40 Memoir Sears Foundation for Marine Research 



Lake'5 and are rather sluggish in habit (p. 20) makes it likely that most of the local 

 inhabitants are permanent residents. In this connection, it would be interesting to know 

 if any Sawfishes move back and forth indifferently between salt and fresh water in the 

 tidal stretches at the mouths of the rivers they frequent or if individual specimens tend 

 to remain constantly in one type of water or the other. 



Throughout most of its American range, P. perotteti inhabits temperatures higher 

 than 20° C (68° F). While it may be subject to temperatures as low as about 18° C 

 (65° F) along the northeast coast of Texas during periods of severe winter weather, 

 this is for short periods only. At the opposite extreme, it certainly is at home in water 

 as warm as 28—30° C (82—86° F), or even warmer, along the shores of the Guianas 

 and northern Brazil. 



In the more strictly tropical part of its range, where it appears to be the most 

 plentiful, as along the coast of French Guiana, small ones far outnumber the large 

 (as is true also of P. fectinatus in its centers of abundance), which is evidence that 

 while many young are produced their rate of survival is low. The fact that all spec- 

 imens reported from the coast of Texas have been large, in contrast with the abun- 

 dance of small ones farther south, also suggests that the production of young is confined 

 chiefly to regions where the temperature of the water is at least as high as about 25— 

 26° C (77—79° F) and that most of the large specimens taken to the northward in 

 cooler water have spread from their tropical nursery, the journey perhaps occupying 

 several years for any individual specimen, without return migration. 



Nothing else is known of its way of life to differentiate it from its relative P. pec- 

 tinatus. But it is of interest that a specimen reported from Texas as 1 5 feet long from 

 front of head to tip of tail had lost its saw so long previously that the wound was entirely 

 healed over,** evidence that a Sawfish can in some way obtain sufficient food without 

 the use of its saw for stirring the bottom. 



Numerical Abundance. No precise information is at hand as to the actual numbers 

 of P. perotteti anywhere, but it has been characterized as common both along tropical 

 West Africa and along French Guiana. The population inhabiting Lake Nicaragua is 

 also so large that an angler reports catching four in one day. And in one summer seven 

 large specimens were taken by one fisherman near Galveston, Texas.'' However, most 

 of the other published records of it have been based on single specimens, while it is 

 described as not common in the Amazon, though well known there.'* 



Range. Both sides of the Atlantic; tropical West Africa in the east,*' middle 

 Brazil to northern Texas, and as a stray to southern Florida, in the west. It is repre- 

 sented by a closely allied form (or forms) along the Pacific Coast of Central America, 

 off northern Australia, off Indo-China, among the East Indies, and in the tropical- 



95. Females taken there dropped their young at the time of capture (Marden, Nat. geogr. Mag., 86, 1944: 184). 



96. Baughman, Copeia, 1943: 45. 97. By E. F. Reid (Baughman, Copeia, 1943: 43). 



98. Woodland, Proc. zool. Soc. Lond., 1934: 33. 



99. An illustration of P. perotteti, or at least of a Sawfish similar to it, is included by Costa in the Fauna Napoli (Pesci 

 Cat. Sist., 3, 1854-1857: pis. 8, 9), but without mention of locality. There is no reason to suppose that P. perotteti 

 ever strays as far north as the Mediterranean. A Sawfish is also reported under this same name from fresh water 

 in South Africa (Barnard, Pict. Guide S. Afr. Fish., 1948: 22; not seen). 



