SIPHONOPHORES IN THE GULF OF MEXICO 



By Mary Sears, Woods Hole Oceanographic Institution 



The siphonophores most often recorded from 

 the Gulf of Mexico are the two large conspicuous 

 species with floats above the surface of the water, 

 Physalia physalis L. and Veltlla velella L. Pos- 

 sibly Porpita umbella O. F. MuUer ' should also 

 be included with these (Whitten, Rosene, and 

 Hedgpeth, 1950). As early as 1886, Fewkes wi'ote, 

 "I have many new localities for this medusa 

 [i. e., Velella] in the Gulf of Mexico." The 

 Atlantis in the winter of 1951 sailed through 

 swarms of Physalia together with large quantities 

 of Velella some miles in extent (Stetson, personal 

 communication) out in the Gulf off the northwest 

 coast of Florida, and newspapers give frequent 

 account of the contamination of west Florida 

 bathing beaches. 



The smaller, more common species, however, 

 have scarcely been noted in the Gulf except at a 

 few localities around its periphery, chief!}' at the 

 Tortugas (Mayer 1900) and in adjacent bodies of 

 water such as the Straits of Florida (Bigelow 1918) , 

 the Caribbean (Fewkes 1889), and the Gulf 

 Stream proper (Bigelow 1918; Fewkes, 1882, 1886, 

 1889). These records are indicative that about 

 25 of the better known species in all probability 

 occur in the Gulf of Mexico proper: 



Abyla carina Haeckel; Abi/Iopsis Idragona Otto; A. 

 eschscholtzii Huxley; Agalma okeni Eschscholtz; 

 Amphicaryon acaule Chun; Bassia bassensis Quoy 

 and Gaimard; Ceratocymba sagiitata Quoy and 

 Gaimard; Chelophyes appendiculata Eschscholtz; 

 Diphyes bojani Chun; Diphyes dispar Chamisso 

 and Ey.senhardt; Enneagonum hyalinum Quoy and 

 Gaimard; Eudoxoides spiralis Bigelow; Galetta 

 auslralis Quoy and Gaimard; Hippopodius hip- 

 popus Forsk&l; Lensia fowleri Bigelow; Rhizophysa 

 eysenhardti Gegenbaur; Rhizophysa filijormis 

 Forsk&l; Sphaeronecles truncata Will; Stephanomia 

 rubra Vogt; Sulculeotaria monoica Chun; Suicide- 

 olaria quadrideniala Quoy and Gaimard; Voglia 

 glabra Bigelow; Voglia pentacantha Kolliker (as 

 they are now named). ^ 



' See Bigelow and Sears (1937J for use of this name. 



2 References which are especially helpful and readily accessible in establish- 

 ing the accepted names are: Bigelow. 1911a, 1911b, 1913, 1918, 1919, 1931; 

 Bigelow and Sears, 1937; Sears, in press; Totton, 1932, 1941, in press. 



2595.'H O— 54- 



19 



In the Gulf of Mexico, one might expect to find 

 possibly 50 other species of Calycophorae, which 

 have been taken in the tropical Atlantic and per- 

 haps as many more among the Physophorae, 

 Rhizophysaliae, and Chondrophorae combined. 

 Most of these species have been taken at one time 

 or another in the tropical Atlantic and might be 

 expected to be carried by the currents into the 

 Gulf of Mexico. The depth of the sill at the 

 entrances to the Caribbean and Gulf of Mexico 

 is sufficiently great to permit entry of even the 

 species that live at considerable depths, a factor 

 which, for example, apparently prevents some 

 siphonophore species from entering the Mediter- 

 ranean (Bigelow and Sears 1937). 



In short, it would not be surprising to find any 

 one of the 140 or more siphonophore species, now 

 known, in the Gulf of Mexico. 



LITERATURE CITED 



Bigelow. H. B. 



1911a. Biscayan plankton collected during a cruise of 

 H. M. S. Research, 1900. XIII. The Siphonophora. 

 Trans. Linn. Soc, Londoli, Ser. 2, Zool., 10 (10): 

 337-358, pi. 28. 



1911b. Reports on the scientific results of the Expedi- 

 tion to the Eastern Tropical Pacific, 1901-1905. 

 XXIII. The Siphonophorae. Mem. Mus. Comp. 

 Zool., Harvard College, 38: 171-402, 32 pis. 



1913. Medusae and Siphonophorae collected by the 

 U. S. Fisheries Steamer Albatross in tlie Northwestern 

 Pacific, 1906. Proc. U. S. Nat. Mus. 44: 1-119, pis. 

 1-6. 



1918. Some Medusae and Siphonophorae from the 

 Western Atlantic. Bull. Mus. Comp. Zool., Harvard 

 College, 62 (8): 365-442, 8 pis. 



1919. Hydromedusae, siphonophores, and ctenophores 

 of the Albatross Philippine Expedition. Bull. U. S. 

 Nat. Mus., No. 100, 1 (5): 279-362, pis. 39-43. 



1931. Siphonophorae from the Arcturus Oceanographic 

 Expedition. Zoologica, N. Y., 8 (11): 525-592, text 

 figs. 185-220. 

 Bigelow, H. B., and M. Sears. 



1937. H. 2. Siphonophorae. Rept. Danish Ocean. 

 Exped., 1908-10, to the Mediterranean and adjacent 

 seas, Biol. 2: 1-144, 83 text figs. 



275 



