REPORT OF COMMISSIONERS OF INLAND FISHERIES, 



57 



V. Rate of Groicth.-^The rate of growth of the mackerel is not 

 known to a certainty, since those who have investigated it have 

 reached somewhat different results. The following table shows in 

 brief the length of mackerel of different ages according to the esti- 

 mates of different European and American observers. Similar 

 figures for the cod and herring are added by way of comparison. The 

 original measurements in millimeters are reduced approximately to 

 inches. 



Young mackerel, newly hatched from the egg, are one-fifth inch 

 in length, according to Cunningham. They have not been reared in 

 confinement to a greater age than four days. " Blinks " are sup- 

 posed to be two years old, " tinkers," three years, and adults of 

 17 or 18 inches, four years old. 



Observations as to the age and size of mackerel at the time of 

 sexual maturity are as yet too few to justify general conclusions. 

 Marion states that fish 9 inches long in February, which he thought 

 to be a year old, had the reproductive organs well developed. 



At Plymouth, in June, Cunningham found no signs of maturity in 



