EXPLANATORY NOTE 



The series embodies results of investigations, usually of restricted 

 scope, intended to aid or direct management or utilization practices .and as 

 guides for administrative or legislative action. It is issued in limited quantities 

 for official use of Federal, State or cooperating agencies and in processed form 

 for economy and to avoid delay in publication . 



The following collection of papers entitled "Contributions to the 

 Study of Subpopulations of Fishes" is a written symposium by members 

 and former members of the Branch of Fishery Biology. It is a substitute 

 for a conference, thus lacking the discussion which is so often stimulating 

 and which contributes to the development of a general consensus which did 

 not exist among the group when the papers were written. The advantage of 

 more leisurely preparation, of not having to meet a deadline, such as a 

 meeting date, may outweigh the lack of debate, however, for although all 

 of the men were engaged in active research, the subjects of some of the 

 papers were collateral to the principal lines of work of some of them at 

 the time of preparation. The papers were written voluntarily on invitation, 

 rather than by assignment as an official function, and thus partake of the 

 nature of contributions to some journal of marine fishery biology (now non- 

 existent). If there is a spontaneous demand for a written symposium upon 

 timely subjects in the future, the Special Scientific Report: --Fisheries, 

 being of a less permanent or formal nature than the older printed publica- 

 tions of the Service, may offer its pages again under a rotating editorship 

 for the symposium issues. 



