ABOUT LOBSTERS 99 



conditions can all be avoided when the temperature is 

 lowered : 



1. The colder water dissolves more oxygen. 



2. At 42° F. the lobster's oxygen consumption 

 rate is half the rate of that at 60° F. 



3. As the amount of dung products is reduced, 

 the consumption of oxygen is also lowered. 



4. The deterioration of texture is insignificant, 

 even when the lobsters have been stored from two 

 to three months. Feeding is no problem as the ani- 

 mals do not eat at low temperatures. 



5. The activity of the animals is low— they do 

 not harm each other and are easy to handle. It is 

 desirable that the lobsters for sale show a certain 

 amount of vitality and it should be noted that the 

 cold as well as the " dull " animals become lively 

 when removed from the tank. 4 



Supply of oxygen. The Maine experiments used two 

 y 2 " aerated nozzles per lobster tank. Additional aeration by 

 compressed air was found unnecessary as long as the recir- 

 culation system was in operation. 



As mentioned in the description of the experiments, 

 the necessary oxygen supply is of the greatest impor- 

 tance. The oxygen in the storage water is replenished 

 when the oxygen of the air is forced down into the 

 water. This may be done by means of a pump which 

 continually sucks the water from the bottom of the 

 tank, then forces it through a sprayer and down into 

 the water again. When the water falls from the sprayer 

 down into the water, it is replenished with oxygen in 

 the air. Especially when the water breaks through the 

 surface, particles of air are forced down into the water, 

 which absorbs the oxygen. When the surface is smooth, 

 only small amounts of oxygen can penetrate it. It is, 

 therefore, important to create the greatest possible 

 movement of the water surface. In larger tanks, it is 



Bramsnaes and Boetius, op. cit. 



