First record of blooms of Cochlodinium sp. (Gymnodiniales, Dinophyceae) causing mortality to aquacultured salmon on the west coast of Canada

The Possibility of Reactive Oxygen Species (ROS)-Independent Toxic Effects ofCochlodinium polykrikoideson Damselfish (Chromis caerulea)

“…[2][3][4]8) In the present study, we found that damselfish were highly susceptible to C. polykrikoides: 100% mortality occurred within 90 min after exposure to dense C. polykrikoides (4 Â 10 3 cells/ml) (Fig. 1).…”

“…Consistently with our results, previous studies conducted with several fish species, such as juvenile Atlantic salmon (Salmo salar) and juvenile slipmouths (Leiognathus nuchalis), found that 20-90% mortality occurred on exposure to C. polykrikoides at cell densities ranging from 10 3 to 10 4 cells/ml. 2,3,8) Even though the potent fish-killing activity of C. polykrikoides was confirmed by these laboratory exposure experiments, the exact toxic mechanism is still controversial.…”

“…2,3,[25][26][27] More recently, blooms of this dinoflagellate have been reported in the United States.…”

“…1,2) HABs due to this dinoflagellate have been reported in Japan, Korea, and other countries, and frequently cause severe damage to fish farming. [1][2][3][4] For instance, blooms of C. polykrikoides have been the cause of losses to fisheries of more than US$100 million in Korea. 5,6) Although the potent fish killing activity of C. polykrikoides has been well documented, the precise mechanism of fish kills by this dinoflagellate is still unclear.…”

Scripps Institution of Oceanography

“…Kofoid & Swezy (1921) observed twenty-five species of Cochlodinium San Diego waters Future investigation will be performed to determine which species of Cochlodinium is being observed in our local waters. Nevertheless, two species of Cochlodinium (Cochlodinium polykrikoides and Cochlodinium catenatum) have been previously reported to cause fish and coral mortality in Korea, Canada, Panama, and Costa Rica when high cell numbers were observed (Guzman et al, 1990;Whyte et al, 2001). The precise means of toxicity of these two species is yet to be determined.…”