NOTES 



SEASONAL SPAWNING CYCLES OF THE 



SCIAENID FISHES GENYONEMUS LINEATUS 



AND SERIPHUS POLITUS 



The white croaker, Genyonemus lineatus (Ay res), 

 and queenfish, Seriphus politus Ayres, are two of 

 the common inshore fishes occurring along the 

 southern California coast (Miller and Lea 1972). 

 Detailed reproductive data are not available for 

 these species. The purpose of this note is to provide 

 information on their seasonal spawning cycles. 



Materials and Methods 



Monthly samples are from November 1974 to 

 October 1975. Most specimens were collected by 

 hook and line from the Santa Monica Pier, Los 

 Angeles County, Calif. Remaining fishes were 

 obtained about 4.2 km south of Santa Monica at 

 the Scattergood Steam Plant, El Segundo, Los 

 Angeles County. Scattergood fishes had been 

 exposed to temperatures between 23° and 41°C. 

 Histological comparisons of these fishes with 

 freshly caught specimens showed the ovaries were 

 not altered by this treatment. Specimens are 

 deposited in the ichthyology collection of the Los 

 Angeles County Museum of Natural History. 



Fishes were immediately slit and placed in 10% 

 Formalin.^ Gonads were embedded in paraffin and 

 histological sections cut at 8 jum. Slides were 

 stained using iron hematoxylin followed by eosin 

 counterstain. Seasonal occurrences of oocytes 

 (Tables 1, 2) were calculated by randomly selecting 

 areas of slides from each monthly representative 

 and classifying oocytes as to their category (Type 

 1, 2, or 3). Areas of a slide were surveyed until at 

 least 100 oocytes were classified. 



Results and Discussion 



Three classes of oocytes are present in the 

 ovaries of G. lineatus (Table 1) and S. politus 

 (Table 2). Type 1 is the most abundant class and 

 varies from those recently derived from oogonia to 

 those approaching Type 2 oocytes. Type 2 oocytes 

 have diameters between 100 and 270 jum and differ 



from Type 1 oocytes in the presence of a zona 

 pellucida and zona granulosa. Small quantities of 

 yolk granules may be found on the periphery of 

 larger representatives of this class. The diameter 

 of yolk filled mature Type 3 oocytes is greater than 

 270 jum. The smallest fishes to contain Type 3 

 oocytes measured 143 mm standard length (SL) 

 for G. lineatus and 148 mm SL for S. politus. 



As shown in Tables 1 and 2 there are several 

 differences in seasonal distribution of oocytes 

 reflecting the spawning cycles of G. lineatus and 

 S. politus. The major difference is in abundance of 

 Type 3 oocytes indicating G. lineatus comes into 

 spawning condition in October and spawns inter- 

 mittently into April. Seriphus politus enters 

 spawning condition in April and spawns into 

 August. These data support the findings of 

 Skogsberg (1939) who reported that S. politus 

 spawns throughout summer and G. lineatus 

 spawns from November through May off 

 California. 



Table 1. -Monthly distribution of Genyonemus lineatus oocytes 

 with mean standard length (mm) ± standard error, November 

 1974-October 1975. 



Table 2.-Monthly distribution of Seriphus politus oocytes with 

 mean standard length (mm) ± standard error, November 1974- 

 October 1975. 



'Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



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