ABSTRACT 



Growth of bluefin tuna Thunnus thynmis (Linnaeus) based on specimens 

 captured mostly in the Cape Cod and Long Island areas was studied by count- 

 ing annuli on scales and vertebrae and by analyzing length-frequency data. 

 Similar results obtained by these two methods support their validity for ages 

 0-4. Older ages were determined by counting annuli only, but tag returns 

 and weight-frequency data afford some corroboration for ages 5-7. Growth 

 is believed to be extremely rapid during the first summer and about four- 

 fifths of an inch per month in the first winter. During the next Syi years, 

 bluefin tuna grow at a rate of about IM inches per month in summer and about 

 one-third of an inch per month in winter, or about 7 inches per year. Tables 

 of estimated sizes for each month of the first 5 years of life, and at midsummer 

 through the age of 10 years, are presented. The growth rate appears to decline 

 gradually to about 4 inches per year in this range. Only slight differences 

 were found between the sizes and growth rates of fish of the same age taken in 

 different years. 



