Sulfated polysaccharides are known to be immune-stimulators in mammals and can be used as food additives to enhance immunity. In this study, the immune-stimulating activity of water-soluble anionic macromolecules F2 fractionation isolated from Codium fragile using ion-exchange chromatography was tested in olive flounder, Paralichythys olivaceus, in vitro and in vivo. The gene expression of interleukin (IL)-1β was adopted to check the immune-affection. As a result, in vitro study revealed that the expression of IL-1β was significantly upregulated in head kidney cells by 1 and 5 μg/ml of polysaccharides 4 h and by 5 μg/ml of polysaccharides at 24 h. In vivo, IL-1β gene expression in head kidney was significantly upregulated by 20 and 100 μg of the polysaccharides at day 1 post-i.p. injection, while downregulated at day 3 but not significant. Meanwhile, in peritoneal cells, it was upregulated by 20 μg of the polysaccharides at day 1 but the upregulation was sustained until day 3 though it was not significant. These results indicate that the sulfated polysaccharides from C. fragile are an immune-stimulator and might be potential feed additives for olive flounder.

급격한 수온의 변화는 어류의 생리학적인 측면에서 스트레스를 유발한다. 본 연구에서는 넙치 (Paralichthys olivaceus)로부터 각 수온별(9, 12, 15, 18 및 21℃) 조건에 따라 24 및 48시간 동 안 노출시킨 후에, 혈액생리학적 분석, 스트레스 단백질로 알려진 Hsp70 mRNA 발현 및 산소 소비량을 조사하였다. 혈액학적 분석에서 hematocrit (Ht) 및 hemoglobin (Hb), 혈장 코티졸 및 글루코스의 변화, aspartate aminotransferase (AST) 및 alanine aminotransferase (ALT), NH3, 삼 투질농도(osmolality) 및 총단백질(total protein, TP)은 9℃ 및 12℃에서 다른 수온별 실험구에 비 해 대부분의 항목에서 유의적인 차이를 보였다. Hsp70 mRNA 발현은 9℃ 및 12℃에서 다른 실험구에 비해 높은 발현량을 확인하였고, 산소소비량은 9℃ 및 12℃에서 21℃에 비해 낮았다. 이러한 결과는 넙치 종자의 장거리 수송을 위한 수온자료로 활용할 수 있다

In order to manage and rebuild fishery resources, the fishing effort should be controlled effectively. Especially in the setting up of the proper level of fishing efforts, economic standards as well as biological standards must be carefully considered to promote the sustainable and economically viable development of fisheries. This study aimed to analyze the optimal economic fishing effort (EMEY) as the most economically efficient one for the Eastern Sea Danish seine fisheries. The results showed that the optimal economic fishing effort (EMEY) of Eastern Sea Danish seine fisheries for blackfin flounder should be reduced by about 27%. That is, reducing fishing efforts up to the level of EMEY could lead to the reduction of fishing costs, thereby resulting in the increased fishing profits.

The purpose of this study was to analyze the production and marketing control effects of aqua-cultured flounder required for stable income growth of aqua-cultured household. We analyzed the supply and demand structure of cultured flounder using the partial equilibrium model approach. And we estimated the optimal yield of cultured flounder and analyzed the effect of marketing control through constructed model. The main results of this study are summarized as follows. First, the fitness and predictive power of the estimated model showed that the RMSPE and MAPE values were less than 5% and Theil’s inequality coefficient was very close to 0 rather than 1. It was evaluated that the prediction ability of the aqua-cultured flounder supply and demand model by dynamic simulation was excellent. Second, dynamic simulation based on policy simulation was conducted to analyze the price increase effect of production and shipment control of cultured flounder. As a result, if the annual production volume is reduced by 1%, 5%, and 10% among 32,852〜37,520 tons, it is analyzed that the price increase effect is from 1.2% to 12.5%. Finally, this study suggests that the production and marketing control can increase the price of aqua-cultured flounder in the market. In this paper, we propose a policy implementation of the total supply system instead of conclusions.