멍게의 물렁증 발생에 미치는 용존산소의 영향 (Effect of Dissolved Oxygen on Occurrence of Tunic Softness Syndrome in Sea Squirt Halocynthia roretzi, Tongyeong, South Coast of Korea)

서지정보

· 발행기관 : 한국환경생물학회
· 수록지 정보 : 환경생물 / 31권 / 3호 / 204 ~ 212페이지
· 저자명 : 신윤경, 박정준, 전제천, 명정인, 양성진

초록

This study analyzed the occurrence of tunic softness, survival rate, metabolic rate and histopathologic changes arising from the effect of hypoxic environment in order to find the causes of occurrences of tunic softness, which manifests as the key phenomenon of mass mortality of Halocynthia roretzi. Regarding the survival of H. roretzi with reduction in dissolved oxygen, all the entities died on the 4th day of exposure to the dissolved oxygen concentration of 2 mg L‑¹ while 50% mortality was observed on the 5th day of exposure to the dissolved oxygen concentration of 3mg L‑¹. Therefore the 5 days-LC50 was found to be 3.55 mg L‑¹ (1.86~4.96 mg L‑¹). However,occurrence of tunic softness was not observed during the period of exposure to low oxygen concentration.
The oxygen consumption rate significantly decreases at the dissolved oxygen concentration of less than 5 mg L‑¹ in comparison to the control group. Therefore, it is presumed that H.
roretzi controls the respiration rate for prescribed period of time when exposed to hypoxic environment. Regarding the histopathologic changes in the gill, digestive gland and cyst of H.
roretzi due to hypoxic environment, necrosis of epithelial layer, in filtration of blood cells, and condensation of nucleus that compose each of the organs were observed. Regarding morphological changes, the decrease in volume with shrinking of the tunic, discoloration of the internal organs and necrosis of gill and hepatopancreas were observed.

영어초록

This study analyzed the occurrence of tunic softness, survival rate, metabolic rate and histopathologic changes arising from the effect of hypoxic environment in order to find the causes of occurrences of tunic softness, which manifests as the key phenomenon of mass mortality of Halocynthia roretzi. Regarding the survival of H. roretzi with reduction in dissolved oxygen, all the entities died on the 4th day of exposure to the dissolved oxygen concentration of 2 mg L‑¹ while 50% mortality was observed on the 5th day of exposure to the dissolved oxygen concentration of 3mg L‑¹. Therefore the 5 days-LC50 was found to be 3.55 mg L‑¹ (1.86~4.96 mg L‑¹). However,occurrence of tunic softness was not observed during the period of exposure to low oxygen concentration.
The oxygen consumption rate significantly decreases at the dissolved oxygen concentration of less than 5 mg L‑¹ in comparison to the control group. Therefore, it is presumed that H.
roretzi controls the respiration rate for prescribed period of time when exposed to hypoxic environment. Regarding the histopathologic changes in the gill, digestive gland and cyst of H.
roretzi due to hypoxic environment, necrosis of epithelial layer, in filtration of blood cells, and condensation of nucleus that compose each of the organs were observed. Regarding morphological changes, the decrease in volume with shrinking of the tunic, discoloration of the internal organs and necrosis of gill and hepatopancreas were observed.

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