Metabolism, body composition (C and N) and estimated net growth efficiency of a calanoid copepod Pseudocalanus newmani raised at different temperatures in the laboratory
2001
Lee, H.W. (Hokkaido Univ., Sapporo (Japan)) | Ikeda, T. | Ban, S.
Metabolism (oxygen consumption) of laboratory-raised Pseudocalanus newmani copepodite stages 1 through 6 (C1-C6) at 10degC, and C6 at 3, 6, and 15degC was determined. Oxygen consumption rates (R:microl O2 indiv. sup(-1) h sup(-1) ) of males were found to be less than the rates of females for the C4-C6, largely because of lesser body mass of the former than the latter. From stepwise regression analysis, R of copepodites was expressed as a function of body dry weight (DW: microg) and temperature (T: degC) as R=0.00172DW+0.00154T-0.00641. While higher temperatures yielded smaller adults, the effect of temperature was not seen in their carbon and nitrogen compositions. Over the temperature range tested, males (mean: 52.7% of DW) were consistently richer in carbon than females (43.1% of DW). Based on these results, the carbon budget was established for males and females growing from C1 to C6 at 3 to 15degC, and the combined effects of temperatures on metabolism and growth were assessed in terms of the net growth efficiency or K2 [growth~100/(growth + metabolism)]. The K2 was highest at 3degC for both males (61.3%) and females (59.9%), decreasing gradually with rising temperatures. At a given temperature, the sexual differences in K2 were not significant. The higher K2 associated with lower temperature suggests higher production potential of this copepod at lower temperatures.
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