Paralytic shellfish poison, the primary source of the poison, the marine plankton organism, Gonyaulax catenella.

Shellfish, such as clams, mussels, and oysters, feed on marine plankton. At least one species of dinoflagellate, Gonyaulax catenella Whedon and Kofoid, has been shown by Sommer and coworkers (1) to be a source of the poison found in the California mussel, Mytdus californianus Conrad. The present investigation was carried out to determine the feasibility of collecting the plankton and extracting and concentrating the poison from this source for chemical studies. The dinoflagellate, Gonyaulax catenella, is too small to be visible to the naked eye. However, if the concentration of these organisms, which multiply very rapidly under favorable conditions, approaches l,OOO,OOO per liter, a reddish brown coloration of the surface water is observed. When the concentration reaches 20 to 40 million cells per liter, the ocean is a deep rust-red by day and brilliantly luminescent by night. High concentrations of certain non-poisonous marine plankton organisms may also appear as “red water.” For the large scale collection, the United States Navy’ supplied a patrol boat equipped with two Sharples supercentrifuges adapted as clarifiers. As red water is easily visible from the air, the Naval Lighter-Than-Air Command patrolled several miles of the coastline of California to find the area of its greatest concentration. The blimp directed the boat by radio contact to a spot in Monterey Bay just south of Santa Crux and dropped smoke flares to locate the exact position of the red water. The boat was allowed to drift into the colored areas, and the surface water of the bay was pumped through the centrifuges. In this way the plankton was removed from 5000 liters of sea water in a period of 3 hours. The plankton, which consisted mainly of Gonyaulax catenella, was de-