BIOLOGY OF THE MUTTONFISH 



75 



The first column shows the number of muttonfish of each age. 



The second column gives the age as estimated hy the otoliths. 



The third column shows the smallest and greatest lengths found for each age. 



The fourth <;-olumn gives the estimated average lengths for each year. For 

 example, it is estimated that on the average a mutto-nfish is 10 cm. long at the end of 

 .the firet year, 16 cm. long at the end of the second year, 21 cm. at the end of the third 

 jear, etc. 



The fifth column gives the proba'ble average growth in cm. for each year. 



The rate of growth is shown in fig. 4. The curve represents the estimated 

 .average lengths for each year. Since the majority of the young fish were taken in 

 early summer, they would not have reached their growth limits for that year and 

 therefore fall to the left of the cui-ve. 



6. EEPRODUCTTON. 



It is impossible to distingiiish the sexes externally except possibly in older speci- 

 mens where the head of the male appears slightly larger and heavier than that of the 

 (female. Females in the environs of the St. Andrew's Biological Station from May 31 

 to October 15, 1918, contained eggs from less than 1 mm. to 5 mm. in diameter. A 

 female 62 cm. in length, weighing 3 pounds 12 ouncee, and probably 17 years of age, 

 •contained 1,805 eggs 5 mm. in diameter. Seventy-ni-ne specimens were opened, and 

 the diameters of the eggs in the ovary and the lengths of the testes were measured. 

 The results are given in the following two tables : — 



EGGS IN OVARIES— DIAMETER. 



