THE PUBLIC AQUARIUM 285 



With a strong flow of sea water and the tanks not crowded a 

 large number of fishes can be carried safely. By using 14 tanks 

 of this size, 800 good-sized fish can be transported from Bermuda 

 or Florida to New York with less than 5 per cent loss. Feeding 

 during shipment (which would foul the water) fortunately is not 

 necessary, except in the case of chsetodonts and other small fishes, 

 which annoy each other when hungry. 



There is an advantage in carrying each lot of fishes in as large 

 a body of water as possible. Wooden shipping tanks strongly bolted 

 together are almost indestructible in ordinary use, while metal 

 tanks are dented easily and rendered leaky by the rough usage they 

 get on shipboard when empty. Sea water eventually rusts them, 

 even when galvanized. 



On shipboard it is not always possible to have tanks carried be- 

 tween decks, and in the cold weather of spring or fall, when placed 

 on the open deck, tropical fishes may become chilled. Wooden tanks 

 keep the water warmer than it can be kept in metal tanks, and the 



Fig. 23. — Steam-driven air compressor for the aeration of tanks on sliipboard 



fish may be protected further with tarpaulins. Their cost is less 

 than half that of metal tanks, and their great weight when loaded 

 is not objectionable, as they are hoisted by steam power. 



As tropical fishes being transported northward can not endure a 

 lower temperature than that to which they have been accustomed, it is 

 unsafe to j^ump sea water into the tanks during the latter part of the 

 voyage to New York. The circulation of water, therefore, is cut off 

 before the vessel passes north of the warm Gulf Stream, and a circula- 

 tion of air is substituted by means of a steam-operated air com- 

 pressor carried along for the purpose. 



Manatees and porpoises, being heavy and entirely aquatic in habit, 

 can not be shipped without the support of water. They are warm- 

 blooded and soon become overheated without this cooling as well as 

 supporting medium. Each porpoise or manatee is shipped in a rough 

 wooden tank sufficiently large to contain it without discomfort and 

 with enough water to float it. The water soon becomes too warm and 

 must be renewed every three or four hours while in transit. With 

 such treatment they can be shipped long distances without danger. 



