Recently, mass mortality of the young abalone Haliotis discus hannai has occurred in commercial seed production farms in Korea. The mortality rate was above 50% of the total cultured organisms in the farm, and the shell length of the moribund organisms was about 3cm. The mortal phenomenon was that the young abalones were weakly scattered on the bottom of the pond from the attachment matrix, or that they could not be moved back to their normal positions. The diseased farmed Pacific abalone had abdominal edema. From the edema in the moribund individuals, three bacterial strains were isolated and all the strains were identified as Vibrio harveyi. These strains were compared with thirty six strains isolated from the fish. The results was that the Vibrio harveyi from the fish were sorted into genogroup A or B; however, the three strains of the diseased farmed Pacific abalone were sorted into genogroup A and the new genogroup C. The identical mortality and pathological symptoms of the naturally infected organisms were reproduced by artificial infection with WA AG-1 and WA CS-5 strains. The LD50 of WA AG-1 and WA CS-5 were each 1.0×103 cfu animal-1 and 1.7×104 cfu animal-1.

생존율은 염분과 관계없이 8℃, 10℃일 때는 98.7~100%였으나, 4℃일 때는 생존율이 25~55%로 나타났다. 혈림프액 내 SOD와 glutathione 농도와 같은 스트레스 지표는 모든 염분구에서 4℃, 6℃일 때 높게 나타났다. THC, hemocyte population, apoptotic cell및 necrotic cell의 비율은 염 분 별로는 26 psu구에서 가장 높게 나타났고, 4~6℃일 때 다른 실험구에 비해 유의하게 높았 다. 이러한 결과들은 26 psu의 염분과 6℃ 이하의 수온에서는 참전복의 스트레스 반응이 증가 하였으나, 30, 34 psu의 염분과 8, 10℃의 수온에서는 대조구와 차이가 없어, 참전복의 수송을 위한 적정 수온 및 염분 조건은 8~10℃, 30~34 psu인 것으로 나타난다.

This study is aimed comparative analysis for business performance of land-based ezo abalone (Haliotis discus hannai) seed farms by standardizing cost structures by region and farming size. The result of survey on average farming incomes by region showed that farming incomes in Haenam and Jindo regions were much higher than those in other regions. Followed by Wando region, incomes in other regions were analyzed to be relatively lower. It is shown that farming incomes became higher as farm size increased. Farming incomes per unit size which were modified from farming incomes by region were highest in Jindo region, followed by East sea region, Wando and Haenam regions. Incomes in Jeju and Yeosu regions were analyzed to be relatively lower. Results on farming incomes per unit size (m2) showed that both farming incomes and profits became higher as size increased. It implies that a scale effectiveness might exist in case of land-based abalone culture system. Impacts of major factors on farming profits and returns on investment in abalone seed aquaculture are summarized as follow. First, only if the survival rate increased by 10% with improvement of component ratio, variable effects became largest. In variable effects of other factors, a variation in Jindo region was largest and on the other hand, a variation in Yeosu region was shown to be smallest.

The moving ranges and behavior of four wild abalones, Haliotis discus hannai, were measured by an acoustic telemetry technique. The shape of the sea bottom of the experimental area was surveyed by a bathymetry system and three self-recording type acoustic receivers were used for monitoring the behavior and measuring the movement range. The abalones (WA1-WA4) attached acoustic tags were released and measured the movement during ten months. Three abalones (WA1, WA3 and WA4) were successively detected around the released point during the experiment and were moved to the V2 area where water depth is deeper than the V1 area. The change of inhabitation depth was also detected from the depth sensor of WA4. As the result, abalones were moved to deeper water area accordance with the decrease of the water temperature. The moved ranges of abalones were approximately 200 - 400m from the release point.