82 ALASKA FISHERIES ANB FUR INDUSTRIES, 1911. 



3 per cent. During the process of water hardening the buckets 

 should be partly submerged to properly regulate the temperature. 

 Due caution must be observed not to move the eggs until water 

 hardening is complete. After a little experience the operator can 

 readily tell, upon carefully inserting the hand and finding the eggs 

 free and hard and no longer soft and velvety, even toward the bottom 

 of the bucket, that they may be moved to the hatchery without fear 

 of loss. 



EGG COUNTS. 



Various methods of measuring quantities of eggs are in vogue, 

 prominent among which is the use of a dipper of a known average 

 egg-capacity determined previously by actual count. Another 

 method is to ascertain by count the average number that will be 

 required to measure up to a mark around the inside of the buckets 

 in which the eggs harden before being placed in the hatching troughs. 

 If the standard for a bucket containing, say, 60,000 eggs is accurately 

 determined and verified from time to time it is even more accurate 

 than the dipper method. The ordinary domestic dipper will not 

 hold much more than 4,000 red-salmon eggs, and as it would be 

 used some 15 times more than a bucket as a unit of measurement 

 the chance for individual variation and error is undoubtedly increased. 



It is well estabhshed that most fish eggs increase in size not only 

 during the early absorptive period of an hour or so while water 

 hardening, but also throughout the period of incubation. At the 

 Yes Bay station it was found that upon water hardening a quart 

 dipper contained 4,416 red-sahnon eggs. Five weeks later but 

 4,160 of these eggs would go into the same dipper, and at ten weeks 

 of age only 4,000, showing an increase of 10 per cent in size. 



To avoid error through any change or variation in the size of eggs 

 all standards of computation ought to be determined by actual 

 comit, repeated at frequent intervals. Measurements by water 

 displacement, the von Bayer gauge, or by graduated scales are con- 

 sidered less desirable in their practical application than the common 

 dipper or bucket method before mentioned. Too much caution can 

 not be exercised in the matter of egg counts, for it is only through 

 accuracy as to detail that such data become valuable either to science 

 or economics. 



Careful computation of the take of eggs minus subsequent losses is 

 the basis for determining the number of fry released, for it is unsatis- 

 factory and impracticable actually to count the fry other tlian the 

 very small number which may die between the time of hatching and 

 planting. Error is bound to result if the output of fry is determined 

 by a volume measurement of the eggs just before hatchmg and using 

 the same standard that was employed near the beginning of the 

 period of incubation. 



