738 VERNBERG 



Fundulus heteroclitus and F. diaphanus (Garside and Morrison, 

 1977) and Gasterosteus aculeatus (Garside, Heinze, and Barbour, 

 1977). Both species of Fundulus preferred higher temperatures in a 

 salinity approximating that of the typical habitat. In Gasterosteus 

 the preferred temperatures increased through thermal acclimation, 

 ranging from 5 to 25° C. Those for the freshwater tests were about 

 2°C lower at each acclimation point than those for seawater tests. 

 Differences might be due to differentials in metabolic loading 

 brought on by osmoregulative stresses. 



Acute changes in temperature and salinity affect pulsation rates 

 in the ephyrae of the jellyfish Aurelia aurita (Dillon, 1977). The rate 

 increases with temperature, although a Qio of 0.97 was found 

 between 20 and 25° C. When salinity is reduced acutely, the pulsation 

 rate is increased for about a 2-day period. 



Numerous physiological processes are influenced by interaction 

 of multiple environmental factors (Kinne, 1963; 1964; Vemberg and 

 Vernberg, 1970; 1972; and Alderdice, 1976). Only a few will be 

 cited here. 



Water Loss 



Humidity and temperature affect the rate of water loss in the 

 shore crab Carcinus maenas and the subtidal crab Portunus 

 marmoreus (Ahsanullah and Newell, 1977). Portunus loses water 

 more readily than Carcinus, probably because of differences in 

 relative gill areas. 



Metabolic Rate 



The results of numerous investigations of the effects of tempera- 

 ture, salinity, and other factors on the metabolic rates of aquatic 

 organisms have been published. The metabolic rate of the goby 

 Gillichthys mirabilis increased with increasing temperature, decreased 

 with decreasing ambient oxygen, but remained constant over a wide 

 range of salinities (Courtois, 1976). Nelson et al. (1977) found that 

 the distribution and migration of juvenile Macrohrachium rosenbergii 

 in natural habitats could be correlated with their metabolic responses 

 to temperature and salinity. Working with the mysid Neomysis 

 intermedia, Simmons and Knight (1975) measured respiration at 

 different combinations of temperature and salinity at three seasons 

 of the year. This species is found in freshwater and in salinities up to 

 18\o- Unlike the goby, their metabolic rate decreases as salinity is 

 increased. As temperature increases, metabolic rate increases. These 

 workers found seasonal changes that may be related to reproduction 



