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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 48, Issue 4 - Nov 2012
Volume 48, Issue 3 - Aug 2012
Volume 48, Issue 2 - May 2012
Volume 48, Issue 1 - Feb 2012
Selecting the target year
Calculation of weight on netting with the changes of size and number of mesh for monofilament gill net fishing gear
Park, Seong-Wook ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 301~309
DOI : 10.3796/KSFT.2012.48.4.301
A net-assembling company for gill net fishing gears makes a design based on the size of nets provided and determines floats, types of weights, and numbers. In addition, through the accurate examination of net weights in the process of fishing gear designing, it can prevent an excessive use of designing costs. The weight of twine can be easily calculated by its thickness differences, but the weight of netting has errors to be calibrated since the weight of netting is not changing exponentially with the changes of number and size of meshes. This study aims to suggest and empirically analyze the methods for estimating the weights of netting in accordance with the changes of number, size and thickness of meshes for a sound management of netting and net-assembling companies. Results indicated that the method using the knots and legs of netting was not practically usable because the errors were increased as the number of mesh increased. However, the method using netting area shown its usage potentiality with the calibration of the increasing ratio of mesh numbers.
Catch characteristics of the biodegradable gill net for flounder
Bae, Bong-Seong ; Cho, Sam-Kwang ; Park, Seong-Wook ; Kim, Seong-Hun ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 310~321
DOI : 10.3796/KSFT.2012.48.4.310
There are many studies of the biodegradable net for fishing to prevent marine pollution in Korea and the snow crab gill nets is developed effectively. Recently, the biodegradable gill net for fishes is being developed. This study is the experiment of the catch characteristics for the biodegradable flounder gill net. The 8 experiments were carried out using the nylon gill net and the biodegradable gill net in from August to October, 2011 in the southern East Sea. The results obtained from the above approaches are summarized as follows; A total of 16 species was caught with most dominant species of Cleisthenes pinetorum followed by Liparis tanakai, Glyptocephalus stelleri, Buccinum striatissimum and Dasycottus setiger. A total of catch of the nylon net was 342,885g and that of the biodegradable net was 236,857g. Thus catch of the nylon net was 1.45 times more than that of the biodegradable net. The length composition of Cleisthenes pinetorum, caught by the biodegradable net was very similar to that of nylon. As a result of analysis on the effect of submerged time, small fish escaped more easily than large fish as the submerged time is getting longer. And catches of the biodegradable net was less than the nylon net`s as higher as wave height. Wave height was more influential factor for fishing capacity than submerged time based on the results of a comparison between catch difference of two kinds of gill nets and catch characteristics.
Catching efficiency of biodegradable trammel net for swimming crab (Portunus trituberculatus) in the Yeonpyeong fishing ground of Korea
Kim, In-Ok ; Lee, Gun-Ho ; Cho, Sam-Kwang ; Cha, Bong-Jin ; Sohn, Byung-Kyu ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 322~336
DOI : 10.3796/KSFT.2012.48.4.322
To study the catching efficiency of biodegradable trammel net for swimming crab (Portunus trituberculatus), three types (biodegradable, monofilament and multifilament) of trammel nets were used in the field test, and the tests were carried out 16 times with two different mesh sizes (105mm and 160mm) in the Yeonpyeong fishing ground of Korea, 2009~2011. The catching efficiency of three type nets was analyzed by catch in number, catch in weight and average weight per individual of small and large size swimming crab by net types and mesh sizes. Statistical T-test was also carried out to verify the efficiency between the three types of nets. The results are as follows. The catch in number of swimming crab was 24,667 and formed about 81.0% of total catch. Of all swimming crab catch, small swimming crabs with less than 64mm in carapace length which is a prohibited landing size by law formed 48.1%, larger swimming crabs with more than 64mm in carapace length which is a landing size formed 51.9%. In 105mm mesh size trammel net test, the catch share in number of small size swimming crab by biodegradable trammel net was 47.5% in comparison with multifilament trammel net and 74.2% in comparison with monofilament trammel net, so biodegradable trammel net has more protective effects on small size swimming crab than other types of trammel nets. The protective effects for small size swimming crab by biodegradable trammel net was 25.8~52.5% in comparison with other types of trammel nets. The catch share in weight of large size swimming crab by biodegradable trammel net was 98.3% in comparison with multifilament trammel net and 92.3% in comparison with monofilament trammel net, so biodegradable trammel net has a similar catch efficiency to multifilament trammel net. The results of 160mm mesh size trammel net test have shown similar results of 105mm mesh size trammel net test. This study shows that biodegradable trammel net is a more useful fishing gear than multifilament and monofilament trammel net because biodegradable trammel net has lower catch rate than other types of nets in small size swimming crab and similar catch rate than multifilament trammel net which is a well used net by fishermen.
Operating Performance of hair-tail angling vessel using the LED and metal halide fishing lamp combination
An, Heui-Chun ; Bae, Bong-Seong ; Lee, Kyoung-Hoon ; Park, Seong-Wook ; Bae, Jae-Hyun ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 337~345
DOI : 10.3796/KSFT.2012.48.4.337
One of representative Korean fisheries, jigging and angling has 5,700 vessels for squid and hairtail. Hairtail angling is the most typical fishery in Jeju and has an enormous impact on regional economy. However, the price hike in oil and labor costs triggered the necessity of developing a high efficient and energy saving fish luring lamp in recent times. For that reason, this study aimed to analyze the fishing performance of the aircooled LED lamp targeting hairtail angling fishery. The experiment was conducted from September through October in 2009-2011 for a 9.77 ton of fishing vessel setting up 100 lamps. The fishing performance was tested compared with 6 vessels using metal halide lamps in the same waters. As the LED lamp`s performance goes up, different lamps were used in 2008 for 80W, 2009 for 120W and 2011 for 180W respectively. The catch and CPUE of the experimental vessel have gradually increased respectively taking the
place in 2009, the
place in 2010, the
place in 2011 among the 7 vessels. In summary, the LED fishing lamp showed higher fishing performance than comparison groups. It saved 33% of oil consumption and cut down on operating expenses and greenhouse gases emission.
Estimating the economic effectiveness of LED fishing light systems for the squid jigging fishery
Seo, Ju-Nam ; An, Heui-Chun ; Kim, Do-Hoon ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 346~351
DOI : 10.3796/KSFT.2012.48.4.346
The fuel cost of fishing lights for squid jigging fishing vessels takes about 30% of total fishing costs and over 65% of total fuel costs, which indicates the necessity of development of cost-reducing and high efficient fishing light system. This study aimed to analyze the economic effectiveness of LED fishing light systems in combination with metal halide lamp for the squid jigging fishery. Analytical results showed that the level of fishing profits of vessels using LED lights could be different with those of vessels using metal halide lights. That is, when a fuel cost could be reduced by 30%, fishing profits of vessels using LED lights might be the same as those of vessels using metal halide lights, and fishing profits of vessels using LED lights could be higher than those of vessels using metal halide lights when a fuel cost could be reduced by 50%.
Estimating the Economic Effectiveness of Increasing Mesh Sizes in the Small Yellow Croaker Gillnet fishery
Oh, Taeg-Yun ; Cho, Young-Bok ; Seo, Young-Il ; Kim, Byung-Yeob ; Lee, Ju-Hee ; Kim, Do-Hoon ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 352~359
DOI : 10.3796/KSFT.2012.48.4.352
For rebuilding and managing fish stocks and fisheries, the biological and socioeconomic evaluations on fisheries management regulations are important. This study aimed to estimate the economic effectiveness of different mesh sizes in the yellow croaker gillnet fishery. In particular, by comparing economic effects of mesh sizes, 50mm and 52mm, it aimed to provide the economic validity for increasing mesh sizes. Analytical results showed that the fishing revenue was higher in the vessels using a mesh size over 52mm than that in the vessels using a mesh size less than 50mm. In addition, the effect of fishing cost reduction was also larger in the vessels using a mesh size over 52mm than that in the vessels using a mesh size less than 50mm.
Economic analysis of development of low-carbon trawl gear
Park, Seong-Wook ; Lee, Kyoung-Hoon ; Kang, Min-Ju ; Park, Seong-Kwae ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 360~369
DOI : 10.3796/KSFT.2012.48.4.360
The main purpose of this study is to analyse economic feasibility of low-carbon-oriented trawl gear. The results of benefit/cost analysis showed that use of the low-carbon fishing gear is economically feasible. Considering the fuel saving and relatively low
emission by reducing the resistance of gear, net present value by such gear improvement was estimated about 2,430~2,853 million won with the benefit-cost ratio 1.65~1.84 and the internal rate of return 29.18~30.48 percent. Development of low-carbon trawl gear would render significant contributions to reducing
emission in fishing operations and lead to reduce fishing costs due to fuel savings.
Distribution characteristic of Octopus minor in the Tando Bay on the southwest coast of Korea
Oh, Taeg-Yun ; Kim, Joo-Il ; Seo, Young-Il ; Lee, Sun-Kil ; Choi, Mun-Seung ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 370~378
DOI : 10.3796/KSFT.2012.48.4.370
This study is to find out the distribution characteristic of Octopus minor in the Tando Bay on the southwest coast of Korea with conducting surveys from May of 2006 to April of 2007. Surveys were carried out at 20 stations on 2 and 3 tide time in the low speed of high tide at night and conducted during 30minutes (4 times fishing) per station. Catch per unit effort (CPUE) was estimated by total catch per 500hooks at each station. Monthly CPUE showed that they put highest in October, November, April and June at 10.4, 10.5, 9.4 and 7.7 individuals respectively. On the other hand, CPUE put lowest in January, the coldest month, and August, the hottest month, at 0.2 and 0.3 individuals respectively. As for geographical mantle length distribution, average mantle length ranged from 6.2cm to 7.3cm at stations near the tidal channels (St. 1, 4, 5, 6, 8, 9, 10, 13, 14, 15, 18, 19 and 20), and was smaller than 6.0cm at stations located inside of bay (St. 2, 3, 7, 11, 12 and 17). In terms of geographical distribution density, CPUE showed higher than 8.0 at St.4 in Changmaeri, St.8 in Taecheonri, St.13 near Seondo, St.18 in Naeri and St.14 in western part of Tando which are located near the main tidal channels. And distribution density showed low that CPUE was lower than 5.0 individuals at stations located inside of bay (St. 1, 3, 5, 6, 7, 11, 12, 16 and 20). Through the results, the difference of distribution density reflects that distribution of Octopus minor is affected by direction of current and inflow of pollutant from land in direct. Therefore, it is considered that bottom composition of tidal flat and distribution of live food are the crucial cause of identifying the distribution characteristics of Octopus minor. For this reason, it is judged to need additional research on it.
Feeding Habits of Sebastiscus marmoratus in the Coastal Waters of Jeju Island, Korea
Lee, Seung-Jong ; Kim, Byung-Yeob ; Cha, Hyung-Kee ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 379~386
DOI : 10.3796/KSFT.2012.48.4.379
The feeding habits of Sebastiscus marmoratus collected from the Western Coastal Waters of Jeju Island between June 2008 and July 2009 were studied based on examination of the stomach contents. A total 254 individuals of S. marmoratus ranged from 13.2 to 29.6cm (mean 20.7cm) in Standard length (SL). S. marmoratus consumed mainly teleosts such as Chromis notata and Sebastes inermis. Its diet also includes shrimps and crabs. The individuals smaller than 15cm SL consumed mainly shrimps, but on the other hand the individuals larger than 25cm SL consumed mainly fishes. The proportion of fish consumption increased with increasing size of S. marmoratus.
Species composition and seasonal variation of the aquatic organism caught by commercial fishing of the pot and gill net in the coastal waters off Taean, Korea
Jeong, Gyeong-Suk ; Im, Yang-Jae ; Cha, Byung-Yul ; Hwang, Hak-Jin ; Kwon, Dae-Hyeon ; Park, Jong-Soo ; Jo, Hyun-Su ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 387~400
DOI : 10.3796/KSFT.2012.48.4.387
Species composition and seasonal variation of aquatic organism in the coastal waters off Taean, Korea were investigated using catches by commercial fishing of the pot and gill net from April 2010 to January 2011. A total of 58 species, 10,602 individuals and 547,569g of aquatic organism were collected during the study. Aquatic organism were composed of 22 species of Pisces, 20 species of Crustacea, 8 species of Gastropoda, 3 species of Echinodea, 2 species of Cephalopoda and Bivalvia, and 1 species of Holothuroidea. 41 species in 9 orders and 22 families were collected by the pot, and 28 species in 15 orders and 22 families were collected by the gill net. Volutharpa ampullacea was the most dominant in the pot, while Okamejei kenojei was the most dominant in the gill net. These two species accounted for 73.9% in the number of individuals, and 64.4% in biomass. The number of species was high in spring in the pot, and autumn in the gill net. The number of individuals and biomass were highest in winter and summer respectively in the pot, and summer in the gill net. The number of species of the consignment quantity caught by commercial fishery of the pot and gill net in Mohang was 12 and 14 respectively. Cluster analysis based on species composition of the 18 most common species showed that the species were separated into 3 different group. Group A was composed of species which were abundant in spring, group B was composed of species which were abundant in summer and autumn, and group C was composed of year-round residents.
Migration and distribution changes of the Sandfish, Arctoscopus japonicus in the East Sea
Yang, Jae-Hyeong ; Lee, Sung-Il ; Park, Kie-Young ; Yoon, Sang-Chul ; Kim, Jong-Bin ; Chun, Young-Yull ; Kim, Sang-Woo ; Lee, Jae-Bong ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 401~414
DOI : 10.3796/KSFT.2012.48.4.401
Distribution pattern and fishing conditions of sandfish, Arctoscopus japonicus in the East Sae were explored using catch and catch per unit effort (CPUE) by eastern sea Danish seine and coastal gill net fisheries from 2004 to 2008. A. japonicus was one of major target species for the eastern sea Danish seine and coastal gill net fisheries in the East Sea, which were caught from April to October for the eastern Danish seine, and from October to December for the coastal gill net, respectively. In recent, the distribution and centroid of fishing ground moved northward, as seawater temperature increased. The species spawned in the coastal areas of Gangwon, northern East Sea, during winter, started to move to deeper water after spawning from spring, extended widely from Gangwon to Ulsan, southern East Sea, during summer, and migrated back to the spawning ground off Gangwon during autumn.
Seasonal variations in species composition of fish assemblage collected by trammel net in coastal waters of the East Sea
Choi, Kwang Ho ; Han, Moon Hee ; Kang, Chang-Keun ; Park, Joo Myun ; Choi, Jung Hwa ; Park, Jeong-Ho ; Sohn, Myong Ho ; Baeck, Gun Wook ; Choy, Eun Jung ; Lee, Chung Il ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 415~427
DOI : 10.3796/KSFT.2012.48.4.415
Seasonal variation in species composition and abundance of fish assemblage in the north coast (NC: Ayajin) and central coast (CC: Hupo) of the East Sea were calculated using samples collected by trammel net during 2011-2012. A total of 20 species from NC and 17 species from CC were collected. Of the fishes collected, the dominant fish species were Glyptocephalus stelleri and Careproctus rastrinus in the NC, and Dasycottus setiger and G. stelleri in the CC. These 2 fishes accounted for 71.7% and 81.0% of the total number of individuals collected in the NC and CC, respectively. The number of fish species, number of individuals, biomass and species diversity indices fluctuated with the seasons. The cluster analysis and non-metric multidimensional scaling (MDS) based on Bray-Curtis similarity revealed that the fish assemblages classified into north and central groups. Analysis of similarity percentages of species contributions (SIMPER) indicated that most individual of G. stelleri and Gadus macrocephalus contributed to north group, and D. setiger and G. stelleri in central group, whereas 15 species contributed to 90% of the dissimilarity.
Seasonal variation in species composition of catch by a coastal beam trawl in Jinhae Bay and Jinju Bay, Korea
Song, Mi-Young ; Kim, Joo Il ; Kim, Sung Tae ; Lee, Jong Hee ; Lee, Jae Bong ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 428~444
DOI : 10.3796/KSFT.2012.48.4.428
The species composition and seasonal variation of fisheries resources in Jinhae bay and Jinju bay, were studied using shrimp beam trawl through a year of 2010. During the study period, a total of 117 species were collected in Jinhae bay. Species included were 63 species in Pisces and 24 in Crustacea. And a total of 106 species were collected in Jinju bay. Species included were 57 species in Pisces and 31 in Crustacea. The dominant species were Zoarces gilli, Crangon hakodatei and Oratosquilla oratoria in Jinhae bay, and Crangon hakodatei, Leiognathus nuchalis and Charybdis bimaculata in Jinju bay. The samples were mainly grouped according to the location and season on the SOM. Group 1 with sample sites in Jinju bay, was characterized by high values of Parapenaeopsis tenella, Leiognathus nuchalis and Hexagrammos otakii. Group 2 with sample sites in April, were dominant Crangon hakodatei and Luidia quinaria. The samples in Group 3 were high values of Charybdis bimaculata and Pleuronichthys cornutus. Group 4 with sample sites in Jinhae bay, was characterized by high densities of Zoarces gilli and Pholis fangi. The dominant species, Crangon hakodatei, were catched egg-bearing females until June. Zoarces gilli and Leiognathus nuchalis were presented small size individuals during study period. It represented that study area is an important role in spawning and nursery ground for fisheries resources.
Forecasting biomass and recruits by age-structured spawner-recruit model incorporating environmental variables
Lee, Jae Bong ; Lee, Dong Woo ; Choi, Ilsu ; Zhang, Chang Ik ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 445~451
DOI : 10.3796/KSFT.2012.48.4.445
We developed an age-based spawner-recruit model incorporating environmental variables to forecast stock biomass and recruits of pelagic fish in this study. We applied the model to the Tsushima stock of jack mackerel, which is shared by Korea and Japan. The stock biomass of jack mackerel (Trachurus japonicus) around Korean waters ranged from 141 thousand metric tons (mt) and 728 thousand mt and recruits ranged from 27 thousand mt to 283 thousand mt. We hind-casted the stock biomass to evaluate the model performance and robustness for the period of 1987~2009. It was found that the model has been useful to forecast stock biomass and recruits for the period of the lifespan of fish species. The model is also capable of forecasting the long-term period, assuming a certain climatic regime.
Seasonal variations in species composition by the stow nets and the stow net on boat fisheries in the Han River Estuary, Korea
Oh, Taeg Yun ; Lee, Jae Bong ; Seo, Young Il ; Lee, Jong Hee ; Choi, Jung Hwa ; Kim, Jung Yun ; Lee, Dong Woo ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 452~468
DOI : 10.3796/KSFT.2012.48.4.452
Marine organisms were collected by the stow nets and the stow net on boat fisheries from April 2010 to November 2011 in the Han River Estuary and categorized as 126 species, 61 families, and 5 taxa. The species were consisted with 34 in Crustacea, 5 in Cephalopoda, 79 in Pisces, unidentified jellyfishes in Cnidaria, and Finless porpoise in Mammals. The major species were composed of fish and crustaceans in the Han River Estuary. The dominant species in Crustacea were Chinese ditch prawn (Palaemon gravieri), blue crab (Portunus trituberculatus), Ridgetail prawn (Exopalaemon carinicauda), and mantis crab (Oratosquilla oratoria), and those in Pisces were Korean anchovy (Coilia nasus), and Japanese grenadier anchovy (Coilia mystus). The length structures of the six dominant species have more than one mode in the Han River Estuary. It reflects that the species inhibit during a part of and/or whole lifetime in the Han River Estuary where they utilize as spawning and/or nursery grounds. Freshwater fishes were collected from station D where is the closest location to the Han River stream, and their appearances were well matched with the large amount of freshwater discharge due to flood periods. Principal components analysis (PCA) was carried out with species compositions and showed temporal and spatial differences by the variations of species.
A Study on System for measuring morphometric characteristis of fish using morphological image processing
Lee, Dong-Gil ; Yang, Yong-Su ; Kim, SeongHun ; Choi, Jung-Hwa ; Kang, Jun-Gu ; Kim, Hee-Je ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 469~478
DOI : 10.3796/KSFT.2012.48.4.469
To manage, sort, and grade fishery resources, it is necessary to measure their morphometric characteristics. This labor-intensive task involves performing repetitive operations on land and on a research vessel. To reduce the amount of labor required, a vision-based automatic measurement system (VAMS) for the measurement of morphometric characteristics of flatfish, such as total length (TL), body width (BW), and body height (BH), has been developed as part of a database management system for fishery resources management. This system can also measure the mass (M) of flatfish. In the present study, we describe a morphological image processing algorithm for the measurement of certain characteristics of flatfish. This algorithm, which involves preprocessing, edge pattern matching, and edge point detection, is effective in cases where the flatfish being measured has a deformed tail and is randomly oriented. The satisfactory performance of the proposed algorithm is also demonstrated by means of experiments involving the measurement of the BW, TL and BH of a flatfish when it is straightened (BW : 117mm, TL : 329mm, BH : 24.5mm), when its tail is deformed, and when it is randomly oriented.
Hearing Ability of Conger eel Conger myriaster caught in the Coast of jeju Island
Ahn, Jang-Young ; Park, Yong-Seok ; Choi, Chan-Moon ; Kim, Seok-Jong ; Lee, Chang-Heon ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 479~486
DOI : 10.3796/KSFT.2012.48.4.479
In order to obtain the fundamental data about the behavior of conger by underwater audible sound, this experiment was carried out to investigate the hearing ability of Conger eel Conger myriaster which was in the coast of Jeju Island by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of conger eel extended from 50Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity over 200Hz. The mean auditory thresholds of conger eel at the frequencies of 50Hz, 80Hz, 100Hz, 200Hz and 300Hz were 105dB, 92dB, 96dB, 128dB and 140dB, respectively. The positive response of conger eel was not evident after the sound projection of over 200Hz. At the results, the sensitive frequency range of conger eel is narrow in spite of swim bladder. Auditory masking was determined for Conger eel by using masking stimuli with the spectrum level range of about 60~70dB (0dB re
). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise including critical ratio at 68dB of white noise from minimum 26dB to maximum 30dB at test frequencies of 80Hz and 100Hz. The noise spectrum level at the start of masking was distributed at the range of about 68dB within 80~100Hz.
Verification and application of Target Strength for Japanese anchovy (Engraulis japonicas) by theoretical acoustic scattering model
Hwang, Kangseok ; Lee, Kyounghoon ; Hwang, Bo-Kyu ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 487~494
DOI : 10.3796/KSFT.2012.48.4.487
Acoustical backscattering characteristics of Japanese anchovy can be estimated by Kirchhoffray mode model (KRM model) due to estimate exact body and swim-bladder shape of the fish, the samples were rapidly frozen by dry-ice and alcohol. X-ray photos for ventral and lateral direction for 6 samples were taken and the 3D coordinates of the body swim-bladder were estimated by digitizing from the photos. The angles between the axis of body and swim-bladder were about
at 38kHz and
at 120kHz, 200kHz. General formula of TS and BL estimated were <
Acoustic method for discriminating plankton from fish in Lake Dom Helvecio of Brazil using a time varied threshold
Kang, Myounghee ;
Journal of the Korean society of Fisheries Technology , volume 48, issue 4, 2012, Pages 495~503
DOI : 10.3796/KSFT.2012.48.4.495
An acoustic method for discriminating plankton from fish, in Lake Dom Helvecio of Brazil, is developed. The flow of data from this method is comprised of time varied threshold (TVT), dilation filter, bitmap and mask functions. The TVT can, of itself, precisely explain how to select an appropriate value. The final results of the echogram, which only shows plankton by masking fish signals, is used to examine the acoustic density of plankton by depth and time. The results indicate that the acoustic density of the plankton is at a depth of between 5m to 15m, its density is especially high at 10m to 15m. The results of the acoustic density of plankton by time indicate that May 7 is higher in density than May 8. Future study plans include the use of net samples, environmental datasets to identify the abundance and ecology described by the Chaoborus spp. from other species.