Food availability
The food availability could also be an essential factor for the outbreak of C. acicula. The food of pteropods like that of most plankton feeders is composed of phytoplankton and protozoa such as diatoms, dinoflagellates and minute crustaceans. It is noteworthy that in Daya Bay, coincident with the temperature increase, the concentration of Chla collected from the samae buoy jumped from 0.96 mg m-3 on June 9, 2020, to 5.53 mg m-3on June 10, 2020, and maintained at a relatively high level of >1 mg m-3 for one week, which might be attributed to high loads of nutrients from runoff induced by heavy rainfall (Fig. 6). It suggested that there is a high supply of food resources for C. acicula , who feeds on phytoplankton and protozoa.