“There are still so many things we don’t know about [a milky sea] beyond that it must be caused by bacteria,” says Steven Haddock, a marine biologist at the Monterey Bay Aquarium Research Institute in Moss Landing, Calif., who collaborates with Hudson on milky seas research. “What are the substrates that fuel the growth of these massive numbers of bacteria, and what are the environmental factors that keep them from getting diluted into the water column?”
https://www.sciencenews.org/article/bioluminescent-milky-seas-predicted
Sounds a bit fishy to me