RANDALL: SURVEY OF CIGUATERA AT MARSHALL ISLANDS 



The toxicity of eight whitetip reef sharks, 

 1,003-1,183 mm PCL (8.4-22.4 kg), from 

 Enewetak was tested. The flesh of all was negative 

 for ciguatoxin by feeding to mongooses, but the 

 viscera of two gave positive reactions of 1. 



Randall (1977) studied the biology of this 

 species. He opened the stomachs of 56 specimens 

 (24 of which were from Enewetak): 33 were empty, 

 6 had eaten octopuses (2 of these also contained 

 fishes), and the rest had the remains of reef fishes, 

 especially scarids and acanthurids. 



Dasyatidae (Sting Rays) 



Taeniura melanospilos Bleeker (Figure 8): The 

 specimens collected in the Marshall Islands were 

 initially called Taeniura brocki Schultz. However, 

 it now seems more likely that they should be iden- 

 tified as T. melanospilos Bleeker. Schultz in 

 Schultz and collaborators (1953) differentiated T. 

 brocki by its having the venomous spine inserted 

 ". . . at about half length of tail . . ." in contrast to a 



little behind the first third on T. melanospilos, in 

 having the snout contained five times in the 

 greatest width of the disc (given as six by Bleeker 

 for T. melanospilos), and in having ". . .very numer- 

 ous irregularly shaped small brownish to blackish 

 spots and blotches speckling dorsal surface of disk 

 ...," as opposed to "... numerous rounded black 

 spots . . ." for T. melanospilos. After noting the 

 measurements of the position of the spine and the 

 length of the tail of his only specimens of T. brocki, 

 Schultz wrote, ". . . end of the tail may have been 



bitten off " On the specimen illustrated herein, 



the spine is inserted at a point 41% the length of 

 the tail from the base. From Schultz' measure- 

 ments, the snout of T. brocki is contained 5.14 

 times in the width of the disc. The snout of the 

 specimen illustrated herein is contained about 5.3 

 times in the disc width. Without knowledge of 

 variation of this character and perhaps propor- 

 tional differences with growth, the differentiation 

 of species on this magnitude of snout length is 

 questionable. Furthermore, Bleeker's (1853) de- 



FIGURE 8.— Taeniura melanospilos, 1,255 mm disc length, 2,008 mm TL, 69 kg, Enewetak, Marshall Islands. 



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