• Journal of Life Science
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• v.25 no.11
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• pp.1204-1213
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• 2015

A comprehensive analysis of the population structure of the sandfish (Arctoscopus japonicas), the most abundant fishery resource in the East Sea of Korea, has not been carried out, despite its importance in Korea. The present study examined the genetic diversity and differences between five populations (two Japanese and three Korean populations) of A. japonicas captured in the East Sea using both the 401 bp sequence of mitochondrial DNA (mtDNA, cytochrome b) and five microsatellite DNA (msDNA) markers. The results of the analysis using the Cyt b sequence revealed 27 haplotypes. Based on msDNA variations, the estimated expected heterozygosity (H_E) in each population ranged from 0.68 (Gampo, Korea) to 0.7765 (Erimo, Japan). Pairwise F_ST and AMOVA tests using both the Cyt b sequence and msDNA data pointed to significant differences between the Korean and Japanese populations (mtDNA; F_ST=0.2648, p<0.05, msDNA; F_ST=0.0814, p<0.05). These results were similar to the results of UPGMA, PCA, and structure analysis. In these analyses, the five populations were assigned to two groups (Korean populations and Japanese populations). These results shed light on the genetic diversity and relationships of A. japonicas and contribute to research on the evaluation, conservation, and utilization of Korean A. japonicas as genetic resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.3
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• pp.331-340
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• 2023

To estimate the biological reference points, suitable for fisheries management of sandfish Arctoscopus japonicas in the East Sea of Korea, we simulated the yield-per-recruit (Y/R) from age 0 to 6 (0-2,555 days). The stimulation was based on two instantaneous natural mortality conditions: size-dependent (M_t, d^-1) and constant (M_cons, d^-1); Subsequently, the biological reference points of the two mortality conditions was compared. M_t decreased from 0.0075 d^-1 to 0.0018 d^-1 depending on growth, and M_cons remained constant at 0.0011 d^-1 for all ages. Our Y/R model showed that the maximum yield of M_cons was 14 times higher than that of the M_t. The length at first capture to maximize the harvest at the F_0.1 points of the two natural mortality conditions was L_c,t=10.2 cm (TL) and L_c,cons=17 cm (TL). We concluded that M_t was more suitable for estimating M than M_cons; this is because L_c,t showed minimal difference from the current fishing regulations (11 cm, TL), and M_t reflected more biological characteristics than M_cons. We suggest that 10.2 cm and 0.8 as the suitable length at first capture and corresponding age, respectively for efficient fisheries management of sandfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.529-541
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• 2015

We examined the species composition and community structure of demersal fish in the middle and southern coastal waters of the East Sea of Korea by surveying a commercial Danish seine fishery from 2010 to 2013. We considered the waters north of $37^{\circ}N$ as middle and those south of $37^{\circ}N$ as southern waters. A total of 79 demersal fish species belonging to 18 families were collected. Of these, 59 species (77.6%) inhabited only the East Sea as opposed to the West and South Seas of Korea, and most were resident species. The species and biomass were similar between the two portions of the study area. The sandfish Arctoscopus japonicus (78.0%) and the blackfin flounder Glyptocephalus stelleri (65.1%) were the most common species and accounted for the most biomass in the middle and southern waters, respectively. Fish were most abundant at shallow depths (50-100 m) in the middle portion of the East Sea. Using a cluster analysis, we divided the species composition and community structure at the sampling stations into three groups: middle portion (group A), deep area of the southern portion (group B), and shallow areas of the southern portion (group C). A. japonicas and G. stelleri were dominant in groups A and B, while G. stelleri and Clupea pallasii were dominant in group C.