New York Times April 11, 1996 The manatee population has suffered a devastating blow so far this year. About 221 manatees have been found dead already. Out of those 221, 128 have no obvious cause of death. Marine biologists have been unable to find the cause of these deaths. They suspect that the Red Tide off of the coast of southwest Florida has some connection with these mysterious deaths. A red tide is a bloom of flagellates which are deadly to marine life, but cause no harm to the human population. Another possible cause is a virus ....