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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society of Fisheries Technology
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Journal DOI :
The Korean Society of Fisheries Technology
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Volume & Issues
Volume 35, Issue 4 - Nov 1999
Volume 35, Issue 3 - Aug 1999
Volume 35, Issue 2 - May 1999
Volume 35, Issue 1 - Feb 1999
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Studies on the Improvement of the Fishing Efficiency of Purse Seine in the Sea Area of Cheju Island -The Changes of Seine Volume and Tension in the Purseline During Pursing-
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 93~101
A simple experimental method was used in an attempt to realize the elevation of the fishing ability of purse seine in the sea area of Cheju Island, the changes of seine volume and tension in the purseline during pursing. Experiments carried out on the six types simplified reduced model seines which were made of knotless nettings. The nettings were woven in different leg length 4.3, 5.0, 5.5, 6.0, 6.6 and 7.7mm of polyester 28 tex two threads two-ply twine, and each of the seines were named I, II, III, IV, V and Ⅵ seine. Dimension of seine models were 450cm for corkline and 85cmfor seine depth, each seines rigged up 160g of float for a floatline and 50g (underwater weight) of lead for a leadline. These model purse seines were made of the scale of 1/200 of its full scale, a 120 ton in the near sea of Cheju Island. Designing and testing for the model purse seines were based on the Tauti's law. Experiments were measured in the observation channel of a flume tank at the static conditions set up shooting and pursing equipments. Motion of purse seine during purse line was recorded by the two sets video camera for VTR which were placed in top and front of the model seine. The reading coordinate of seine volume carried out by the video digitization system, disk data for the purseline tension. An analysis were performed on the changes seine volume and tension in the purseline during pursing. The results obtained were as follows: 1. The seine volume during pursing was largest for Ⅵ seine with smallest d/l followed by V, IV, III, II and I seines, and tension in the purseline was small. 2. Seine volume during pursing can be expressed by the following equation; CVt=l-EXP[｛2.79 (d/l）＋0.35｝t-33.37 (d/l) ＋ 0.57] Where CVt is volume ratio, d is twine diameter, l is leg length and t is pursing time (sec). 3. Tension in the purse line during pursing can be expressed by the following equation; T= 1- EXP ｛0.57t ＋ 13.36 (d/l)+2.97｝ Where T is tension (kg) in the purseline during pursing.
Vertical and horizontal distribution of squids in relation to oceanographic structure in the North Pacific Ocean
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 102~117
Vertical distribution of squids in relation to oceanographic structure was analyzed on the basis of experimental squid hand jigging fishing by R/V Pusan 851 in the area of 34°∼47° N, 150° E∼170°W in the North Pacific in summer from 1987 through 1993 with exception of 1991. The 6 species of squids showed different patterns of vertical and horizontal distribution as following; Boreopacific gonate squid (Gonatopsis borealis) were mainly caught in the layer of 71-80m fishing depth of the Subarctic Domain with water temperature of 6∼11℃ and salinity of 32.2∼33.6‰ and distributed in the latitudes of 41°∼43° N. Boreal clubhook squid (Onychoteuthis borealijaponica) were mainly caught in the layer of 11∼20m fishing depth of the Subarctic Domain with water temperature of 10∼12℃ and salinity of 32.9∼33.6‰ and distributed in the latitudes of 41°∼42N°. Tapanese flying squid (Todarodes pacificus) were mainly caught in the layer of 11∼20m fishing depth of the Transition Zone and the Subtropical Domain with water temperature of 15∼18℃ and salinity of 33.6∼34.0‰ and distributed in the latitudes of 40°∼42°N. Neon flying squid (Ommastrephes bartrami) were mainly caught in the layer of surface∼10m fishing depth of the Subarctic Convergence Zone and the Transition Zone with water temperature of 16∼17℃ and salinity of 33.7∼34.4‰ and distributed in the latitudes of 39 °∼41°N. Luminous flying squid (Symplectoteuthis luminosa) were mainly caught in the layer of 11 20m fishing depth of the Transition Zone and the Subtropical Domain with water temperature of 18∼20℃ and salinity of 33.8∼34.6‰ and distributed in the latitudes of 37°∼39°N. Purpleback flying squid (Symplectoteuthis oualaniensis) were mainly caught in the layer of surface∼10m fishing depth of the Subtropical Domain with water temperature of 24∼25℃ and salinity of 34.2∼34.4‰ and distributed in the latitude of 36°∼37°N.
Analysis of the Net Mouth Shape for a Midwater Trawl Gear
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 118~128
The shape of the net mouth in a midwater trawl gear is examined by measuring towing speed, gear resistance, the width of otter boards, net height, and so on of a full-scale gear in operation. In addition, a mathematical model is developed to predict shapes of the net mouth. In the model, shapes of head, ground, side ropes, which governs the shape of net mouth, are assumed as a catenary. The validity of the model is tested with observations. The results can be summarized as follows: 1. The warp tension and vertical opening of the gear is highly dependent to the towing speed. The depth of the gear and width of otter boards are very sensitive to the variations of the warp length. 2. The model results indicate that the wing tip of the head and side ropes is reduced and the vertical distances of the head and side ropes sagged to the back with increasing towing speed. 3. The results of comparing the measured net height with calculated side rope height were satisfying. 4. The results of analysis showed the vertical axis of the net mouth was decreased and the width of the net mouth was little changed when the towing speed increased.
A Study on the Telemetry System for the Inhabitant Environment and Distribution of Fish-II -Current Direction, Velocity, Sea Ambient Noise and Distribution of Fishes-
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 129~135
The telemetry system for the current speed and direction, the underwater ambient noise and the distribution ecology of fishes was constructed by the author and his collaborator in order to product and manage effectively in shallow sea culture and setnets fisheries, and then the experiments for the telemetry system carried out at set net fishing ground located Nungpobay in Kojedo from October 1996 to June 1997. As this results, the techniques suggested in the telemetry system gave full display its function even though far away 1.5 km from transmitting part, but with the suggested telemetry system could not be ascertained relationship between physical environment and distribution ecology of fishes.
A Study on the Telemetry System for the Inhabitant Environment and Distribution of Fish-III -Oxygen, pH, Turbidity and Distribution of Fishes-
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 136~146
The telemetry system for the oxygen, pH, turbidity and the distribution ecology of fishes was constructed by the authors in order to product and manage effectively in shallow sea culture and setnets fisheries, and then the experiments for the telemetry system carried out at the culturing fishing ground in coast of Sanyang-Myon, Kyoungsangnam-Do and the set net fishing ground located Nungpo bay in Kojedo province respectively from October, 1997 to June 1998.As those results, the techniques suggested in the telemetry system for which find out the relationship between the physical and chemical environment in the sea and the distribution ecology of fishes gave full display its function, and its system could be operated as real time system. This research can also provide base-line data to develope a hybrid system unifying the marine environment information and the fisheries resources information in order to manage effectively coastal fishing ground.
The Stability Analysis of the 8 Ton Class Fishing Vessel in Seaway
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 147~155
In this study, the stability analysis of a fishing vessel in a seaway was done. The stability analysis is an important item in the ship design, and so the ship registers of each nation constrain the ships to be followed the stability criterion. Stability variation, exciting forces due to wave and wind, and the broaching phenomena cause the capsizing of a ship. In this study, the stability analysis to study of the capsizing of a fishing vessel was performed. The relation between the speed of the ship and the wave length, that makes the encountering frequency vanish, was obtained. It was found that the encountering frequency tend to be zero when the wave whose length and direction are similar to those of ship. In this case, the possibility of dangerous situation becomes high. The calculated restoring arm becomes small when the ship is located near the wave crest. In general, the selected small fishing vessel is better than the large ship with respect to the stability, however the wave height becomes relatively high because of her small length Kim(l994) calculated the stability variation of the large cargo ship, the results of which showed the changes in stability great. But in the selected small fishing vessel in this study, the changes was small in comparison with the larger ship. This reason seems to be the shape of her midship section. In large cargo ships, the block coefficient is large, but that of the fishing vessel is relatively small and the small fishing vessel has chine, therefore the center of buoyancy moves much when the ship is inclined. It is desirable that the dynamic stability analysis for a fishing vessel, whose speed and direction are similar to those of waves, shall be done in the near future.
The Hearing Ability of the Scorpion Fish Sebastiscus marmoratus to Audible Sound 1. The Auditory Threshold
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 156~160
This experiment was carried out to investigate the auditory threshold of the scorpion fish Sebastiscus marmoratus which was suitable for Marine ranching by a classical respiatory conditioning technique using a sound coupled with a delayed electric shock. The thresholds were determined by analyzing the electrocardiogram. The auditory thresholds were observed among the 12 fish with much difference from 100Hz to 300Hz. The audible range of the scorpion fish extended from 80 to 800Hz with a peak sensitivity of 90㏈(0㏈=
Pa) at 100Hz. As the frequency became higher than 300Hz, the auditory threshold increased rapidly. The scorpion fish was least sensitive to sound of 500Hz among 6 frequency points and the value was about 12㏈.
Behavior of amber fish, Seriola aureovittata released in the setnet
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 161~169
This paper describes the swimming and escaping behavior of amber fish, Seriola aureovittata released in the first bag net of the setnet and observed with telemetry techniques. The setnet used in experiment is composed of a leader, a fish court with a flying net and two bag nets having ramp net. The behavior of the fish attached an ultrasonic depth pinger of 50 KHz is observed using a prototype LBL fish tracking system. The 3-D underwater position ofthe fish is calculated by hyperbolic method with three channels of receiver and the depth of pinger. The results obtained are as follows: 1. The fish released on the sea surface was escaped down to 15 m depth and rised up to near the sea surface during 5 minutes after release. The average swimming speed of the fish during this time was 0.87 m/sec. 2. The swimming speed of the fish is decreased slowly in relation to the time elapsed and the fish showed some escaping behavior forward to the fish court staying 1 to 7 m depth layer near the ramp net. The average speed of the fish during this time was 0.52 m/sec. 3. During 25 minutes after beginning of hauling net, the fish showed a faster swimming speed than before hauling and an escaping behavior repeatedly from the first ramp net to the second one in horizontal. In vertical, the fish moved up and down between the sea surface and 20 m depth. After this time, the fish showed the escaping behavior forward to fish court after come back to the first ramp net in spite of the hauling was continued. It is found that the fish was escaped from the first ramp net to the fish court while the hauling was carried out. The average speed of the fish after beginning of hauling was 0.72 m/sec which increased 38.5 ％ than right before the hauling and showed 0.44 to 0.82 m/see of speed till escaping the first bag net. The average swimming speed during observation was 0.67 m/sec (2.2 times of body length).
Distribution of Fish by Echo Sounder and Environment of Oceanography in Southern Sea of Korea
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 170~177
In order to research the relationship between distribution of fish and the ocean environment in Southern Sea of Korea, echo survey and oceanographic observation were carried out from July 27 to 31 in 1998. The DSL(Depth Scattering Layer) and high density of fishes were appeared in northeastern Cheju Island and offshore of Karnak bay by color echo sounder. The relative Sa(area backscattering coefficient) in offshore of Karnak bay was 5,500 at 28KHz, 12,500 at 200KHz and Northeastern Cheju Island was 6,000 at 28KHz, 20,000 at 200KHz. During the acoustic survey period, Ocean environment of high density of fishes area were as the follows. The surface Northeastern Cheju Island were ranged 20~
and that bottom were ranged 16~
. The shallow water area in offshore of Karnak bay were ranged 24~
Seasonal Variations in Species Composition and Abundance of Fishes Collected by an Otter Trawl in Nakdong River Estuary
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 178~195
The species composition and seasonal variation in abundance of fishes in the Nakdong River estuary were investigated monthly from February 1987 to January 1988. During the study period, 23,008 specimens belonging to 100 species were collected. The most abundant fish species were Repomucenus valenciennei, Pholis fangi, Leiognathus nuchalis, Trachurus japonicus, and Sardinella zunasi. These five species comprised 63.0% of total fishes and 47.8% of total biomass collected. The seasonal dominant fish species were P. fangi and R. valenciennei in spring, R. valenciennei and Cynoglossus joyneri in summer, Thryssa kammalensis and Apogon lineatus in fall, and R. valenciennei, L. nuchalis and S. zunasi in winter. The number of fish species, number of individuals collected, and species diversity indices fluctuated with the seasons. The number of species and number of individuals decreased significantly in the upper estuary. While temperature was an important factor which influenced on seasonal fluctuation of the fish community, salinity determined the spatial distribution of fishes.
Study on the Characteristics of Erosion-Corrosion for Heat Exchanger of Shell and Tube Type(I)
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 196~200
In the case that erosion and corrosion occurs in machinery and structure at the same time, the synergy effect by erosion-corrosion affects fatal effect to durability of machinery and structure. Therefore, in machinery and structure which use corrosion liquid, the study of the synergy effect of erosion-corrosion which affects metal material is requested. In this paper. the flow corrosion experiment about the effect of temperature change and liquid velocity change in sea water was carried out to study the characteristics of erosion-corrosion for tube material Cu heat exchanger The main results obtained are as follows. (1) Damage appearance of tube outside by erosion-corrosion becomes dull because electrode potentials of Cu tube is higher than electrode potential of STPG38 shell. (2) In the cooling system by sea water, the weight loss rate of Cu at tube outside liquid temperature of
is higher than that of temperature of
. (3) In cooling system by sea water, the weight loss rate of Cu at liquid velocity of 5.1m/s is higher than that of velocity of 1.47m/s. But as the testing time passed, the weight loss rate of Cu at velocity of 5.1m/s is almost steady and becomes dull at velocity of 1.47m/s.
Optimal Design of Mooring Steel Pile for Submersible Fish Cage
Journal of the Korean society of Fisheries Technology , volume 35, issue 2, 1999, Pages 201~208
To develop a new fish cage which is required for offshore or moving cage culturing system has been gradually increased against being closely dense of fish cage in shallow water. Though submersible fish cage culturing system is essential technology for converting from shallow water into the offshore, it was pointed out the serious problem about stability of which are sinking and floating state. This study is presented conceptual design of submersible fish cage centered with a mooring steel pile to acquire stability and faculty. Design of mooring steel pile for submersible fish cage culturing system needs to carry out optimal design of mooring steel pile for which much efforts are required. Formulation and optimal design process of submersible fish cage are organized into using Sequential Quadratic Programming method of numerical optimization. For submersible fish cage system centered with a mooring steel pile, process of the optimal design is proposed and the optimal solutions are obtained