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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society of Fisheries Technology
Journal Basic Information
Journal DOI :
The Korean Society of Fisheries Technology
Editor in Chief :
Volume & Issues
Volume 25, Issue 4 - Dec 1989
Volume 25, Issue 3 - Sep 1989
Volume 25, Issue 2 - Jun 1989
Volume 25, Issue 1 - Mar 1989
Selecting the target year
Response of Rudder Fish to the White Lights
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 37~43
The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both in daytime and at night by suing Rudder fish, Girella punctata(Gray). An experimental tank(360L*50W*55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three light bulbs(10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes prior to the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 2.98 lux(1.90-4.40 lux) at daytime and 298.56 lux(188.44-444.96 lux) at night. The variation of the gathering rate of fish in illumination time was great and irregularly fluctuated, but did not show any definite pattern. It was somewhat difference between daytime and night.
The Characteristics of a Fishing Ground at Yeosu Bay - Pound Net Fishing Ground -
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 44~53
In order to grasp the characteristics of a fishing ground at yeosu bay, the fluctuation in condition of the coast and that in catch by pound nets in the coast were investigated respectively. The results obtained are summarized as follows: 1. The water temperature in spring and summer was higher at the coast side than off shore, but in autumn and winter took the reverse. 2. The salinity was higher in spring and winter than in summer and autumn. A lower salinity zone was found at the Dolsan Do coast and higher ones were made off shore. 3. A eddy current was found at the Dolsan Do coast and a thermocline were made at the depth of 30 to 40 m in summer. But in autumn and winter the water became homogeneous. 4. The annual catch by the pound net was highest in 1984 and then decreased gradually. The monthly catch was highest in June and then decreased gradually. 5. The catches seemed to increase with the sea water temperature and salinity, and great catch was shown in 21
and 33.80% to 34.00%. 6. The component rate of fishes was 28.4% in spanish mackerel, 17.9% in anchovy, 19.5% in horse mackerel, 21.0% in sardine, 7.2% in hairtail, and 1% in common mackerel. 7. The fishes appeared continuously on way of fishing operation were spanish mackerel, hairtail, Yellow talil, crab, etc. An anchovy and sardine were caught mainly from March to July or August, horese mackerel and common mackerel from May to November. but puffer, swell fish, saury and filefish were caught mainly from April to October. 8. The sum of catch was largest in June, at which the wind direction was NE to SSW, the speed below 3.2m/sec, the atmospheric pressure below 1008mb, and precipitation beyond 154mm.
Tracking of an Individual Fish by Use of the Ultrasonic Tag
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 54~60
This paper described on the tracking of an individual fish at the fishing ground of set net by use of a small ultrasonic fish tag. The apparatuses used were composed with a tag, three receivers and two time-interval counter oscilloscope. A pulsed ultrasonic transmitter tag fitted to back of a dorsal fin of a yellowtail specimen, Seriola quinqueradidta TEMMINCK et SCHLEGEL is tracked by measuring differences in the time of arrival of the acoustic pulses at an arrangement of three receivers in the freeding tank. The successive positions of the fish were calculated from the differences in the received time of the signals. A fish carying the tag was tracked in the fishing ground of set net by use of the hydrophone and Loran-C. The results of the tests showed that this method gave good positional information to track the movement of an individual fish in the fishing ground of set net.
Studies on the Mackerel Purse Seine operating in the Sea Area of Cheju island - 3. Fishing Ability of Purse Seiner by Classes of Boat-Size -
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 61~69
Mackerel purse seine fishery operating in the sea area of Cheju and Tsushima is one of the most important fishery in Korean off shore fishery, which a fishing fleet are generally composed with one purse seiner, two light ships and three or four fish carriers. In this study, purse seiners are classified in to four classes in term of their gross tonnage : A class(80-100tons), B class(100-120tons), C class(130-140tons), and D class(140-150tons). Operating sea area are divided into five sectors including east and west sea area of Tsushima Island, coastal sea area of Cheju Island and south and west sea area of Cheju Island. The performance of the purse seiner, the fishing efficiency, the dimension of fishing gear and variation of CPUE in each operating sea area are summarized as follows: 1. The relationship between a gross tonnage x and net area of purse seine y of a purse seiner can be expressed as : y=538.8x+99657.3 2. The index of seasonal variation of CPUE from May to October is lower than the standard value, whereas index from November to April is higher. 3. The power factor of fishing efficiency by classes of boat-size shows significant differences with 1% level in each operating sea area. 4. The net efficiency of purse seiner by classes of boat-sea shows that B and C classes are higher than A and D classes.
A Study on the Maneuverabilities of the M . S . Cheju 402 Stern Trawler
Jeong, Kong-Heon ; Ahn, Jang-Young ; Ahn, Young-Wha ;
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 70~74
This paper, described on the maneuverabilities of M.S. Cheju 402, the stern trawler (159 G.T.), training ship of Cheju National University which carried out the turning circle tests at helm angle 35
Ztests of her. The results obtained were as follows; 1. The advances of the starboard and port turning circles were 79.1m, about 2.6 times of the length of the ship, and 81.4m, about 2.7 times of it, respectively. 2. The rates of speed reduction were about 0.49 together, and mean values of turning angular velocity of her at helm angle 35
into the starboard and port sides were 4.3
/sec and 4
/sec during the turning movement. 3. Overshoot angles of starboard side werelarger than those of port side at all Z tests, and mean values of them of the starboard and port sides at 10
Z tests were 110.5
respectively. 4. The maneuvering indices K and T of experimental ship at 10
, Z tests were 0.755 and 3.468, 0.566, and 1.621, and 0.481 and 1.547 respectively. Consequently, the experimental ship showed that her turning ability was more in effective as the helm angle was becomed larger and her obeying ability was more effective as it was becomed larger.
Study on the Improvement of Stow Net Fishing Technique and the Enlargement of Fishing Ground to the Distant Waters - 3 . Field Experiment on the Efficiency of Newly Designed Net and the Stern Operation System
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 75~81
In this paper, the authors describe on the field experiment of the newly designed actual stow net, standing on the result of the model experiment to examine the performance of the conventional net and the newly designed net, presented in two previous reports of this series. Concurrently the additional experiment to find out the possibility of changing of operating system from the side to the stern was carried out. 1. Fundamental shape of the experimented net was 20 times aslarge asthe newly designed model net. Performance of the net was detected by using two ultrasonic echo sounders: one was set downward at the top-most spreader of the shearing device to detect the opening height of the device from the sea bed, and the other sidewise at the starboard top-most spreader to detect the top-most opening width of the devices. Opening height of the newly designed net showed about 3m smaller than the conventional net at slow current of 0.6m/sec and less but it overcome 1m at speedy current of 0.8m/sec and more. Opening width of the newly designed net was 1.4 times as large as that of the conventional net, ant the front projection area of the newly designed net mouth was estimated as 1.3~1.6 times as large as that of the conventional net. 2. The experiment on the stern operating system was tightly limited by the structure of the ship employed in the experiment, which was a stern trawler of 2275 GT. The ship confronted by the wind with main anchor, while the net was put over the stern slipway and the hauling line of shearing device was operated through the top rollers of gallows. The experiment was very suggestive in the view point to mechanize the operating system, and so to decrease the man power except the following question. The of bow-stern line of ship, and that of net is much different.
A Study on the Effects of Heating of Fuel Oil on Combustion Characteristics and Engine Performance
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 82~86
This paper is concerned with the effects of temperature of diesel fuel on combustion characteristics and engine performance in a home-made precombustion diesel engine for small-sized fishing boat. The results may be summarized as follows: 1. The fuel injection timing was delayed with increase in temperature for diesel fuel, and remarkably delayed at low load. 2. The point of maximum pressure was delayed with increase in temperature for diesel fuel, the maximum pressure decreased with increase in temperature for diesel fuel but increased with increase in load. 3. The brake specific fuel comsumption (BSFC) decreased with increase in load, the optimum temperature of the heated fuel was about 15
. 4. The smoke emissions increased with increase in load and temperature for diesel fuel.
Corrosion Fatigue Cracking Propagation Characteristics and its Protection for the AL-Alloys of Shipbuilding
Lim, Uh-Joh ; Kim, Soo-Byung ; Lee, Jin-Yel ;
Journal of the Korean society of Fisheries Technology , volume 25, issue 2, 1989, Pages 87~104
Recently, with the tendency of more lightening, high-strength and high-speed in the marine industries such as marine structures, ships and chemical plants, the use of the aluminium Alloy is rapidly enlarge and there occurs much interest in the study of corrosion fatigue crack characteristics. In this paper, the initiation of surface crack and the propagation characteristics on the base metal and weld zone of 5086-H116 Aluminium Alloy Plate which is one of the Al-Mg serious alloy(A5000serious) used most when building the special vessels, were investigated by the plane bending corrosion fatigue under the environments of marine, air and applying cathodic protection. The effects of various specific resistances on the initiation, propagation behavior of corrosion fatigue crack and corrosion fatigue life in the base metal and heat affected zone were examined and its corrosion sensitivity was quantitatively obtained. The effects of corrosion on the crack depth in relation to the uniform surface crack length were also investigated. Also, the structural, mechanical and electro-chemical characteristics of the metal at the weld zone were inspected to verify the reasons of crack propagation behavior in the corrosion fatigue fracture. In addition, the effect of cathodic protection in the fracture surface of weld zone was examined fractographically by Scanning Electron Microscope(S.E.M.). The main results obtained are as follows; (1) The initial corrosion fatigue crack sensitibity under specific resistance of 25Ω.cm% show 2.22 in the base metal and 19.6 in the HEZ, and the sensitivity decreases as specific resistance increases (2) By removing reinforcement of weldment, the initiation and propagation of corrosion crack in the HAZ are delayed, and corrosion fatigue life increases. (3) As specific resistance decreases, the sensitivity difference of corrosion fatigue life in the base metal and HAZ is more susceptible than that of intial corrosion fatigue crack. (4) Experimental constant, m(Paris' rule) in the marine environment is in the range of about 3.69 to 4.26, and as specific resistance increases, thje magnitude of experimental constant, also increases and the effect by corrosion decreases. (5) Comparing surface crack length with crack depth, the crack depth toward the thickness of specimen in air is more deeply propagated than that in corrosion environment. (6) The propagation particulars of corrosion fatigue crack for HAZ under initial stress intensity factor range of
k sub(li) =27.2kgf.mm super(-3/2) and stress ratio of R=0 shows the retardative phenomenon of crack propagation by the plastic deformation at crack tip. (7) Number of stress cycles to corrosion fatigue crack initiation of the base metal and the welding heat affected zone are delayed by the cathodic protection under the natural sea water. The cathodic protection effect for corrosion fatigue crack initiation is eminent when the protection potential is -1100 mV(SCE). (8) When the protection potential E=-1100 mV(SCE), the corrosion fatigue crack propagation of welding heat affected zone is more rapid than that of the case without protection, because of the microfissure caused by welding heat cycle.