BIOLOGY AND NATURAL HISTORY 123 



viduals are part of a continuous resident population or are detached from the 

 migrating mass is not definitely known. 



The age and sex composition of the migrating fish is interesting in that 

 the group spending the early summer in New England waters contains 90 

 per cent females, most of which are two or three years old. This condition is 

 explained by the fact that the migration coincides with the spawning season. 

 As pointed out earlier, females do not spawn until the end of their fourth 

 year while males mature at the end of the second year. Since fish of both 

 sexes remain in fresh or brackish water for two years, the only fish which 

 are available for the migration are females too young to spawn (the 2- and 

 3-year olds). However, the migration also includes some larger females which 

 are of spawning age but do not contain eggs. This fact suggests that females 

 do not spawn every year. 



There is a second and less numerous migration in early summer, after the 

 spawning season. This migration is composed of individuals and small groups 

 of larger females which have spawned and are moving north for the summer. 

 The movements of these larger females is reflected in the fishing records of 

 New England, where catches prior to June consist of smaller fish and the 

 catches during the summer and fall contain a greater percentage of the larger 

 size fish — more than can be accounted for by the growth of the earlier and 

 smaller migrants. 



Information regarding the migratory habits of the male striped bass is 

 needed. According to the literature, the sex ratio on the spawning grounds is 

 10 to 50 males per female, and the summer populations in the north, resulting 

 from migrations described above, are 90 per cent females. A large number of 

 males are therefore unaccounted for during the summer, except by Merri- 

 man's statement that the "strikingly abnormal sex ratio does not exist in 

 waters farther south." If the second migration (females which have spawned) 

 is large enough to influence materially the northern catch, there should be 

 10 to 50 times as many males to distribute themselves along the coast, and 

 there should be some southern localities where the summer population is 

 predominantly male. Future studies on this species may clear up this phase 

 of the life history. 



The migrations described above involve only a part of the coastal popula- 

 tion of striped bass. Although it is found from Florida to Nova Scotia, only 

 those fish from Chesapeake Bay to Cape Cod normally participate in the 

 migration described. It is believed, on the basis of tagging experiments, that 

 the Albemarle Sound population contributes very little to the northern migra- 

 tion and that very few of the south-bound migrants reach North Carolina in 

 the fall or winter. The Nova Scotia population also seems to be a separate 

 group and contributes very little to the New England population. On the 

 basis of observations made by Parr (1933), Merriman suggests that a cold 



