ABOUT LOBSTERS 93 



weeks in apparent good condition and were then trans- 

 ferred to the storage tank undamaged 



So far, it has not been possible to point out why 

 the lobsters became weak when removed from the stor- 

 age tank as described in the experiment. 



The question of how often to change the artificial 

 sea water depends primarily upon the type of tank used. 

 .... Like most living animals, the lobster is dependent 

 on the oxygen in the air in order to breathe. In its nat- 

 ural habitat, the lobster utilizes the oxygen which is 

 found in liberal amounts in fresh sea water. 



When sea water contains as much oxygen as can 

 possibly be dissolved in it, it is " saturated." The amount 

 of oxygen dissolved in sea water depends on the tem- 

 perature of the water; the wanner the water, the less 

 oxygen it contains. 



Thus, one of the greatest problems of storing live 

 lobsters in tanks on land for commercial purposes is the 

 necessity of producing the required supply of oxygen. 

 Because of limited space, the water content of the tank 

 is necessarily small in comparison to the number of lob- 

 sters stored, which very soon consume the supply of 

 oxygen on hand. If the water was not constantly sup- 

 plied with fresh oxygen, the lobsters would simply 

 choke to death. During the experiments, it has been 

 found that the lobsters became " lifeless " when the oxy- 

 gen content of the water went below approximately ]/<\ 

 of the oxygen content of saturated water. If this " life- 

 less " condition has already set in, it is essential for the 

 lobster, in order to survive, to be supplied with fresh 

 water within an hour or two. The technical require- 

 ments of the storage tank are mainly based on the neces- 

 sity of a constant supply of oxygen. It should be noted 

 that if the supply of oxygen should fail ( for instance, in 

 case of a motor stop ) , it is most important to make sure 

 that the tank containing the lobsters is quickly emptied. 

 In case of a motor stop, the drainage system should 

 automatically start 



