Relationships between growth rate and RNA,DNA, protein and dry weight in Artemia salina and Euchaeta elongata

The concentrations of RNA, DNA and protein, and the dry weight in 3 cultures of the anostracan Artemia salina (L.) were measured to investigate the usefulness of the RNA-growth relationship in estimating growth or productivity. Similar analyses were performed on Copepodid stages III to VI of the calanoid copepod Euchaeta elongata Esterly collected periodically over 7 months in Haro Strait and over 4 months in Saanich Inlet, British Columbia, Canada. It was found that the RNA-growth relationship derived by Sutcliffe (1965) did not agree with that found for A. salina in this study. Also, neither equation accurately predicted growth rates for E. elongata copepodids. It is concluded that the general positive relationship between RNA concentration and growth rate lacks sufficient specificity to be used as a method for predicting growth rates in these species.