In this chapter is discussed a miscel- 

 lany of flagellates, most of which are 

 found in the digestive tract. Only a few 

 are pathogenic, the great majority being 

 commensal. Some are not parasitic at all 

 but are coprophilic or have been found as 

 contaminants in washings from the sheath 

 of bulls; these are mentioned because they 

 must be differentiated from parasitic 

 forms. A few other species are free-liv- 

 ing toxin-producers. 



TOXIC MARINE PHYTOFLAGELLATES 



The great majority of phytoflagellates 

 are free-living and holophytic. Some of 

 them produce powerful toxins which may 

 kill fish or even man. 



Gonyaulax catanella is a marine dino- 

 flagellate, found particularly off the coast 

 of California, which causes a fatal dis- 

 ease of man known as mussel poisoning. 

 Its toxin is one of the most powerful known. 

 Under conditions still largely unknown, the 

 protozoa multiply tremendously, forming 

 a luminescent "bloom" in the ocean. Mus- 

 sels and certain other shellfish feeding on 

 plankton are not harmed by the toxin but 

 accumulate it in their internal organs. 

 People who eat these mussels may then be 

 killed by the toxin. 



The blooming of other dinoflagellates, 

 including several species of Gymnodinium, 

 cause the "red tide" or "red water" which 

 sometimes kills huge numbers of fish, de- 

 positing them in rotting windrows on the 

 shore. This condition is particularly 

 common off the coast of Florida, where it 

 is associated with the discharge of phos- 

 phates into the ocean, but it also occurs 

 off the Texas coast and elsewhere (Hutner 

 and McLaughlin, 1958). 



A third marine phytoflagellate, the 

 chrysomonad Prymnesium parvmn, has 

 killed fish en masse in brackish fish ponds 

 in Israel, and has formed blooms accom- 

 panying fish kills in Holland and Denmark 

 (McLaughlin, 1958). 



,RY 





Chapter 6 



OTHER 

 HAGBUATES 



- 107 



