RESPIRATION 



59 



motility and body metabolism. An instance of the latter is provided from 

 experiments on the goby Gillichthys mirabilis, which shows reduced rates 

 of metabolism when exposed for several weeks to high environmental 

 temperatures (1 5a, 164). 



Several species of animals are now known to exhibit seasonal acclima- 

 tization of metabolism, dependent on temperature changes. Fundulus 

 parvipinnis taken from cold water in winter possess a higher rate than 



77 13 15 11 

 Temperature (°C) 



19 21 



Fig. 4.10. Effect of Temperature on the Respiration of 

 the Lobster Homarus vulgaris 

 Curves refer to oxygen uptake by the gills, rate of gill ventilation and percentage of 

 oxygen extracted by a lobster weighing 345 g in sea water having an oxygen concentra- 

 tion of 5-3 ml/1. (From Thomas (150).) 



specimens measured during the summer (tested at 12 C C and 20°C). More- 

 over, when kept at a constant temperature, these fish still show a seasonal 

 rhythm with higher winter respiration. In the sand crab Emerita talpoida 

 oxygen consumption in winter is greater than in summer at temperatures 

 below 20 C; augmentation of winter metabolism is about fourfold at 3 C. 

 Similarly, excised tissues of the bivalve Mercenaria mercenaria tend to show 

 higher winter rates of oxygen consumption. These animals become adjusted 

 to seasonal changes in temperature with the result that the metabolic rate 



