In a three week period Seven manatees have died in the Lagoon in Brevard County. All seven showed no outward signs of illness, but had stringy-looking shell casings of a marine worm in its digestive tract. The species of worm has yet to be identified as the cause of death and has not shown up in any other dead manatees found in the state so far this year. A biologist from the U.S. Geological Survey’s Sirenia project will examine sediment from the lagoon bottom to see if the worms or something else may be getting into the manatee’s food chain. Biologists at Harbor Branch Oceanographic Institute are examining tissue samples from the dead manatees. A paralyzing worm in the brains of sea turtles contributed to a record 1,337 sea turtles found dead in Florida in 2001, the most since monitoring began in 1980. Boating injuries were also at an all-time high, along with entanglement in shrimp nets. Researchers believe the destruction and shrinkage of habitats and the effects of pollution might be stressing animals high on the food chain and lowering their defenses to disease.