Reproductive capability
The capacity to produce a large amount of larva is an essential
necessity for the outbreak of a species’ bloom. C. acicula has
this capability partly contributed to its parthenogenetic behaviour.
Based on our laboratory observation, one single C. acicula can
produce one or more “egg capsules” in a reproductive cycle, each
capsule contains as many as 700-1000 oosperms. Therefore, C.
acicula population probably can always produce huge amount of oosperms,
however, the vast majority cannot develop into larva stage or cannot
grow up into mature individuals under natural conditions. They dead
either due to rigorous environmental conditions or eaten by predator.
Hence, we may can assume that the environment conditions of the bay in
June and/or theretofore were suitable or tolerable for C.
acicula, while did not for its competitor or predator, therefore, huge
number of individuals survived and the bloom was formed.
In conclusion, the abundance of C. acicula is controlled by
various physical and chemical parameters of the environment, such as
temperature, salinity, food, and biological parameters such as
competitor and predator. For the present case in Daya bay, higher
temperature and Chl a , and lower salinity may have possibly
triggerred this event. However, not a single condition on its own could
have caused the outbreak. Most likely, these conditions combined with
other unknown factors led to such a tremendous surge in the amount ofC. acicula . Unfortunately, till now, there is very limited
information on the life history, physiological metabolism, and feeding
habit of C. acicula . The specific inherent mechanism triggering
such an intensive bloom of C. acicula remains unknown. The
possiblities of a second surge of C. acicula in Daya Bay, its
occurrences of blooms elsewhere, and its potential of becoming a global
recurrent issue like jellyfish certainly deserve attention. To better
characterize and understand this organism, test hypothesis raised in
this report, and assess possible ecological sequences and second
outbreak of C. acicula , our lab analysis and field surveys will
continue into the future.