FISHERY BULLETIN: VOL. 80, NO. 4 



shark and among the six species (Fig. 4). Stride 

 length is defined as the distance travelled per tail 

 beat (Wardle 1975). In teleosts, specific stride 

 length (stride length/L) typically takes values of 

 0.6 to 0.8, and does not vary with speed (Wardle 

 1975). In blacktip sharks, specific stride lengths 

 comparable with those of teleosts were seen only 

 at low speeds and stride length was lower at 

 higher speeds. Specific stride length was similar 

 to the teleost values in the more fusiform sharks, 

 but was lower in more elongate species, the low- 

 est value of 0.51 L being found for nurse sharks 

 (Table 1, Fig. 4). 



Data on specific wavelengths were only mea- 

 sured with sufficient accuracy for the three 

 smaller species. Values ranged from 0.77 to 1.07 

 L, and tended to be larger for the more fusiform 

 species. Specific wavelength decreased with spe- 

 cific swimming speed in blacktip sharks (Fig. 5), 

 contrasting with teleosts, where specific wave- 

 length is usually independent of speed (Webb 

 1971, 1973; Wardle and Videler 1980). 



Rates of change in amplitude were measured 

 along the body length. In the sharks, there was 

 an area along the body, about 0.2 Lfrom the nose, 

 where both amplitude and its rate of change with 

 body length were least (Fig. 6). Anterior to this 

 area, rates of change in amplitude were negative 

 where amplitude increased rostrally due to yaw- 

 ing of the nose. These patterns are similar to 

 those of teleosts. The maximum rate of increase 

 in amplitude in sharks occurred from 0.5 to 0.7 L, 

 and declined over more posterior portions of the 

 body. This particular pattern has not been de- 

 scribed in teleosts, which usually show an early 

 rise in amplitude (e.g., eel) or sustain increasing 

 rates of amplitude over the whole caudal region 

 (e.g., fusiform teleosts). The area over which 

 amplitude begins to increase in sharks is close to 



t- 



u 



UJ 



a. 



U/L- SPECIFIC SWIMMING SPEED (L.s" 1 ) 



Figure 4.— The relationship between specific stride length, 

 S/L, and specific swimming speed, U/L for several sharks. The 

 key to symbols is in Figure 1. 



the region of the trailing edge of the first dorsal 

 fin (Thomson and Simanek 1977). 



DISCUSSION 



The diversity of swimming kinematics in fish 

 was originally described and classified by Breder 



X/L- I 29 - 0I7±006 U/L 



12 3 4 



U/L- SPECIFIC SWIMMING SPEED (L.s H ) 



Figure 5.— The relationship between specific wavelength, 

 X/L and specific swimming speed, U/L for three species of 

 shark. Vertical and horizontal bars are ±2SE. The functional 

 regression was fitted only to data for the blacktip shark. The 

 key to symbols is in Figure 1. 



UJ 

 Q 



3 



_l 

 0. 



O X 



u. >- 



oo 



o 



$ m 



X H 



< 



or 



0-8 



0-6 



0-4 



0-2 







-0-2 



-0-4 



0-2 0-4 0-6 08 10 



(nose) LOCATION ALONG BODY (tail) 



Figure 6.— The relationship between the rate of change of am- 

 plitude along the body length and the position along the body in 

 some fishes. The data for fusiform teleosts (solid hexagons 

 linked by solid lines) were taken from Bainbridge (1963) for 

 dace, Lewiscus leuciscus, and bream, Ambramis brama. Data 

 for Anguilla (open hexagons linked by a solid line) were taken 

 from Gray (1933). Data for the sharks (see key in Fig. 1) were 

 taken from Figure 2; the dotted line was fitted by eye through 

 the data for sharks. 



808 



