAR) and adipocyte protein 2 (aP2). Finally, PNO significantly increased leptin secretion in a dose-dependent manner. Taken together, these results support the notion that PNO is useful for weight management in overweight individuals.

• Korean Journal of Ichthyology
• /
• v.33 no.3
• /
• pp.177-183
• /
• 2021

Distribution aspects and extinction threat evaluation of the endangered species, Rhynchocypris semotilus were investigated in Goseong-gun, Gangwon-do, Korea, June 2020. Among the 12 sampling sites investigated during the study period, samples of R. semotilus were collected 268 individuals at 6 sites. The streams inhabited of R. semotilus were Songhyeoncheon (3 stations), Gojindong (2 stations) and Osodong (1 station). The main habitats of R. semotilus were uppermost and upper stream (Aa type) with 3~15 m water flow width, 0.3~1.3 m depth and high ratio boulder and cobble bottoms. The estimated age of the R. semotilus (June) based on their total length distribution indicated that 0-, 1-, 2-, 3- and more than 4-year-old were 6~27 mm, 38~59 mm, 60~75 mm, 78~93 mm and 96~125 mm, respectively, and their has matured reproductive organs over two years old. R. semotilus investigation results of the threat of extinction showed no tendency to decrease in population size, but estimated to be less than 1,000 mature individuals, with a small range of extend of occurrence (39.668 km²), area of occupancy (16 km²), and number of disconnected locations (3 locations). Therefore, R. semotilus is now considered vulnerable (VU D2) based on the IUCN Red List categories and criteria.

• Korean Journal of Organic Agriculture
• /
• v.31 no.4
• /
• pp.413-426
• /
• 2023

These experiments were conducted for 3 years from 2021 to 2023 to develop a method that can be safely used to prevent the leakage of Golden apple snails (Pomacea canaliculata) from eco-friendly rice plantations. In the southern part of Jeollanam-do, after planting rice, the young golden apple snails placed in the rice field become adults around mid-July and begin spawning. These individuals can overwinter in drains that do not dry out, but individuals hatched after mid-July will not mature enough to overwinter. The size of golden apple snails overwintered in the drainage canal was more than 2.5cm in shell height. Installing a net at the inlet could block 95% of the inflow of snails, and 99% of outflow was blocked by installing an improved water trap and net at the drain. During the mid-drying period and pre-harvest drying period, a water path was created with a power paddy pottery machine. 59.5% of snails were attracted to the waterway, and it took 130 minutes to build the waterway and collect the snails. Based on these results, seasonal paddy management tips for the safe use of giant snails in rice fields were suggested.

• Animal Systematics, Evolution and Diversity
• /
• v.20 no.2
• /
• pp.201-214
• /
• 2004

Some actiniarians were collected from the coasts of Jejudo and Baekdo Islands in Korean waters from 1971 to 2004. They are identified into three species within three families, which are newly recorded to Korean actiniarian fauna: Halcampella maxima Hertwig, 1888 within the tribe Athenaria, and also Aulactinia coccinea (Verrill, 1866) and Stichodactyla tapetum (Ehrenberg, 1834) within the tribe Thenaria. They are described in detail with figures and tables together with the distribution and size of cnidae. In preserved specimens, mature oocytes of H. maxima were observed in winter. Also oocytes and sperm sacs of S. tapetum were surveyed at separate individuals in summer. The unique feature of A. coccinea is a body wall with simple adhesive verrucae extended from margin to limbus in longitudinal rows. In the genus Stichodactyla, the smallest species, S. tapetum is distinguished from S. haddoni by short bulbous tentacles, less than 1.0 mm long, densely packed on the oral disc and also conical marginal ones, 1.5-2.0 mm long. As a result of this study, the Korean actiniarian fauna consists of four athenarian and 23 thenarian species in suborder Nynantheae