Article Ocean Sci J (2015) 50(4):657667 http://dx.doi.org/10.1007/s12601-015-0060-y Available online at http://link.springer.com Article pISSN 1738-5261 eISSN 2005-7172 Marine Environmental Impact Assessment of Abalone, Haliotis discus hannai, Cage Farm in Wan-do, Republic of Korea Hyun-Taik Oh1*, Rae-Hong Jung2, Yoon-Sik Cho3, Dong-Woon Hwang2, and Yong-Min Yi1 Marine and Fisheries Environmental Impact Assessment Center, National Institute of Fisheries Science (NIFS), Busan 46083, Korea Marine Environment Research Division, National Institute of Fisheries Science (NIFS), Busan 46083, Korea Coastal Wetland Research Institute, National Institute of Fisheries Science (NIFS), Gunsan 54014, Korea Received 22 February 2015; Revised 10 August 2015; Accepted 30 August 2015  KSO, KIOST and Springer 2015 Abstract  To assess the marine environmental impacts of abalone, Haliotis discus hannai, cage farms in Wan-do, we monitored the benthic environment on top of the sediment underneath cage farm stations and reference stations We applied two methods for this assessment One was the A- and B-investigation of the MOM system (Modeling – On fish farm – Monitoring) developed in Norway The other was a general environmental monitoring method which is widely used In this study, we found benthic animals in all samples that belonged to condition which were based on group 1(presence of macrofauna) of the B-investigation method The values of redox potential (group – pH, redox potential) in all samples were above +65 mV belonging to condition Based on sensory results (group – gas, color, odor, thickness of deposits), five out of seven experiment samples showed condition while stations and showed condition 2, which have been cultured for 10 years in semi-closed waters As group takes precedence over group 3, the level of the conditions for B-investigation results consequently showed condition in all stations We found that pollutants and trace metals in the sediment underneath cage farms were lower than the pollution standard This led us to conclude that the environmental impacts of the cage farms in this study were not significant Key words  environmental impact assessment, abalone cage farm, MOM, benthic environment Introduction Concerns about the marine environmental impact of fish farms have grown as marine pollution caused by fish farming has increased Marine cage farming affects the marine environment in a variety of ways In general, the impact of *Corresponding author E-mail: ohtek@korea.kr fish cage farms is more serious than that of shellfish cage farms like abalone cultures and long-line cultures like oysters and clams This is due to overfeeding, nutrient loading of individual organisms, and waste from fish farm facilities (Silvert 1992; Naylor et al 2000; Sarà et al 2004) The enrichment of organic materials both from fish and abalone cage farms may cause the reduction of demanded oxygen (DO) in lower levels of water, not only generating a high concentration of acid-volatile sulfide (AVS) in sediment, but changing benthic communities around the farms (Yokoyama 2002, 2003; Kalantzi and Karakassis 2006) The environmental impact assessment (EIA) of cage farms has been studied and monitored in Africa, Asia-Pacific, Europe, and America with different specialized methods for each case (FAO 2009) The highest application of EIA to cage farms has been found in the finfish aquaculture industries of salmon, seabream, sea bass, and tuna around Europe and also in shellfish and seaweed farming in Europe, Norway, Australia, and China (Hansen et al 2001; Crawford et al 2003; Borja et al 2009; Zhang et al 2009) A report from the Food and Agriculture Organization (FAO) of the United Nations documented that the Norwegian Modeling – On fish farming – Monitoring (MOM) is reliable, fit for the purpose, and is cost-effective to assess the marine environmental impact of cage culture (FAO 2009) Even though the MOM system was developed primarily as an environmental impact assessment tool for fish cage farming, it is based on the general parameters for proper marine environmental management of cage farms, including finfish, shellfish, and seaweed culture (Zhang et al 2009) The MOM has A-B-C investigation methods according to temporal and spatial features 658 Oh, H.-T et al The A-investigation is a monthly or seasonal measurement of the sedimentation rate of the organic material underneath a cage farm It provides fish-farmers with immediate information regarding the load as a part of their internal control routines, which not have any environmental quality standards (Hansen et al 2001) The B-investigation is performed annually or biannually in the local impact zone, and combines benthic communities from Group 1, the pH-redox potential from Group 2, and sensory parameters from Group The Cinvestigation is performed from the intermediate impact zone to the regional impact zone, and is the study of a benthic community structure (Ervik et al 1997; Maroni 2000) The frequency of monitoring depends on the degree of environmental impact For A-investigation and B-investigation, the frequencies of monitoring are every month, every 2nd month, every 3rd month and twice a year, every year, every 2nd year, respectively Abalone, Haliotis discus hannal, production in South Korea soared to 1,065 tons in 2003 from 85 tons at the beginning of 2000 thanks to the development of net cage technology which is a coastal water-based culture (Park and Kim 2013) The cost of abalone farming is generally much cheaper than that of land-based culture In 2011, Korea produced 6,800 tons of abalone and it was the second largest amount in the world Jeollanam-do is the leading producer of abalone, accounting for 99% of the total production in S Korea Located within Jeollanam-do, Wan-do produces about 94% of this total and this is why the island is called the Mecca of the abalone industry in Korea The gravest threat to the abalone industry in Wan-do is the increasing mortality rate The reasons for the increasing mortality rate are very complicated and diverse Causes include: deteriorated currents due to the densely distributed farms, depleted-oxygen due to long-chained farms and seaweed Vulnerability caused by storms and typhoons during the summer also contributes to this problem Nonetheless, most of the studies that have been conducted have focused on the environmental impact of fish farming and research on shell farming has seldom been carried out In this context, this study is aimed at evaluating the impacts of bio-deposits excreted by abalone and fall-offs of seaweed in the benthic environment using the Norwegian MOM system at a variety of licensed abalone farms in Wan-do Through this experiment, we aim to determine two things Firstly, we will determine the immediate quantification of the benthic environment on site using the B-investigation methods Secondly, we will collect detailed environmental information including the condition of benthic communities and the concentration of pollutants and trace metals underneath abalone farms through laboratory analysis Data and Methods Study sites The study sites are located in Wan-do, Jeollanam-do, in the southern seas of the Korean peninsula The sampling stations for the benthic environmental assessment are underneath the abalone cage farms near Saengil-do and Geumil-do (Fig 1) The average depth of the study sites are approximately 18 m, and the depth of each station and license information are shown in Table The field trip for sediment sampling and investigation on site took place between November and November 3, 2013 The tidal range in Wan-do is about m and the sea water is exchanged by the tide through open channels The average velocities of the currents are between 89.2 cm·s-1 and 93.9 cm·s-1 (Yang 2011) Around these islands, sea-farmers have developed abalone culture facilities next to seaweed farms since 2003 with the supplementation of abalone seedling production in the waters (Park and Kim 2013) As the abalone eat the abundant forms of seaweed such as kelp, Saccharina japonica, and undaria, Undaria pinnatitida, Wan-do has become an optimal location for abalone farms since the early 2000s Sampling and analysis For this study, stations for benthic samples and investigation were selected on the basis of the period of time they had been involved in abalone aquaculture Taking vessel tracks into account, we chose stations in possession of licenses for abalone aquaculture for almost 9–10 years (1, 2, 7) and stations that were in possession of the same licenses for 4–6 years (3, 4, 5, 6) (Table 1) We chose two reference stations which were neither utilized for abalone culture nor seaweed culture in the inner waters (8) and on the way to a channel (9) Samples for the benthic environmental assessment were in accordance with MOM B-investigation data and were collected at abalone farms (1 to 7) and reference stations (8 to 9) by a van Veen grab (0.05 m2) Using the first collection of the samples, we monitored the pH-redox potential and sensory parameters on site, and then moved those samples to a sieve and added two more collections for the macrofauna abundance experiment (0.15 m2) Finally, benthic samples were sieved with a 1-mm mesh sieve, checked for remaining 659 Environmental Impact Assessment of Abalone Farms Fig (a) The research site in Wan-do and sampling stations for experiment (#1–#7) and reference (#8–#9), (b) The sampling station of abalone cage farms and the research vessel, (c) abalone net cage culture Table The information of sampling stations including license number, first date of license, name of species for culture, renew date, area of farms, and water depth (* indicates 9–10 years old abalone cage farms) No #1 #2 #3 #4 #5 #6 #7 #8 #9 License No 11711 12076 12470 12723 12738 12464 11792 - License Date 2003-06-24 * 2004-09-23 * 2007-08-21 2009-01-22 2009-04-01 2007-08-21 2004-08-10 * - Species Net cage (Abalone) Net cage (Abalone) Net cage (Abalone) Net cage (Abalone) Net cage (Abalone) Net cage (Abalone) Net cage (Abalone) - macrofauna left on the sieve, and then preserved for laboratory analysis and macrofauna classification In addition, the unsieved sediment samples were preserved on site and transferred to the laboratory to analyze the total organic carbon (TOC, mg·g-1), total nitrogen (TN, mg·g-1), ignition loss (IL, %), and trace metals such as Arsenic (As, mg·kg-1), Cadmium (Cd, mg·kg-1), Chromium (Cr, mg·kg-1), Copper (Cu, mg·kg-1), Lead (Pb, mg·kg-1), Zink (Zn, mg·kg-1) and Mercury (Hg, mg·kg-1) We analyzed the content of COD, IL, and TOC based on the standard experimental method for the marine environment For the analysis of trace metals, dried samples were digested in a mixture of HNO3, HF and HClO4 and analyzed using an inductively coupled plasma Renew Date 2013-06-23 2015-09-22 2017-08-20 2019-01-21 2019-03-31 2017-08-20 2014-08-09 - Area(Ha) 10 - Depth(m) 20 15 20 25 15 20 20 12 15 mass spectrometer (ICP-MS, Perkin Elmer Elan-6000) at the National Institute of Fisheries Science (NIFS) The recovery rates for the target heavy metals in the standard reference materials were reasonably good (82–100%) MOM modeling In each station, we followed the scoring system of the MOM B-investigation and this generally means that the lower the score is, the better the benthic environment is, following the Norwegian Standards Association (Ervik et al 1997; Hansen et al 2001) For macrofauna, we assigned a score of if materials remaining on the mesh screen contained macrofauna, or otherwise For the investigation of the benthic 660 Oh, H.-T et al Table Environmental monitoring methodology of both Norwegian MOM investigation A-B and general environmental monitoring in Korea Type Determinant Unit Scoring Condition A-Investigation Sedimentation rate mm/year Value Presence = mean score  0.5: condition 1, or Group ind./0.15m2 Absence = mean score > 0.5: condition (Presence of macrofauna) mean score  1: condition 0, 1, 2, 3, Group < mean score  2: condition mV (Schaanning and (pH and redox) < mean score  3: condition Hansen, 2005) mean score > 3: condition Quantitative Absence = Outgassing assessment of Presence = gas bubbles Subjective Pale/Gray = Color visual Brown/Black = assessment B-Investigation Subjective None = Smell olfactory Medium = mean score < 4: condition Group assessment Strong = 4  mean score < 10: condition (Sensory 10  mean score  14: condition Subjective Firm = parameters) mean score > 14: condition Consistency tactile Soft = assessment Loose = Quantitative < 1/4 = Grab volume assessment of 1/4 ~3/4 = grab volume > 3/4 = Quantitative < cm = Thickness of assessment of ~ cm = deposits seposits > cm = Sedimentary parameters TOC, TN : mg-1 Concentration General (TOC, TN, IL) IL : % investigation Trace metals (As, Cd, Cr, Cu, Pb, Zn, Hg)Concentration mg kg-1 communities underneath the abalone farms, a qualified taxonomist investigated the macrofauna species Based on the observation results of the pH and redox potential at cm depth in all sites, we assigned the score of 0, 1, 2, 3, and in accordance with the Norwegian standards(Schaanning and Hansen 2005) Sensory parameters such as outgassing, color, smell, consistency, grab volume and the thickness of deposits were scored 0, 1, or depending on the extent to which a parameter is affected by organic enrichment The more the sediment is affected by organic materials, the higher the score assigned to the sensory parameters (Table 2) The analysis of the aforementioned parameters is shown in Table below Results Group (benthic community) The group parameter is a determinant of whether sediment samples contain macrofauna or not Macrofauna were found in all of the samples from all stations after sieving through a 1-mm mesh sieve, so all sites were given the score of which means that circumstances at all stations were acceptable or satisfactory The mean score of all the samples at the study sites was 0, indicating that the group condition was normal at the study sites The most abundant species at each sample station were polychaetes A total of 41 polychaetes were identified with Paralacydonia paradoxa, Sternaspis scutata, Amaeana occidentalis, Cirrophorus branchiatus and Flabelligeridae unid making up the majority, and their appearance frequencies were 67%, 78%, 44%, 44% and 56%, respectively (Table 3) The number of the species in each station ranged from 4–18 per 0.15 m2 The highest quantities were found at the inner sites near the islands (#5, #7, #8) The lowest quantity was found at the reference station #9 in the open channel where we could take only small sediment samples due to strong currents and hard consistency with no cage farms around Even if a taxonomist could classify the lowest number polychaete species at sampling station 9, its evaluated 661 Environmental Impact Assessment of Abalone Farms Table The macrofauna abundance (ind./0.15 m2) at experiment sites (#1#7) and reference sites (#8#9) Species of macrofauna #1 #2 #3 #4 #5 #6 #7 Existence Yes Yes Yes Yes Yes Yes Yes Score 0 0 0 Level of condition (1~3) (1~3) (1~3) (1~3) (1~3) (1~3) (1~3) Amaeana occidentalis 10 10 20 Ammotrypane aulogaster Ampharete arcrica 10 Amphisamytha japonica 10 Aphelochaeta monilaris 5 5 Archianellida unid 10 Capitella capitata Cirrophorus branchiatus 15 20 15 Dorvillea rudolphi Euchone alicaudata Flabelligeridae unid 10 10 Glycera chirori 10 Harmothoe imbricata Harmothoninae unid Heteromastus filiformis 15 5 Lagis bocki Lepidonotinae unid 10 Lumbrineris cruzensis Magelona japonica Mediomastus californiensis 40 20 15 Minuspio multibranchiata Nectoneanthes multignatha Nephtys polybranchia 10 Paralacydonia paradoxa 40 10 5 35 Paraonis glacilis japonica 15 Paraprionospio cordifolia Poecilochaetidae unid 5 Praxillella affinis 10 Prionospio saccifera 10 Scolelepis sp 10 Scoloplos armeger Sigambra tentaculata 10 10 Spiochaetopterus koreana Sternaspis scutata 25 20 30 10 Sthenolepis japonica 5 Syllidae unid.1 10 Terebellides japonica 10 Tharyx sp Thelepus sp 10 Species number 8 13 18 Diversity index 2.61 2.91 2.65 2.93 3.53 2.04 3.92 sediment condition was still based on group and 3, showing that nutrient concentration and trace metals were #8 Yes (1~3) 10 #9 Yes (1~3) 10 10 10 30 5 25 35 5 5 10 10 14 3.38 1.91 still good (Table 4, Table 5) The Shannon-Wiener index ranged between 1.91–3.92 662 Oh, H.-T et al Table The pH and redox potential values, concentration of nutrients, and trace metals in the sediment Content Parameter Unit #1 #2 #3 #4 #5 #6 pH 7.95 7.81 7.81 7.95 7.75 7.85 B-Investigation redox potential mV 99.5 79.9 85.2 115.5 65.5 110.5 (Group 2) Level of condition 1 1 1 IL % 5.47 5.58 4.46 5.78 3.58 5.16 Sedimentary TN mg·g-1 1.45 1.41 0.71 1.35 0.45 1.15 parameters TOC mg·g-1 10.31 9.95 5.51 9.85 3.35 8.31 Sand % 1.1 0.8 5.2 1.5 27.3 3.1 Silt % 50.1 48.2 36.6 33.2 43.6 53.6 Clay % 48.8 51.0 58.2 65.3 29.1 43.3 Sediment grain Mean Φ 7.9 8.1 8.5 9.2 6.2 7.2 Sort 3.3 3.3 3.4 3.0 3.4 3.3 Skewness 0.2 0.1 -0.1 -0.3 0.9 0.4 Kurtosis 1.7 1.6 1.7 2.0 2.4 1.7 As mg·kg-1 6.78 6.66 6.01 6.93 5.34 5.99 Cd mg·kg-1 0.03 0.05 0.04 0.03 0.03 0.05 50.19 52.39 49.81 53.38 40.13 48.14 Cr mg·kg-1 Harmful Cu mg·kg-1 16.95 18.14 14.72 18.39 11.81 16.31 substances Pb mg·kg-1 25.73 26.72 22.37 27.41 19.78 22.45 86.17 90.42 80 92.41 64.19 96.6 Zn mg·kg-1 Hg mg·kg-1 0.02 0.015 0.008 0.014 0.008 0.013 Table Sensory results both for abalone cage farm stations (#1–#7) and reference stations (#8–#9) Content Parameter #1 #2 #3 #4 #5 B-Investigation (Group 3) Outgassing 0 0 Color 0 0 Smell 0 0 Consistency 2 2 Grab volume 1 Thickness of deposits 0 0 Sum(scores) 3 Level of condition 1 which indicated that the conditions of all stations in our study were better than those of shellfish and seaweed farming areas in a similar study (1.8–2.3) carried out in China (Zhang et al 2009) Group and polychaete community results revealed that there were not any significant differences between sampling stations in terms of the number of species, as the results of ANOVA showed that the significance probability was above 0.05 Overall, the sediments underneath abalone cage farms in the study sites were still in an acceptable or satisfactory condition Group (chemical values) Group parameters for the Norwegian B-investigation are based on the measurement of pH and redox potential #6 0 #7 7.71 105.5 5.21 0.95 6.95 2.7 56.1 41.2 7.8 3.3 0.5 1.7 6.14 0.03 57.95 17.72 26.96 89.86 0.013 #8 7.8 135.5 5.61 1.25 9.35 5.5 40.7 53.8 8.9 3.4 0.0 1.8 5.29 0.05 51.37 17.13 23.43 85.13 0.014 #9 7.8 130.5 5.45 1.15 7.85 1.9 53.1 45.0 7.5 3.3 0.3 1.6 6.12 0.03 54.02 17.41 24.07 85.3 0.014 #7 2 #8 0 #9 0 0 1 ascertained by inserting electrodes into the sediment (Hansen et al 1997) The pH and redox potential in the sediment was measured immediately after the samples were collected from a depth of 20 mm at all stations The pH and redox potential (Eh) values ranged between 7.71–8.09 and 65.0–135.1 mV, respectively The assigned scores based on the pH and redox potential values are (#4, #6, #7, #8, #9) and (#1, #2, #3, #5), so the level of the conditions at all sites is (Table 4) Scores for the pH and redox potential were analyzed or according to a previous study by Schannig and Hansen (2005), and the scores were applicable to all sampling stations for condition This was based on group of the B-investigation method Even though the values of reference stations (#8, #9) were higher than those of the experimental stations (#1–#7), the Environmental Impact Assessment of Abalone Farms differences were trivial and all values were mostly concentrated in the border of and According to the group result, the environmental conditions in all stations meet the standards for a well-oxygenated marine environment with low organic input and favorable conditions for the presence of benthic communities Our measurements were not made at different levels of depth but only at a depth of 20 mm to examine the systematic pH and redox potential differences between farming grounds and reference stations The sand, silt, and clay amounts or ratios were collected underneath the cage farms using a ternary figure based on the Shepard classification scheme (Shepard 1954) The average composition of gravel, sand, silt and clay were recorded as 0%, 5.5%, 46.1% and 48.4% respectively (Table 4) The sediments mostly consisted of silty clay and clayish silt except at station which was primarily made up of sand at 27.3% The grain size ranged between 6.2–9.2 Ф which means that it consisted of very fine silt which was mostly clay The sorting values and skewness values ranged between 3.0–3.4 Ф and -0.3–0.9, which means very poorly sorted and very coarse skewed, respectively The sorting kurtosis showed very leptokurtic curves with the value of 1.6–2.4 Our study sites have cultured abalone since 2004, but the sedimentary composition has not yet been affected by abalone cage farms The concentration of sedimentary parameters such as IL (%), TN (mg·g-1), and TOC (mg·g-1) ranged between 3.58– 5.78%, 0.45–1.45 mg·g-1, 3.35–10.30 mg·g-1 respectively The values of IL were mostly within the range of 5.1–5.8%, but station had the lowest value of 3.58% due to its higher composition of sand at 27.3% At station 9, both the TN and TOC concentrations were lower than those at other stations, too Results indicated that the finer the sediment, the higher the concentration of pollutants This is similar to the results of other related studies conducted at the surface sediment of cage farms (Matthaei et al 2006) In Japan, if the concentration of TOC is above 10.3 mg·g-1 in a fish farm, the responsible local authority would issue a warning to farmers to take action to preserve the marine environment according to environmental quality status (EQS) (Yokoyama 2003) In Europe, if the concentration of TOC is lower than 11.9 mg·g-1, farmers get a “Good” or “High” rating based on the European EQS (Bakke et al 2010) If the TOC standard of Europe was applied to abalone cage farms in this study, the values of TOC in all stations would have been lower than the standard, which indicates 663 that sediment conditions are quite good The concentrations of TOC in most of stations were lower than the standards applied in Japan except for station (10.31 mg·g-1) where the cage culture has been established since 2003 These parameters at the cage farms did not reveal any significantly lower values than those at the reference stations (Table 4) We found that sedimentary environmental conditions in out of stations were still good based on the standards of Japan, and all stations were still environmentally healthy according to European standards The trace metals in the sediment are measured to check the safety of the abalone cage farming grounds In this study, the content of trace metals such as As, Cd, Cr, Cu, Pb, Zn and Hg were measured underneath cage grounds and reference stations According to the United States National Ocean and Atmosphere Administration (NOAA)’s reference tables for trace metals in sediment, the critical values of effect range low (ERL) for As, Cd, Cr, Cu, Pb, Zn and Hg are 8.2 mg·kg-1, 1.2 mg·kg-1, 81.0 mg·kg-1, 34.0 mg·kg-1, 46.7 mg·kg-1, 150.0 mg·kg-1 and 0.15 mg·kg-1 respectively (Buchman 2008) The values for harmful substances at all stations were lower than those of the sediment quality guidelines (SQGs) This suggests that the impacts of trace metals on benthic communities were negligible The study sites in Wan-do were also found not to be significantly polluted by harmful substances, and healthy sediment conditions had been maintained The As value of station was below the standard but close to the threshold (85%), so more studies are required to identify the potential causes of metal pollution in abalone cage farms (Table 4) Group (sensory values) Group parameters of the B-investigation show many sensory variables representing organic enrichment such as gas ebullition, color, odor, consistency and thickness of sludge The results of sensory parameters are shown in Table Outgassing was not found in any of the sample stations, so we assigned an on- site score of to them The colors of sample sites were gray (score = 0) except at station which was brown-black (score 2) There was no smell from the sediment samples, but there was a slight sulfide smell from station The consistency of the sediment was soft and gentle (score = 2), but station was hard (score = 0) Mostly, the grab volume was not greater than 3/4 except at station which got a full volume grab The thickness of sludge accumulated on top of the original sediment ranged between 0.6–1.5 cm, 664 Oh, H.-T et al Fig The results of pH and redox potential based on previous measurements from various cage farms in Europe (Schanning and Hansen 2005) so we a score of was assigned for all stations The total scores of group in the B-investigation ranged from 1–7, with station with the highest score and station with the lowest score A sum less than falls into condition while the sum equal to or greater than and less than falls into condition Therefore, the level of condition based on the sum of scores was condition for (#1, #3, #4, #5, #6, #7, #8) and condition for (#2, #7) (Table 5) As a whole, general conditions were given by the results of the group 1, 2, of the B-investigation Most sample stations (#1, #3, #4, #5, #6, #8, #9) showed the same level of conditions with both group and containing macrofauna Therefore, we determined that the general condition of stations 1, 3, 4, 5, 6, and were However, samples from station and were different from group and If they are different, group takes precedence over group (Ervik et al 1997; Hanse et al 2001) Therefore we determined that the general conditions of station and were because the condition of the station is determined by group (Table 6) We found that sedimentary environmental conditions in all Table General level of condition of the sediment in Wan-do Content #1 #2 #3 Group condition Yes Yes Yes Group condition 1 Group condition General condition 1 Sedimentary condition Normal Good Good Trace metals (ERL) None None None Fig Ternary diagram for sedimentary composition around cage farm in Wan-do sites were still good judging by the concentration of IL, TN and TOC, even though the value of TOC in station was similar to the value of standard applied in Japan for marine environmental fish farm preservation In Wan-do, the concentrations of trace metals were below the limit of ERL, which indicates that the environment is still clean (Table 4) Discussion The increasing age of a farm is likely related to worsening conditions Abalone cage farms in Wan-do, Jeollanam-do have been intensely developed since the early 2000s with the development of net cage technology in coastal waters With the increasing abalone mortality rate, farmers have become seriously concerns about the environmental impacts of the abalone cage farms and the densely distributed facilities in a limited site area #4 Yes 1 Good None #5 Yes 1 Good None #6 Yes 1 Good None #7 Yes Good None #8 Yes 1 Good None #9 Yes 1 Good None Environmental Impact Assessment of Abalone Farms Meanwhile, a marine environmental monitoring program by the NIFS has been undertaken in the coastal waters of S Korea Even though there are a number of observation stations, they are not close to the abalone farms in Wan-do The nearest station of the NIFS is located 3.2 km to the north and 4.7 km to the west of the abalone cage farms in this study To assess the marine environmental impacts of cage farms, regular monitoring is needed directly underneath cage farms because the impacts of sedimentary parameters should be measured within 30 to 50 m of cage centered grounds In this study, we concluded that the general conditions underneath abalone cage farms were pretty good, though the values of some stations were a little higher than those of the reference stations In particular, the 10 year-old licensed cage farms (stations and 7) showed the level of condition according to the sensory parameters of the B-investigation method Also, the value of TOC at station 1, a 10 year-old licensed cage farm, was higher than the standard applied at fish farms in Japan (Yokoyama 2003) More extensive and regular interdisciplinary studies in close proximity to abalone cage farms are required to investigate the potential pollution of bio-deposits excreted by abalone, fall-off from seaweed, and harmful substances in the sediment Without the environmental impact assessment of abalone cage farms, a local authority cannot take prompt action to determine the causes of unexpected deaths among abalone cultures which may be related to oxygen-depletion and environmental changes K-MOM necessity The MOM system was developed for the assessment of the marine environmental impacts of intensive marine fish farming in Norwegian waters (Ervik et al 1997) It covers the environmental impacts not only in local and intermediate zones through the A and B investigation methods but also in intermediate and regional zones by C-investigation methods And it allows for an immediate assessment to be carried out on site and can be conducted easily and the results sent to the laboratory for analysis by professionally skilled technicians and taxonomists This convenient method allows local fishermen to receive the training to carry out the measurements The general concept of the MOM system is based on a general assessment of the marine environment regardless of the species being reared or cultivated Both fish cage farming and abalone cage farming have similar impacts on the benthic environment, even though fish cage farming affects the marine environment in a slightly more detrimental manner 665 than abalone cage farming To date, most of the researches conducted have been focusing on fish farming However, environmental problems have started to occur in the abalone cage farming industry and this has led to a decrease in productivity We have ascertained that the environmental impact around abalone cage farms in Wan-do can also be assessed using this system We assigned a score range to a schematic assessment map based on our observation results To use this pH-redox potential method frequently, we need to collect more measurements from several more culture grounds Measurements need to be made at different levels of depth in core samples, and then the lowest pH and the corresponding redox potential should be used to assign scores The group parameters provide reliable information on sediment conditions Visual observation is also a good way to obtain valuable information on the marine environment, but it has been underestimated as an adequate tool to obtain measurement results with respect to sedimentary parameters and trace metals More extensive studies on sensory parameters are required to improve them as a reliable method This can be accomplished through a questionnaire survey by experts based on a dataset Eventually, we need to put in place Korea – MOM (K-MOM) to properly evaluate the licensed culture farms Better understanding of hydrodynamics The marine environmental impacts of cage farms are closely related to farming locations (Karakassis et al 2000) The stronger the current is, the less polluted the environment is with fewer deposits of pollutants and pseudofaeces by abalone and the absence of excessive input of seaweed deposits underneath farms Densely distributed facilities of abalone cage farms and long-chained farms cause the slowing of water flow and water exchange, especially in semi-closed waters Although we have data on average current speeds and tidal range from Wan-do, these are not reliable as they were not measured close to the cage farms In the study sites, the speed and patterns of currents as well as the amount of sea water exchanges could be one of the main reasons for variations in biological and chemical parameters, but those physical characteristics were beyond the scope of this study On a national and regional level, the concerned authorities should consider those physical characteristics when they prepare the relocation of and new licenses for abalone cage farms in the near future Our knowledge of hydrodynamic conditions can help us better understand the parameters that 666 Oh, H.-T et al are represented and where alternative farming sites should be located Conclusion In this study, we evaluated the marine environmental impacts of abalone cage farms using the MOM system and compared sedimentary parameters and trace metals in Wan-do, S Korea We found the general level of the condition which was given by the results of group 1, 2, of B-investigation methods was in all abalone cage and references stations We found macrofauna in all stations The most abundant species was polychaete with Sternaspis scutata, Paralacydonia paradoxa, Cirrophorus branchiatus, Flabelligeridae unid and Amaeana occidentalis as the major variety The pH and redox potential (Eh) values ranged between 7.71–8.09, 65.0–135.1 mV, respectively The assigned scores based on the pH and redox potential are (#4, #6, #7, #8, #9) and (#1, #2, #3, #5), so the level of conditions in all sites is The total scores of group in the B-investigation ranged between 1–7, and the level of the conditions based on the sum of the scores was condition (#1, #3, #4, #5, #6, #7, #8) and condition (#2, #7) If group and group bring a different result, group takes precedence over group Therefore, we determined the level of the general condition as condition We found that sedimentary environmental conditions are still good in all sites judging by the concentration of IL, TN, and TOC The concentration of the trace metals was below the limit of ERL which indicates that the areas are in a good environmental condition Acknowledgements This work is funded by a grant from the 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