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.