Gonyaulax excavata

White, A. W., Sensitivity of marine fishes to toxins from the red-tide dinoflagellate Gonyaulax excavata and implications for fish kills, Mar. Biol., 65, 255, 1981. 

White, A.W., Salinity effects on growth and toxin content of Gonyaulax excavata, a marine dinoflagellate causing paralytic shellfish poisoning, J. Phycol. 14, 475, 1978. 

Figure 23.42 Distribution of STX-type toxins between Gonyaulax excavata and Placopecten magellanicus.

Station 5 is nearshore. Station 1 is approximately 25 miles offshore. Summer (July) 1979. After Holligan et al. (submitted) (8). Gonyaulax tamarensis var. excavata comprised a major percent of phytoplankton biomass from 0-60 m. Station 5 = 0% station 4 = 307o station 3 = 467 station 2 = 47 station 1 = 07o. 

Figure 5. Pigment per cell of Gonyaulax tamerensis var excavata grown under 1007o (266 juEin cm s ) and 25% (66 juEin cm - )...

Figure 6. Diagram of chloroplast size and shape observed using epifluorescence microscopy. Gonyaulax tamarensis var. excavata-A. grown at 266 pEin cm s l and B. at 50%, or 133 juEin cm s . ...

The discovery of the relationship of G. catenella to poisonous shellfish by Sommer, Whedon and associates led Canadian investigators Needier (3) and Prakash (4) to the discovery that Gonyaulax tamarensis (var. excavata) caused clams and scallops along the northeast coast of North America and the northeast coast of England to become poisonous. 

A phytoplanktivorous fish would have to eat about one or two million excavata cells, which means clearing only about 100 mL or so of red water which can contain many millions of Gonyaulax cells per liter. A zooplanktivorous fish would only have to eat 1 g or so wet weight of zooplankton during a toxic Gonyaulax bloom (see Table IV). Filter-feeding shellfish commonly acquire 6000 pg toxins per 100 g of... 

Saxitoxin is an alkaloid of nonplant origin. It is the neurotoxic constituent of dinoflagel-lates (Gonyaulax catenella and G. excavata) the so-called red tide found along the U.S. coast. Shellfish, clams, and scallops consume this and become extremely poisonous for human consumption. 

Anderson, D.M. and Wall, D., Potential importance of benthic cysts of Gonyaulax tamarensis and G. excavata in initiating toxic dinoflagellate blooms, J. Phycol. 14, 224, 1978. 

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