굴 수평망식 양식장의 먹이가용성에 대한 연구

정우건,조상만 한국패류학회 2021 The Korean Journal of Malacology Vol.37 No.3

To optimize the cultural performance for oyster rack culture in tidal flat, the scope for growth (SFG) and food availability (FA) were estimated from primary production and the metabolic rates of the oysters cultured on the northeastern coast of Wando Island, Korea. The estimated unit energy content of the seawater ranged from 1.18 to 25.39 Kcal/m3/day in typical productive features of the temperate zone. The absorbed energy allocated in the order of respiration (15.9-97.3%), meat growth (0-70%) and shell growth (0.9-31.8%), respectively . Scope for growth (SFG) ranged from ―2.2 to 45.0 Kcal/m3/day regulated by mainly temperature and salinity. Food availability (FA) ranged from 1.1 to 329 which met food requirements resulting in no mortality. Between the late spring and summer season , low FA resulted in food deficiency and further served as a factor for mortality when especially coupled with physical stress such as typhoons . The energetic cost of reproduction infferred from summer mortality corresponded to 15% for one year-old and 60% for 2 year-old oyster . Our results indicated that one of the factors for effective oyster culture , stocking time should be determined upon consideration of spat size. Small -sized spats in shell height should introduce in spring but large-sized (> 5 cm) in autumn to achieve the commercial oyster before next summer without significant mortality.

진동만 패류양식해역의 환경특성

정우건,조상만 한국패류학회 2003 The Korean Journal of Malacology Vol.19 No.2

Seawater and sediment quality analysed was calculated to examinate the present environmental characteristics and pollution load was also calculated to evaluate the effect of farming area on the coastal environment. The measurements for seawater quality demonstrate the coastal environment has relatively eutrophicated with significantly decreased DO (0.2-8.5 mg/l) and elevated COD (9.6-31.2 mg/l) in summer. It was also evident that the water quality in Jindong Bay has been influenced by residues tide from Masan Bay with high metal concentration in August of 2002. Annual total pollution load (land and farm-driven) was estimated at 37,316 ton (SS) /yr: 9,809 ton/yr (26.3%) of land-driven load, 23,576 ton/yr (63.2%) of coastal sedimentation and 3,932 ton/yr (10.5%) of feces of cultural organisms. When all ark shell seedling farms are permitted species conversion to ascidian farm, the pollution load would increase by 196%, which may be another source for accelerating the eutrophication of the environment in Jindong Bay.

Effects of Dietary Perilla Oil and Enteromorpha compressa Meal on Growth, Fatty Acid Composition and Hematology of the Cultured Sweet Smelt (Plecoglossus altivelis)

정우건,김인수,문수경,이상민,정보영,장희숙,Masashi Maita,임동훈 한국수산과학회 2004 Fisheries and Aquatic Sciences Vol.7 No.1

Sweet smelt (Plecoglossus altivelis) were fed four different diets supplemented with either perilla oil (2.0%) rich in 18:3n-3 (CP), and perilla oil and Enteromorpha compressa meal (2.0%) (CPA), soybean oil rich in 18:2n-6 (CO), or soybean oil and algal meal (CA) for 4 weeks. The growth performance, fatty acid composition of muscle, plasma lipid peroxidation and blood components of the sweet smelt were then determined. The specific growth rate and feed efficiency in the fish fed the CPA diet were the highest, while the other groups showed similar results. The fatty acid composition of muscle in sweet smelt reflected the dietary lipids; 18:3n-3 was higher in the fish fed the CP and CPA diets, and 18:2n-6 was higher in the fish fed the CO and CA diets. The other fatty acid profiles presented almost no differences with respect to the diet composition. The fish fed the CA, CP and CPA diets contained significantly lower levels of triglyceride, thiobarbituric acid-reactive substances and hydroxyl radical in their plasma than that fed the CO diet. Phagocytic activity was the highest in the fish fed the CPA diet and higher in those of the fish fed the CP and CA diets compared to the CO diet group. The results from this study suggest that a dietary supplement of 2.0% perilla oil together with 2.0% E. compressa meal may improve the growth and health of cultured sweet smelt.

Estimation of primary production of the waters around rack oyster farm at Wando, Korea

정우건,조상만 한국수산과학회 2018 Fisheries and Aquatic Sciences Vol.21 No.2

To establish a comprehensive management strategy, as part of the optimization of cultural practice for an oyster rack culture system, we used a numerical model to estimate the primary production in the waters on the eastern coast of Wando island, South Korea. The estimated primary production ranged from 17.12 to 1052.55 mgC m−2 day−1 (204.22 ± 224.75 mgC m−2 day−1 in average). Except for the times of peak phytoplankton blooms, the estimated primary production (PP) was consistently under 200 mgC m−2 day−1, which is more similar to the value of PP measured off the western coast of South Korea than the southern coast. No clear relationship was observed between nitrogen content and rainfall with the exception of heavy rainfall events, indicating that precipitation might not be the main source of nutrients in these waters. No clear influence was observed from Doam tidal discharge, located 24 km north from these waters due to main tide comes in this area from the channel between Gunwe-myeon in Wando island and Pukpyeong-myeon in Haenam-gun. Because of the shallow water depth and strong tidal current, resuspension of sediments, which causes an input of nitrogen into the system, could be easily caused by even mild wind and the infrequent passing of ships. Microscopic examination of the phytoplankton composition showed additional contribution of benthic species such as Paralia sulcata into the waters, which increase the productivity of oyster farms in the waters. The availability of nitrate and phosphate for primary production was temporarily limited throughout most of the spring and autumn blooming season.

Studies for the Sustainable Management of Oyster Farms in Pukman Bay, Korea: Estimate of Primary Production

정우건,조상만,이상준 한국수산과학회 2009 Fisheries and Aquatic Sciences Vol.12 No.2

To develop sustainable management strategies for oyster farms in Pukman Bay, Korea, we estimated primary production using a numerical model. Because oysters are filter feeders, estimations of primary production (PP) are essential in developing management strategies. The daily PP ranged from 0.07 to 1.5 gC/m2/d and showed significant spatial variations. The spatial distribution of PP was strongly associated with hydrodynamic features, and distinct patterns were observed in three different regions. In the inner bay, high PP was directly influenced by urban and agricultural sewage. The middle part of the bay had low PP, whereas PP in the outer area was high. PP was relatively low during the main oyster growth season, from late autumn to early winter. These findings represent important information for developing a management model for oyster farms in Pukman Bay

완도해역 수평망식 양식 굴의 기생충 감염 특성

정우건,조상만 한국패류학회 2019 The Korean Journal of Malacology Vol.35 No.4

In the tidal flat oyster rack culture introduced in 2010, we investigated the parasitic infection from November 2015 to June 2017. The water temperature and salinity were ranged from 7.32℃ to 27.18℃ and from 27.6 psu to 32.7 psu, respectively. From the two serial growth experiments, commercial market sized oysters can be achieved within 18 months, one size group from the 2015 population with 88.67 ± 7.52 mm in shell length, 79.74 ± 13.33 g in total weight in August 2016 and, and the another from the 2016 population with 93.77 ± 12.11 mm in shell length, 78.99 ± 20.84 g in total weight in June 2017, respectively. Sex ratio represented at 1:1 ratio being closed to mature season but some intersex oysters were observed in immature period. Parasitic infection was ranged from 26 to 100% in prevalence and from 1.6 to 4.0 in intensity, which being associated with water temperature and gonad development index. Using the PNA clamping PCR, the parasite was identified as Apicomplexa which including Perkinsiosis pathogen in manila clam. There is no evidence which Apicomplexa can negatively affect cultural performance of oyster but more elaborated studies are necessary to maintain the sustainability of the rack oyster culture in Wando coast, Korea.

안정만 패류양식해역의 표층퇴적물의 지화학적특성과 중금속 함량

정우건,조상만,이상준 한국패류학회 2014 The Korean Journal of Malacology Vol.30 No.4

Total 20 surface sediments were collected in Anjung bay to investigate the physicochemical environment and heavy metal contents. The physicochemical investigation ranged from 6.41% to 11.68% (average 9.52 ± 1.28%) for ignition loss (IL), from 17.99 mg/g to 43.84 mg/g (average 27.53 ± 6.39 mg/g) for chemical oxygen demand (COD), and from 0.05 mg/g to 0.61 mg/g (average 0.17 ± 0.14 mg/g) for acid volatile sulfide (AVS) with significant correlation between water content (W/C) and COD. A contour of spatial distribution indicated higher organic pollution at the bottom of ascidian, Stylea clava, cultural waters. Most of metals contents was not exceeded the NOAA’s effect range-low (ERL). Estimated enrichment factor (EF) ranging 0.96-1.12 indicated that the sediment environment of the studied waters was relatively pristine from heavy metal pollution in spite of increased vessel traffics, so far. 굴양식이 성행하는 안정만 해역은 인근 연안에 LNG비축기지, 조선소 등의 공단이 가동되고 있어 일부 양식장은 품종을전환하고 있다. 이 연구는 안정만 해역의 연안생태계에 영향을미치는 저질환경 특성을 조사하기 위하여 2009년부터 2010년까지 2회에 걸쳐 20개 정점의 표층퇴적물을 채집, 분석하였다. 안정만 해역의 표층퇴적물의 IL은 6.41-11.68% (평균 9.52 ± 1.28%) 의 범위였고, COD는 17.99-43.84 mg/g (평균27.53 ± 6.39 mg/g), 그리고 AVS는 0.05-0.61 mg/g (평균0.17 ± 0.14 mg/g) 의 범위였다. 유기물함량은 저질의 수분함량과 밀접한 상관관계가 있었고, 이는 양식품종의 분포 패턴과도 관계가 있어 흰멍게로 양식품종이 변화된 북부해역의 COD 가 비교적 높게 나타났다. 일부 조사정점을 제외하고 대부분의 중금속함량은 NOAA 의 ERL 기준치 이하였고, 중금속 부화지수는 0.96-1.12의 범위로 중금속 오염에서는 비교적 청정한 것으로 판단되지만, 증가하는 선박 통행량을 고려할 때, 지속적인 저질환경 모니터링이 요구된다.

북만의 양식 참굴, Crassostrea gigas의 수하시기에 따른 육중량 변화

정우건,조상만,조창환 한국패류학회 1999 The Korean Journal of Malacology Vol.15 No.1

굴의 육중량 변화는 수온과 chlorophyll에 의해 지배되지만, chlorophyll 양이 일정량 이상이 되면 이러한 경향은 다소 감소하였다. 수온에 따른 굴의 성장은 수온 하강 초기에는 강한 역상관 관계를 나타내었지만, 적정 수온이하로 하강하게 되면 상관관계가 다소 낮아졌다. 각 수하시기에 따른 육중량 성장식을 6월은 3차 방정식의 성장곡선이 나타났고, 7, 8월에 수하한 경우 지수형 곡선을 나타내었다. 그러나 9-11월의 경우 정량적인 성장을 하는 일차방정식의 성장패턴을 나타내었다. 성장 방정식으로부터 각 수하시기에 따라 목표중량 5 g까지 성장하는데 소요되는 기간을 계산하면 9월이 123일로 가장 성장이 빨랐고, 8월이 220일로 가장 오랜 기간이 소요되었다. 굴 종패의 수하적기는 수온상승기 말기부터 수온하강기 초기인 8월말부터 9월 중순 사이가 적당한 시기로 추정되고, 상품크기 5 g까지 성장하는데 평균 4-5개월이 소요되며, 이 시기는 12-1월경에 해당한다. From September 1994 to April 1996, we observed the suspending time dependant meat increase (dry weight) for oysters at Pukman Bay in Korea. The oysters which suspended in September increased to 5 g in meat weight (dry weight) by January. Ones in June increased rapidly but lessened during summer and this stagnation of meat increase extended to autumn. It took long time to compensate for the loss of meat weight owing to spawning. Oysters suspended in July or August showed low growth or stagnation due to the high water temperature and spawning activities after suspending. However, meat weight showed sudden increasement after December and achieved 5 g at the late farm period. The meat increase of oysters suspended in October or November was very slow during entire growing period. Most of them did not achieved 5 g during farm period. The negative correlation was observed between meat growth and water temperature in September. Also, there was a high correlation between meat growth and chlorophyll-a. It was believed that deficiency of food organisms in the water column lead slow growth in terms of meat growth, particularly right after transplanting seed oysters to the farm. Our study suggests that proper time for transplanting oysters is between August and mid-September. However, the data indicate that good growth of oysters is depending upon amount of food available in the water column.

한국산 및 일본산 굴, Crassostrea gigas 종패의 성장비교

정우건,조상만,문수경,정보영 한국패류학회 2001 The Korean Journal of Malacology Vol.17 No.1

일본산에서 이식한 종패의 성장과 한국산 굴의 성장을 조사하고자 1995년 6월부터 12월까지 경상남도 통영시 북만해역에 두 종패를 수하하여 패각 및 육성장을 조사하였다. 조사기간 중 수온은 표층 11.2-27.8$^{\circ}C$ (평균 19.84 $\pm$ 5.47$^{\circ}C$), 저층11.1-23.6$^{\circ}C$ (18.31 $\pm$ 4.18$^{\circ}C$) 였고, 염분은 표층 31.45-34.57 (평균 33.10 $\pm$ 1.16), 저층 31.69-34.35 (평균 33.24$\pm$ 1.06) 이었으며, 월별로는 9, 10월이 가장 낮았고, 12월이 가장 높았다. 클로로필은 1.66-2.67 mg/㎥ (평균 2.01 $\pm$0.36 mg/m$^3$) 의 범위였으며, 11월이 1.66 mg/$^3$으로 가장 낮았다. 패각 성장은 일본산이 한국산 보다 월등히 높은 성장량을 나타내어 12월 수확시 한국산은 70.3 $\pm$ 12.5 mm, 일본산은 96.2 $\pm$ 14.6 mm였다. 6-7월간의 성장이 가장 빨랐고, 한국산은 10월 이후 패각성장이 둔화된 반면, 일본산은 11월 이후 다시 급격한 성장을 하였다. 육중량은 9월까지 한국산과 일본산은 거의 비슷하였으나, 9월 이후 현저하게 차이가 나타나기 시작하였다. 12월 수확시한국산 4.6 $\pm$ 1.9 g, 일본산 7.5 $\pm$ 2.9 g으로 일본산의 육성장이 양호하였다. 그러나 일본산은 11월에 8.1 $\pm$ 3.0 g으로 가장 높은 육중량을 나타내었다가 12월에 다시 감소하였는데, 이는 먹이량에 의한 양식장의 수용력에 의해 조절된 것 같다(정, 1998). 한국산은 산란 후 회복이 느려 10월까지 비만도가 감소한 반면, 일본산은 9월부터 다소 증가하기 시작하여 10월 이후 급증하였고, 11-12월에 다시 급격히 감소하였다. 12월 수확시 비만도를 보면, 한국산은 12.8, 일본산은 15.3으로 일본산이 훨씬 높았다. 이상의 결과로 볼 때, 일본에서 이식한 종패의 성장이 모든면에서 한국산보다 우수하였다. 북만에 수하 양성한 한국산 및 일본산 굴 종패의 각고-각장 상관식은 아래와 같다. Korean oysters: S$_{h}$ = 2.922St - 4.8024 ($r^2$= 0.8541) Japanese oysters: S$_{h}$ = 3.623St - 5.1239 ($r^2$= 0.7782) Bae et al. (1976)과 Lee et al. (1992)이 보고한 한국산 종패의 각고-각장 상관식과는 기울기 차이가 현저하여 각고의 길이가 늘어나 일본산 종패 이식이후 한국산 굴의 형태적 변화가 있음을 알 수 있었다. To study the growth of transplanted Pacific oysters, Crassostrea gigas, we sampled Korean and Japanese oysters attached in Chinhae Bay near Gaduk Island and in Seto inland sea in Japan, respectively, suspended in Pukman Bay. Water Temperature ranged from 11.2 to 27.8$^{\circ}C$ (mean 19.84 ${\pm}$ 5.47$^{\circ}C$) on the surface, and 11.1 to 23.6$^{\circ}C$ (mean 18.31 ${\pm}$ 4.18$^{\circ}C$) on the bottom. Salinity ranged from 31.45 to 34.57 (mean 33.10 ${\pm}$ 1.16) on the surface, and from 31.69 to 34.35 (mean 33.24 ${\pm}$ 1.06) on the bottom. salinity was the lowest in September and October, and the highest in December. Growth of oysters in shell height showed a significant difference after being suspended at the farm, reaching 70.3 ${\pm}$ 12.5 mm in the Korean oysters and 96.2 ${\pm}$ 14.6 mm in the Japanese oysters in December. While the Korean oysters showed relatively low growth rate and cessation of growth after sudden growth between June and July, the Japanese oysters showed continuous growth during the whole farming period, although stepwise growth was observed. It was not until September that meat weight showed a significant difference between the two. After September, there was a sudden increase in the Japanese oysters, reaching 7.5 ${\pm}$ 2.9 g in December, but growth of the Korean oysters showed slow growth rate during whole farming period, reaching 4.6 ${\pm}$ 1.9 g in December. here was an obvious decrease in the meat weight of Japanese oysters in December, which might be attributed to restriction of food. Condition factors rebounded in October in the Korean oysters and in September in the Japanese oysters, respectively, attaining 12.8 in the Korean oysters and 15.3 in the Japanese oysters at the end of investigation on December. Shell length-height regression equations were as follows: Korean oysters: S$\sub$h/=2.922S$\sub$t/,-4.8024 (r$^2$= 0.8541) Japanese oysters: S$\sub$t/=3.623S$\sub$h/,-5.1239 (r$^2$=0.7782) This showed the possibility of morphological transformation in the shell of the Korean oysters since shell height was longer than those reported by Bae et al. (1976) and Lee et al. (1992).

수평망식 굴양식의 입식 시기에 따른 성장 비교

정우건,조상만 한국패류학회 2020 The Korean Journal of Malacology Vol.36 No.3

In order to investigate the effect of stocking time on the growth performances, the oyster, in a density of 100 individuals per bag, introduced into rack culture farm on Wando tidal flat at three different time, April 2011 (APR-11), June 2012 (JUN-12) and November 2012 (NOV-12), respectively. In APR-11 and NOV-12, the growth of oysters was, with an initial size of 20 g in total weight and 3-5 cm in shell height, reached to commercial size over 80 g in total weight within 6-8 months. Regardless of stocking time, the crash season from summer mortality began in June, which difference between air and surface seawater temperature become increasing. Age or size dependent mortality was observed by 20-30% for 1-year-old oysters (APR-11), and 70-80% for 2-year-old oysters (NOV-12), respectively. Because of the stresses from transfer handling in hot summer season and direct impact of typhoons in 2012, JUN-12 did not reached to commercial size throughout the experimental period. Our data indicated that stocking time is one of the most important cultural practices for strategic approach to achieve the successful oyster farming of rack culture. In Wando, to avoid disastrous mortality, it is not recommend for 2 year old oysters to be exposed by oversummering for more growth.