XOTKS OX XKW JKIfSF.Y FISHES. 357 



the laterally vibrated strokes uear the surface a kind of rippling 

 or rattling splash is produced. Sometimes over a large area hun- 

 dreds will be found rattling, every few rods a wake appearing at the 

 surface, and again a dozen may jump at once. As the herring 

 gradually develop from the fry and reach a somewhat advanced adoles- 

 cent stage, the condition of taking food appears to be different. 

 This is thought probably due to the undeveloped branchial apparatus, 

 it not yet having formed a fully-developed sieve to capture the food 

 taken by the adult. It is at this stage that they will devour most 

 any aquatic insect or small invertebrate, and only then may they be 

 lured l)y the angler with his fly. Passing on down the river and 

 reaching the sea they develop gradually the adult conditions and 

 finally live in the ocean. The prevalent theory of the fishermen 

 seems to be that the fish follow the current of the Delaware basin 

 out into the Gulf Stream, where they may obtain suitable food. 

 They also think that there is probably more southern migration, 

 and that in the following spring the ascending herring enter the 

 bays and rivers as the suitable food lures them on. This herring is 

 variously called by the fishermen alewife, alewi, bulger or rattler. 



Although I have not taken them myself, they have been taken on 

 Burlington Island in the Delaware and have been reported to run 

 in the small guts sometimes in the spring. 



Pomolobus aestivalis (Mitchill). 

 Black Bellied Herring. 



The "''black back" is sometimes numerous in Eaccoon Creek, at 

 Bridgeport, Gloucester county, according to the fishermen. It is 

 valued as food. 



Mr. J. B. Vanderveer, of Trenton, says that this fish is distin- 

 guished by the fishermen of the Delaware Eiver chiefly by the black 

 peritoneum and its more slender form. It ascends the river much 

 later than the alewife, appearing usually about three weeks after- 

 ward, sometimes four, or near the middle of or late in May, accord- 

 ing, of course, to conditions. At least it is always conspicuously later. 

 It appears sometimes in considerable numbers, though it does not seem 

 to be (|uite so abundant on the "whole as the alewife. When ascend- 

 ing it is like the alewife, vigorous and apparently without need of 



