Bull., U.S.B.F. (No. 15.) 
Figure 1. — Normal and marked pink-salmon fry at time of seaward migration. 
Figure 2. — Apparatus used in marking pink-salmon fry. Operator stands in front of shallow square net that rests on sides of 
tank just at surface of water. The small amount of water in the center of the net is sufficient to maintain fry in a semiasphyxi- 
ated state when they are placed there preparatory to marking. The two reading lenses, 4 inches in diameter, suspended above 
near side of net more than double image of a fry when it is held under them while being marked. The gas lamp beside net 
provides a direct light for operator and incidently radiates heat upon the hand that is used to catch the fry and hold them while 
being marked. Tanks are supplied wdth running water from stream. In order to keep an accurate account of number of fry 
marked the tally counter mounted on side of tank near frame that supports the reading lenses, is tripped every time operator 
marks a fry. Upper compartment of each tank is used to provide temporary storage for unmarked fry. After marking , fry 
are released in lower compartments where they are held from 12 to 24 hours before liberation in stream. ' 
