美國魚類大批死亡或因軟骨藻酸中毒

美國魚類大批死亡或因軟骨藻酸中毒
2011年03月17日09:00
來源：新華社

　美國研究人員12日公布的一項最新調查結果顯示,污染可能是導致日前美國洛杉磯以南的國王海港海域數百萬條魚死亡的主要原因,這一結論否定了這起事件與環境污染無關的說法。

　　9日,美國加利福尼亞州漁獵局公布的一項調查稱,當地近日連續發生暴風雨,大批魚類被趕進封閉的碼頭區,擁擠的空間內含氧量不足是導致這些魚類因窒息死亡的原因。

　　但美國南加州大學海洋學家戴維 卡倫指出,研究人員在對死魚進行解剖化驗后發現,這些死魚體內含有高水平的有毒化學物質軟骨藻酸。

　　軟骨藻酸是由擬菱形藻屬硅藻產生的一種強烈神經毒素,能夠污染魚和貝類等海洋生物。卡倫解釋說,一種可能是,由於體內含毒,大量聚集在國王海港海域的魚類無法適應擁擠的空間,最終大批死亡;另一種可能是,這些魚類在“中毒”后失去了方向,結果大批聚集在狹窄的空間內,最終導致窒息死亡。

　　調查還發現,距離國王海港不遠處的洛杉磯聖莫尼卡灣近日因海藻泛濫出現赤潮,研究人員認為這一現象可能與國王海港海域大量魚類死亡有關。

　　目前,國王海港海域死魚清理工作正在加緊進行,整個清理工作可能要花費超過10萬美元。據估計,死魚大約有70噸,它們大多是喜歡成群結隊活動的沙丁魚,此外還有鳳尾魚、鯖魚和其他小魚。

http://env.people.com.cn/BIG5/14165601.html

報告：神經毒素發現在南加州碼頭漂浮的死沙丁魚
Report: Neurotoxin found in dead sardines found floating in Southern California marina
Associated Press
Last update: March 12, 2011 - 1:17 AM

LOS ANGELES - The millions of sardines that were found floating dead in a Southern California marina this week tested positive for a powerful neurotoxin, researchers said Friday.

High levels of domoic acid were found in the sardines, which may have distressed them off the Los Angeles coastline and caused them to swim into the Redondo Beach marina, University of Southern California biologist David Caron wrote in a summary of his laboratory's findings which were reported by the Los Angeles Times.

Caron said that he still believes that critically low oxygen levels in the water caused the sardines to suffocate, but it's possible the toxin may have been one explanation for why they crowded into the marina.

The California Department of Fish and Game has blamed the die-off on oxygen deprivation and is also testing fish for toxins at its animal forensics laboratory. Results are not expected until next week.

Domoic acid is often found in the stomach of fish that have been feeding on plankton during toxic algae blooms. The toxin has been linked to neurological disorders, illnesses and deaths in seabirds, sea lions, sea otters and whales.

Caron's lab is working to determine if the poisoning was caused by a toxic algae bloom spotted off Redondo Beach on Wednesday.

The presence of the toxin in the sardines could lead to health complications for pelicans, gulls and other sea life that have been feasting on the dead fish.

"There were tons of birds feeding on these fish and it's conceivable that we'll see some bird mortality as a result," Caron said.

The fish died late Monday and carpeted the water's surface the next morning, stacking up to 2 feet deep in some places. Crews have already scooped and hauled away more than 85 tons of fish to a composting center where they will turn into fertilizer.

http://www.startribune.com/nation/117844043.html