RED TIDE 



By Reuben Lasker and F. G. Walton Smith, Marine Laboratory, University of Miami ' 



The nature of phytoplankton blooms, i. e., the 

 extensive production of microscopic aquatic flora 

 in localized areas, is today, as in the past, an un- 

 solved problem facing the biologist, oceanographer, 

 and limnologist. Many scientific reports attrib- 

 ute the wholesale death of fishes and other ma- 

 rine organisms to these phenomena. Since the 

 water which is affected is discolored, resulting in 

 an amber or red color, the popular terminology 

 has provided names for an outburst of this sort 

 ranging froni "yellow water," "rotten water," and 

 "red plague," to the term now in common use, 

 the "red tide." 



Outbreaks of discolored water are common 

 throughout the oceans of the world. These may 

 or may not be associated with fish mortalities. A 

 comprehensive record of fish mortalities due to 

 poisoning of water by dinoflagellates and other 

 phytoplankton is given bv Brongersma-Sanders 

 (1948). 



The Gulf of Mexico has probably been the scene 

 of fish mortalities throughout its geological history 

 (Brongersma-Sanders, 1948). Written records, 

 however, date back only to 1844. Recorded fish 

 mortalities took place in the Gulf of Mexico in 

 the years 1844, 1854, 1878, 1880, 1882, 1883, 1908, 

 1916, and 1946. In some places, such as Offatts 

 Bayou in Galveston Bay, there is an annual re- 

 curring mortality (Connell and Cross, 1950). 



The events associated with the 1844 and 1854 

 incidents are briefly recorded by Ingersoll (1882) 

 in the Proceedings of the U. S. National Museum. 

 The 1878 outburst was located near Cedar Keys 

 and particularly off the Anclotes. Vast quan- 

 tities of dead sponges were found, and the profit- 

 able sponging grounds in that area were badly 

 depleted. In 1880 an area extending from the 

 southern shore of Tampa Bay, from Egmont Key 

 at its mouth, southward to Shark River and 

 Whitewater Bay, was the scene of mass fish mor- 

 talities. Hordes of fishes and other aquatic ani- 



■Contribution No. 104 from the Marine Laboratory, University of Miami. 



mals were found dead and dying. Fatal patches 

 were also found southward through Bahia Honda 

 passage, beyond Key West, and in some places as 

 far as the Tortugas. 



Another account of "poisoned water" in the 

 Gulf (Anonymous, 1883) cited an area off Indian 

 Pass, approximately 1 mile long, between Clear- 

 water and Egmont Light. The streak of "poisoned 

 water" was covered with all varieties of dead 

 fish. The total of individual fish deaths was not 

 estimated. 



Similar mortalities broke out in this area in 

 1883, 1908, and 1916. The 1916 instance was 

 particularly severe and lasted from October 3 un- 

 til the end of November of that year. Represent- 

 atives of all fishes local to the area between Boca 

 Grande and Marco were killed, although few other 

 aquatic animals were affected. Taylor (1917) 

 found no extraordinary numbers of dinoflagellates 

 but observed that "the evidences contrary to such 

 an explanation [were] not altogether convincing." 

 His late arrival on the scene of the then current 

 red tide may have accounted for the absence of 

 the organisms. 



In most cases, nauseating odors and the ten- 

 dency for sneezing and respiratory distress were 

 present. Discolored water was reported in all but 

 a few accounts of mortality. It is quite plausible 

 that the noxiousness, and particularly the dis- 

 coloration of the water, was due to heavy concen- 

 trations of toxigenic phytoplanktonic organisms in 

 practically all the cited cases. 



Most of our information regarding recent out- 

 breaks of red tide in the Gulf of Mexico stems 

 from investigations made by several independent 

 workers and organizations during the red tide of 

 1946-1947. (Gunter, 1947; Gunter et al., 1948; 

 Davis, 1948; Ketchum and Keen, 1948; King, 1950; 

 Smith, 1949; Woodcock, 1948.) An excellent re- 

 view is offered by Galtsoff (1948, 1949). 



Between November 1946 and August 1947 ap- 

 proximately half a million fish were annihilated. 

 The Florida west coast fishery industry suffered 



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