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Journal of the Korean society of Fisheries Technology
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The Korean Society of Fisheries Technology
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Volume & Issues
Volume 46, Issue 4 - Nov 2010
Volume 46, Issue 3 - Aug 2010
Volume 46, Issue 2 - May 2010
Volume 46, Issue 1 - Feb 2010
Selecting the target year
Mesh selectivity of monofilament and multifilament nylon gill net for Marbled sole (Pleuronectes yokohamae) in the western sea of Korea
Kim, In-Ok ; Park, Chang-Doo ; Cho, Sam-Kwang ; Kim, Hyun-Young ; Cha, Bong-Jin ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 281~291
DOI : 10.3796/KSFT.2010.46.4.281
To estimate the mesh selectivity of monofilament and multifilament gill net for Marbled sole, Pleuronectes yokohamae, the field testes were carried out 12 times with five different mesh sizes (86.6, 101.0, 121.2, 137.7, 151.5mm) in the western sea of Korea, 2007-2009. The master curve of selectivity was estimated by the extended Kitahara`s method. In the field testes, the total number of species and catch were 26 and 987, respectively. The catch number of marbled sole was 728 and occupied 73.8% in total catch. The optimum values of l/m for 1.0 of retention probability in monofilament and multifilament gill net were estimated 0.288 and 0.307, respectively and l/m was estimated to be 0.189, 0.203, 0.213, 0.222 and 0.230 in case of monofilament gill net and 0.171, 0.191, 0.205, 0.216 and 0.227 in case of multifilament gill net when the retention probability were 0.1, 0.2, 0.3, 0.4 and 0.5, respectively. The 0.5 selection range of multifilament gill net was wider about 1.5 times than that of monofilament gill net according as multifilament gill net was 0.216 and monofilament gill net was 0.148. So the multifilament gill net has a low selectivity than that of the monofilament gill net. To estimate the optimum mesh size on first maturity length 19.5cm of marbled sole, the retention probability value of 0.1 was adopted in consideration of using the gill net for marbled sole at present. The optimum mesh size were estimated to be 103.2mm and 114.0mm in monofilament gill net and multifilament gill net, respectively, on first maturity length 19.5cm of marbled sole.
Fishing power estimation of biodegradable traps in the East Sea
Bae, Bong-Seong ; An, Heui-Chun ; Jeong, Eui-Cheol ; Park, Hae-Hoon ; Park, Seong-Wook ; Park, Chang-Doo ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 292~301
DOI : 10.3796/KSFT.2010.46.4.292
For an effective management of fisheries resources, it is very important that to make clean inhabitation environment and to preserve fisheries resources. The material which is mainly used as fishing gear in modern times, is polyethylene, polypropylene, polyamide, etc., chemical fiber. And lost fishing gears which are make of these, occur ghost fishing and ocean pollution. To solve these problem, we development biodegradable fishing trap using the polybutylene succinate (PBS). Developed traps are for red snow crab (Chionoecetes japonicus) and shrimp, major traps in the East Sea, and we carried out fishing research using two kind traps in the coastal sea of Ayajin-port (Goseong) to analysis fishing efficiency of PE trap and PBS trap. As a result for fishing experiment (year 2005-2006) of red snow crab trap, two kind traps were almost the same in catches and length composition. During a experiment, parts of meshes, used for over 1 year, were cut by biodegradation. As a result for fishing experiment (year 2007) of shrimp trap, northern shrimp (Pandalus eous), coonstripe shrimp (Pandalus hypsinotus) and morotoge shrimp (Pandalopsis japonica) were catched, and the almost is northern shrimp. Two kind traps were almost the same in catches and length composition. In accordance with these result, it is recommended that the developed traps are have to commercialized because the fishing powers of PE traps and PBS traps were same. But biodegradation speed is have to controled in consideration of ocean microorganism volume and traps life.
The performance of a wedge type jellyfish excluder device inserted in a trawl net
Park, Chang-Doo ; Kim, In-Ok ; Lee, Kyoung-Hoon ; Lee, Gun-Ho ; Park, Seong-Wook ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 302~312
DOI : 10.3796/KSFT.2010.46.4.302
In order to describe the performance of a wedge type jellyfish excluder device, a series of fishing experiments was carried out in the coastal areas of Yokji Island, southern Korea in 2009, using a trawl net with a cover net. The body size and weight of each individual (fish or jellyfish) caught in the experimental fishing were measured. In the case of giant jellyfish the bell diameter and weight were measured. The catch species was composed of giant jellyfish (Nemopilema nomurai), silver croaker (Pennahia argentata), yellow croaker (Larimichthys polyactics), finespotted flounder (Pleuronichthys cornutus), largehead hairtail (Trichiuruslepturus), melon seed (Psenopsisanomala) and so on. The weight ratio and individual ratio of total fish escaped through the outlet of the excluder device were 0.322 and 0.320, respectively. The weight ratios of giant jellyfish excluded from the trawl net ranged from 0.740 to 0.921 (average 0.852/haul). It means that the wedge type jellyfish excluder device performed well and allowed the most of the giant jellyfish to exclude through the trawl net. The approximately 70% of fish entered in trawl net was caught. The wedge type excluder device needs some improvements to minimize the fish escape from the trawl nets in the future.
Low-Carbon trawl design with analysis of a gear drags and calculation of construction costs using numerical methods
Lee, Ji-Hoon ; Lee, Chun-Woo ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 313~323
DOI : 10.3796/KSFT.2010.46.4.313
Fuel consumption in fisheries is a primary concern due to environmental effects and costs to fishermen. Much research has been carried out to reduce the fuel consumption related to fishing operations. The fuel consumption of fishing gear during fishing operation is generally related to hydrodynamic resistance on the gear. This research demonstrates a new approach using numerical methods to reduce fuel consumption. By designing the fishing gear using drawing software, the whole and partial resistance force on the gear can be calculated as a result of simulations. The simulation results will suggest suitable materials or gear structure for reducing the hydrodynamic forces on the gear while maintaining the performance of the gear. This research will helpful to reduce the
emissions from fishing operations and lead to reduce fishing costs due to fuel savings.
Investigation of bycatch and discards of funnel net in the coastal waters of Yeosu
Shin, Hyeong-Ho ; Jeong, Sun-Beom ; Oh, Taeg-Yun ; Shin, Jong-Keun ; Cho, Young-Bok ; Kim, Hyung-Seok ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 324~334
DOI : 10.3796/KSFT.2010.46.4.324
This investigation was carried out to research on the actual states for bycatch and discards of catches caught by funnel net from December, 2007 to June, 2010. Fishing grounds were Manheung-dong and Ocheon-dong in the coastal waters of Yeosu. The number of the investigation was 21 in Manheung-dong and 7 in Ocheon-dong fishing ground. In Manheung-dong, the species of catches were 26 of fish, 6 of cephalopod and 5 of crustacean. In Ocheon-dong, the species of catches were 25 of fish, 6 of cephalopod and 4 of crustacean. In the two all fishing grounds, the largest amount of species was revealed as gray mullet. Among these catches, the number of non marketable species that were classified and discarded ones, were 9 in Manheung-dong and 7 in Ocheon-dong. Also, among the marketable species which were small entity or too tiny catches to commercialize and not fresh ones were discarded. The proportion that they dominate in the whole catches was 37.1% in the number of catches and 5.4% in the weight of catches in Manheung-dong, and 6.9% in the number of catches and 0.3% in the weight of catches in Ocheon-dong. In case of Manheung-dong, the monthly discarding proportion was the highest with 59.4% in the number of catches in may and 17.6% in the weight of catches in November, and in case of Ocheon-dong, the both of them were the highest in February, with 28.0% in the number of catches and 5.1% in the weight of catches.
Seasonal variation of fish assemblage in Sacheon marine ranching, the southern coast of Korea
Kim, Young-Seup ; Choi, Jung-Hwa ; Kim, Jung-Nyun ; Oh, Taeg-Yun ; Choi, Kwang-Ho ; Lee, Dong-Woo ; Cha, Hyung-Kee ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 335~345
DOI : 10.3796/KSFT.2010.46.4.335
Species composition and seasonal variation of fish assemblage in Sacheon marine ranching, Korea were examined. Sampling was seasonally made by a shrimp trawl from February 2009 to November 2009. A total of 55 species were collected. Of these, five species was dominant species comprising 51.1% of the total number of individuals. Nine species represented 57.3% of the total biomass. While total abundance (number of individuals) was high in spring, total biomass and species richness (number of species) and diversity were high in autumn. Cluster analysis, based on seasonally abundance data of the 21 most common species, showed that the species were separated into 4 different groups. Group A composed of Pholis nebulosa, Pleuronectes yokohamae, Hypodytes rubripinnis, Hexagrammos otakii, Tridentiger trigonocephalus and Paracercis sexfasciata, which were year round residents, group B Congr myriaster, Leiognathus nuchalis, and Platycephalus indicus, which were abundant in autumn, group C Sillago japonica, Pseudaesopia japonica, Zoarces gilli, Pholis fangi, and Pleuronichthys cornutus which were abundant in spring, and group D Sillago sihama, Cociella sp., Johnius grypotus, Cynoglossus joyneri, Cynoglossus robustus, and Pennahia argentata, which were abundant in summer. Principal component analysis revealed that seasonal variation in the fish assemblage was attributed to the abundance of temporal species such as conger and sand smelt fishes, which were abundant in summer, due to seasonal variation of water temperature.
Age and growth of the black rockfish, Sebastes inermis, in the Jeonnam marine ranching area in the southern Sea of Korea
Kim, Hee-Yong ; Kim, Sang-Hwa ; Huh, Sun-Jung ; Seo, Young-Il ; Lee, Sun-Gil ; Ko, Jun-Chul ; Cha, Hyung-Kee ; Choi, Mun-Sung ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 346~357
DOI : 10.3796/KSFT.2010.46.4.346
Characteristics of age and growth of the black rockfish, Sebastes inermis sampled in the Jeonnam Marine Ranching Area (JMRA) around Geumo Islands south of Yeosu were investigated using 642 otoliths from March 2009 to February 2010. The opaque zone was formed in September once a year and hence it was used as an annulus. The parturient period was December to January, and therefore the duration from fertilization to the complete formation of the opaque zone was nineteen months. From the parameters calculated using the average length when the year ring was formed, growth of S. inermis were expressed by von Bertalanffy growth equation as
Feeding habits of Acentrogobius pellidebilis in an eelgrass(Zostera marina) bed
Kwak, Seok-Nam ; Huh, Sung-Hoi ; Kim, Ha-Won ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 358~367
DOI : 10.3796/KSFT.2010.46.4.358
Feeding habits of Acentrogobius pellidebilis collected from in an eelgrass(Zostera marina) bed from January to December 2006 were studied. A. pellidebilis ranged form 1.6 to 6.9 cm in standard length were determined. A. pellidebilis was a carnivore which consumed mainly copepods, polychaetes, and amphipods. Its diets included small quantities of isopods, seaweeds, nematods, and gastropods. It showed ontogenetic changes in feeding habits. Smaller individuals (<2.0cm SL) fed mainly on copepods. While the consumption of copepods decreased with increasing fish size, the consumption of polychaetes and amphipods were increased. Dietary breadth index was varied with fish size.
Reproductive ecology of the blackthroat seaperch, Doderleinia berycoides (Hilgendorf) in South Sea of Korean waters
Cha, Hyung-Kee ; Kang, Su-Kyung ; Oh, Taeg-Yun ; Choi, Jung-Hwa ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 368~375
DOI : 10.3796/KSFT.2010.46.4.368
Maturation and spawning of the Blackthroat seaperch, Doderleinia berycoides were investigated based on the samples captured in Korean waters from January 2008 to December 2009. Gonadosomatic index began to increase in June, and reached maximum between July to September. After spawning it began to decrease from October. Reproductive season was estimated to July-September, with peak in August. Fecundity was proportional to the size of the female, with the clutch size varying from 115,500 eggs in the smallest female (TL〓28.2cm) to 652,000 eggs in the largest (TL〓33.5cm). Size at 50% sexual maturity (
), determined from mature females, was 29.6cm. Annual reproductive cycles of this species could be divided into six successive stages; immature stage (October-May), nucleolus stage (June-July), yolk vesicle stage (July-August), vitellogenic stage (June-September), ripe and spent stage (August-October).
Seasonal variation of species composition by depths in deep sea ecosystem of the East Sea of Korea
Sohn, Myoung-Ho ; Lee, Hae-Won ; Hong, Byung-Kyu ; Chun, Yong-Yul ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 376~391
DOI : 10.3796/KSFT.2010.46.4.376
To investigate seasonal variation and species composition by depth layers in the deep sea ecosystem of the East Sea of Korea, bottom trawl survey was conducted at 4 depth layers during spring and autumn from 2007 to 2009. A total of 47 species were collected and were composed of 23 fish species, 9 crustacea, 6 cephalopoda and 9 gastropoda. The main dominant species at each depth layers were Chionoecetes opilio in 300m, Berryteuthis magister in 500m, Chionoecetes japonicus in 700m and 900m. In spring, richness indices (R) showed low value of 2.01 in 500m depth, and high value of 2.16 in 300m depth. Diversity indices (H`) showed low value of 1.53 in 300m depth, and high value of 2.09 in 700m depth. Dominance indices (D) showed low value of 0.15 in 700m depth, and high value of 0.31 in 300m depth. In Autumn, richness indices showed low value of 1.48 in 900m depth, and high value of 2.69 in 300m depth. Diversity` indices (H`) showed low value of 1.13 in 300m depth, and high value of 2.23 in 700m depth. Dominance indices (D) showed low value of 0.14 in 700m depth, and high value of 0.54 in 300m depth. In spring, similarity analysis in each depth layers showed the difference between 900m and othe depth layer, on the contrary 500m and 700m showed the similarity. In autumn, similarity analyssis in each depth layers showed the difference between 700m and other depth layers, on the contrary 300m and 500m showed the similarity.
Long-term changes in the small yellow croaker, Larimichthys polyactis, population in the Yellow and East China Seas
Yeon, In-Ja ; Lee, Dong-Woo ; Lee, Jae-Bong ; Choi, Kwang-Ho ; Hong, Byung-Kyu ; Kim, Joo-Il ; Kim, Young-Seop ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 392~405
DOI : 10.3796/KSFT.2010.46.4.392
The population of small yellow croaker, Larimichthys polyactis, in the Yellow and East China Seas has decreased significantly since the mid 1970s. Several management measures have been introduced to conserve it, but population size remains low. To rebuild this population, it is now necessary to consider more effective management methods based on the stock assessment. To determine long-term population changes, fishery and biological data collected over 34 years (1969-2002) were analysed. Yearly fish length compositions were analysed for the time periods 1968 through 1970, 1978 through 1982, and 1993 through 2002; and catch data was available from 1969 to 2002. Annual population sizes were calculated based on length composition, the relationship between total length and body weight, and total landings. Analyses showed that since the 1970s, average size of harvested fish decreased; the proportion of less mature fish (smaller than the 50% maturity length, 19cm) in catches has increased and the estimated biomass has decreased significantly. Consequently, the main management recommendation is that juvenile fish need to be better protected to allow the rebuilding of resources to a more sustainable population level. This will require fish size limit, permissible mesh size, and closed area and season regulations.
Acharacteristics on the forming of fishing ground and population ecological study of Yellow tail, Seriola quinqueradiata, in the coastal waters off Gim-nyeong of Jeju Island, Korea
Chang, Dae-Soo ; Yoo, Joon-Taek ; Kim, Byung-Yeob ; Lee, Seung-Jong ; Kwon, Dae-Hyeon ; Koo, Jun-Ho ; Ahn, Gem-Ma ; Oh, Im-Yeol ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 406~415
DOI : 10.3796/KSFT.2010.46.4.406
The forming of fishing ground and the population ecological characteristics of yellowtail, Seriola quinqueradiata, in the coastal waters off Gim-nyeong of Jeju Island were investigated. The stock of yellowtail, Seriola quinqueradiata, between Jeju Island and coastal areas of the East Sea is probably the same. Water temperature probably is a major factor for controlling distribution of yellowtails in deeper, offshore areas off Jeju Island. However, the major factor that determines aggregation of yellowtails in coastal areas of Jeju Island, especially off Gim-nyeong is probably strong tidal currents driven by distribution of yellowtails rather than hydrological conditions such as Yellowtails collected off Jeju Island were from 1 to 4yrs old and about 50% of them were
old, probably indicating overfishing. Jack mackerel was the major prey item for yellowtails off Gim-nyeong from October to March, suggesting concurrence of the two species.
A study on the market-based fisheries resource management for the sustainable fishery
Kim, Jin-Yeong ; Zhang, Chang-Ik ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 416~429
DOI : 10.3796/KSFT.2010.46.4.416
The market-based fisheries resources management system was reviewed and the improvement scheme was studied for seeking the sustainability of marine ecosystems and their fisheries resources. A demand-side policy is currently emerging to the management of fisheries resources by reducing over-exploitation, based on the consumer`s selection. The role of consumers in the sustainable fishery was studied by comparing the social responsibility and consumer`s activity between Korea and foreign countries and international NGO groups, based on the FAO guideline. The adoption of the Marine Stewardship Council (MSC)`s eco-labelling certificate was suggested by expanding the existing environment-friendly certification system in Korea. This new system will contribute to the protection of young immature fish and spawners in coastal and offshore fisheries as well as to the international trade of seafood in terms of fish products from well-managed fisheries. It is noted that the consumer`s activities in the markets as regulators will contribute to the ecosystem health and sustainability.
Fishing status of jack mackerel fishery in the southeastern Pacific Ocean
Kim, Doo-Nam ; Lee, Dong-Woo ; Oh, Taeg-Yun ; Choi, Young-Min ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 430~440
DOI : 10.3796/KSFT.2010.46.4.430
To investigate the catches of jack mackerel fishery, a series of fishing experiments was conducted in the high seas of the southeastern Pacific Ocean (
) during the period of 9 August to 18 December, 2003 by commercial fishing vessel and research vessel. The number of 205 tows fishing was carried out in the southeastern Pacific Ocean. The total catch was 1,988 ton and CPUE was 2.4 ton/hour. CPUE showed high values in the frontal zone during the survey. Main target species caught from the experimental fishing were the jack mackerel, Trachurus murphyi (98.1%) and chub mackerel, Scomber japonicus (1.9%) as bycatch. Body length of the jack mackerel was different between female and male. The high mean catch per unit effort of jack mackerel was showed when the fishing ground of jack mackerel fishery was over the
in the southeastern Pacific Ocean. But the fluctuation of the catch per unit effort in the western part of fishing ground was not matched with those year. Reliable physical and oceanographical information will be useful for the efficiency of fishing activity. According to the result of monthly movement of center of fishing ground, the fishing activity of jack mackerel fishery was performed northward in the southeastern Pacific Ocean as time passes.
Characteristics of lost fishing gear distribution on the sea bed around gillnet fishing ground for yellow croaker in the near sea of Jeju, Korea
Kim, Byung-Yeob ; Seo, Du-Ok ; Choi, Chan-Moon ; Lee, Chang-Heon ; Chang, Dae-Soo ; Oh, Taeg-Yun ; Kim, Yeong-Hye ; Kim, Jung-Nyun ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 441~448
DOI : 10.3796/KSFT.2010.46.4.441
This paper was concentrated on the distribution and the composition of lost fishing gear on the sea bed around yellow croaker fishing ground in the near sea of Jeju, Korea from April to October 2009 in order to improve the fishery environment. Recovering lost fishing gears was carried out total 10 times with a trawlnet along the isobath. As the result, it seems reasonable to conclude that the amount of lost fishing gear has a deep connection with the dip of the sea bed as well as the fishing gear scale, fishing ground and so on. The amount of recovered lost fishing gears were in order of gillnets, dragged gears, traps and ropes. In particular, traps were recovered almost every time within the survey area.
Measurement of vertical migration speed of Sound Scattering Layer using an bottom mooring type Acoustic Doppler Current Profiler
Jo, Hyeon-Jeong ; Lee, Kyoung-Hoon ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 449~457
DOI : 10.3796/KSFT.2010.46.4.449
This study shows that the vertical migration speed of sound scattering layers (SSLs), which is distributed in near Funka Bay, were measured by 3D velocity components acquired from a bottom moorng ADCP. While the bottom mooring type has a problem to measure the velocity vectors of sound scattering layer distributed near to surface, both the continuous vertical migration patterns and variability of backscatterers were routinely investigated as well. In addition, the velocity vectors were compared with the vertical migration velocity estimated from echograms of Mean Volume Backscattering Strength, and estimated to produce observational bias due to SSLs which is composed of backscatterers such as euphausiids, nekton, and fishes have swimming ability.
Relationship between roar sound characteristics and body size of Steller sea lion
Park, Tae-Geon ; Iida, Kohji ; Mukai, Tohru ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 458~465
DOI : 10.3796/KSFT.2010.46.4.458
Hundreds of Steller sea lions, Eumetopias jubatus, migrate from Sakhalin and the northern Kuril Islands to Hokkaido every winter. During this migration, they may use their roaring sounds to navigate and to maintain their groups. We recorded the roars of wild Steller sea lions that had landed on reefs on the west coast of Hokkaido, and those of captive sea lions, while making video recordings. A total of 300 roars of wild sea lions and 870 roars of captive sea lions were sampled. The fundamental frequency (
), formant frequency (
), pulse repetition rate (PRR), and duration of syllables (T) were analyzed using a sonagraph.
, and PRR of the roars emitted by captive sea lions increased in the order male, female, and juvenile. By contrast, the
of wild males was lower than that of females, while the
and PRR of wild males and females did not differ statistically. Moreover, the
frequencies for captive sea lions were higher than those of wild sea lions, while PRR in captive sea lions was lower than in wild sea lions. Since there was a linear relationship between body length and the
frequencies in captive sea lions, the body length distribution of wild sea lions could be estimated from the
frequency distribution using a regression equation. These results roughly agree with the body length distribution derived from photographic geometry. As the volume of the oral cavity and the length of the vocal cords are generally proportional to body length, sampled roars can provide useful information about a population, such as the body length distribution and sex ratio.
A study on the work in fishing convention, 2007 and the fishing vessel`s accommodation facilities standards in national fishing vessel act
Kim, Wook-Sung ; Park, Moon-Gap ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 466~475
DOI : 10.3796/KSFT.2010.46.4.466
This study intends to present a direction for the better reforming of fishers`onboard living conditions and proposals for preparing for ratification of the Work in Fishing Convention by means of making a comparison between standards on recent national fishing vessel accommodation facilities and standards on the Work in Fishing Convention and Its Recommendation, 2007, ILO. For the most part of standards on national fishing vessel accommodation facilities are somewhat insufficient to satisfy the provisions in Annex III of the Convention. Considering by items on fishing vessel accommodation facilities, the standards on insect protector, noise and vibration, heating and air conditioning, lighting, persons per sleeping room, recreational facility are not provided in national law. Headroom, separation of accommodation, sleeping room floor area, mattress size, mess room, galley and food storage are partially sufficient for the Convention. In case of sanitary facilities, national standards are not sufficient for the Convention. The other side, facilities related safety of ship and crew such as emergency escape etc., are fully sufficient for the Convention. These insufficiencies caused by different types of fishing vessel depend on originality of fishing method and practices. In the comparison between equivalent tonnage about vessel`s length on convention and calculated tonnage of national existing fishing vessel, the difference are 226tons about length 24m and 501tons about length 45m. For that reason, headroom, persons per sleeping room, cabin of sicker and injured, sanitary facilities may decide to use gross tonnage in place of length (L) and the alleviating measure basis of convention. But in case of standards on sanitary facilities which are unsufficient for the Convention, specially in coastal fishing vessel length basis should be adopted with alleviating basis for less than length 24m.
Redesigning nozzle propeller of trawl vessel for improving towing speed
Hong, Jin-Keun ; Kang, Il-Kwon ; Kim, Hyung-Seok ; Jeong, Seong-Jae ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 476~486
DOI : 10.3796/KSFT.2010.46.4.476
Fishing efficiency of a trawl vessel can be enhanced by increasing the swept area per unit time, which can be attained either by increasing the mouth size of the net, or by increasing the towing speed. To improve fishing and fuel efficiency of trawl vessels targeting fishes of greater mobility, in which the towing speed is more critical in determining fishing efficiency, we conducted a series of model tests to evaluate the performance of the newly-designed nozzle propeller before installing it in a trawl vessel to verify its towing speed and fuel efficiency in the sea. By conducting further model tests in the experimental basin, we redesigned the propeller of stern trawler to improve the resistance and propulsion performance. Through actual fishing operations, we evaluated the improvement in fuel and fishing efficiency by installing the new nozzle propeller. The trawling speed increased by 0.6kts at the same engine power (RPM), while the engine margin increased by more than 20%. The increased towing speed by installing the redesigned propeller is expected to enhance fishing performance through increasing the number of hauling- and casting operations per unit times, while shortening the towing duration. Analysis of the Catch-Per-Unit-Effort (CPUE) data indicated that the mean CPUE of trawl fishery increased from 3.04kg/m in year 2007 to 6.15kg/m in year 2008, confirming enhanced fishing efficiency by adopting the redesigned propeller.
An experimental study on characteristics of exhaust emissions with fuel properties changes in a diesel engine for small-sized fishing vessel
Suh, Jung-Ju ; Wang, Woo-Kyung ; Kim, Sang-Am ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 487~494
DOI : 10.3796/KSFT.2010.46.4.487
In order to test the applicability of bunker-A in a diesel engine for small-fishing boat, the investigation of the engine performance and the exhaust emission was performed under various conditions of fuel property, intake air pressure and fuel temperature. It was also performed based on IMO NOx Technical code. At high load, the energy consumption rate of bunker-A was lower than that of diesel oil, and the characteristics of exhaust emission of bunker-A were similar to those, and NOx emission rates of both fuels satisfied the IMO NOx emission regulation limits. The energy consumption rate and characteristics of exhaust emission were improved as the intake air pressure was increased, but these were not improved remarkably as the temperature of bunker-A was heated. However, at low load the energy consumption rate, CO emission rate and HC emission rate of bunker-A were higher than those of diesel oil, but NOx emission rates of the fuels were about the same. In addition, at low load the energy consumption rate and CO emission rate of bunker-A were increased as the intake air pressure and the temperature were higher than normal conditions. Accordingly, it is thought that the use of bunker-A in a kind of test engine is possible at high load. On the other hand, it is thought that more research is needed to improve the combustion efficiency under low temperature and low load condition.
Effect of load upon the abrasive wear characteristics of glass fiber reinforced polyurethane composites
Koh, Sung-Wi ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 495~502
DOI : 10.3796/KSFT.2010.46.4.495
The effect of load and sliding speed on abrasive wear characteristics of glass fiber/polyurethane (GF/PUR) composites were investigated at ambient temperature by pin-on-disc friction test. The friction coefficient, cumulative wear volume and surface roughness of these materials against SiC abrasive paper were determined experimentally. Experimental results showed that the surface roughness of the GF/PUR composites was increased as applied load was higher in wear test. The cumulative wear volume tended to increase nonlinearly with increase of sliding distance and depended on applied load and sliding speed for these composites. It could be verified by scanning electric microscopy (SEM) photograph of surface tested that major failure mechanisms were lapping layers, ploughing, delamination, deformation of resin and cracking.
A study on the accommodation of common LED to shipboard
Jeong, Ji-Hyun ; Park, Hwan-Chul ; Kim, Yong-Joo ; Seo, Sang-Do ; Han, Seung-Jae ; Kim, Min-Sok ;
Journal of the Korean society of Fisheries Technology , volume 46, issue 4, 2010, Pages 503~508
Common LED (Light Emitting Diode) lamp has many advantages to compare with fluorescent lamp, long life and no pollution matter like the mercury. The LED lamp is a good light source especially for shipboard lighting because of its compact structure which prevents explosion and shock. Also, low maintenance cost is expected due to its longer life time in comparison with conventional lamps. The LED lamp, however, need some estimates that change of voltage and frequency, vibration, moisture on board to definite accommodation of the LED lamp to shipboard. The purpose of this study is to compare physical properties of a fluorescent lamp with one of the common LED lamp so as to analyze accommodation of common LED lamp on board. This study was carried out in two stages. First, temperature, humidity of illumination, voltage, electric current, frequency and electric power were measured by using experimental equipments. Second, a comparative analysis of consumption electric power, annual oil charge, annual CO2 emission and lamp life time, etc of the fluorescent lamp and common LED one was made. As a result of the study, the consumption electric power of fluorescent lamp was 50% higher than one of the common LED lamp. As a result of measuring life time, it was found that life time of common LED lamp was more about 3.5 fold than one of the fluorescent lamp. Considering these results, it's thought that common LED lamp is verified that energy saving is possible and using is possible as substitute for fluorescent lamp on board.