MARINE AQUARIUM 

 PROCEDURES AND TECHNIQUES 



By Yves B. PIcssis, Assistant Director 



National Museum of Natural History, Paris, France 



Abstract. — A closed-circuit system is used as the most dependable means of main- 

 taining a balance of physical and chemical factors with a minimum of attention and 

 maintenance. Several appliances as adjuncts to this system are discussed in detail, 

 e.g., exhausting devices and capillary siphons which produce artificial tides. A special 

 habitat for the breeding of intertidal animals in the laboratory, and a sand-bottom tank, 

 designed from an esthetic point of view for public exhibition, are described. 



Our present contribution to the aquar- 

 ium sciences is concerned specifically with 

 the field of experiment. The techniques 

 that are already known, but which will be 

 enhanced by details based on our experi- 

 ence, and the new, more important ele- 

 ments that make it possible to produce 

 complex artificial environments will — 

 hope — be of service to the investi- 



we 



gator as well as to those who main- 

 tain aquariums for exhibit purposes. The 

 milieux that we have created for experi- 

 mental uses have their place behind the 

 scenes of a large public installation; they 

 may also have their place amidst the tanks 

 shown to visitors provided that they have 

 been adapted and modified for that pur- 

 pose. 



DESCRIPTION 



Being far away from the sea, we have 

 been forced to use the same water over and 

 over. It is not possible to obtain a bio- 

 logical equilibrium in an aquarium except 

 by allowing the physicochemical factors 

 as little variability as possible and, in any 

 case, as is compatible with the survival of 

 the population. The greater the volume 

 of the water, the slower the changes occur 

 and — in a general way — the easier it is 

 to compensate for them. Moreover, a 

 closed circuit with a large capacity is the 

 most dependable means of keeping the 

 desired balance. 



There are several models of breeding 

 installations that are adapted to the needs 



This paper was prepared In French ; It was trans- 

 lated Into English by a commercial translating service. 



of marine biology. Most of them, in- 

 cluding the one described here, have a re- 

 serve tank, a water circulation system, 

 breeding tanks, and a filtering system. 



RESERVE TANK 



The reserve tank may consist of various 

 materials but must have all of the follow- 

 ing properties: Strength, water-tightness, 

 and neutrality toward sea water. 



A glass tank is relatively neutral but, 

 unfortunately, is fragile. If it is large, 

 stresses, changes of temperature, or vibra- 

 tions may cause its destruction at any time. 



If the tank is of concrete and well made, 

 it has the advantage of being strong, but 

 frequently it cannot be moved. Liquid 

 that comes in contact with fresh concrete 



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