162 



Fishery Bulletin 93(1). 1995 



250.0 



150 -■ 



_, 100.0 



50.0 



O C (S) □ F 



• C V H 



A S (S) ▼ p 



AS O T 



50 100 150 200 



RNA (figmL"' homogenate) - FIA 



1 1 1 



2 5 5 7.5 10 12 5 15.0 17 5 20 22.5 25.0 



DNA (figmL -1 homogenate) - FIA 



6 8 



RNA/DNA - FIA 



Figure 2 



Mean RNA and DNA concentrations and RNA/DNA ratios of 24 crude fish 

 homogenates obtained by flow injection analysis (FIA) versus values trans- 

 formed from conventional fluorometric analysis (CFA) by functional regres- 

 sion coefficients in Table 2. Solid line represents a 1:1 correspondence be- 

 tween the two methods. Species abbreviations as in Table 1. 



genates for this study were chosen from six fish spe- 

 cies and assayed across far greater ranges of age and 

 nucleic acid concentrations than reported previously 

 (Clemmesen 1988, 1993; Caldarone and Buckley, 1991; 

 McGurk and Kusser, 1992) in order to broaden the scope 

 of comparison and statistical inference. A comparative 

 study of FIA and CFA techniques within the more lim- 

 ited range of sample concentrations encountered dur- 

 ing routine processing of individual larvae of a single 

 species would have undoubtedly yielded higher corre- 

 lations between estimates. 



The FIA and CFA procedures differ primarily in 

 the choice of instrumentation as both use sample 

 extraction by sarcosine. Caldarone and Buckley 

 (1991) reported that nucleic acids in larval fish 

 samples (<200 /ig dry weight) were completely ex- 

 tracted in one hour at room temperature. Sample 

 nucleic acid concentrations of fish homogenates in 

 this study were prepared to be similar to those ob- 

 tained from assays of individual larvae, suggesting 

 that incomplete or differential extraction of homo- 

 genates by sarcosine between FIA and CIA is un- 



