Respiration and Metabolism 



239 



metabolism.-" •' If this work on Carassins is experimentally sound, then it 

 becomes a behavioristic problem, because the effect of numbers in reducing 

 metabolism can be prevented by darkening the aquarium or blindfolding the 

 fish. Conversely, according to Schlaifer, the owgen consumption is decreased 

 if mirrors are added to increase the apparent number of fish seen by the experi- 

 mental animal. Indeed, even dead fish and fish mounts produce the same 

 effect. A "group effect" also demonstrated in Perca may be attributed to the 

 depressant action of metabolites produced by additional fish.'-' 

 ' The correlation between oxygen consumption and habitat is perhaps best 



TABLE 42. OXYGEN CONSUMPTION OF RELATED ORGANISMS 

 FBOM DIFFERENT HABITATS 



(Ex'pressed in cc./gm./hr.) 



Animal 



Habitat or Habit 



Weight 



Cgm-) 



Consumption 



Isopods* 



Aselliis aqjwficits"^ 



Asellus aqiiaticus"^ 

 Trichopterids* 



Limnophilus vittatus^^^ 



Hydropsyche sp. ^" 

 Small ephemerid nymphs* 



Coenis sp."^ 



Cloeon diptertim'" 



Ephemerella ignflffl'" 



Baetis rhodani"' 

 Large ephemerid nymphs* 



Ephemera vulgata"^ 



Ephemera danica^^'^ 



Ecdyonnrus venosus^" 

 Crayfisht 



Astacus leptodactyliis'^'^ 



Astaciis torrenthim'''" 

 Fish 



Mackerel (Scomber scomhriisy^ 



Butterfish (Poronotiis tricanthusy 



Scup (Stenotomus chrysopsy^ 



Tautog (Tautog onitisy^ 



Puffer {Spheroides macnlatusy*° 



Lungfish (Lepidosiren paradoxaf 



Pirarucus (Arapaima gxgasf'' 



.51 



.51 



.77 



.29 

 .61 

 .95 



2.57 



.28 

 .37 

 .61 



.07 

 .10 



.726 

 .30U 



.174: 



.062 

 .062 

 .042 

 .009 



considered in regard to oxygen utilization and critical oxygen tensions. Never- 

 theless, oxygen-rich and oxygen-deficient media are significant and naturally 

 have been investigated widely, although not extensively enough. "•^- -'■'^ A 

 number of arthropods and several fish from different habitats and with differ- 

 ent habits are listed in Table 42, with oxygen consumption measurements as 

 determined at rest under laboratory conditions. In the aquatic arthropods, the 

 more agitated and oxygenated the medium, the greater the oxygen consump- 



* Determined at 10° C under mild urethane or chloretone anaesthesia. 



t Determined at 19-21° C. 



X Wrong in author's summary and since confused in literature. 



