• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.351-360
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• 2014

The experiments were carried out to decide the selective fishing gear of the shrimp beam trawl fishery. The model nets were made of General type, Double-level type and Grid type. The model experiments were carried out to test opening efficiency and towing tension. The experimental tanks were the flume tank [$8.0L{\times}2.8W{\times}1.4H(m)$] and the towing tank [$85L{\times}10W{\times}3.5H(m)$] in National Fisheries Research and Development Institute. The full scale experiments were carried out to compare the selectivity of General type net, Double-level type net and Grid type net in the southern sea of korea. The vertical opening (net height) of the model nets can be expressed as a function of the towing velocity as the straight line. The towing tension of the model nets can be expressed as a function of the towing velocity as the parabola. The shrimp catching rates of upper cod end in Boryeong and tongyeong were 78%, 9% respectively, but the rates of lower cod end were 23%, 91% respectively. The number bycatch rates of General type and Grid type were 23%, 11% respectively, and the weight bycatch rates were 34%, 31% respectively. A selective shrimp beam trawl net is Grid type in korea coastal sea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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• pp.223-233
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• 2009

It has been considered that fishing areas for shrimp beam trawl have been in ruin because Korean local governments have permitted trawling into the areas limited by the fisheries local regulations from 1994. Physical and biological effects of the trawling were investigated in the study. Physical effects were investigated by optical methods such as trawling tracking by side scan sonar and comparing the gear both before and after trawling. Biological aspects were investigated by grab sampling of benthic animals, concentration of trace metals in sediment and a flux evaluation of ${NH_4}^+,\;{PO_4}^-,\;and\;SiO_2$ by coring. The fishing activity had physical impacts on the seabed but these recovered naturally in less than fourty days naturally, which increased the benthic biodiversity, increases the trace metal concentration of and nutrient flux into the seawater, especially phosphate and silicate. This method and these results can help in further studies looking for disturbances by fishing.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.1
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• pp.211-220
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• 2016

Species composition of aquatic organism in the marine ranching area of Gunsan, Korea were investigated using shrimp beam trawl from May to December in 2010. A total of 91 species, $98,127ind./km^2$ and $877.6kg/km^2$ of aquatic organism were collected. Among them, species were included 60 species in Pisces, 21 in Crustacea and 10 in Mollusca. The individual dominant species, occupying over 10% of total individuals, were Latreutes anoplonyx($47,327ind/km^2$, 48.23%), Crangon hakodatei($11,578ind./km^2$, 11.80%) and Trachysalambria curvirostris($10,237ind./km^2$, 10.40%). And the biomass dominant species, occupying over 9% of total biomass, were Paralichthys olivaceus($135kg/km^2$, 15.4%), Okamejei kenojei($98.2kg/km^2$, 11.2%) and Portunus tribuberculatus($84.8kg/km^2$, 9.6%). From the cluster and MDS analysis based on Bray-Curtis similarity matrix of fourth root transformed data of number of species and individuals per unit area collected more than two times during this survey by each month and station was divided into three different groups. Group A showed seasonal similarity of characteristic of distribution in August and November, Group B in December and Group C in May.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.2
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• pp.105-120
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• 2019

The species composition and abundance variations of fishery resources in the adjacent marine ranching area, Tongyeong, Korea, were investigated by shrimp trawl, gill net, and longline during the period of July, September, and October in 2016. During the study period, the total catch were 8,522.9 kg with 34 species from the shrimp trawl, 32 species from the gill net, and nine species from the longline. The dominant species were different by gear, which were Hypodytes rubripinnis and Parapercis sexfasciata in the shrimp trawl, Platycephalus indicus and Raja kenojei in the gill net, and Conger myriaster and Scomber Japonicus in the longline. In terms of spatial distribution, Yongchodo showed the highest total catch in number as well as of in weight while Jukdo showed the lowest total catch in number and Bijindo showed the lowest total catch in weight. The amount of demersal fish resources in the survey area estimated as 301 ha, was 99,396 individuals which was converted to be 8,552.9 kg. The amount of demersal fish resources by gear were of trawling area, which area is 127 ha, were 76,251 and 3,489.5 kg, 74 ha in the gill net and longline survey area was 16,213 and 3,457.3 kg, and the other 100 ha area was 6,932 and 1,606.1 kg. In this study, the minimum resources for demersal fish is 61,687 and 4,265.2 kg, and the maximum is 149,439 and 14,197.9 kg.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.63-76
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• 2003

Species composition and seasonal variations of shrimp caught in the adjacent waters Geomundo, Korea were studied using the monthly catch of beam trawl fishery from November 1998 to October 1999. During in the study period, a total of 700,765 shrimps consisting 36 species, 27 genus and 11 families were collected. The community was dominated by Palaemon gravieri, Parapenaeopsis tenellus, Solenocela melantho and Plesionika izumiae. The peak abundance of shrimp occurred in summer, and low abundance in winter and spring. Major species occurred in area A, B and C was P. gravieri, and P. tenellus, and P. izumiae and S. melantho, respectively. The number of individual and abundance showed in July, and low in November. It was noted that values of species diversity, dominance and evenness indices were high in adjacent water Geomundo and lower in adjacent water Chodo and Chodo-Sonjukdo. Analysis of dendrogram of the clustering showed that there were two distinct groups; Geomundo group and Chodo-Sonjukdo group.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.1
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• pp.53-57
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• 2007

We examined seasonal variation In the abundance and species composition of shrimp communities in Doam Bay and around Naro-do, Korea. Samples were collected monthly from March 2001 to February 2002 (Doam Bay) and from December 2000 to November 2001 (Naro-do) usinga beam trawl. A total of 19 shrimp species representing eight families were collected from Doam Bay. The dominant species were Exopalaemon carinicauda, Trachysalambria curvirostris, Parapenaeopsis tenella and Crangon hakodatei, which accounted for 92.6% of individuals and 92.8% of biomass. In the Naro-do area, a total of 18 shrimp species representing eight families were collected. The dominant species were C. hakodatei and P. tenella, which accounted for 78.6% of individuals. Exopalaemon carinicauda, T. curvirostris, P. tenella, C. hakodatei and Metapenaeus joyneri accounted for 89.6% of biomass. In each season, the pattern of species appearances differed in the two areas.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.455-466
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• 2014

Seasonal variations in species composition of catches were explored using seasonal samples caught by shrimp beam trawl in the Geum river estuary in 2011. During the study period, total catches were collected 91 species as fish 47 species, crustacean 28 species, mollusca 4 species, gastropoda 5 species, shellfish 3 species and others 4 species. The dominant species were Exopalaemon carinicauda, Eriocheir leptognathus, Palaemon gravieri, Mugil cephalus, Acanthogobius hasta, Cynoglossus joyneri, Pennahia argentata and Coilia nasus. The amount of species in spring and summer was higher than in autumn. The diversity index (H') was 0.43~0.96, evenness index (EI) was 0.14~0.25, and richness index (RI) was 1.54~4.25. Using cluster analysis 91 species were divided into 4 groups. Group I appeared mainly in spring and summer. Group II appeared only in summer. Group III appeared in winter and spring, and Group IV in spring and autumn.

• Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.325-332
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• 2015

An active stimulating method for juvenile fishes to drive escaping from mesh of the codend was examined by shaking canvas in the bottom trawl followed by shrimp beam trawl. Field fishing trials by a bottom trawl were carried out between the Geomoondo and Jejudo in west of South sea, Korea by conver-net methods to examine the effect on the reduction of juvenile fish as a discard catch by generating a shaking movement of the codend using two pieces of asymmetrical semi-circular canvas. The mean period of the shaking motion with the round canvas was 10-15 s, and the range of amplitude as a vertical depth change was up to 0.4-0.6 m when towing speed 3.4-4.3 k't as estimated by peak event analysis. The escape rate of juvenile fish in conver-net by total juvenile bycatch (codend and cover-net) in 14 trials increased from 20% in a steady codend to 34% using a shaking codend in the bottom trawl, while the marketing catch or total bycatch was similar between steady and shaking cod ends. There was no difference in the body size of the fish and species composition between the steady and shaking cod ends. Above results demonstrate a new method for bycatch reduction actually up to 18% using an active stimulating device, although further experiments are needed to increase an effective shaking motion of the codend in amplitude and period for more bycatch reduction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.375-386
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• 2015

The study aims at a selective effect of the Grid and Window net in the shrimp beam trawl. The experimental trawling of the Proto type, Grid type and Grid and Window net type was performed in a sea area of Geo-je and Tong-yeong from Mar, 2006 to Apr, 2010. The obtained results are as follows; Catch per unit area (Number) of the Proto type net and Grid type net were $0.18/m^2$, $0.23/m^2$, respectively. The Grid type demonstrated 2.4% lower bycatch rate than the proto type (6.6% vs 4.2%, respectively). In addition, in terms of total weight, the bycatch rate of Grid type was 7.6% lower than the proto type (50.2% vs 42.6%, respectively). In the comparison of shrimp catch, the Proto type demonstrated better haul outcome ($0.02case/m^2$) than the Grid & Window type ($0.02case/m^2$). The Grid & Window net type demonstrated 16.4% lower bycatch rate than the Proto type (32.2% vs 48.6%, respectively). In addition, in terms of total weight, the bycatch rate of Grid & Window net type was 8.3% lower than the Proto type (85.9% vs 94.2% respectively).

• Journal of Aquaculture
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• v.17 no.1
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• pp.51-57
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• 2004

Species composition and seasonal change were examined monthly with shrimp assemblage caught in the coastal waters of Solido, Korea. Samplings were conducted in Solido using a beam trawl from June 2000 to May 2001. In the study period, a total of 16 species of shrimp belonging to six families were collected. Species was dominated by Palaemon gravieri, Crangon hakodatei, Trachysalambria curvirostris and Metapenaeus joyneri. Higher abundance of shrimp occurred in September and November, and lower abundance in June. Species diversity was reached its maximum (0.82) in November and its minimum (0.06) in January. Shrimp species in the study area can be grouped into three groups on the basis of their occurrence patterns: resident, seasonal and temporary species.