DeMARTINI and FOUNTAIN: OVARIAN CYCLING FREQUENCY IN QUEENFISH 



production than smaller females. The average 42 

 g fish produces 287 eggs/g of ovary-free body 

 weight. Values range from an average 218 eggs/g 

 to 494 eggs/g respectively (Figure 8) in a 10.5 cm 

 and a 25 cm fish. Ripening (Stage 2, Table 1) 

 ovaries compose 3.8% (for small fish <13.5 cm) 

 and 4.29c (large fish >13.5 cm) of body weight. 

 Ripe ovaries containing hydrated ( Stage 3) oocytes 

 made up an average 7.1% and 8.0% of the body 

 weight of small and large S. politus, respectively. 

 The average female produces about 4,570 eggs/g of 

 Stage 3 ovary. 



Egg Size 



The Gilson's fluid-fixed, hydrated and non- 

 hydrated oocytes of S. politus average 540 yttm 

 and 400 /xm in diameter, respectively, and egg 



Month 



Figure 9. — Median diameters (random axis, Gilson's fixed) of 

 the largest size-frequency class of oocytes present in subsampled 

 queenfish of all body sizes collected March -August 1979. Data for 

 fish with Stage 2 and Stage 3 ovaries are plotted separately. 

 Numbers of sample fish are indicated. 



Table 8. — Results of two-way analysis of variance of the effects 

 of month and female size on the median diameter of the largest 

 oocytes in ripening (Stage 2) ovaries of queenfish. Sample size 

 = 417 fish. 



size in general declines as the spawning season 

 progresses (Figure 9). Eggs fixed in Gilson's fluid 

 are 85% the diameter of fresh eggs; thus actual 

 egg size declined from about 685 to 580 /u,m 

 between March and August 1979. Egg size also 

 varied among different-sized females (Table 8). 

 Throughout the season larger females generally 

 produced larger eggs than did smaller females. 



DISCUSSION 



Size at Sexual Maturity 



The smallest S. politus that contained ripe 

 (Stage 3) eggs were 10.0-10.5 cm SL. At this size 

 females are in their first spring or second summer 

 following birth and average about 13 mo old 

 (DeMartini et al. footnote 4). The onset of egg 

 production by recruit spawners is variable, how- 

 ever; on average only 38% of the females this 

 small contained mature eggs throughout the sea- 

 son, and >10% were generally immature at all 

 lengths <13.5cm (Table 2). A variable body size at 

 first sexual maturity is a common feature of serial 

 spawners and fishes in general (Nikolskii 1969). 



Goldberg (1976) found no histological evidence 

 of sexual maturity in female S. politus <14.8 cm 

 SL among those he examined during November 

 1974-October 1975 from Santa Monica Bay Calif., 

 about 110 km upcoast of our study area. This might 

 be due to geographic or annual variation in size at 

 maturity, but more likely reflects chance error as 

 only two fish <14.8 cm SL were among those 

 examined (Goldberg^). 



Body Size and Length of Spawning Season 



Duration of the spawning season of repeat- 

 spawning S. politus is in general about twice as 

 long as the season for recruit spawners (Table 2). 

 An earlier onset and later cessation of spawning 

 by larger, older individuals is knowm for other 

 serial spawning fishes of southern California, 

 including northern anchovy (perhaps: see Hunter 

 and Macewicz 1980); Pacific sardine, Sardinops 

 sagax caeruleus (Clark 1934); jack mackerel, 

 Trachurus symmetricus (Wine and Knaggs 1975); 

 Pacific mackerel. Scomber japonicus (Knaggs and 

 Parrish 1973); and California grunion, Leuresthes 



'Spawning season partitioned into 6 mo: March, April, May, June, July, 

 August 1979. 



^Females divided into five length classes: 10.6-12.5, 12.6-14.5, 14.6-16.5, 

 16.6-18.5, >18.5cm SL. 



^Stephen R. Goldberg, Department of Biology, Whittier Col- 

 lege, Whittier, Calif., pars, commun. August 1978. 



555 



