FISHERY BULLETIN: VOL. 79, NO. 3 



.500 - 



T: .400 



c/> 



.300 - 



.200 - 



.100 



10 



30 



50 



70 



90 



110 



130 



150 



Gonad Index (-^xio«) 



SL3 



Figure 3. — Scattergraph of the median diameter (random axis) of the largest size-frequency mode of oocytes plotted against gonad 

 index of the respective female queenfish. Asymptote ( noted by arrow! occurs at an oocytediameterofabout 350 /u.m, corresponding to a 

 gonad index of about 40. 



Table 2. — Percent offemale queenfish ofvarious length classes' 

 that were sexually mature during the 1979 spawning period. 



'An average of 90 female queenfish per length class were examined 

 each month. 



spawners to 6 mo in the largest fish. Relatively 

 few females start spavi^ning at age I. Of all 

 sexually active (Stages 2-4, Table 1) females 

 captured during the 1979 spawning season, 6 and 

 34% were <12 cm and <13.5 cm, respectively. 



Ovarian Cycling 



Monthly peaks in the proportion of females 

 in ready-to-spawn condition occurred during the 

 moon's first quarter (contingency chi square = 

 27.7; 3 df; P< 0.0005; Siegel 1956). At such times 



from 19 to 42% of all the adult females in the day's 

 samples had ovaries containing eggs in a hydrated 

 state (Figure 2B). 



Female S. politus begin hydrating oocytes after 

 dawn and spawn between late afternoon and 

 evening. No difference existed between the per- 

 cent frequency occurrence of ready-to-spawn 

 females in samples collected at different times 

 during daylight hours; and no fish caught at 

 any time during the night were ready to spawn 

 (Table 3). These results were reexamined for 

 subsample ovaries, using accepted histological 

 criteria for distinguishing hydrated from non- 



TaBLE 3. — Frequency occurrence of mature female queenfish 

 whose ovaries contained oocytes in a hydrated vs. a nonhydrated 

 state in samples collected during various 6-h intervals on 25-28 

 June 1979. 



550 



