570 



ECOLOGY AND BEHAVIOR 



Those maturing at 

 less than 150 cm 



Those maturing between 

 150 and 200 cm 



Those maturing at 

 more than 200 cm 



C. sealei 



C. melanopterus 



C. sorrah 



C. spallanzani 



C. brevipinna 

 C. limbatus 

 C. plumbeus 

 C. albimarginatus 



C. leucas 



C. amboinensis. 



C. amboinensis and C. leucas are relatively large, slow-swimming species 

 armed with broad erect cusps on the teeth of their upper jaws. C. plumbeus 

 has similar teeth but is somewhat smaller and possibly slightly faster. C. 

 albimarginatus, C. brevipinna, and C. limbatus are sleek, speedy species with 

 erect, relatively narrow-cusped teeth while C. sealei, C. melanopterus, C. 

 sorrah, and C. spallanzani are small to medium-sized sharks with obliquely 

 cusped teeth. 



C. amboinensis and C. leucas are remarkably similar in external appearance 

 but are easily distinguished by their different habitat preferences, at least on 

 the African coast. C. leucas is commonly found in very shallow coastal 

 waters while the young spend at least part of their lives in rivers and inland 

 lake systems. C. amboinensis is found in slightly deeper waters off the African 

 coast. The nursery areas for this population are not known; almost all the 

 specimens taken off Natal have been immature but well above birth size. At 

 Madagascar a different situation occurs. There C. leucas appears to be absent 

 and C. amboinensis is found in very shallow water and possibly also in fresh- 

 water. The two sharks appear to be complementary to each other in that C. 

 leucas is dominant off the east African coast while C. amboinensis is domi- 

 nant near Madagascar and possibly also near the offshore islands of the south- 

 west Indian Ocean. 



The four medium-sized inshore species can be split into two groups ac- 

 cording to their dentition. C. brevipinna and C. limbatus have relatively 

 narrow cusps to their teeth and are apparently adapted to feeding on smaller 

 prey than C. plumbeus and C. albimarginatus, which have broader cusps on 

 the teeth of their upper jaws. Differences in the ecological preferences of 

 C. plumbeus and C. albimarginatus are not clearly defined in present data. 

 C. albimarginatus appears to be faster swimming and may inhabit, on the 

 average, shallower water than C. plumbeus. In addition, C. albimarginatus is 

 confined to clear water (it does not occur south of Tongaland), while C. 

 plumbeus juveniles (but not newborn young) are fairly common in the 

 relatively dirty water of the northern and southern Natal coasts. For some 

 reason this shark is virtually absent from the central Natal coast but fairly 

 common on the northern and southern Natal coasts, where it is usually caught 

 over muddy bottoms. The only clear difference between C. limbatus and C. 

 brevipinna is their use of separate nursery areas. The Natal coast is commonly 



