laid down from the position of the ring on the shell 

 between the check mark made at time of tagging 

 and the margin. On this basis, the 1958 ring 

 appears to have been laid down about 27 weeks 

 after the date of tagging. This places ring forma- 

 tion at March 30, just 6 months after October 1, 

 which is the usual date of spawning by sea scallops 



in this area (Posgay and Norman, 1958). The 

 true age at the time of ring formation in this area 

 is, therefore, the number of the ring minus one- 

 half year. There is a possibility, now under 

 investigation, that the first definable ring, at 

 about 20 mm., is not laid down during the first 

 year of life but rather in the second. 



Figure 12. — Upper valve of a sea scallop that has been tagged, released, and recaptured, 

 row points to the nick which was made in the margin at the time of release.) 



(The ar- 



ANNUAL MARKS ON SHELL OF SEA SCALLOP 



309 



