• 한국수산과학회지
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• 제55권2호
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• pp.154-170
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• 2022

The zooplankton composition, abundance, community structure, and species diversity in the major commercial fishery species spawning grounds in the southern coast of Korea were investigated in this study. A total of 80 taxa were sampled, with the mean abundance range of 5,612-11,720 ind. m^-3 and the mean biomass range of 41.6-1,086.8 mg m^-3. The dominant species were Paracalanus copepodites, Paracalanus parvus s. l., Oithona copepodites, Paracalanus nauplii, Noctiluca scintillans, Oithona similis, and Ditrichocorycaeus affinis. The species diversity indices were highest in August, suggesting that diversity is influenced by neritic and oceanic warm-water species. A cluster analysis with non-metric multidimensional scaling (nMDS) revealed three groups of zooplankton communities. The April and May samples clustered into Group A, having the highest mean total zooplankton abundance and lowest species diversity, consisting mainly of temperate species located in the middle region of the southern coast of Korea. Cluster Group B was from the early summer season (June) and contained the highest species diversity with some oceanic and neritic zooplankton species. Cluster Group C from the summer season (July and August) mainly comprised P. parvus s. l. and O. similis. The redundancy analysis (RDA) indicated that abundance is positively correlated with salinity, and chlorophyll-a concentrations.

• 한국수산과학회지
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• 제55권1호
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• pp.61-66
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• 2022

Amphioctopus fangsiao is a crucial fishery stock located off Korea's western and southern coasts. In this study, we present data on the spawning period and estimated recreational catch of A. fangsiao in the coastal waters of Jeollanam-do, South Korea. The overall sex ratio was estimated to be 1:1.13 (female: male); in females and males, the gonadosomatic index ranged from 1.22 to 12.14 and 0.17 to 3.44, respectively. The breeding season lasted from December to May, with spawning peaks observed between March and May. Furthermore, the estimated total annual recreational catch of A. fangsiao was 185,085 kg, with November recording the highest recreational catch. A. fangsiao catch per unit effort (CPUE) ranged from 3 to 302.4 kg per vessel d^-1. Therefore, these findings underscore the need for additional monitoring, as any further assessment of A. fangsiao stock necessitates an understanding of recreational catch assessment and fishing efforts in Jeollanam- do's coastal waters.

• 한국수산과학회지
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• 제55권4호
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• pp.461-477
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• 2022

We investigated the community structure and performed detailed characterization of fish larvae assemblages collected from the southern coast of Korea in the spring and summer of 2021. The total abundance of fish larvae varied from 193.6 to 1,915.6 ind. 10 m^-3. The species were distributed across 10 orders with 23 families, and 41 taxa. The dominant taxa were Gobiidae spp., Engraulis japonicus, Nibea albiflora, Sebastiscus spp., Callionymus valenciennei, Pennahia argentata, Sebastes thompsoni, Parablennius yatabei, and Platycephalus indicus. Engraulis japonicus individuals were collected from April to August and their presence contributed greatly to the total abundance of fish larvae. The total number and abundance of species peaked in early summer and the Shannon-Weaver index was in the range 0.11-1.49. Redundancy analyses revealed that the major environmental factors affecting the fish larvae assemblage differed according to the dominant taxa. Water temperature, zooplankton density, and Paracalanus parvus s. l. density were the key factors affecting the spatial and temporal distribution of fish larvae in the southern coast of Korea in spring and summer.

• 한국수산과학회지
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• 제56권1호
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• pp.54-65
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• 2023

Effect of environmental factors on the seasonal variations of zooplankton communities was investigated in the semi-closed Yeoja Bay, Korea from February, April to August, and November 2021. Out of a total 49 species of zooplankton were collected with a predominant of neritic copepods (mainly Paracalanus orientalis, Acartia omorii, Acartia ohtsukai, Centropages abdominalis, Ditrichocorycaeus affinis, and Oithona sp.), accounting for 58.9% of the total abundance of zooplankton. The diversity indices indicated a relatively highest in July, suggesting that diversity is influenced by seasonal temperature, N. scintillans, and neritic copepods species. A cluster analysis with non-metric multidimensional scaling revealed four groups of zooplankton communities. The February sample clustered into Group A, having the lowest mean total abundance and species diversity of zooplankton, consisting mainly of N. scintillans located the whole region. Cluster Group B from the spring season (April to May) and contained the species diversity with some neritic copepods. Cluster Group C from the summer season (June to August) mainly comprised P. orientalis, A. ohtsukai, Oithona sp., and hydromedusae. Cluster Group D from the autumn season (November) mainly comprised P. orientalis, Temora discaudata. Redundancy analysis indicated that abundance is positively correlated with temperature, salinity, and pico chlorophyll-a concentrations. This study showed that planktonic larvae (such as branchyura larvae) and some copepods (including A. omorii, A. ohtsukai, C. sinicus, and C. abdominalis) were significantly vulnerable to zooplankton community of temperature, salinity, and pico chlorophyll-a concentrations.

• 수산해양기술연구
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• 제56권2호
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• pp.105-113
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• 2020

The fish influx and behavioral properties at a set-net off Goseong, South Korea were investigated using an imaging sonar. As a result, the average influx of fish was 33.9% at day time and 66.1% at night time, respectively, which indicated that a majority of fish entered into a playground in the set-net at night. The fish behavioral properties such as target (fish) length, range, orientation and major-axis angle were examined and compared among survey dates (4, 5, and 6 June 2019) using the statistical analysis tool (analysis of variance, ANOVA). The behavioral properties presented differently sometime of survey dates. This is preparatory study to support fish behavior properties in a set-net. It is expected that more elaborated behavioral information of fishes in the set-net is beneficial for designing and deploying a set-net fishing gear as well as general fish behavior research in the future.

• 한국수산과학회지
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• 제36권6호
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• pp.669-675
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• 2003

To increase fishery resources in coastal waters, juvenile fish and bivalves are artificially released every year in Korea. This study provides a methodology to estimate an optimal release quantity based on the carrying capacity of the receiving basins. Carrying capacity was defined by E.p. Odum's theory of ecosystem development as the upper limit of biomass, where total system respiration equals total primary production. The Ecopath trophic ecological model was used to determine carrying capacity in the surfzone ecosystem of Bangjukpo on the southern coast of Korea. Using a top-down control method, various biomasses of fish groups were given to the simulation, with primary production constant and no catch. The results showed that biomass of selected fish groups increased by two orders of magnitude, yielding a five-fold increase in overall consumer biomass. The resultant values are 10 times higher than those estimated in open seas. This can be explained by higher primary production in the Bangjukpo surfzone ecosystem. This method can be used for strategic releases and ecosystem management, particularly when based on an ecological background.

• Preventive Nutrition and Food Science
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• 제18권4호
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• pp.242-248
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• 2013

In recent years, manufacturers of animal-based foods with health claims have encountered difficulties in the labeling of their products because of a lack of regulation on defining the functionality of animal-based foods. Therefore, this study was conducted to establish the basic requirements for the development of a definition for functional animal-based foods by investigating consumer and industry awareness. Survey data were collected from 114 industry representatives and 1,100 consumers. The questions of the survey included items on production status and future production plans, functionality labeling, promotion plans, establishment of definition, the role of the government, consumer perception, and selection of products. The results show that both industry representatives and consumers believe that legislation and the provision of scientific evidence should be improved for the development of a functional animal-based foods market. The results obtained from this study will contribute to consumer trust by supplying correct information and can be utilized in the industry as basic data for the development of functional animal-based food products.

• 한국수산과학회지
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• 제44권4호
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• pp.390-396
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• 2011

Southern rough shrimp Trachysalambria curvirostris is exploited mainly by small shrimp beam trawl in coastal regions of Korea. To determine the size selectivity of a shrimp beam trawl for this species, a series of comparative fishing experiments was conducted in the sea adjacent to Geoje Island off the southern cost of Korea in June and November, 2010, using codends with four different mesh sizes(14.2, 17.8, 25.5, and 35.3 mm). The extended Share Each Length's Catch Total(SELECT) analysis method, based on a multinomial distribution, was applied to the fishing data to obtain a master selection curve. The model with the estimated split parameters fit the catch data best. The master selection curve was estimated to be: s(R)=exp(15.183R-7.872)/[1+exp(15.183R-7.872)], where the relative carapace length, R, is the ratio of carapace length to mesh size. The relative carapace length for 50% retention was 0.518, and the selection range was 0.145. The results suggest that codends with a larger mesh size allow more small-sized shrimps to escape.

• 수산해양기술연구
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• 제42권3호
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• pp.127-133
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• 2006

An estimation of the headline height of a bottom trammel net set across under uniform current was achieved numerically from a differential equations describing the forces of the net and compared with the measured value in a flume tank experiment. The analysis on the shape of the bottom trammel net with the headline free was based on the equilibrium equation of the bottom gill net which was modified and slack of the trammel net was varied with net depth as shown in the tank experiment. The differential equations were solved by a forth-order Runge-Kutta method. The estimated headline heights with varied slack was found to be closer than that with constant slack when compared with the actual values.

• 수산경영론집
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• 제26권1호
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• pp.41-54
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• 1995

Recently our government intended to change the present fisheries management system into the allocated catch quota system, which is to increase the income of fishermen and to recover the depleted resources up to a desirable level. This paper is to find out the difficulties of introducing the allocated catch quota system into our fisheries mangement system and to reduce the possible errors for the enforcement of this system. The allocated catch quota system can be devided by two kinds, the one is to allocate among industries or fisheries with total allowable catch(TAC) and the other is to allocate among fishermen or individual vessels with individual fish quota(ITQ). The latter is a much advanced control system compared with the former and is what this study treats. This paper reviewed the case of Newzealand and Canada where the ITQ system is introduced earlier and classified the problems by two parts for successful introduction into Korea as follows : (1) allocation method problems, (2) enforcement problems. For the first part the problems to be considered are 1) a scientific oath qouta calculation system is necessary, 2) the quota must be opened, 3) by-catch problems. 4) interactions with adjoining countries. For the second part the problems to be considered are 1) monitoring system, 2) quota transferability, 3) quota flexibility, 4) the enforcement of the system must be connected with the reduction of fishing power, 5) a mass communication and decision making system between government and fishermen is essential.