METHODS OF HATCHING FISH EGGS. 
215 
time of hatchiug-out approaches it has become tender and there is danger of prema- 
turely bursting the shell. Pour the eggs carefully into a pan nearly full of water. 
With the scaff- net slightly disturb the water, and as the shells rise skim them off. 
After all the shells are removed, put a part of the eggs on the picking-tray and remove 
any dead. By gently sifting the tray and turning the eggs over with a feather, the 
fry can be made to drop through the meshes into the pan below, from whence they are 
easily transferred to the rearing quarters prepared for their reception. 
MEASURING THE EGGS. 
The question of measuring the eggs is a most important one to the fish-culturist, 
and yet, to judge from the various ways of measuring eggs, it is one that has received 
little attention. Every branch of trade has a standard measure, but flsh-culture has 
remained without standard or rational unit; each workman establishing for himself a 
system of determination, and varying that system from year to year as the exigencies 
of the season demanded. There has not only been a want of harmony in the various 
so-called measures used, but the ‘^measures” themselves have lacked the elements of 
reliability, being in many cases the most arbitrary and irrational. The records of 
results of work in the earlier days of fish-culture were but wild guessing, and, sad to 
say, many records are yet made in the same manner. 
The practice of arriving at the number of any given lot of eggs by estimating 
each parent fish to contain an unvarying quantity of eggs, and multiplying this quan- 
tity by the number of females spawned has justly gone out of use. How various and 
how far wide of the mark such estimates were is shown by the following: Seth Green 
estimates a shad to contain from 20,000 to 28,000 eggs;^ O. 0. Smith, of Connecticut, 
puts it at 50,000 Dr. H, C. Yarrow estimates a shad to contain from 100,000 to 
150,000 eggs;* and Prof. J. A. Ryder, embryologist of the U. S. Fish Commission, 
says a shad may have 250,000 ova in process of maturation at one time in her roes.* 
These statements are made to show the absurdity of the old method of determination. 
There is no desire to attach odium to any one; but the wish is earnest to call to the atten- 
tion of all interested the necessity of some recognized standard of measurement to be 
known and used by all fish-culturists. Not unfrequentiy has it happened that a con- 
signment of eggs when estimated by the recipient has fallen short of the invoiced 
number. Sometimes these occurrences have led to accusations of fraud. In a former 
article in a Bulletin of the U, S. Fish Commission, I have shown that the discrepancy 
may often result in part froui other causes, and instead of being actual is to some 
extent but apparent. Whitefish and shad eggs, and possibly others, after several 
hours in the packing-crates, undergo a shrinkage, amounting to nearly 12 per cent, 
of their bulk. After being several hours in the jars the eggs reabsorb the water and 
resume their normal size. But the main reason for the discrepancy in the measure- 
ments at the receiving and shipping points will be found in the want of harmony in 
the methods of measuring. 
In many hatcheries, especially those hatching heavy eggs, the system of deter- 
mination is based on the diameter of the egg. It will be found very difficult to estab- 
^U. S. Fish Conmiissiou Report, Part ii, p. 427. 
^Ibid., p. 455. 
2 U. S. Fish Coramis.sioii Bulletin, Vol. in, p. 196. 
