NOTES 



NOTES ON REPRODUCTION IN 



THE SCALLOPED HAMMERHEAD, SPHYRNA 



LEWINI, IN NORTHEASTERN TAIWAN WATERS 



The reproductive mode of hammerhead sharks 

 (family Sphyrnidae) is placental viviparity, fol- 

 lowing Teshima's (1981) designations. Three spe- 

 cies of hammerhead sharks are known from 

 northeastern Taiwanese waters: Sphyrna lewini 

 (Griffith and Smith), S. mokarran (Riippel), and 

 S. zygaena (Linnaeus). The scalloped hammer- 

 head, S. lewini, commonly found from Pung-Chia 

 Island to Guei-Shan Island (Fig. 1) is one of the 

 most abundant shark species in this area. Based 

 on data from the Nan Fan Ao Fish Market (lo- 



cated in northeastern Taiwan), 460-510 t/year 

 from 1982 through 1984 were landed, represent- 

 ing one-fourth of the total catches of sharks in 

 this area (the total landing being 1,760-2,240 t/ 

 year). Catches peaked in spring and winter and 

 were lower in summer and autumn. 



This species is also distributed in western and 

 southern waters of Taiwan; however, the catch 

 from those areas were smaller. The employees of 

 the southern and western fish markets explained 

 that the scalloped hammerhead is occasionally 

 seen in small numbers in those areas, but there 

 are no landing data. It is also common in coastal 

 warm temperate and tropical seas throughout 

 much of the world (Compagno 1984). Although 



26°N 



Figure 1. — Sampling area of 

 Sphyrna lewini. 



FISHERY BULLETIN; VOL. 86, NO. 2, 1988 



25°N 



