WATER VELOCITY (cm/sec) 



Figure E-l. The relationship between fish fork length and ability to move 

 100 m against water velocities of 0-80 cm/sec in 10 min. The same curves 

 may also be used to indicate the ability to make progress against these 

 currents over shorter distances. For instance, to cross a 50-m barrier in 

 10 min the curves should be shifted 8 cm/sec to the right; to cross a 25-m 

 barrier in 10 min the curves should be shifted 12 cm/sec to the right. The 

 line for char is derived from the hypothetical equation V = 17 L°*' and 

 represents the measured value in these experiments (from Jones 1975). 



132 



