NATURAL HISTORY OF THE SANDBAR SHARK 



*i: 



Figure 2. — Eulamia milberli turning in front of the camera at Marineland, Fla. Note that the pectoral fins are quite 

 broad at their bases, relatively pointed and not strongly concave on their trailing edges. With the exception of 

 the caudal fin, all fins function as rudders or stabilizers and cannot be used independently i for locomotion The 

 pectorals provide lift to offset the lift of the asymmetrical caudal since without a forward lift-the shark would tend 

 to somersault. The large stiff fins in forward positions reduce the ability of this species to roll and twist but may 

 be expected to increase the precision of its forward swoops at creatures on the sea bottom. (Photograph courtesy 

 of Marine Studios, Marineland, Fla.) 



growth may take in different species. Data to 

 show adequately the differential growth in car- 

 charhinids are lacking. But one example will 

 suffice to show how unreliable proportional meas- 

 urements can be for comparisons between species 

 in which specimens of different sizes and ages 

 are involved, and in which the growth patterns 

 of the species l)cing compared are mikncnvn. In 

 three examples of young ^- milberti, 685. 680, 

 iiiid r)?);") mm. long, from the vicinity of Woods 

 Hole, Mass.. the lengths of pectoral fins (meas- 

 ured on their outer margins or leading edges) 

 are 16.2, 15.0. and 15.0 percent of the total length 

 of the sharks. In three adult milberti from oflt 



Englewood. Fla., 2.210. 2,070, and 2,240 mm. long, 

 tlte pectoral fin lengths are 21.3, 21.5. and 21.0 

 jiercent of the total length. Let us compare these 

 ])roportions with measurements of pectoral fin 

 lengths of the whitetip shark. Ptcrolamiops 

 longiminiiis (Poey). A late-embryo whitetip 530 

 mm. long, taken l.''>5 miles off Xew Smyrna. Fla., 

 has a pectoral fin length 22. (i percent of the total 

 length; a young wliiteti]) 1.020 mm. long, taken 

 olf Tumpico, Mexico, lias a pectoral fin 25.5 per- 

 cent of the total length; and an adult whitetip, 

 2.310 mm. long, from the central Caribbean, has 

 a pectoral fin 22.0 percent of the total length. 

 The figures indicate a proportionately longer 



