96 "U.S. BUEEAU OF FISHERIES 



jected to any great strain. To date there have been only about 1 

 percent returns from a total of 5,228 tagged scup. This low percent- 

 age cannot be attributed wholly to the loss of tags by becoming 

 detached or to the death of the fish as a result of the marking opera- 

 tion, since returns were well distributed over a period of almost a 

 year. Moreover, in laboratory tests it has been found that tagging 

 causes very little mortality, and that virtually all scup retain the 

 external celluloid disk tags for a period of 4 months, and the major- 

 ity for at least 1 year. But in order to eliminate any uncertainty 

 due to a possible loss of tags, we may confine our consideration to 

 the returns for the first 4 months after tagging. During such periods, 

 less than 1 percent of the marked scup were returned. This is 

 exceedingly low in comparison with returns of 4 to 20 percent obtained 

 during comparable periods with squeteague, cod, and striped bass, 

 and may be taken to indicate that the fishery at present is catching 

 only a very small part of the general stock of scup in the sea. 



It appears, therefore, that although now subject to year-round 

 exploitation, the scup fishery has not to date shown any indication 

 of an appreciable decline in abundance directly attributable to the 

 additional strain. Consequently, there appears to be no present need 

 for restriction of the fishery. 



It is important, however, that observation be continued, for this 

 conclusion is based on present conditions of abundance and fishing 

 intensity; and experience has shown that both are subject to rapid 

 change. Each year since 1929 has seen a greater number of trawlers 

 engaged in the winter and summer fisheries, and there is no indication 

 that this increased strain has reached its maximum. The history of 

 the fishery suggests that the yield must eventually decline from 

 present levels, and when this occurs the Bureau should be in a position 

 to judge whether the decline is natural or whether it is due to over- 

 fishing, and to make new recommendations to fit the new conditions. 

 This can be done only if observations of abundance, age composition, 

 fishery intensity, and hydrography are continued. 



Butterfish. — Continuation of butterfish studies by H. M. Bearse in 

 1932 has confirmed the view that fluctuations in yield of this fishery 

 are caused primarily by dominant year classes, and that no depletion 

 by overfishing has taken place. Appearance of another large year 

 class in 1932 indicates that a continuation of good yields is to be 

 expected in the immediate future. 



CHESAPEAKE BAY INVESTIGATIONS 



The studies of the life history of the striped bass or rockfish {Roc- 

 cus lineatus) begun by John C. Pearson in 1931 were continued until 

 June 30, 1932, when curtailment of appropriations forced abandon- 

 ment of this activity. 



Of three hundred and four 2-year-old striped bass tagged during 

 July and August 1931 off Annapolis, Md., a total of 81 fish or 26K 

 percent were retaken by anglers and commercial fishermen within the 

 first year after release. Most of the recaptured fish were secured 

 north of Annapolis, in the upper bay and tributaries, during the fall 

 and winter following release. In the spring of 1932, however, several 

 recoveries as far south as the upper Potomac and Wicomico Rivers 

 indicated a dispersion of striped bass throughout the upper half of 



