218 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



problem is involved. We must know the state of the fishery and the principal facts 

 pertaining to the life and habits of this animal. 1 



Until within a few years the life-history of the lobster was very imperfectly known, 

 and this ignorance has nowhere been more clearly reflected than in the attempts to 

 cure existing evils by legislation. Knowing the general facts of the case, we must 

 interpret them in accordance with the principles of science and common sense. The 

 principal facts are these 2 : 



(1) The fishery is declining, and this decline is due to the persistence with which 

 it has been conducted during the last 25 years. There is no evidence that the animal 

 is being driven to the wall by any new or unusual disturbance of the forces of nature. 



(2) The lobster is migratory only to the extent of moving to and from the shore, 

 and is, therefore, practically a sedentary animal. Its movements are governed chiefly 

 by the abundance of food and the temperature of the water. 



(3) The female may be impregnated or provided with a supply of sperm for future 

 use by the male at any time, and the sperm, which is deposited in an external pouch 

 or sperm r< ceptacle, has remarkable vitality. Copulation occurs commonly in spring, 

 and the eggs are fertilized outside the body. 



(4) Female lobsters become sexually mature when from 8 to 12 inches long. The 

 majority of all lobsters 10 inches long are mature. It is rare to find a female less 

 than 8 inches long which has spawned, or one over 12 inches in length which has never 

 borne eggs. 



(.")) The spawning interval is a biennial one, two years elapsing between each 

 period of egg-laying. 



(6) The spawning period for the majority of lobsters is July and August. A few 

 lay eggs at other seasons of the year in the fall, winter, and probably in the spring. 



(7) The period of spawning lasts about six weeks, and fluctuates slightly from 

 year to year. The individual variation in the time of extrusion of ova is explained 

 by the long period during which the eggs attain the limits of growth. Anything 

 which affects the vital condition of the female during this period of two years may 

 affect the time of spawning. 



(8) The spawning period in the middle and eastern districts of Maine is two weeks 

 later than in Vineyard Sound, Massachusetts. In 1893 71 per cent of eggs examined 

 from the coast of Maine were extruded in the first half of August. 



(9) The number of eggs laid varies with the size of the animal. The law of produc- 

 tion may be arithmetically expressed as follows: The number of eggs produced at each 

 reproductive period varies in a geometrical series, while the length of lobsters producing 

 these eggs varies in an arithmetical scries. According to this law an 8-inch lobster 

 produces 5,000 eggs, a lobster 10 inches long 10,000, a 12-inch lobster 20,000. This 

 high rate of production is not maintained beyond the length of 14 to 10 inches. The 

 largest number of eggs recorded for a female is 97,440. A lobster 10 inches long 

 produces, on the average, nearly l.'i,()00 eggs. 



(10) The period of incubation <>f summer ejrgs at Woods Hole is about ten months, 

 July 15-August 15 to May 15-June 15. The, hatching of a single brood lasts about a 

 week, owing to the slightly une<|iial rate of development of individual eggs. 



1 In discns.sin^ this subject I have not attempted to discriminate between conditions which may 

 exist in the United States and the Maritime Provinces. The questions to be considered have primarily 

 a general significance. 



8 For further details see The American Lobster, Bull. U. 8. F. C. 18!C>, pp. 1-252. 



