330 U.S. BUREAU OF FISHERIES 



of squeteague during the period 1928-32 consisted of fish which 

 had spent their first two growing seasons south of Delaware Bay. 

 This implies that replenishment of the northern stocks of seque- 

 teague dej^ends a great deal less on local reproduction than on im- 

 migration from more productive southern spawning areas. Further- 

 findings during 1933 necessitate substantial modification of this 

 view. 



Although these findings strongly support the view that the great 

 majority of the squeteague taken in the northern fishery enter that 

 fishery for the first time as 2-year-old fish after having spent a year 

 as yearlings south of Delaware Bay, it now appears that approxi- 

 mately half of these immigrant 2-year-olds originate in the North, 

 and return there after a year spent in the South. This compels a 

 revision of the opinion that northern spawning ordinarily makes no^ 

 significant contribution to northern stocks of adults. It still ap- 

 pears, however, that these stocks are dependent on southern spawn- 

 ing areas for about half of their increment. 



The evidence for this modified view of the rather complex be- 

 havior of squeteague consists in part of the results of 1932 tagging- 

 experiments, in part of further analysis of scale collections, and in 

 part of the results of a hatching experiment with squeteague eggs. 

 These will be discussed in turn. 



During the following summer 47 belly tags were returned from. 

 1,900 juvenile squeteague tagged in October 1932, near Montauk, 

 N.Y. Of these, 14 were taken south of Delaware Bay, 24 in or north, 

 of Delaware Bay, and 9 were not accompanied by records of date 

 and locality of recapture. It is certain that many more tagged fish 

 were recaptured than were reported, especially between May and 

 September, for internal tags are not discovered unless the fish are 

 gutted. Since the fish were small (average length 8 inches) when 

 tagged, many were undoubtedly culled from the catch and dis- 

 carded without examination. Because of the slower growth of 

 southern yearlings, it is probable that a larger proportion of the 

 southern than of the northern summer recaptures were not reported. 

 Thus it is apparent that the southern yearlings which provide 

 the bulk of the northern increment of 2-year-old fish in the follow- 

 ing year include an unlniown but possibly considerable number of 

 squeteague which originated in the North. 



More useful is the evidence from further analysis of the scale 

 structure of fish in representative samples of the commercial catch, 

 for it permits a quantitative estimate of the respective contribu- 

 tions of northern and southern spawning and nursery areas to the 

 northern stock of adults. 



The method used previously, that of comparing the early growth 

 increments (as calculated from the scales) of northern adults with 

 the corresponding observed increments of northern and southern 

 juveniles and yearlings, although satisfactory for distinguishing 

 those northern adults which have been in the South as yearlings from 

 those which had been in the North, has not proved adequate to 

 determine where these fish were as juveniles (i.e., fish less than a 

 year old). 



In 1933 a method yvns employed which appears to permit separa- 

 tion of the northern adults according to orisin. This consists of 



