• The Korean Journal of Malacology
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• v.1 no.1
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• pp.1-4
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• 1985

The investigation of freshwater molluscs in the South Han River was carried out from 1984 and in 1985. The authors selected 12 stations and collected freshwater snails and mussels. We here publish the catalogue of molluscs in South and North Han River. The catalogue of molluscs in the South Han River is as follows; two classes, four orders, six families including twenty species(Semisulcospira coreana, Semisulcospira globus, Semisulcospira gottschei, Semisulcospira forticosta, Parafossarulus manchouricus, Gabbia misella, Radix auricularia coreana, Austroppepleaollura, Limnoperma lucustris, Lamprotula gottschei, Lanceolariaacrorhyncha, Unio douglasiae, Unio sp, Solenaia triangulalis, Anodonta fukudai, Anodonta woodiana, Corbicula felnouilliana, Corbiculafluminea, Corbicula sp).

• Journal of Microbiology
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• v.39 no.2
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• pp.133-138
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• 2001

We investigated the antagonism of indigenous bacteria isolated from stressed mussels and their extracellular metabolites on the adult zebra mussel, Dreissena polymorpha. Selective bacterial isolates including Aeromonas media, A. salmonicida, A. veronii, and Shewanella putrefaciens, showed strong lethality against adult mussels and 100% mortality was observed within 5 days of incubation. Bacterial metabolites, fractionated and concentrated from stationary-phase culture supernatants of these bacterial isolates, displayed varying degrees of antagonistic effects on zebra mussels. Among the three size fractions examined, <5, 5-10, and >10 kDa, the mast lethal fraction seems to be >10 kDa for three of the four isolates tested. Further chemical analyses of these size fractions revealed that the predominant constituents were polysaccharides and proteins. No 2-keto-3-deoxyoctanoic acid (2-KDO), deoxyribonucleic acids (DNA) or uranic acid were detectable. Extraction of supernatants of two antagonistic isolates with polar solvent suggested that polar molecules are present in the active fraction. Our data suggest that extracellular metabolites produced by antagonistic bacteria are also involved in disease development in zebra mussels and elucidation of the mechanisms involved may offer a novel strategy for control of biofouling invertebrates.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.288-294
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• 2014

Host mussel utilization for spawning of the oily shinner, Sarcocheilichthys variegatus wakiyae (Pisces: Cyprinidae), from Korea was investigated in part of the Dalcheon (river) in Cheongcheon-myeon, Goesan-gun, Chungcheongbuk-do, Korea from April to June 2011, 2013. The non-synchronicity of mature and immature eggs obtained from females of S. v. wakiyae and the number of spawned eggs found was less than those in the mussels, suggesting that these fish may be batch spawners. Five species of freshwater mussels - Unio douglasiae sinuolatus, Lanceolaria grayana, Anodonata arcaeformis flavotincta, Lamprotula leai, Corbicula fluminea - were found at the survey area (wild conditions) but three species of freshwater mussels - A. a. flavotincta (oviposition rate, 50.0%), U. d. sinuolatus (16.2%), L. leai (11.1%) - were host of S. v. wakiyae. Spawning of S. v. wakiyae occurred mainly in the mantle cavity (wild conditions, 77.4%; experiment, 62.8%) of the mussels that were connected more to the inhalant siphon than the suprabranchial cavity (22.6%; 31.8%) that linked to the exhalant siphon. Bitterlings prefer to lay eggs in L. leai and S. v. wakiyae prefers A. a. flavotincta as a spawning host. These were considered to be the result of niche partitioning.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.83-88
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• 2014

An endemic Korean bitterling, Acheilognathus signifer, known as using freshwater mussels for its spawning activity, much prefers Lamprotula leai in Dalcheon stream (Goesan population) and Unio douglasiae sinuolatus in Gadaecheon (Danyang population) stream, Korea. The spawning pattern between two mussels and one bitterling was carried out in two populations from April to June, 2011 and 2013. L. leai in the Goesan population was bigger shell length and have more eggs, larvae or both with A. signifer than those of U. d. sinuolatus in the Danyang population. Also, A. signifer in the Goesan population appeared to have a longer ovipositor and lay ripen eggs more than those of A. signifer in the Danyang population. Glochidium, a larval stage, of some L. leai in the Goesan population was incubated in all the demibranch, whereas for all of U. d. sinuolatus in the Danyang population was found in the outer demibranch only. For L. leai in the Goesan population, the eggs, larvae or both of A. signifer were much more in the non-breeding mussels (giving no glochidium) than the breeding mussels having the glochidium. For U. d. sinuolatus in the Danyang population, in contrast, the non-breeding mussels have fewer eggs, larvae or both less than the breeding one.

• Korean Journal of Ichthyology
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• v.25 no.4
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• pp.208-215
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• 2013

Host species preference of Acheilognathus signifer for spawning in freshwater mussels was investigated at the part of the Dalcheon Stream (site 1) and the Gaedaecheon Stream (site 2) in Chungcheongbuk-do, Korea from April to June (spawning period) 2011. The spawned mussel rate of A. signifer at the study site 1 (wild condition) was 63.6% in Lamprotula leai and 2.1% in Unio douglasiae sinuolatus. It was not found in Anodnta arcaeformis flavotincta and Lanceolaria grayana. The number of eggs, larvae, or both of A. signifer at the study site 1 (wild condition) was 1~41 ($12.0{\pm}9.21$) in L. leai and 6 in U. d. sinuolatus. As a result of experiment 1, A. signifer was only spawned in L. leai with 60% of spawned mussel rate and the number of eggs, larvae, or both was 1~19 ($6.8{\pm}5.44$). According to experiment 2, A. signifer was spawned in all mussels. Spawned mussel rate of A. signifer was 75.0% in L. leai, 42.9% in U. d. sinuolatus and 21.4% in A. a. flavotincta and the number of eggs, larvae, or both was 1~35 ($13.0{\pm}8.80$) in L. leai, 1~26 ($5.2{\pm}6.92$) in U. d. sinuolatus and 2~19 ($8.6{\pm}5.64$) in A. a. flavotincta. Experiment 3 showed A. signifer was solely spawned in L. leai and the number of egg was from 2 to 10 ($6.7{\pm}4.16$). This study confirmed A. singifer is not so much generalist as specialist. We found the most preference species for spawning in the mussels by A. signifer was L. leai.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.614-621
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• 2010

A indigenous freshwater bivalve Unio douglasiae was introduced to compare the differences in the efficacy of algal bloom control and the appearances of mussel-mediated adverse effects between two different reservoirs such as mesotrophic (Shingu r.) and hypertrophic (Seokmun r.). We constructed the study mesocosm in the shore of each reservoir, stocked the mussel at density of $30indiv./m^3$ for 7 days, and measured daily the phytoplankton density and water quality. In mesotrophic reservoir, even though approximately 38% of suspended solids and chlorophyll-a was reduced by stocked bivalves for the first 3 days, algal density, ammonia and soluble reactive phosphorus gradually increased with increasing mussel death. In hypertrophic reservoir, mussels strongly inhibited suspended solids and chlorophyll-a by the termination of study with no increase of mussel death and nutrient, especially ammonia concentration. In both reservoirs, a strong selectivity showed mussels preferred to diatom rather than cyanobacteria and green algae without algal density and nutrient level. Our results indicate that an introduction of freshwater bivalve U. douglasiae is more strategic to improve water quality of hypertrophic than mesotrophic reservoir, but many preliminary studies on the treatment method and the selection of target water system are required.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.317-330
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• 2009

To diminish the levels of organic matters, a novel S-CROM (continuous removal of organic matters in the stream system using freshwater bivalve), was developed and applied to the polluted stream discharging from the wastewater treatment plant, Pocheon stream, Pocheon city (Korea). Major pollutants of the stream were human population and industrial wastewaters. The study was conducted at a small dam constructed within the stream, often called 'bo', and designed with four tanks; no mussels and no sediment (negative control), no mussels and sediment (positive control), 30 mussels and sediment (D1), and 60 mussels and sediment (D2). Physicochemical and biological parameters were measured at 12 hours interval (day and night) after mussel stocking. Results indicated that Anodonta woodiana Lea (D2) clearly removed approximately 72% of chl-$\alpha$ and 57% of suspended solids on second day, however, there were no differences in removal activities between animal densities (P>0.5). Dislike a laboratory CROM system, which previously developed, there were no huge release of nutrient ($NH_3$-N and SRP), due perhaps to the higher flow rate and the lower animal density. Therefore, we may suggest that if we can determine the relevant current and the animal density considering the stream state, an S-CROM system has a strong potential to water quality improvement of eutrophic streams. Some characteristics on both CROM and S-CROM were compared.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.161-171
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• 2009

A 'continuous removal of organic matters (CROM) system' using a native freshwater bivalve in Korea Anodonta woordiana, was developed to determine its potential of controlling various sestons in eutrophic lake system, and to evaluate its effect on water quality improvement under consideration of sediment addition as habitat. We designed CROM experiments with four treatments: no mussels and no sediment (W, negative control), no mussels and sediment (WS, positive control), mussels and no sediment (WM), and mussels and sediment (WMS). The experiments were performed at the condition of 18${\sim}$25 L $h^{-1}$ of inflow, mussel density of 486.1 indiv. $m^{-2}$, and temperatures between 15 and $22^{\circ}C$ for 13 consecutive days. Physicochemical and biological parameters were measured at daily (10:00 am) intervals after the mussel addition. Results indicated that mussel stockings without addition of sediment effectively removed sestons (suspended solids and chlorophyll-a) at nearly same level over 80 percentage of the control during the study, while there were no differences in removal activities of sestons between with and without sediment (P>0.5). Therefore, it clearly suggests that CROM system using A. woordiana has a strong potential to control the seston in surface water of eutrophic lake.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.148-155
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• 2010

Water quality and plankton community dynamics after the introduction of two domestic freshwater shellfishes (Unio douglasiae Griffith & Pidgeon and Cipangoplaudina chinese malleata Reeve), were monitored daily in enclosures, which constructed in the tidal zone of eutrophic agricultural reservoir (Shingu reservoir, Korea) for one week between July 31 and August 6, 2007. This biomanipulation study to improve the water quality of eutrophic lake, comprised eight enclosures (duplicate x four kinds), enclosure had no mussels (Control), stocked only with U. douglasiae at density of 60 individuals (UD), stocked only with C. chinese malleata at density of 60 individuals (CCM), and combined-stocked with 30 individuals of UD and 30 individuals of CCM (MIX), respectively. Our results clearly indicate that UD strongly decreased the concentration of chlorophyll-a and increased the water transparency, whereas CCM and MIX (included CCM) did increase algal density or decrease transparency, due perhaps to the disturbance of C. chinese malleata. Therefore, the field application of shellfish to enhance the water quality of eutrophic agricultural reservoir, should consider the grazing characteristics of biological control agents, especially active moving animals like snail.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.437-450
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• 2010

Ecological influences of indigenous freshwater bivalve Unio douglasiae on the water quality and epilithic diatom community was examined with artificial stream (AST), which constructed in a laboratory daily receiving the eutrophic lake water. For the colonization of new periphyton community, forty commercial slide glasses were deposited as a substrate into the lowest part of each AST. Prior to 1 week, the AST was operated to induce the freely-colonization of the algal community in the absence of mussels. After the mussels was introduced at 435 indiv. $m^{-2}$ between step 1 and step 5, the passed water and substrates were daily collected to analysis the change of water quality and lotic and lentic algae abundance for 10 days. Compared to the control, turbidity (60.0% of control), suspended solids (62.5%), and chlorophyll-$\alpha$ (72.2%) in mussel-passed waters were decreased significantly, while a strong increase of ammonia (up to 800% of control) was companied with the decrease of dissolved oxygen (19.5% of control) and total phosphorus (23.9%), respectively. On average, the concentrations of suspended solids (67.0% of control) and chlorophyll-$\alpha$ (89.4%) in mussel-treated substrates were remarkably increased, however algal abundance in its water simultaneously decreased. These results indicate that incidentally or purposely mussel introductions can decrease organic matter of the stream and increase transparency of stream water, however, mussel-mediated nutrient and pseudofeces release may stimulate the adverse growth of periphyton or phytoplankton community in the lower stream or reservoir.