240 BULLETIN OF THE BUREAU OF FISHERIES. 
EVIDENCE OF INCREASE IN LOBSTER SUPPLY. 
The young lobsters have been liberated mainly in the upper half of Narra- 
gansett Bay, because for many years previous to our operations small lobsters 
have been conspicuously absent from these precincts, according to the statements 
of fishermen. Within the last three or four years a great many reports have 
come in of small lobsters from an inch to 4 or 5 inches in length being caught in 
the lobster pots and escaping through the slats when the pots were drawn up; 
also of small lobsters up to 8 inches in length dug out of the mud in the early 
spring by the clam diggers. These reports have been numerous and are increas- 
ing and apply to those particular districts in the upper part of the bay in which 
our lobsters have been liberated. They have occasioned remarks of surprise 
by the fishermen, because this region has been so long barren of small lobsters. 
Whether this can be taken as good evidence of the effect of liberating in these 
waters about half a million of young lobsters reared to the bottom stage (the 
number up to two years ago) is at present of course entirely a matter of opinion. 
ECONOMIC EFFICIENCY OF THE METHOD. 
At the end of an account of the method of rearing lobsters and of the 
results actually attained, a brief speculation with regard to the efficiency of the 
method from the economic standpoint may be permissible. 
It is often true in biology that one can draw conclusions as to causes and 
effects from observation and comparison of normal occurrences. In the breed- 
ing of animals we seem to have a case in point. Fishes which produce many 
thousands of eggs at a time, but whose young are left almost utterly unpro- 
tected, often do not maintain so great a numerical abundance as do other 
species (like the dogfish), which produce only a very few individuals at a time, 
but give the young a high degree of protection. 
While the relative values of the larval and fourth-stage lobsters can not, 
for a long time at any rate, be determined accurately by direct experiment, it 
would seem that a comparison of the breeding habits of the lobster and the 
crayfish would, as Ehrenbaum has pointed out, furnish data for a tentative 
valuation. Where the lobster produces at one time 20,000 fry (Herrick got 
an average of 21,351 eggs from 414 observations of 12-inch lobsters), the cray- 
fish produces approximately 100 young (Ehrenbaum), which it protects to a 
stage comparable with the fourth-stage lobster. Assuming, then, that the 
100 young fourth-stage lobsters and the 20,000 newly hatched lobster fry are 
of equal value for maintaining the species, the ratio of individual values would 
be 200 :1. Our method of artificial culture is capable of obtaining 8,000 fourth- 
stage lobsters from 20,000 fry. It is able, therefore, by taking advantage of 
the lobster’s great productivity, to obtain 80 times as many young of this 
particular advanced stage as are necessary for the maintenance of the species 
under natural conditions. 
