McCabe and Tracy: Spawning and early life history of Aapenser transmontanus 



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strate, were dislodged by water currents and carried 

 downstream. 



Substrate in the river section, where stage-2 eggs 

 were most abundant, was primarily cobble and boul- 

 der. We are not sure of the composition of the sub- 

 strate near rkm 193; however, there are small rocky 

 islands in the area, and on occasion large amounts 



of sand were collected in the plankton net. In addi- 

 tion, there is a rocky reef several kilometers upstream 

 from this sampling site. 



At the index site, stage-2 eggs were collected over 

 a range of environmental conditions from 1988 

 through 1991 (Table 3). Water temperatures ranged 

 from 10 to 18°C, bottom water turbidities from 2.2 to 



