BARHAM. GOWDY, and WOLFSON: ACANTHASTER IN GULF OF CALIFORNIA 



It would be of considerable interest to know if 

 Acauthaster is present on the Tres Marias 

 Islands and along the great stretch between 

 Farallon, San Ignacio, and Panama, or if the 

 distribution of the genus is indeed as discon- 

 tinuous as it now appears. 



CONCLUSION 



Our adherence to the taxon, Acauthaster 

 ellisii, stems from the conviction that the bino- 

 men is valid for the Gulf of California. Regard- 

 less of final decisions on the taxonomy of the 

 more southerly, oceanic populations of Acan- 

 tJiaster, we believe that the Gulf populations 

 constitute a distinct form. 



Dana and Wolfson (1970), who have observed 

 both A. plaiici and A. ellisii in the field, point 

 out that the behavior of the two species is strik- 

 ingly different. The information presented here 

 indicates that, unlike A. pkuici, A. ellisii is not 

 cryptic during daylight hours and feeds both 

 night and day. Even where its population densi- 

 ties are similar to those given by Chesher (1969) 

 for infestation levels of A. plaiici, A. ellisii does 

 not appear to aggregate or to migrate as a popu- 

 lation. 



In gross morphology, A. ellisii also appears 

 to be quite distinct from A. planci. Madsen 

 (1955) stresses the disk-diameter to arm-length 

 ratio as the most conspicuous difference be- 

 tween the American and Indo-West Pacific 

 forms; our ratios fall well below the 1.9:2.2 

 ratio established for A. platici. (Other taxonomic 

 characteristics appear to be too subtle and 

 variable for comment by a nonspecialist.) 



In conclusion, from the evidence presented in 

 this paper, A. ellisii gives every appearance of 

 living in harmony with its environment. There 

 is nothing to suggest that it represents a threat 

 to the coral fauna within its geographic range 

 or a potential threat to any area beyond it. 



ACKNOWLEDGMENTS 



We thank John Faulkner, Scripps Institution 

 of Oceanography, for generously contributing 

 his notes and observations. David Pawson, 



Smithsonian Institution; John Garth, Allan 

 Hancock Foundation; and Peter Glynn, Smith- 

 sonian Tropical Research Institute, have for- 

 warded literature and information. John Hall. 

 Steven Leatherwood, I. E. Davies and, particu- 

 larly, George Pickwell of the Naval Undersea 

 Center have aided in the field work. Chief War- 

 rant Officer Russell Ludwig and the crew of the 

 U.S. Navy yawl, Saluda, rendered logistic 

 support. Our investigations in Mexican waters 

 were made possible through the courtesy of 

 the Mexican Government, Department of 

 Industiy and Commerce, National Institute of 

 Biological Fishery Research. The work was 

 initiated under Task No. 0588 supported by the 

 U.S. Naval Ships System Command but was 

 brought to conclusion as independent research 

 in the spirit of the Navy's Environmental 

 Protection Program. 



LITERATURE CITED 



Barham, E. G., and I. E. Davies. 



1968. Gorgonians and water motion studies in Gulf 

 of California. Underwater Nat., p. 24-29. 



Barnes, J. H. 



1966. The crown of thorns starfish as a destroyer of 

 coral. Aus. Mus. Mag. 15:257-261. 

 Barnes, D. J., R. W. Brauer, and M. R. Jordan. 



1970. Locomotory response of Acanthaster planci to 

 various species of coral. Nature (Lond.) 228:342-344. 

 Brauer, R. W., M. R. Jordan, and D. J. Barnes. 



1970. Triggering of the stomach eversion reflex of 

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 228:344-346. 

 Caso, M. E. 



1962. Estudios sobre asteridos de Mexico. Observa- 

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 Chesher, R. 



1969. Destruction of Pacific coral reefs by the sea 

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Dana, T. 



1970. Acanthaster: a rarity in the past? Science 

 (Wash., D.C.) 169:894. 



Dana, T., and A. Wolfson. 



1970. Eastern Pacific crown-of-thorns starfish popu- 

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1972. Acanthaster aggregations: interpreted as pri- 

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