636 MARINE PRODUCTS OF COMMERCE 



Habits of the Adult Lobster. The sea bottom is the natural abode of the adult 

 lobster, the source of its food, and the scene of all its activities. It never forsakes 

 the water or leaves the bottom of its own accord. Lobsters wander close to the 

 shore and out to depths of over 100 fathoms in search of prey. In traveling over 

 the bottom the lobster walks nimbly upon the tips of its slender legs; but when 

 transferred from sea to land it can only crawl in vain attempts to walk, owing to 

 the greater weight of its body which its slender legs are unable to sustain. In the 

 water the lobster is agile, wary, pugnacious, capable of defending itself against 

 its enemies, and sometimes moves at a high rate of speed. 



Lobsters do not migrate up and down the coast at definite periods or in con- 

 siderable numbers as do many fishes and birds; but in the spring they come in 

 closer to the shore and in the fall they retire to deeper water. The optimum tem- 

 perature of the lobster lies between 50 and 60° F. 



The lobster is essentially a creature of nocturnal activity. Adult lobsters dig 

 up the sea bottom in their search for shellfish, and often cover themselves with 

 mud during cold weather. 



Lobsters are great scavengers and live chiefly on fish, alive or dead, and on the 

 invertebrates which inhabit the bottom and come within their reach. They catch 

 many small live fish and a few of the more sluggish larger fish. Adult as well as 

 larval lobsters are cannibalistic and when crowded together quickly destroy each 

 other. 



Color. Normal adult lobsters are dark green. The hard shell is an opaque lifeless 

 substance; its characteristic coloring is caused by pigments which are excreted 

 by the chromatoblasts of the soft underlying skin. These are immediately exposed 

 upon removing the shell, and the delicate skin underneath is seen to be flecked 

 or mottled with scarlet. The excreted pigments undergo physical and chemical 

 changes in the hard cuticular shell and may thus become a decidedly different 

 color from the parent chromatoblasts. Upon dehydration, oxidation, and other 

 chemical changes the pigments of the lobster shell, due to the presence of chro- 

 mogens, become converted into a red lipochrome, resembling rhodophan. This 

 accounts for the wonderful change of color which the lobster undergoes when 

 boiled. 



Propagation of Lobsters 



Need of Artificial Propagation. Since lobsters are normally unable to multiply 

 fast enough to keep up with the extensive fishing now carried out along the Atlan- 

 tic Coast, it is evident that either protection or artificial propagation is required 

 to maintain their numbers at the present level. Both means of increasing the lob- 

 ster fisheries have been tried, but for various reasons neither has been very suc- 

 cessful. Many protective laws have been enacted in states possessing important 

 lobster fisheries and in various European countries. Table 136 (p. 637) contains a 

 brief digest of these regulations. 



Methods. Artificial propagation of lobsters was first successfully carried out by 

 Guillon and Coste (1865). Since that time many attempts have been made to 

 rear lobsters from eggs, but none were successful on a large scale until 1905. 

 In that year Bumpus and Mead carried out experiments on the culture of lobsters 

 in agitated sea water. By this method nearly half of all lobsters hatched can be 

 successfully carried to the fourth stage, or the state at which the young lobsters 



