Testing several hypotheses on the outbreak mechanisms of Cochlodinium polykrikoides
blooms in the southern coastal waters of Korea
Yeseul Kim1,2, Sinjae Yoo1,2, Young baek Son1 and Soonmi Lee1,2
1
Korea Institute of Ocean Science and Technology, Jeju, R Korea
E-mail: yees0408@kiost.ac.kr
2
Ocean Science and Technology School, Korea Maritime and Ocean University/Korea
Institute of Ocean and Science Technology Joint Program, Busan, R Korea
Harmful Cochlodinium polykrikoides blooms have continuously occurred and caused large
damages to the fishing industry since 1995 in the southern coastal waters of Korea. Earlier
studies proposed hypotheses on the outbreak mechanisms of C. polykrikoides blooms, which
include water mass stratification, nutrient input through precipitation, solar irradiance and
wind. These studies, however, have limitations in that the proposed hypotheses of C.
polykrikoides blooms focused only on specific incidences, and so require testing in a more
rigorous manner. In this study, a comparative analysis was conducted to determine whether
these hypotheses can explain bloom outbreaks across different locations for longer time
period using meteorologic and oceanographic survey data (2000-2014). The results of the
analysis indicate that none of the proposed factors consistently explain C. polykrikoides
bloom outbreaks over this period, and that the critical factors differ from area to area. For
example, precipitation showed a significant correlation with the outbreak duration in Yeosu
for the period 1996-2003 but not for the whole period (1996-2014). Likewise, wind (direction
and speed) and front formation could explain incidences in only certain area for some part of
the period. These findings suggest the actual outbreak mechanisms are a complicated mix of
multiple pathways whose switching depend on the balance of many factors working in
sequence rather than simultaneously.