300 



250 



200 



I I 1 uL 



-J UJ I I 1— i L- 



-20 t-15 -10 

 CONCEPTION 

 (-16 3 mo) 



1 1 6 cm/mo 



4 5 cm /mo 



10 



-150 



100 Globicephalg 

 melaena 



- 50 



?? 



FISHERY BULLETIN; VOL. 74, NO. 2 

 550 



78 cm/mo. 



I I I I I I J I I 



-I5| -10 -5 



CONCEPTION 

 (-14.6 mo) 



I I I I I 



Phy seter 

 catodon 



27.8 cm /mo 



15 



-200 



—J — 1 — I — I — I 1 1 I 1 1 1 1 1 1 i I I 1 



15 20 



Figure 9. — Fetal growth and average postnatal growth during a period equal to the gestation period in five odontocete 

 cetaceans: Phocoena phocoena (gestation period and postnatal growth from M</)hl-Hansen 1954; to from Laws 1959; length at 

 birth from Fisher and Harrison 1970); Delphinapterus leucas (from Brodie 1971); Globicephala melaena (from Sergeant 1962); 

 Physeter catodon (from Best 1968, 1970); and Stenella coeruleoalba (from Kasuya 1972). 



fetal rate and the average rate during a postnatal 

 period equal to the gestation period differs among 

 the five odontocete species for which sufficient 

 data exist (Figure 9) and is correlated with length 

 at birth (Figure 10). The least-squares line for log 

 of the difference between fetal and postnatal 



growth rates (Y ) on log of length at birth (X ) yields 

 Y = -1.33 + 0.997X, from which a predicted Y of 

 3.75 cm/mo is estimated for S. attenuata and an 

 average growth rate in the first year of 4.66 cm/mo 

 is estimated. This average rate is close to those for 

 the other three delphinids (5.1 forS. coeruleoalba, 



238 



