• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.171-182
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• 2022

The habitat degradation caused by large-scale reclamation leads to devastating impacts, such as fine sediment and mud shrimp Upogebia major settlement on Manila clam Ruditapes philippinarum aquaculture in the eastern Cheonsu Bay tidal flats, Republic of Korea. Despite these impacts, there is a lack of studies on the influence of fine sediments on tidal flats that constitute key mud shrimp habitats. This study provides information on the seawater-sediment environment and the influence of dissolved inorganic nitrogen (DIN) fluctuations depending on mud shrimp burrow hole density. Additionally, it discusses countermeasures for Manila clam habitat management. The results show that mean DIN effluxes in areas with a high-density of burrow holes were up to 4 times (0.12 mmol m^-2 d^-1) higher than those in sites of low-density (0.03 mmol m^-2 d^-1) within the Saho and Songhak-ri tidal flats. To manage interference within the competition zone of Songhak-ri tidal flat, it is important to utilize the settlements of spawning season in all three dimensions. Consequently, additional studies in other tidal flats are essential and research in zones where mud shrimps and juvenile clams coexist will help to determine the priorities in the efficient management of clam aquaculture.

• Animal Systematics, Evolution and Diversity
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• v.25 no.2
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• pp.205-207
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• 2009

The specimens of Peregrinamor ohshimai, an ecto-commensal species to Upogebia major, were collected from the mudflat of Chilcheondo Is., Geoje-si, Gyungsangnam-do, Korea and diagnostic characters of P. ohshimai were analyzed. The genus Peregrinamor is reported in Korean fauna for the first time.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.310-319
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• 2019

Although mud shrimp (Upogebia Major) provides benefits on the tidal flat ecosystem, it is causing the mass mortality of Manila clam (Tapes philippinarum) and large economic loss to the aquaculture farmer due to spreading in the entire coastal clam farm area of the West Sea of Korea. In this study, a mud shrimp blocking box for cultivating clam was tested to prevent the mud shrimp from invading the habitat of the clam. To determine the effect of the blocking box, the growth characteristics of the clams under various culture conditions were investigated. The shell length, total weight, condition index, the presence of mud shrimp in the box, and the soil decay in the box were examined according to whether the clams were raised in the box or in natural state, whether the box is covered with a net or not and the gap size of the box. As a result, no significant differences in shell length, total weight, and condition index were found between the clam grown in the box and the natural state (P>0.05) without any evidence of invading of mud shrimp to the box. In addition, the soil inside the box was in good condition, not decayed. Therefore, using the mud shrimp blocking box, mud shrimp can be prevented from propagating to the habitat of the clam, thereby contributing to the normal production of the clam and thus to restoring the clam farming.

• Animal Systematics, Evolution and Diversity
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• v.29 no.2
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• pp.152-159
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• 2013

As a result of continuous taxonomic studies on the Korean crabs, two varunid crabs, Hemigrapsus takanoi Asakura and Watanabe, 2005 and Sestrostoma toriumii (Takeda, 1974), are newly reported from Korean waters. Hemigrapsus takanoi, as a sibling species of H. penicillatus, has not been recognized in Korean waters, and this species occurs in the sympatric habitat with H. penicillatus in the Korean peninsula. Sestrostoma toriumii (Takeda, 1974) is associated with thallassinid Upogebia major (De Haan, 1841) and echiuran Urechis unicintus (Von Drache, 1881) as the case of S. balssi (Shen, 1932). The Korean S. toriumii showed smaller size than those mentioned in the original description. Their illustrations and pictures are provided with descriptions, and the distributions of these species in the Korean peninsula are also provided.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.167-182
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• 2021

This study was carried out to investigate temporal and spatial distribution of macrobenthic community and elucidate effects of environmental factors on change of community structure in an intertidal flat, Hakseong-ri, Boryeong, Korea. Field surveys were seasonally conducted to collect samples of sediment and macrobenthos using can core in triplicate at nine stations in 2016 and 2017. Our results showed that sediment had high mud content (above 60%) in most samples and mean content of loss on ignition was 2.3% in 2016. A total of 79 species was collected in the study site during the study period. Mean density and biomass were 611 ind./m² and 64.1 gWWt/m², respectively. Heteromastus filiformis was the dominant species (48.6%, 297 ind./m²) followed by Macrophthalmus japonicus (10.1%, 62 ind./m²) and Upogebia major (6.9%, 42 ind./m²). Three assembly groups resulted from cluster analysis were more distinguished by interaction between organisms and frequency of dominant species than by physical and chemical environment characteristics. In addition, macrobenthic community in the Hakseong intertidal flat showed seasonal changes based on non metric multidimensional scaling using species abundance.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.4
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• pp.143-157
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• 2023

This study confirmed the characteristics of macrobenthic community due to anthropogenic environmental changes in the Boryeong Jugyo tidal flat, where the habitat of manila clam (Ruditapes philippinarum) and mud shrimp (Upogebia major) is separated. The total number of occurring species was 55 during the study period with an average habitat density of 338 ind./m² and a biomass of 212.2 gWWt/m². The number of occuring species increased from 27 species at the upper flat to 37 species at the lower flat, and the dominant species differed by tide levels (Upper: Leonnates persica, Middle: Heteromastus filiformis, Lower: R. philippinarum). The macro-benthic community sturctures of the top 10 species using cluster analysis and nMDS were divided into two groups, focusing on Manila clam culture farm of lower flats and middle flats with high habitat density, reflecting the influence of specific species. The sediment composition of the U. major habitat space fluctuated highly, but it was maintained annually, and the sorting coefficient was 2.1 𝜑, and the proportion of the same particle size was increased. In particular, because the middle flat has a dense anthropogenic impact, a dominant species, H. filiformis dominated and revealed a relationship with the density of burrow holes of U. major, which is considered to be a biological interaction between these two macrofauna in this tidal flat.