SEASONAL SPAWNING CYCLE OF 



THE LONGFIN SANDDAB, 



CITHARICHTHYS XANTHOSTIGMA 



(BOTHIDAE) 



This note contains the first description of the sea- 

 sonal spawning cycle of the longfin sanddab, 

 Citharichthys xanthostigma. This fish is common 

 off southern California, but rare north of Santa 

 Barbara and occurs at depths from 2 to 201 m 

 (Miller and Lea 1976). 



Methods 



Fish were collected by otter trawl off the coast 

 of southern California at depths of 45-64 m from 

 San Clemente (lat. 33°20'N, long. 117°38'W) to 

 Huntington Beach (lat. 33°40'N, long. 118°00'W). 

 Collections were made during January-Decem- 

 ber 1978. Only females were examined. Speci- 

 mens were immediately slit along the abdomen 

 and placed in 10% Formalin 1 . Ovarian histologi- 

 cal sections from 137 C. xanthostigmawere cut at 

 8 fim and stained with iron hematoxylin. Season- 

 al gonosomatic indices (ovary wt/fish wt X 100) 

 were calculated from preserved fish. Ovaries 

 were classified histologically into four stages 

 (Table 1). 



Table 1.— Monthly distribution of body sizes (SL) and stages 

 in Citharichthys xanthostigma spawning cycle, January-De- 

 cember 1978. 



Results 



Most C. xanthostigma spawn in winter (Table 

 1). At this time the majority of females contain 

 yolk-filled oocytes (>290 M m in diameter) and 

 gonosomatic indices reach their highest values 

 (Fig. 1). Females were in spawning condition in 

 December. The presence of mature (yolk-filled) 



60-| 



8 50 



5 40- 



O 

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^ 3 



I 20 

 o 



1 0- 



12 



I 



18 



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20 



17 



21 



18 



rr 



I 



I 



— I 1 1 1 1 1 1 1 — 



JAN FEB APR MAY JUN JUL OCT DEC 



Month 



Figure 1.— Seasonal gonosomatic indices for Citharichthys 

 xanthostigma. Vertical line = range; horizontal line = mean; 

 rectangle = 95% confidence interval. Sample size above each 

 month. 



oocytes from an incipient spawning, and of post- 

 ovulatory follicles which are remnants of the 

 follicular walls of recently spawned oocytes 

 (Hunter and Goldberg 1980), and of maturing 

 oocytes for a subsequent spawning in the same 

 ovary indicated that C. xanthostigma spawns 

 more than once each season. The number of 

 spawnings per season is unknown, however. Post- 

 ovulatory follicles were similar to those of other 

 teleost fishes (Hunter and Goldberg 1980). The 

 smallest mature ( ripe) female measured 107 mm 

 SL (standard length); the largest, 181 mm SL. 

 Miller and Lea (1976) reported this species may 

 reach 250 mm TL (total length). 



The incidence of spawning females decreased 

 in spring. At this time most females contained 

 regressed ovaries (Table 1 ) consisting of primary 

 oocytes (53 jum) or regressing ovaries in which 

 oocytes in various stages of vitellogenesis were 

 undergoing atresia. Ovaries from fish taken dur- 

 ing July were regressed, and gonosomatic indices 

 were reduced (Fig. 1). Ovarian activity for the 

 new spawning cycle began during autumn. This 

 was apparent in October (Table 1 ) when previtel- 

 logenic females containing slightly enlarged, 

 vacuolated oocytes (118 jum) and vitellogenic fe- 

 males (yolk deposition in enlarging oocytes) were 

 present. 



Discussion 



'Reference to trade names does not imply endorsement by 

 the National Marine Fisheries Service. NOAA. 



My data have shown C. xanthostigma is a win- 

 ter spawner in southern California. Spawning 



906 



FISHERY BULLETIN: VOL. 80. NO. 4, 1982. 



