Variations in Species Composition, Biomass, and Density in Shrimp Trawl Bycatch Across Seasons and Tidal Phases in Southern Korean Waters: Developing a Fisheries Risk Management Approach

Oh, Chul-Woong,Kim, Sung-Tae,Na, Jong-Hun The Korean Society of Fisheries and Aquatic Scienc 2009 Fisheries and Aquatic Sciences Vol.12 No.2

We quantitatively investigated compositions of fish and invertebrate bycatch in Korean shrimp fisheries. We sampled shrimp trawl bycatch from 48 commercial trawls over 1 year. These samples contained 108 taxa from 50 families, with 60 fish taxa contributing 51.2% of the total biomass and 48 invertebrate taxa 48.8%. However, 86.32% of the total individual organism density comprised invertebrates, while individual fishes made up the remainder. Within the bycatch, two fish species varied in population size structure by season, suggesting recruitment is seasonal in these taxa. Overall general catch characteristics (total bycatch biomass and organism density) varied significantly by season and tide, and a significant interaction effect was observed (season$\times$tide) on total density, but not on total biomass. The data collected will be used in designing a program of long-term bycatch monitoring.

Target Strength Measurements of Live Golden Cuttlefish Sepia esculenta at 70 and 120 kHz

Lee, Dae-Jae,Demer, David A. The Korean Society of Fisheries and Aquatic Scienc 2014 Fisheries and Aquatic Sciences Vol.17 No.3

Cuttlefish Sepia esculenta are commercially important in Korea. Assessments of their biomass currently depend on fishery-landings data, which may be biased. Towards fishery-independent acoustic surveys of cuttlefish, target strength (TS) measurements at 70 and 120 kHz were made of 23 live cuttlefish, in early May 2010. The fish were caught by traps in the inshore waters around Geojedo, Korea. The TS were measured using split-beam echosounders (Simrad ES60 and EY500, respectively). The cuttlefish mantle lengths (L) ranged from 15.6 to 23.5 cm (mean L=17.8 cm) and their masses (W) ranged from 335 to 1020 g (mean W=556.1 g). Their mean TS values at 70 and 120 kHz were -33.01 dB (std=1.39 dB) and -31.76 dB (std=2.15 dB), respectively. The mean TS at 70 kHz was 0.17 dB higher than the TS-length relationship resulting from a least-squares fit to the data ($TS=24.67{\log}_{10}L(cm)-64.03$, $r^2$ = 0.52, N=23). The mean TS at 120 kHz was 0.45 dB higher than the fitted TS-length relationship ($TS=40.59{\log}_{10}L(cm)-82.96$, $r^2$ = 0.58, N=23). The differences between the mean TS values and an equation regressed from all of the TS measurements at both frequencies ($TS=24.92{\log}_{10}L(cm)-4.92{\log}_{10}{\lambda}(m)-22.82$, $r^2$ = 0.86, N=46) was 0.22 dB at 70 kHz and 0.31 dB at 120 kHz, respectively.

An assessment of post-harvest fish losses and preservation practices in Siavonga district, Southern Zambia

Maulu, Sahya,Hasimuna, Oliver J.,Monde, Concilia,Mweemba, Malawo The Korean Society of Fisheries and Aquatic Scienc 2020 Fisheries and Aquatic Sciences Vol.23 No.9

Fish is an extremely perishable food product which requires proper handling soon after harvest. The present study was aimed at assessing post-harvest fish losses and preservation practices in Siavonga district, Southern Zambia. Structured and semi-structured questionnaires were used to collect data on post-harvest fish losses and preservation practices from aquaculture producers, artisanal, and commercial fishers. All the fishers who landed on the lakeshore were interviewed, while aquaculture producers were randomly selected based on the information provided by the local department of fisheries. The results of the study revealed that all the fishers experienced post-harvest fish losses at varying degrees with those losing up to 10% of the total catch being in the majority. In contrast, aquaculture producers did not report any post-harvest fish losses. Most aquaculture producers commonly used chilling as preservation practice contrary to artisanal and commercial fishers who commonly used smoking and sun sun-drying respectively. Furthermore, fish product safety and quality control were poorly practiced in the district. Lack of cold storage facilities and fluctuating weather conditions were the major challenges impacting fish post-harvest activities. Therefore, to curb the loss of revenue due to post-harvest fish losses, we propose the introduction of new technology, self-development skills for fishing communities, and enhanced access to refrigeration facilities.

Asian Aquaculture Journals: Problems and Possibilities

Pandian, T.-J. The Korean Society of Fisheries and Aquatic Scienc 2001 韓國養殖學會誌 Vol.14 No.1

Global status of aquaculture and aquaculture scientific journals is briefly described. Asia is the centre of fishing and aquaculture activities but most publishers, editors and editorial board members of fisheries and aquaculture journals are from Europe and/or USA. The contribution by Asian fisheries/aquaculture scientists to these journals remains low. Language barrier and requirement for monitory investment seem to inhibit Asian participation in this realm of scientific activity. The need for glob-alization of aquaculture scientific journals is emphasized. Selected strategies, which are adopted by the Western journals to improve their image and management, are indicated.

Genetic Analysis of Asian Chum Salmon Populations Based on Microsatellite DNA Variation

Yoon, Moon-Geun,Abe, Syuiti,Jin, Deuk-Hee The Korean Society of Fisheries and Aquatic Scienc 2007 Fisheries and Aquatic Sciences Vol.10 No.4

We examined the genetic variability of Asian chum salmon (Oncorhynchus keta) populations using nuclear microsatellite (ms) DNA analysis with four polymorphic loci (OKM4, OKM5, OKM7, and OKM8) in 397 individuals from nine populations, including one in Korea, seven in Japan, and one in Russia. The msDNA gene diversity was highest in the Japanese populations, suggesting greater genetic variation in the populations in Japan than in populations in Korea and Russia. The pairwise $F_{ST}$ estimates based on our msDNA data showed that the Korean population was genetically different from the Japanese and Russian populations, and there were higher $F_{ST}$ estimates between Hokkaido and Honshu populations than between other population pairs. A neighbor-joining tree showed that the Korean population was distinct from two other clusters, representing the populations in Honshu and the populations in Hokkaido and Russia. These results suggest that the observed population genetic patterns of Asian chum salmon might be influenced by low or restricted gene flow.

Temperature-dependent Index of Mitotic Interval (τ₀) for Chromosome Manipulation in Korean Rose Bitterling Rhodeus uyekii

Kim, Bong-Seok,Lim, Sang-Gu,Gil, Hyun-Woo,Park, In-Seok The Korean Society of Fisheries and Aquatic Scienc 2011 Fisheries and Aquatic Sciences Vol.14 No.4

Eggs of Korean rose bitterling Rhodeus uyekii were collected and fertilized to observe temperature-related cleavage rates and mitotic intervals (${\tau}_0$). As the water temperature was increased, the slope of first cleavage frequency with elapsed time after fertilization increased, and approximately 30% of fertilized eggs reached first cleavage frequency at every 15 min. At higher temperatures, eggs developed faster and underwent further identical developmental processes. There were strong, negative correlations between ${\tau}_0$ and water temperatures at all temperatures studied (Y = -1.225X + 70.05, $r^2=0.988$, where Y is ${\tau}_0$ and X is temperature).

Semiautomated Analysis of Data from an Imaging Sonar for Fish Counting, Sizing, and Tracking in a Post-Processing Application

Kang, Myoung-Hee The Korean Society of Fisheries and Aquatic Scienc 2011 Fisheries and Aquatic Sciences Vol.14 No.3

Dual frequency identification sonar (DIDSON) is an imaging sonar that has been used for numerous fisheries investigations in a diverse range of freshwater and marine environments. The main purpose of DIDSON is fish counting, fish sizing, and fish behavioral studies. DIDSON records video-quality data, so processing power for handling the vast amount of data with high speed is a priority. Therefore, a semiautomated analysis of DIDSON data for fish counting, sizing, and fish behavior in Echoview (fisheries acoustic data analysis software) was accomplished using testing data collected on the Rakaia River, New Zealand. Using this data, the methods and algorithms for background noise subtraction, image smoothing, target (fish) detection, and conversion to single targets were precisely illustrated. Verification by visualization identified the resulting targets. As a result, not only fish counts but also fish sizing information such as length, thickness, perimeter, compactness, and orientation were obtained. The alpha-beta fish tracking algorithm was employed to extract the speed, change in depth, and the distributed depth relating to fish behavior. Tail-beat pattern was depicted using the maximum intensity of all beams. This methodology can be used as a template and applied to data from BlueView two-dimensional imaging sonar.

Galatheoid squat lobsters (Crustacea: Decapoda: Anomura) from Korean waters

Kim, Jung Nyun,Kim, Mi Hyang,Choi, Jung Hwa,Im, Yang Jae The Korean Society of Fisheries and Aquatic Scienc 2016 Fisheries and Aquatic Sciences Vol.19 No.8

Ten species of Galatheoidea (squat lobsters), belonging to two families, were collected in the Korean exclusive economic zone: Galathea balssi Miyake and Baba, 1964, Galathea orientalis Stimpson, 1858, Galathea pubescens Stimpson, 1858, and Galathea rubromaculata Miyake and Baba, 1967 belonging to Galatheidae; Bathymunida brevirostris Yokoya, 1933, Cervimunida princeps Benedict, 1902, Munida caesura Macpherson and Baba, 1993, Munida japonica Stimpson, 1858, Munida pherusa Macpherson and Baba, 1993, and Paramunida scabra (Henderson, 1885) belonging to Munididae. The present study comprises the morphological description of these ten species, including drawings and color photographs, a brief review of their regional records, and a key for their identification. Although all species are common in Japanese waters, G. balssi, G. rubromaculata, B. brevirostris, C. princeps, M. caesura, and M. pherusa are new to Korean marine fauna.

Nutrients and bioactive potentials of edible green and red seaweed in Korea

Sanjeewa, K.K. Asanka,Lee, WonWoo,Jeon, You-Jin The Korean Society of Fisheries and Aquatic Scienc 2018 Fisheries and Aquatic Sciences Vol.21 No.7

Background: Traditionally, East-Asians (Korea, Japan, and China) utilize seaweeds as a food source and ingredient in traditional medicine. Korea is one of the biggest seaweed producer and consumer in the global trade. Especially, side dishes made from seaweeds are very popular in the traditional Korean cuisines. Seaweeds are popular as fresh vegetable salads and soup or eaten as snacks. Main body: Seaweeds are rich in essential nutrients, minerals, and vitamins as well as a promising source of novel bioactive compounds. The compounds (polysaccharides, polyphenols, and sterols) present in the edible Korean seaweeds possess important bioactive properties such as antioxidant, anti-inflammation, anticancer, anti-diabetic, and anticoagulant properties. Thus, the long-term consumption of seaweed has a potential to reduce the risk of cancer, diabetes, obesity, and inflammation-related complications. However, seaweed consumption is limited to the small population around the globe. Thus, it is important to increase the awareness of the health benefits of seaweeds consumption among the general population. Short conclusion: In the present study, we discussed some popular green and red edible Korean seaweeds and their health-promoting properties. This study might be useful to increase the public awareness of the consumption of seaweed as a food source.

The systematic sampling for inferring the survey indices of Korean groundfish stocks

Hyun, Saang-Yoon,Seo, Young IL The Korean Society of Fisheries and Aquatic Scienc 2018 Fisheries and Aquatic Sciences Vol.21 No.8

The Korean bottom trawl survey has been deployed on a regular basis for about the last decade as part of groundfish stock assessments. The regularity indicates that they sample groundfish once per grid cell whose sides are half of one latitude and that of one longitude, respectively, and whose inside is furthermore divided into nine nested grids. Unless they have a special reason (e.g., running into a rocky bottom), their sample location is at the center grid of the nine nested grids. Given data collected by the survey, we intended to show how to appropriately estimate not only the survey index of a fish stock but also its uncertainty. For the regularity reason, we applied the systematic sampling theory for the above purposes and compared its results with a reference, which was based on the simple random sampling. When using the survey data about 11 fish stocks, collected by the spring and fall surveys in 2014, the survey indices of those stocks estimated under the systematic sampling were overall more precise than those under the simple random sampling. In estimates of the survey indices in number, the standard errors of those estimates under the systematic sampling were reduced from those under the simple random sampling by 0.23~27.44%, while in estimates of the survey indices in weight, they decreased by 0.04~31.97%. In bias of the estimates, the systematic sampling was the same as the simple random sampling. Our paper is first in formally showing how to apply the systematic sampling theory to the actual data collected by the Korean bottom trawl surveys.