CHAPTER V. 



ECOLOGICAL COMBINATIONS OF SPECIES. 



In many localities it was not profitable to mark the specimens separately in 

 such a way that their exact locality could be retained. For instance, all species 

 taken on the sand-bar at Rockstone were marked " Rockstone Sand-bar." Later it 

 became evident that it might have been profitable to keep separate: (a) the species 

 taken at night from a bay on the bar — they were largely big fishes; (6) those taken 

 on the river side of the bar; (c) those taken in the bayou on the land side of the 

 bar; (d) those taken with a large net from the lower end of the bar. Each of 

 these places yielded its own fauna, but their separation must be left to someone else. 



The places of greatest interest in this connection are probably one of the 

 trenches in the Botanic Garden, a woodland brook on Gluck Island, the Konawaruk 

 pool, and the Warraputa, or Amatuk, Cataracts. In each of these places a single 

 unit was studied exhaustively. At Amatuk, however, where the cataract furnished 

 most of the specimens, a few species were obtained by seining on the sand-bar 

 below the fall. From each of these units practically a complete list of species and 

 the relative number of individuals of each species can be given. 



In the Botanic Garden a trench, said to have been undisturbed for twenty 

 years or more, was drained and most of its contents preserved. On Gluck Island 

 a short stretch of a small woodland brook was poisoned and everything but a few 

 larger catfishes and cichlids preserved. At Konawaruk everything in a pool less 

 than one hundred feet in diameter was killed and preserved. In the cataracts at 

 Amatuk and at Warraputa the fishes were either all killed or driven out by poison, 

 and everything possible secured and preserved. A list of the captures at these 

 places will therefore give us the ecological composition of the various faunas. 61 In 

 the following tables species not taken elsewhere are in italics. 



el These might be supplemented by the list of fishes taken at Erukin, where everything in the lower two 

 hundred yards of the stream was taken, and by that at Aruataima. All but Corymbophanes, Pygidium, and 

 Lithogenes of the fishes listed from Aruataima came from the small brooks. 



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