FISHERY BULLETIN: VOL. 74, NO. 1 



stream. The prickly sculpin was not found more 

 than about 1 km upstream from high tide mark 

 where the stream gradient did not exceed 1.5%, 

 whereas the coastrange sculpin penetrated up- 

 stream some 1.6-2.7 km from high tide mark in a 

 range of stream gradients not exceeding 6%. In 

 Cabin Creek, the smallest stream, the same gen- 

 eral difference between the two species in lon- 

 gitudinal distribution prevailed, but the dis- 

 tances involved were reduced by a factor of 10. 



The upstream distributional limits of both species 

 in all four streams are indicated in Figure 1. 



Habitat segregation was evident in cohabitated 

 stream areas, large Casper occupying the 

 deepest locations in pools, under log jams and 

 undercut banks. Intermediate-sized C. asper and 

 large C. aleuticus were also found at these sites 

 but at shallower depths. Riffle and glide areas 

 were mainly occupied by small and medium-sized 

 C. aleuticus. 



CABIN CREEK 



 Caleuticus 



LB D C osper 

 I 



35 cm f oils 



45cm fails 



225 

 200 



100 



75 

 50 

 25 



-3 3 6 9 12 15 18 21 24 27 



DISTANCE FROM HIGH TIDE (0) IN TENS OF METERS 







5 

 < 



^ 60 



45 



30 



15 



150 



125 



100 



75 



50 



25 



24 

 mpassable log 



27 



•s. 



< 



a. 



h 



UJ 



Z 



o 



rO 



a. 



UJ 



a. 



I 



O 3 6 9 12 15 18 21 24 



DISTANCE FROM HIGH TIDE MARK (0) IN HUNDREDS OF METERS 



Figure l. — Autumnal distribution and abundance of Cottus aleuticus and C. asper in relation 

 to stream profile and streambed obstructions. High time mark (0) is a reference benchmark 

 determined by the highest spring tide. 



134 



