FISHERY BULLETIN: VOL. 78, NO. 2 



Table 5. — Some marine teleosts which spawn plank. tonic eggs and are known or suspected of spawn- 

 ing only at particular times of the day. 



diel and lunar spawning periodicity in some coral 

 reef fishes (e.g., Lobel 1978; Johannes 1978; May 

 et al.l979). References cited in Breder and Rosen 

 (1966) indicate that at least 70 freshwater and 

 marine teleosts with demersal or attached eggs 

 may spawn or oviposit at particular times of the 

 day. Even though many of the data are only 

 suggestive, there are indications that diel spawn- 

 ing periodicity may be a common and widespread 

 phenomenon among fishes. 



Diel spawning periodicity in fishes may be due 



to physiological constraints or may be adaptive. 

 Woodhead ( 1966) and Blaxter ( 1965, 1970) pointed 

 out that light may restrict spawning to a particu- 

 lar time of day, especially in species where vision is 

 important in sexual displays, courtship, and pair- 

 ing. Woodhead (1966) noted, however, that species 

 which require daylight for courtship might still 

 spawn or oviposit at other times of the day. Obvi- 

 ously, nocturnal spawners are not light limited. If 

 adaptive, the value of reproductive periodicity 

 may be found in the synchronization of reproduc- 



460 



