본 연구는 저염분 상태에서 수온 및 사육밀도와 같은 환경요인이 흰다리새우(Litopenaeus vannamei)의 성장에 미치는 영향을 조사하기 위하여 수행하였다. 연구 결과, 흰다리새우는 저 염분 상태에서 전반적으로 수온이 높을수록 생존율이 높게 나타났고, 사육밀도가 낮을수록 생 존율이 높아졌다. 사료효율에 관한 연구에서는 수온이 높을수록 증체량(WG)이 증가하였고, 사 육밀도가 증가할수록 증체량은 감소하였다. 수온이 높을수록(수온 31℃) 성장 속도가 빨랐다. 또한 사육밀도에 따른 성장도의 평가에서도 사육밀도가 낮은 상태에서 성장 속도가 빨라지는 것을 확인하였다. 본 연구 결과를 흰다리새우의 최적 성장을 위한 적정 사육밀도 및 사육수온 의 결정에 유용하게 적용되리라 사료된다.

In this study, using a continuous behavior measurement technique, the short-term behavioral responses and tolerance limits of red seabream Pagrus major fingerlings to sudden exposure to low salinity in a controlled environment were observed. The activity of the fingerlings suddenly exposed to 21.4, 17.3, and 9.8 psu increased temporarily at the initial exposure to show irregular swimming behavior, but then recovered a stable activity pattern through rapid salinity adaptation. However, the organisms suddenly exposed to 7.3 and 4.3 psu could not withstand the salinity stress, and their swimming behavior was severely disturbed and all individuals died within 48 hours. The findings suggest that red seabream underwent a temporary salinity stress process at the beginning of the exposure to concentrations of 10.0 psu or higher. At these concentrations, osmotic control was possible within at least 11 hours, so stable metabolic activity was also possible. However, organisms suddenly exposed to concentrations below 5.0 psu exceeded the tolerance to low salinity and the sublethal limit. In red seabream exposed to this concentration range, severe behavioral and metabolic disturbances were observed, and death was observed due to osmotic control failure. In conclusion, a salinity range of 5.0 to 10.0 psu can be predicted to correspond to a concentration range in which the osmotic control ability of the red seabream fingerlings is lost, and sub-lethal reactions occur.

The salinity of the brining solution for preparing kimchi imparts saltiness to kimchi, and affects its overall taste. In this study, the changes in the overall taste and quality of kimchi depending on the salinity of the brining solution (6% and 12%) were investigated. The salinity of kimchi brined in 6% NaCl solution was approximately 1.3%, and its umami (2.22±0.22) was lower than that (2.96±0.16) of the conventional kimchi, brined in 12% NaCl solution. In contrast, its bitterness (-3.77±0.05) was higher than that of the conventional kimchi (-4.48±0.12). The sensory evaluation results showed that the overall taste score of the low-salinity kimchi (2.8±0.4) was significantly lower than that of the conventional kimchi (4.5±1.1). To overcome the deterioration in the overall taste, a taste enhancer with a sea tangle extract and anchovy extract was added to the low-salinity kimchi. The overall taste score (4.4±1.2) of the seasoned kimchi, which is the low-salinity kimchi supplemented with the taste enhancer, was comparable to that (4.5±1.1) of the conventional kimchi, while maintaining a salinity of 1.7%. This study demonstrated the benefits of proper taste enhancer for improving the taste of low-salinity kimchi.

The preparation of commercial, low-salinity kimchi needs to be carefully monitored to maintain the taste of kimchi. To address this, the taste profiles of three brands of commercial kimchi were examined using a taste sensing system, as well as a sensory evaluation. The average sensory score (4.3/9.0) in the overall taste of low-salinity kimchi (A', B', and C') was significantly lower than that (5.1/9.0) of conventional kimchi (A, B, and C). The explanation for the result of A' seemed to be its decrease in saltiness (3.51) and increase in bitterness (8.55) compared to those (6.55 and 7.65, respectively) of A. In B', the saltiness (4.25) and the overall taste (3.7) were significantly decreased compared to B (6.23 and 4.8, respectively). Interestingly, no significant difference was observed in the overall taste (5.1) and saltiness (6.70) of C' when compared to C (5.3 and 6.46, respectively), confirming that salinity is a crucial factor in determining overall taste. Consistent with this finding, the overall taste of low-salinity kimchi correlated positively with its saltiness (>0.98) and umami (>0.82). These results advocate the careful determination of salinity required to maintain the taste of conventional kimchi in preparing low-salinity kimchi, while also pointing towards the need to develop effective taste enhancers for supplementing overall taste.

본 연구는 참굴(Crassostrea gigas)의 패각운동을 이용하여, 연안역에서 발생하는 저염수에 대한 조기경보가능성을 살펴보았다. 30 psu와 20 psu에서 패각운동은 각각 7.32±3.21회/hr와 7.11±3.90회/hr였으며, 파형과 횟수는 차이가 없었다(t-test, p>0.001). 하지만 10 psu와 5 psu 에서는 모든 개체가 폐각상태를 지속하였다. 수온과 염분의 복합실험결과, Group 1(수온 15 ×염분 15 psu)은 20 30 psu에서 보인 패각운 동 후(약 2 3시간), 장시간 폐각을 하였다. Group 2(수온 30 ×염분 15 psu)에서는 Group 1의 패각 개폐운동보다 더 빠르고 자주 나타나, 참 굴의 생리적인 위기상황에 대한 신호를 나타내었다. 따라서 이러한 파형은 하계 저염수 출현 시 나타낼 수 있는 조기경보 신호로 충분히 활용될 수 있을 것으로 보인다.

한반도 서남부해역은 하계 양자강의 유출에 의해 저염분 현상이 발생한다. 중국 대통(Datong)에서 지난 65년(1922­1986)간 장기관측한 자료에 의하면 매년 양자강 유출량은 일정하지 않으며, 최대 유출량은 최소유출량의 2배 이상이 됨을 보여주고 있다. 따라서 양자강의 유출량을 달리하여 저염확산을 수치모델로 연구하고자 하였다. 수치모델은 POM(Princeton Ocean Model)을 사용하였다. POM은 연직적으로 Σ­좌표계를 사용하는 3차원 해양순환모델이다. 모델 수행 후 연구해역내 대륙사면에서 유속이 강하게 나타났다. 또한 제주도 서쪽을 통해 북상하여 황해중앙부로 들어가는 흐름이 있으며, 대륙연안을 따라 남하하는 흐름이 있음을 알 수 있다. 양자강 유출량을 부여한 후 수행한 모델의 결과를 보면 양자강 유출량이 많을수록 저염분역이 제주도에 가깝게 나타남을 알 수 있다.