manual of fish-culture. 237 



hatchinct apparatus and operations. 



Experiments conducted during a series of years having demonstrated 

 that the automatic hatching-jar was the best form of ap])aratus for 

 hatching lobster eggs, it has been adopted at the stations of the Com- 

 mission since 1889. A full descrii)tion of this jar is given in the article 

 on shad-culture, pp. 150-15ii. The manipulation and operation of the jar 

 is ])ractically the same as with shad eggs, except that frequently, where 

 the water supply is inadequate, three jars are connected by means of 

 rubber tubing and the water used over and over. This is accomi^lished 

 by connecting the overflow from the first jar with the su^jply to the 

 second and so on, but can only be done during the early stages before 

 the fry commence to hatch. When first placed in the jar the eggs are 

 matted together by the fine hair-like fibers, but after a few days they 

 separate and work very much like shad eggs. 



From 400,000 to 500,000 eggs (equivalent to about 2 to 2^ quarts) are 

 usually placed in each jar, although at times when the hatchery is 

 crowded a few more may be successfully cared for. 



The fry pass voluntarily from these jars to cylindrical glass jars, 9 

 inches in diameter and either 9 or 18 inches high, placed in the center 

 of the table and covered with cheese-cloth at the top to prevent their 

 escape. 



The i^eriod of incubation de^jends entirely upon the age of the egg 

 when collected. For example, eggs taken in October do not hatch until 

 the following May, whereas eggs collected in June freipiently hatch 

 in 24 hours after being placed in the jars. During one season eggs 

 collected from December 12 to January 25, numbering 1,717,000, at a 

 temperature of 1:50, commenced hatching May 25 at a temperature of 

 54°. To determine how soon the new-laid eggs can be taken from the 

 parent and hatched artificially, collections were begun early in July 

 and continued until fall, for several seasons, the eggs being j^laced in 

 hatching-jars at the Woods Hole Station ; all those collected prior to 

 October 15 died. In JSTovember, 1895, 15,000,000 were placed in jars 

 and carried through the winter under very unfavorable conditions, but 

 hatched with a loss of only 50 per cent. The density of the water at 

 Woods Hole varies from 1.023 to 1.025, its average temperature being 

 from 490 to 640 during the months of April, May, and June. 



THE LOBSTER FRY. 



Owing to the cannibalistic habits of young lobsters when closely 

 crowded, it has been the jiolicy of the Commission to liberate the fry 

 as soon after hatching as possible. They are taken out in ordinary 

 10-gallon transportation cans, about 200,000 being placed in a can for 

 short shipments and 125,000 for long shipments, and liberated in the 

 vicinity of the grounds from which the adult lobsters were taken. 

 W^hen this is impracticable, they are liberated in Vineyard Sound and 

 Buzzards Bay with an outgoing tide, so as to insuie their wide distri- 



