CONFERENCE OF GOVERNORS. 53 



and it must pass a long and dangerous larval period before reach- 

 ing maturity. 



What, then, is the life rate or rate of survival in the lobster? 

 Probably not more than 2 in 30,000, and certainly not more than 

 2 in 10,000. This number would be exactly known, provided we 

 knew the proportion of the sexes or the proportion of the total 

 number of males to the total number of females, and the average 

 number of eggs laid by mature females during their entire life. 



Since the sexes are about equal numerically, it is only necessary,, 

 to maintain the species at an equilibrium, for each pair of adults 

 or for each adult female to leave two children which attain adult 

 age, whatever the actual length of life in either generation. If the 

 adult progeny exceeds two, the race will increase; if less than two, 

 it will diminish. Since under present conditions the race of this 

 animal is falling off, the actual rate of survival for the individual 

 having remained the same, the total number of survivals only has. 

 changed. In other words, there is at present a deficiency of eggs. 



What is the average number of eggs for the entire life of this 

 animal? We know the minimal and maxiraal limits of egg pro- 

 duction in individuals (roughly, 3,000 and 100,000) ; we know the 

 average number of eggs borne at the average age of maturity (at 

 the 10-inch size, 10,000 eggs) ; but, as Allen,^ in discussing this 

 question, points out, we do not Imow the number of female lobsters 

 destroyed at different ages. Many after laying their first eggs- 

 are killed before any young are allowed to hatch, and the number 

 which survive to produce successive broods is a constantly dimin- 

 ishing one; but this is made good in part by the rapid increase in 

 the number of eggs. 



The average number of eggs borne by all the berried lobsters 

 captured should give us an indication of the average number of 

 eggs borne by all female lobsters during life, — the number sought. 

 In 4,645 egg lobsters from the Woods Hole region, Massachusetts, 

 the average number of eggs was 32,000, which would correspond 

 to a 13 or 13i/2-iiich lobster which had produced three or more 

 broods. Allen found the number of eggs borne by 96,098 lob- 

 sters caught in Newfoundland to be 2,247,908,000, which would 

 give an average of 23,000 to each female. This number corre- 

 sponds to an animal 12 or 12% inches long, which, as he remarks, 

 from the known average age at which female lobsters mature 

 (10-101/2 inches), would be carrying at least a second brood. 



' Allen, E. J. : "The Reproduction of the Lobster," Journal Marine Biological Associa- 

 tion, Vol. iv. (N. S.). Plymouth, 1895-97. 



