PEOGKESS IN BIOLOGICAL INQUIRIES, 19 31 459 



of the pound-net fishery. In view of its present importance it is 

 desirable to determine whether it is in need of protection to insure 

 continuation of satisfactory yields. 



Analysis by H. M. Bearse of length-frequency data for three years, 

 coupled with the results obtained from study of the catch records, 

 has shown that the abundance of butterfish is definitely related to 

 variations in success of reproduction from year to year. The New 

 Jersey State records and the individual pound-net company records 

 show an unusually good catch per unit of gear for the year 1929. 

 The length frequencies for the year 1928 demonstrate the presence of 

 a group" of small and medium fish dominating the catches at most 

 points along the coast; those for 1929, a group of medium and large 

 fish appearing in overwhelming numbers; and those of 1930, domi- 

 nated by large fish. From the consistent behavior of the size varia- 

 tions for the three years it is clear that the catches during that period 

 have been made up largely of fish resulting from a single spawning, 

 presumably that of 1926. 



The effect of this large brood was to increase the total catch of 

 butterfish as well as the catch per unit of gear for the season of 1929 

 in New Jersey. Although a large proportion of the fish taken by 

 pound nets in 1928 and 1930 was of the same brood as those taken 

 in 1929, the yields for these years were moderate. In 1928, however, 

 these fish were for the most part too small to be salable, and the 

 majority of those taken did not enter into the recorded catch. The 

 decline in 1930 probably was due either to natural mortality and to 

 the fishing, or to a change in habits with age similar to that described 

 for the scup. No evidence on this point is available, as few butterfish 

 are taken by gear other than pound nets. 



It appears, therefore, that the restoration to nearly record levels in 

 1929 without protection demonstrates the ability of the butterfish 

 to withstand the strain of the fishery, vinless unforeseen developments 

 should increase the exploitation of this species. 



Early-life histories. — Studies of spawning and nui^sery grounds of 

 Middle Atlantic fishes were continued under the able direction of 

 Prof. A. E. Parr, curator of the Bingham Oceanographic Founda- 

 tion, Yale Univereity. The work which began in Delaware Bay 

 in 1929 was continued in 1931 and extended to Barnegat Bay and 

 Sandy Hook Bay. Many data bearing on the abundance and rate 

 of growth of young squeteague, scup, spot, and sea bass were col- 

 lected. 



Of special interest is the observation that the presence of even very 

 small juveniles in a locality does not necessarily imply successful 

 local reproduction. This is illustrated by two species — the mullet, 

 Mugil cejjJiaJus., and the spot, Leiostomus xanthvnis. The former 

 species does not spawn in New Jersey ; in fact, it is doubtful whether 

 the adults occur there at any time; yet juveniles are common. Juve- 

 niles of the spot, less than an inch in length, appear along the shores 

 of New Jersey and New York. Since this species spawns in vrinter 

 when neither adults nor larvae occur north of the mouth of Chesa- 

 peake Bay, these juveniles can not have resulted from local spawn- 

 ing; but they must have migrated from localities well to the south, 

 perhaps in part from North Carolina waters. While they are in 



