FISHERY BULLETIN: VOL. 80, NO. 3 



crease gradually declined during larval develop- 

 ment (Tables 1, 2). This trend was reflected by 

 decreasing m of fitted regression curves: —0.074 

 in the Z-l, -0.045 in the Z-2, and -0.031 in the 

 megalopa. In Figure 2 only the first regression 

 (Z-l) is shown as the most accurately measured 

 example (the curve for starved zoeae given in the 

 same graph will be discussed below). 



Growth in zoeal stages can also be described as 

 a power function of t: In y = b + m In (t + 1), where 

 y is any measure of biomass except FW (DW, C, 

 N, H, J). The lvalues were almost identical with 

 the logarithms of the initial biomass measure 

 under consideration, the m values varied be- 

 tween 0.29 and 0.48 (Table 3). 



The fitted curves describe the actual growth 

 patterns until late premolt was reached. In this 

 very advanced period in the Z-l stage (days 12 

 and 13), growth ceased or even switched to a 

 slight loss. These last values were not included in 

 the Z-l regressions. The fitted growth curves 

 were converted to percentage values of early 

 postmolt levels, so that direct comparison of 

 relative increase rates became possible (Fig. 3; 

 Z-l curves for 1980 values only). 



In zoeae the individual energy content (J) re- 

 vealed the strongest increment, DW the weakest. 

 The rate of increase in N was similar to that in 

 DW, whereas C and H increased at a higher rate 

 during individual growth (Table 3). A compari- 

 son of the biomass values in first zoeae obtained 

 in two different seasons and years shows that the 

 1979 larvae were not only less viable (see above), 

 but also showed lower initial biomass (reflected 

 by lower b values in all regression equations 

 describing growth) and lower growth rates (re- 

 flected by m values), especially in C, H, and J. 



TABLE 3.— Parameters of regression equa- 

 tions for individual growth in larval stages 

 of Hyas araneus: In y = 6 + m  In (t + 1). t= 

 time (d); r = correlation coefficient; df = 

 degrees of freedom; dry weight (DW), car- 

 bon (C), nitrogen (N), hydrogen (H) in /ug. 

 and energy contents (J). 



'1979 observation (all others from 1980) 



Figure 2.— Hyas araneus. Water content (% fresh weight) in Z- 

 1 larvae fed and starved for different lengths of time. 



20 24 



Figure 3. — Hyas araneus. Growth patterns [dry weight (DW), 

 energy contents (J), carbon (C), nitrogen (N), and hydrogen (H) 

 per individual] in all larval stages expressed as percentage of 

 early postmolt levels. Solid curves: fitted by equations (see 

 text); dotted curves: fitted by eye. 



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