LOVE ET AL.: LIFE HISTORY AND FISHERY OF CALIFORNIA SCORPIONFISH 



we observed the development of the opaque zone 

 on the sections' edges in fishes with 2-5 opaque 

 zones. Opaque zone deposition was seasonal, from 

 late winter through summer (Table 2). A relatively 

 large number of pterygiophores (208 = 34%) were 

 not readable because of malformed or poorly de- 

 lineated annuli. One hundred and eighty-two females 

 (ages 1-21 yr) and 222 males (ages 1-15 yr) were 

 aged. 



Table 2.— Monthly percentages of 2-5 yr old 

 California scorpionfisfi with opaque margins. 



where L, = length at time t. 



theoretical maximum length 

 constant expressing the rate of ap- 

 proach to L^ 

 theoretical age at which L, = 



k = 



^n = 



was fitted to the direct observation age-length data. 



Since females grew significantly faster than males 

 (ANOVA, F = 12.5, P < 0.001) and reach a greater 

 size (Fig. 5), we have separated growth data by sex 

 (Table 3). 



Mean lengths at ages from direct observations of 

 annuli and those generated by the von Bertalanffy 

 equations are plotted in Figure 5. The oldest female 

 we observed was 21 yr old, the oldest male 15. We 

 have few samples of fish older than 11 yr, and back- 

 calculated lengths (Tables 4, 5) are computed to this 

 age. 



Lengths at ages were estimated by direct obser- 

 vation of pterygiophore annuli, back calculated ages, 

 and the von Bertalanffy growth curve model (Tom- 

 linson and Abramson 1961). 



L, = L^[l - exp - k{t - to)] 



Table 3.— Parameters of the von Bertalanffy equa- 

 tion for California scorpionfish off Southern 

 California. 



40 



30 



I 

 t- 



o 



20 



10 



MALES 



8 9 10, 11 12 13 14 15 16 17 18 19 20 21 

 AGE(YEARS) 



Figure 5.— Von Bertalanffy growth curves of female and male California scorpionfish. 

 Also included are mean lengths at age computed from direct observation of pterygiophore 

 annuli. Based on 183 females and 222 males taken in the Southern California Bight, 

 1981-83. 



105 



