NOTES 



PARALYTIC SHELLFISH POISONING 



IN TENAKEE, SOUTHEASTERN ALASKA: 



A POSSIBLE CAUSE 



PSP (paralytic shellfish poisoning) has been 

 reported from much of the west coast of North 

 America. Recent reviews (Halstead 1965: 157-240; 

 Quayle 1969) summarizing many aspects of the 

 problem have emphasized its causative organism, 

 Gonyaulax catenella (and possibly G. acatenella). 



Chemical studies (Schantz and Magnusson 1964) 

 indicate that the poison is chemically similar 

 throughout the range of G. catenella— Califorma 

 through Alaska. Because of this similarity, and the 

 reported occurrence of G. catenella in Alaska 

 (Meyers and Hilliard 1955; Sparks 1966; Neal 1967), 

 it has often been assumed that this species is the 

 cause of PSP in Alaska. This assumption has not 

 been well verified, however. A 2-yr study in 

 southeastern Alaska by the University of Alaska 

 failed to find a significant correlation between the 

 occurrence of PSP and G. catenella (Chang 1971). 

 Sparks (1966) and Neal (1967) reported a correla- 

 tion in their occurrence near Ketchikan, but the 

 number of G. catenella was so low that very long 

 toxification periods would have been required to 

 cause lethal clams. 



The difficulty in verifying the relationship re- 

 sults, in part, from the very low densities of G. 

 catenella in Alaska plankton (Schantz 1966; Chang 

 1971). Sparks (1966) stated that it has even been 

 difficult to demonstrate that G. catenella occurs in 

 Alaska waters. Since toxic shellfish occur quite 

 frequently in southeastern Alaska, some observers 

 (Schantz and Magnusson 1964; Neal 1967; Chang 

 1971) have concluded that organisms other than G. 

 catenella might also cause PSP. 



We believe the events reported in this paper 

 provide the first demonstration of a localized G. 

 catenella bloom followed by a PSP outbreak in 

 Alaska waters. 



Methods and Results 



On 20 September 1973, 5 days before an out- 

 break of shellfish poisoning in humans occurred, 

 very high bioluminescence was seen in Tenakee 

 Harbor (lat. 57°48'N; long. 135°14'W). During 

 darkness, glowing outlines of large individual fish 



and schools of fish were clearly seen moving in the 

 water. Long-time residents remarked that it was 

 the greatest amount of "phosphorous" (biolumin- 

 escence) they had ever seen there. 



The RV Maybeso, Alaska Department of Envi- 

 ronmental Conservation, was in the area at the 

 time, and curiosity about the bioluminescence 

 prompted the crew to collect a small (lOO-cm"*) 

 water sample, which was preserved with 

 Formalin.' Water temperature at the time of 

 collection was 11.5°C, and salinity was 22.18"/(xi. 

 The water could not be microscopically examined 

 until 1 October, when the Mayba^o returned to 

 Juneau. At that time the sample was given to the 

 senior author, who was coordinating a PSP re- 

 search program for the Department of Environ- 

 mental Conservation. Large numbers 

 (235,000/liter) of G. catenella were found in the 

 sample. Other dinoflagellate species were present 

 but only in trace amounts. No organism other than 

 G. catenella was found in high enough numbers to 

 cause intense bioluminescence. 



We learned that on 25 September 1973, several 

 families had dug the butter clam, Saxidomus 

 giganteus, near the boat harbor in Tenakee. After 

 eating the clams, two people reported severe 

 symptoms of PSP to the Alaska Department of 

 Health and Social Services. When interviewed, the 

 victims, as well as other Tenakee residents, stated 

 that they had eaten clams from the same area 

 earlier in the year without any toxic reactions. 



Using conventional methods (Quayle 1969; Pra- 

 kash et al. 1971), the Alaska Division of Public 

 Health Southeast Regional Laboratory deter- 

 mined that the level of toxin in the uneaten 

 portion of some of the cooked clams from Tenakee 

 was 4,550 jug/lOO g. The toxin was distributed 

 throughout the body and was not concentrated in 

 the siphons. Indeed, one of the illnesses was caused 

 by ingesting clams from which the siphons had 

 been removed before cooking. 



We flew to Tenakee on 5 October, about 2 wk 

 after the outbreak, but found no G. catenella in the 

 water. We did not test any clams for toxin levels at 

 that time, but the mussel, Mytilus edulis, growing 

 on harbor pilings had high levels of toxin (2,300 

 /xg/lOOg). 



'Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



679 



