velocity, substrate, cover, and proximity to riffles where 

 grayling spawning may have occurred. Macrohabitat areas were 

 measured to develop an index of availability for habitat 

 parameters such as depth, velocity, substrate, and cover. These 

 macrohabitat areas were located in areas that contained large 

 concentrations of YOY grayling and may not represent the true 

 habitat availability. 



The east channel of the Big Hole River below the town of 

 Wisdom had the highest concentrations of YOY grayling of the ten 

 sections surveyed. The west channel of the river, also below 

 Wisdom, and an irrigation ditch above Wisdom also supported 

 relatively high densities of these YOY fish. 



Young-of-the-year Arctic grayling increased in mean total 

 length (TL+SD) from 2.52 (±.08) inches on July 6 to 4.08 (±.24) 

 inches on August 28, 1989. This growth rate is quite similar to 

 that presented by Skaar (1989) for this same area in 1988. 

 Condition factors for age I and older grayling averaged 1.10 

 (±.20) which is higher than that reported for 1988 (Skaar 1989) 

 and much higher than that reported for 1979 (Liknes 1981) . This 

 result indicates that the individual fish were in better 

 condition in 1989 than they were in either 1979 or 1988. 



Macrohabitat areas selected by YOY grayling were typically 

 one riffle-pool-riffle complex and could be characterized as 

 having sloughing banks, being in close proximity to relatively 

 'clean' substrate materials, having at least one pool in excess 

 of 1.5 feet in depth, and having abundant cover (usually in the 

 form of aquatic vegetation). Orange-colored 'spawning flags', 

 marking the locations where Montana Department of Fish, Wildlife 

 and Parks personnel captured spawning grayling in late April and 

 early May of 1989, were often in close association with the 

 macrohabitat areas where large concentrations of YOY grayling 

 were captured. 



Microhabitat areas selected by YOY grayling averaged 

 slightly deeper and had higher velocities than the surrounding 

 macrohabitat areas. Cover was typically within one foot of a 



