PROGRESS IN BIOLOGICAL INQUIRIES, 1930 573 



1930. Ill that locality larvse as well as eggs were found in both years, 

 and length measurements indicated that juveniles grew regularly 

 and attained, by the end of the season, a length commensurate with 

 that of yearlings appearing in commercial catches in the spring. 



Two years' observations in but one of the several northern locali- 

 ties frequented by juveniles are insufficient to prove that reproduction 

 is always a failure, either in Delaware Bay or elsew'here. They do, 

 however, indicate the need for continuation of observations in Dela- 

 ware Bay and their extensions to other localities. 



The inost direct method of testing these hypotheses is a study 

 of migrations and of the survival of marked juveniles. Unfortu- 

 nately, squeteague are difficult, to mark. Two field experiments in the 

 tagging of this fish have failed to produce satisfactory returns. Al- 

 though all external tags have so far failed in both laboratory and 

 field experiments, the Woods Hole experiments have demonstrated 

 that young squeteague will carry small strips of celluloid in the 

 body cavity Avithout injury. This mark is inconspicuous and will 

 not be observed until the fihh are cleaned. On the other hand, it 

 may be applied to very small fish and probably will be retained 

 indefinitely by the majority marked. 



W. C. Neville has analyzed scup data collected in the course of the 

 investigation, and he finds that this species has been subject to con- 

 siderable fluctuation in yield during the past 40 years. The yield in 

 New Jersey in 1926 was, save for 1908, the lowest of any year in 

 wdiich statistical canvasses were carried out. A remarkable recovery 

 occurred in 1929; the pound-net catch arose to the highest total ever 

 recorded and continued to be high in 1930. This phenomenon is 

 seen to be the result of a high survival from the spawning of 1927. 

 Scup of this year class appeared in large numbers in northern New 

 Jersey in 1928; but as they w-ere too small to be marketable, they 

 had no effect on the reported yield. In 1929 and 1930 they were 

 salable, and consequently the catch increased greatly. It is notable 

 that the 1927 brood spawned in a year when the reserve of spawning 

 adults was at a very low ebb, indicating that success of reproduction 

 is independent of the spawning reserve within wide limits. 



The yield of butterfish, although subject to considerable fluctua- 

 tion, has been satisfactory in recent years. Age determination has 

 proven difficult, as the scales are illegible and length frequencies diffi- 

 cult to interpret. The studies of H. M. Bearse^ who has analyzed 

 length-frequency data, indicate that dominance of the fishery by 

 occasional large broods is largely responsible for the fluctuations 

 which occur. 



Spot, or Lafayette, is not ordinarily of much importance in New 

 York and New Jersey. In 1926, however, the yield in New Jersey 

 reached 1,217,000 pounds, and in New York 436,000 pounds. Tlie 

 observation of C. M. Breder, jr., of the NeAv York Aquarium, to the 

 effect that young spot, too small to market, were unusually abundant 

 in New York Harbor in 1925 supports the view that the large yield 

 in 1926 was due to an unusually large brood and that the spot may 

 be added to the long list of si)ecies known to be subject to natural 

 fluctuations caused by variation from year to year in success of 

 reproduction. 



