FRESH-WATER FISHES OF SlAM, OR THAILAND 365 



Paknampo sections report having known of the capture in their early 

 days of fish somewhat over 3 meters long. It would probably be safe 

 to assert that fish 3 meters or more in length may never again be 

 observed. The smallest specimens obtained were 9 to 10 cm. long. 

 Most of the fish reaching the Bangkok market from the upper river 

 in recent years were 40 to 60 cm. long. 



This fish rivals in size the celebrated 'pla hiik {Pangasianodon gigas) 

 of the Mekong, but it is not to be confused therewith, having entirely 

 different appearance and structural details. Outstanding features are 

 the vomero-palatine dentition, the greatly produced filamentous rays 

 in the dorsal, caudal, anal, ventral, and pectoral fins, the enormous 

 pectoral spines which in the largest examples may have a length of 

 60 cm., and the conspicuous white humeral spot. 



The fish is not very common, and its numbers appear to be decreas- 

 ing yearly with the increase in the activity and efficiency of fishing 

 operations. It is not the object of a special fishery but is taken in- 

 cidentally in seines and traps used for miscellaneous fishes. Dur- 

 ing high-water stages it frequents deep holes in the rivers and is 

 then rarely caught. 



Owing to its formidable pectoral spines, the fish is always handled 

 by the fishermen with great circumspection. In 1925 a fish 2.5 meters 

 long was caught in a cast net above Raheng, and when the fisherman 

 dived to clear the net the fish inflicted a deep stab wound in the side, 

 from the effects of which the man died. 



There have been no observations on the spawning habits, spawning 

 grounds, hatching, and rate of growtli. 



In popular estimation the food value of this fish is less than that 

 of other large pangasiids, such as pla tepo (P. larnaudii) and pla 

 Hawai {P. pangashis). The reputation is based in part on the in- 

 ferior quality of the flesh and in part on the feeding habits of the fish, 

 for it is known to have a fondness for dogs, whose floating carcasses 

 are common throughout the river. When large fish are to be sent to 

 market, it is sometimes the practice to cut off the fins and thus remove 

 a ready means of identification. 



This fish is very well known throughout its range and is called pla 

 ihepa, a name never applied to any other species. 



PANGASIUS FOWLERI H. M. Smith 



Pangasius foiclerl Smith, 1931a, p. 28 (Lopburi River). — Fowlee, 1935a, p. 98, 

 fig. 18 (Srisawat). 



This is apparently a rare species. The type, 19.5 cm. long, taken 

 m the Lopburi River at Lopburi in October 1926 was the only specimen 

 known until Fowler (1935a) recorded a specimen 20.3 cm. from the 

 east branch of the Meklong at Srisawat. 



