Effect of temperature on physiology and bioenergetics of adult Harris mud crab Rhithropanopeus harrisii (Gould, 1841) from the southern Baltic Sea

摘要

Rates of physiological processes and bioenergetics of the Harris mud crab Rhithropanopeus harrisii were determined during a 7-day experiment on adult males (mean wet weight 0.83 ± 0.16 g) exposed to temperatures of 15oC and 20oC (S = 7). The results show that the change in temperature by 5oC caused detectable changes in locomotor activity, food consumption and faeces production and significant (p < 0.05) changes in metabolic rates. Food assimilation efficiency and the ammonia excretion rate did not change significantly (p > 0.05). The energy expended on metabolic processes was similar at both temperatures (15oC and 20oC) and amounted to 17.7 ± 6.4% and 16.7 ± 4.3% of the assimilated energy, respectively. Similar values were obtained for net production efficiency K2 (P/A) at 15oC and 20oC, i.e. 80.4 ± 22.4% and 82.9 ± 9.7%, respectively. The amount of energy available for production was 2-fold higher at a temperature of 20oC than at 15oC and amounted to 103.69 ± 25.61 and 206.40 ± 20.76 J d~(-1)g~(-1) wet wt, respectively. The results show that from the bioenergetic point of view, higher experimental temperature is more "profitable" for adult R. harrisii specimens because it provides better conditions for the growth and reproduction.