• Fisheries and Aquatic Sciences
• /
• v.2 no.1
• /
• pp.58-65
• /
• 1999

Fibrocapsa japonica (Raphidophyceae) is regarded as a harmful algal bloom organism in Japanese waters, where it has been linked to fish kills. Fibrocapsa is a common species in New Zealand coastal waters, particularly in the Hauraki Gulf, where it has regularly bloomed in the spring under E1 Nino climate conditions for the past six years. The New Zealand isolate had 1.4 times more total polyunsaturated acids than the Japanese isolate under the same growth conditions, suggesting that eicosapentaenoic acid in particular coold be used as a discriminating chemotaxonomic marker. The molecular probes tested showed no differential binding of the raphidophytes to lectins, but oligonucleotide probes targeted F. japonica ribosomal RNA bound specifically to both isolates. Neither strain was toxic in mouse or neuroblastoma bioassays. There is no evidence that the New Zealand F. japonica isolates investigated to date produce ichthyotoxins.

• Fisheries and Aquatic Sciences
• /
• v.2 no.1
• /
• pp.17-24
• /
• 1999

The blooms caused by Fibrocapsa japonica have occurred regularly in New Zea1andean coastal waters, and no fish kills and economic impacts have been reported. However, Fibrocapsa japonica in Japan killed caged juvenile fish and has been regarded as a harmful micro algae. In this comparative study a New Zealand isolate was found to be morphologically similar to a Japanese isolate, although slightly larger on average than. Optimal temperatures for growth differed, with fastest growth rates occurring at $22-24^{\circ}C$ for the New Zealand strain and $16-22^{\circ}C$ for the Japanese strain, with a decrease in growth rate exhibited by the latter at $25^{\circ}C$. Both isolates had low salinity optima of 20-25 PSU, although they grew between 15 and 30 PSU. Growth declined significantly for both strains above 30 PSU.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.16 no.4
• /
• pp.381-386
• /
• 2010

We have cultured the bluefin tuna in Yokjido, Tongyeong with floating cage which was vulnerable to harmful dinoflagellate, Cochiodinium polykrikoides. This study inspected a vertical migration of phytoplankton and Chl-a for reasonable sinking depth in floating cage. Furthermore, we analyzed the fluctuation of the phytoplankton including harmful dinoflagellates occurring in Yokgido for 6 years. Total cell density showed a significant monthly variation and the flora was predominated with diatoms. Gymnodinium sp. occurred 19 times, the greatest number of occurrence in all kinds of dinoflagellates during summer. In particular, the total number of occurrence at C. polykrikoides was 8, and harmful dinoflagellates such as Karenia brevis/Fibrcapsa japonica occurred. The relationship between Chl-a concentration/total cell number and sunset/sunrise was significant and reasonable sinking depth in floating cage was found to be at least 3m from the water surface, which was associated with massive fish kills caused by C. polykrikoides.