Karenia mikimotoi

Karenia mikimotoi has yellow-brown chloroplasts and, like other species in its genus, is able to activate photosynthetically. It lacks thecal plates, and is more ovular. Blooms usually form during warmer months. The toxicity of Karenia mikimotoi is not fully understood, whereas other species in Karenia have identified toxins that are shown to kill marine life. For example, Karenia brevis has brevetoxins. It is believed that its killing effects are due to a combination of the creation of an anoxic environment by the physical bloom itself in addition to some sort of toxin. New toxins called gymnocin A and B were discovered in 2005, but their low toxicity is inconsistent with the high number of deaths Karenia mikimotoi causes. It is believed that in red tides, Karenia mikimotoi fills in the fish's gills, thereby allowing direct contact with toxins. This is a more likely approach to the toxin's mechanisms.