Scientists from the Florida Marine Research Institute believe that a toxin called saxitoxin was responsible for the poisoning of 19 people in Florida between January and April of this year after consuming puffer fish. This is the first time that saxitoxin has been found in Florida waters. The toxin is produced by a microscopic algae Pyrodinium bahamense var. bahamense, native to the Atlantic Ocean. This algae generally does not produce saxitoxin but the Pacific Ocean variety Pyrodinium bahamense var. compressum is known to produce this deadly toxin. It is possible that the Pacific Ocean variety has crossbred with the Atlantic variety. Other theories are that the Pacific variety was introduced and that environmental conditions triggered toxin production that had never been observed before. The algae is toxic at concentrations over 1 million per liter. In Guatemala 26 people died in 1987 due to saxitoxin present in shellfish. This same strain of algae is believed to be present in the Indian River Lagoon. The algae has been observed between Cocoa and Sebastian with algae completely covering the water in Grant. It is described as resembling the contents of a lava lamp. The dissolved oxygen levels in these areas tended to be low. At night the algae glows in the dark when the water is stirred. The Florida Fish and Wildlife Conservation Commission has banned the catching and consumption of puffer fish in about five counties in Florida. In the past five years the southern puffer fish population has been increasing in the northern portion of the lagoon. The highest amount of saxitoxin was found in the southern puffer fish in the Titusville area. Scientists believe that the high levels found around Titusville may be associated with the low level of water circulation in the Northern Lagoon. It is also thought that the puffer fish may have accumulated the toxin from consuming clams. Other fishes are less tolerant to the toxin and might die from consuming toxin-infested clams before humans can consume them. Researchers also believe that the presence of this saxitoxin in algae could be responsible for the unusual die-off of dolphins in the Indian River Lagoon in the past two years. In the summer of 2000 and 2001, approximately 120 dolphins died in the Indian River Lagoon, twice the typical levels.