• Title/Summary/Keyword: Southwestern Pacific

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Comparison of Biological Characteristics of Pacific Cod Gadus microcephalus between the East and Yellow Seas, Korea (동해와 황해 대구(Gadus macrocephalus)의 생물학적 특성 비교)

  • Lee, Kyunghwan;Cha, Hyung Kee;Kim, Yeonghye;Lee, Jeong-Yong;Jung, Sukgeun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.4
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    • pp.499-508
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    • 2016
  • We investigated regional differences in the growth and maturation rate of Pacific cod in the East and Yellow Seas. Significant regional differences were detected in the von Bertalanffy growth equation and mean length at maturity (L50). Cod in the East Sea grew at a faster rate than those in the Yellow Sea, with females growing faster than males in both populations. Cod of both sexes matured earlier in the Yellow Sea (age of maturity: 2.3 years for males, 2.6 years for females) than in the East Sea (age of maturity: 3.9 years for males, 4 years for females). These regional differences suggest that Pacific cod in the Yellow Sea, which is at the southwestern extremity of global cod distribution and thus likely to be an inhospitable habitat for this species, have adapted to their environment by developing earlier maturation and slower growth than cod in the East Sea or the Korea Strait. These regional differences must be taken into account when setting biological reference points for management of the Pacific cod fishery in Korean waters.

A Study of Three-dimensional Magnetization Vector Inversion (MVI) Modeling Using Bathymetry Data and Magnetic Data of TA (Tofua Arc) 12 Seamount in Tonga Arc, Southwestern Pacific (남서태평양 통가열도 TA (Tofua Arc) 12 해저산의 해저지형과 자력자료를 이용한 3차원 자화벡터역산 모델 연구)

  • Choi, Soon Young;Kim, Chang Hwan;Park, Chan Hong;Kim, Hyung Rae
    • Geophysics and Geophysical Exploration
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    • v.23 no.1
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    • pp.22-37
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    • 2020
  • We analyze the comprehensive three-dimensional (3D) magnetic structure characteristics from the seafloor to the deep layer of the Tofua Arc (TA) 12 seamount in the Tonga Arc, Southwestern Pacific, using bathymetric and geomagnetic data, and magnetization vector inversion (MVI) results. The seafloor features surrounding TA 12 highlight a NW-SE-oriented elliptical caldera at the summit of the seamount, two small cones in the depressed area. A large-scale sea valley is present on the western flank of the seamount, extending from these caldera cones to the southwestern base of the seamount. TA 12 seamount exhibits a low magnetic anomaly in the caldera depression, whereas a high magnetic anomaly is observed surrounding the low magnetic anomaly across the caldera summit. It is therefore presumed that there may be a strong magnetic material distribution or magma intrusion in the caldera. The 3D MVI results show that the high anomaly zones are mainly present in the surrounding slopes of the seamount from the seafloor to the -3,000 m (below the seafloor) level, with the magnetic susceptibility intensity increasing as the seafloor level increases at the caldera depression. However, small high anomaly zones are present across the study area near the seafloor level. Therefore, we expect that the magma ascent in TA 12 seamount migrated from the flanks to the depression area. Furthermore, we assume that the complex magnetic distribution near the seafloor is due to the remnant magnetization.

The Exploitation of World Fishery Resources for 10 Years under the New Regime in the Sea (신해양질서 10년후 세계어업자원 이용동향)

  • 이장욱;허영희
    • The Journal of Fisheries Business Administration
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    • v.23 no.1
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    • pp.43-87
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    • 1992
  • In this paper, state of exploitation of world fishery resources after 10 years under the new regime in the sea, called the era of exclusive economic zone (EEZ) expending up to a 200 nautical miles from coastal line, was reviewed to determine effect from establishing EEZ in the world fishery production and its export/import volume based on the fishery statistics annually published by the Food and Agriculture Organization (FAO) of United Nation. The world total production from marine living resources had a trend showing a waned increase during 1970's when most of coastal states were translated into the reality of EEZ. From mid-1980's onwards, it increased rapidly, reaching about 85 million tons . Such increase in production was basically from the Pacific Ocean, accounting for more than 60% of the world total production. Fishing areas where showed increase in the production after the new regime in the sea were the southwestern Atlantic (FAO area 41) , the eastern Indian (FAO area 57) and the whole fishing areas in the Pacific except the eastern central Pacific (FAO area 77). Increase in the production from distant-water fishing countries came from the regions of the southwest Atlantic (FAO area 41) and the southwest Pacific (FAO area 81) . The production from coastal states was up from the regions of the eastern Indian (FAO area 57) , the northwest and northeast Pacific (FAO areas 61 and 67) and the southeast Pacific (FAO area 87) . It was likely that the exploitation of the fishable stocks was well monitored in the areas of the northwest Atlantic (FAO area 21) , the eastern central Atlantic (FAO area 34) and the northeast Pacific (FAO area 67) through appropriate management measures such as annual harvest level, establishment of total allowable catch etc. The marine fisheries resources that have made contribution to the world production, despite expansion of 200 EEZ by coastal states, were sardinellas, Atlantic cod, blue whiting and squids in the Atlantic Ocean : tunas which mainly include skipjack, yellowfin and bigeye tuna, croakers and pony fishes in the Indian Ocean : and sardine, Chilean pilchard, Alaska pollock, tunas (skipjack and yellowfin tuna) , blue grenadier and blue whiting including anchoveta in the Pacific Ocean. It was identified that both fishery production and its export since introduction of the new regime in the sea were dominated by such coastal states as USA, Canada, Indonesia, Thailand, Mexico, South Africa and Newzealand. But difficulties have been experienced in the European countries including Norway, Spain, Japan and Rep. of Korea. Therefore, majority of coastal states are unlikely to have yet undertaken proper utilization as well as rational management of marine living resources in their jurisdiction during the last two decades. The main target species groups which led the world fishery production to go up were Alaska pollock, cods, tunas, sardinellas, chub and jack mackerel and anchoveta. These stocks are largely expected to continue to contribute to the production. The fisheries resources which are unexploited, underexploited and/or lightly exploited at present and which will be contributed to the world production in future are identified with cephalopods, Pacific jack mackerel and Atlantic mackerel, silver hake including anchovies. These resources mainly distribute in the Pacific regions, especially FAO statistical fishing areas 67, 77 and 87. It was likely to premature to conclude that the new regime in the sea was only in favour of coastal states in fishey production.

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Physical and Acoustic Properties for Unconsolidated Sediment in the Kwangyang Bay: In Comparison with the Continental Terrace Sediment in the North Pacific (광양만 미고결 퇴적물의 물리적 및 음향학적 성질 : 북태평양 대륙붕 및 사면 자료와의 비교)

  • KIM Dae-Choul;KIM Gil-Young
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.24 no.5
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    • pp.289-302
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    • 1991
  • Laboratory determination of acoustic property for unconsolidated sediment of Kwangyang Bay was carried out. The compressional wave velocity was correlated to other physical properties and sediment textures to establish a geoacoustic model of the bay. The model was compared to the North Pacific continental terrace sediment. Velocity of the bay is systematically lower(0.02-0.04km/s) than that of the North Pacific. Average velocity of the bay is 1.521km/s. The lowest velocity is measured at the southwestern part of the bay. This area coincides with high amount of fine-grained sediment related to slower circulation. The overall tendency is, however, similar to the North Pacific continental terrace sediment.

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Lack of Association Between Helicobacter pylori Infection and Oral Lichen Planus

  • Pourshahidi, Sara;Fakhri, Farnaz;Ebrahimi, Hooman;Fakhraei, Bahareh;Alipour, Abbas;Ghapanchi, Janan;Farjadian, Shirin
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.5
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    • pp.1745-1747
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    • 2012
  • Oral lichen planus is a premalignant chronic inflammatory mucosal disorder with unknown etiology. It is a multifactorial disease and in addition to genetic background, infections, stress, drug reactions are suggested as risk factors. Helicobacter pylori which is involved in development of many gastrointestinal lesions may also be implicated in oral lichen planus induction. This is of clear importance for cancer prevention and the present study was performed to determine any association between H. pylori infection and oral lichen planus in southwestern Iran. Anti H. pylori IgG levels were determined in 41 patients and 82 sex-age matched controls. The results showed no association between H. pylori infection and oral lichen planus (51% in patients vs. 66% in control). or any of its clinical presentations.

Population Structure and Reproduction of Padina concrescens Thivy(Dictyotales: Phaeophyta) in Southwest Baja California Peninsula, Mexico

  • Rafael, Riosmena-Rodriguez;Consuelo, Ortuno-Aginrre
    • ALGAE
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    • v.24 no.1
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    • pp.31-38
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    • 2009
  • The brown algae padina concrescens is widely distributed in the northwestern Pacific Mexico. We described the population of P. concrescens based on population parameters such as cover, density and size structure and reproduc-tion at two levels tide at the intertidal area in the southwestern Baja. California Peninsula. Monthly visits from January to December 2003 were done. Both cover and density were measured in situ by quadrants method. Samples were collected to obtain size structure and percentage of reproductive fronds. Our results show there is sparial vari-ation in the population structure more than temporal. Thus, cover and density peak were at different months ineach tide level studied, the lower tide level shows the high values in cover as well as density. The frond develop-ment was observed in height/width ratio this relation was consistent only in the low tidal zone. Size class distribu-tion has consistently small size plants in both tide levels.Reproduction was seasonal in the tide channel but in both tide levels all the reproductive plants were tetrasporophyte. Our results suggest that this population is pseudopere-nial and it strongly as a consequence of the intense competition in the intertidal zone.

Verifying a new distribution of the genus Amalthea (Halymeniales, Rhodophyta) with description of A. rubida sp. nov. from Korea

  • Lee, Hyung Woo;Yang, Mi Yeon;Kim, Myung Sook
    • ALGAE
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    • v.31 no.4
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    • pp.341-349
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    • 2016
  • The red algal genus Amalthea was first described from New Zealand with one species, A. freemaniae. We discovered a new species of Amalthea from Korea, Amalthea rubida sp. nov., and described it based on morphology and rbcL sequences. A. rubida is characterized by a foliose, membranous and soft thallus having loosely arranged anticlinal medullary filaments, much like A. freemaniae, except for a difference of the cortex thickness in the basal part of vegetative structure. In the rbcL phylogenetic analyses, A. rubida formed a clade with A. freemaniae from New Zealand and Halymenia abyssicola from Mexico. A. rubida showed 5.7% interspecific divergence to A. freemaniae and 4.7% to H. abyssicola. Our discovery of A. rubida expands the distribution of Amalthea from the oceanic southwestern Pacific into the continental northwestern. A targeted global study is needed to fully reveal the species diversity and phylogenetic relationships of the genus Amalthea and members of the order Halymeniales.

Additional Description of the Vent Scale Worm Thermopolynoe branchiata (Polychaeta: Polynoidae) from the North Fiji Basin

  • Won-Kyung Lee;Geon Hyeok Lee;Se-Jong Ju;Se-Joo Kim
    • Animal Systematics, Evolution and Diversity
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    • v.39 no.1
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    • pp.47-52
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    • 2023
  • Thermopolynoe Miura, 1994 is a monotypic genus in Lepidonotopodinae that comprises species endemic to chemosynthesis-based ecosystems. Here, we examined T. branchiata collected from the hydrothermal vents in the North Fiji Basin. For the first time in Thermopolynoe, we report sexual dimorphism detecting nephridial papillae on segments 11-13 in males, additionally describe the morphology on elytra with round to conical microtubercles on the surface, and distinguish presence of small neuropodial lobes on segments 3-26. We also revised couple of errors and ambiguities in the original description: incongruence between the description and figure and existence of individual variation in ratio of tentacular cirri and palps. In addition, three COI sequences of T. branchiata specimens from the North Fiji Basin were newly obtained and sequences divergence with other Lepidonotopodinae species were determined. These results would contribute to the taxonomy of polynoids in a chemosynthesis-based ecosystem.

Features of Korean Rainfall Variability by Western Pacific Teleconnection Pattern (서태평양 원격패턴에 따른 한국 4월 강수량의 변동 특성)

  • Choi, Jae-Won;Park, Ki-Jun;Lee, Kyungmi;Kim, Jeoung-Yun;Kim, Baek-Jo
    • Journal of Environmental Science International
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    • v.24 no.7
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    • pp.893-905
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    • 2015
  • This study analyzes the correlation between Western Pacific (WP) teleconnection pattern index (WPI) in April during 1954-2008 and rainfall amounts in the same month. Based on the results, it is identified that there have been strong positive correlations between central China, Korea and the southwestern part of Japan in the East Asian region. Through differences between 10 positive WP years and 10 negative WP years selected from the April WPI excluding ENSO years, it is found that rainfall amounts increase in April of positive WP years due to the following characteristics. Increases in rainfall amounts are evident in the East Asian middle latitudinal region where the positive correlation between the two variables is the highest and this is because anomalous southwesterlies are strengthened in the East Asian middle latitudinal region due to the spatial pattern of a south-low-north-high anomalous pressure system centered on this region that is made by anomalous anticyclones centered on the southeastern side of the region and other anomalous anticyclones centered on the northeastern side of the region. In addition, anomalous westerlies (jet) are strengthen in the upper troposphere of the East Asian middle latitudinal region and as a result, anomalous upward flows are strengthened in this region and thus anomalous warm air temperatures are formed in the entire level of the troposphere in the region. In addition to atmospheric environments, anomalous warm sea surface temperatures are formed in the seas in the East Asian middle latitudinal region to help the rainfall amount increases in the East Asian middle latitudinal region.

Variability of Surface Water Properties in the Japan/East Sea on Different Time Scales

  • Ponomarev, Vladimir;Rudykh, Natalya;Dmitrieva, Elena;Ishida, Hajime
    • Ocean and Polar Research
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    • v.31 no.2
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    • pp.177-187
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    • 2009
  • This study examined the multi-scale variabilities of sea surface temperature (SST) and salinity in the Japan/East Sea (JES) based on statistical analyses of observational data, with a focus on the northwestern part of the sea. The regionality of JES SST variability was estimated for different frequency ranges on semimonthly (11-17 days), monthly to seasonal (30-90 days), quasi-semiannual (157-220 days), and quasi-biennial (1.5-3 years) time scales using cluster analyses of daily gridded SST data for 1996 to 2007 from the Japan Meteorological Agency (JMA). Several significant peaks and regional cores were found in each frequency range of the SST anomaly (SSTA) oscillations. Quasi-semiannual SSTA oscillations with high amplitude were found in the south-southwestern part of the Japan Basin ($41-43^{\circ}N$) and were amplified in the area adjacent to Peter the Great Bay. Oscillations with periods of 79 and 55 days also prevailed over the southwest Japan Basin between the Yamato Rise and the continental slope. A similar method was applied to classify SST and the annual cycle of surface salinity using Generalized Digital Environmental Model (GDEM) gridded data. The Tatarskii Strait and adjacent area showed the most specific annual cycles and variability in salinity on interannual to interdecadal time scales. The most significant inverse relationship between surface salinity in the Tatarskii Strait and southern JES areas was found on the interdecadal time scale. Linkages of sea water salinity in the Tatarskii Strait with Amur River discharge and wind velocity over Amurskii Liman were also revealed.