HERRING, GA8PEREAU, SHAD AND OTHER CLUPEOIDS 



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SESSIONAL PAPER No. 22a f/09^/l 



ments, like a horizontal colunm of draughts or disks in the herring, sprat and pilchard 

 (Plate VIII., figs. 1, 2, 6, 7,'0-tindl7), but in the shad andgasperean (Plate VIIL, figs. 

 iO- and ■^),1its structure is that of an irregular network, or complex meshwork, as in 

 most cases not belonging to the herring family. This peculiar regular arrangement of 

 the notochordal cells is a striking feature and facilitates the recognition of many newly- 

 hatched Olupeoids, when mingled with other fish-larvae; but the extremely posterior 

 /» position of the anus, usually with a little bay or indentation in the ventral marginal 

 I fin (Plate VIII., fig. 44-, and Plate IX., figs. 17, 18, 19), and the regular series of stellate 

 black spots, either in a single or double line, along the upper or the lower contour of 

 the digestive canal, are, as far as at present known, characteristic of all the herring 

 family. Other stellate spots of a black colour, few in number, may occur on the head 

 around the cylindrical kidney tubes or on the caudal fin-expansion at the posterior 

 termination of the notochord. These fishes, therefore, present a great contrast to the 

 young stages of the majority of species of other families, in which elaborate arrange- 

 ments of colour, yellow, reddish brown, orange, ochre, black, purple, blueish and green- 

 ish spots may occur, massed in many species as bars or patches along the body. The 

 surface of the protruding yolk-sac may also be brilliantly diversified as well as the 

 wide marginal fin-membrane. As the yolk and fin-membranes and the body generally 

 in the herring, shad and clupeoids are usually colourless, their delicacy of structure 

 and glassy transparency are thereby increased. Some, as the sprat, show absolutely no 

 pigment at all when they emerge from the ovum (Plate VIII., fig. 8). The yoUc, mor(^- 

 over, in most species, is comparatively small compared with the length of the elongated 

 eel-like body, and does not form the exaggerated protruberance seen in so many fishes, 

 e.g., salmon, trout, cod, &c. On comparing the newly-hatched larvse of various species 

 of clupeoids a considerable variation in their length is observable, the length of the 

 sprat (Clupea sprattus) from the tip of the snout to tip of the tail is 3 ;6 mm. (Vi inch), 

 the pilchard (C. pilchardus) , 3.8 mm. (^ inch) ; the alewife or gaspereau (Pomolohus 

 pseudoharengus, Wilson), 5 mm. (^ inch) ; the sea-herring (C harengus, L.), 5 to 7 

 mm. (A inch); the Twaite shad {Clupea or Alosa -finta, Guv.), 4-25 mm. mm. (less 

 than i inch, i.e., and the common shad (Alosa sapidissima, Wilson), 9*29 mm. 

 (1^ inch). Thus, the pilchard would appear to be rather more than one- third of tho 

 length of the shad, the gaspereau rather more than half, the Twaite shad less than 

 half, and the sea-herring considerably more than half the size, while the sprat is about 

 the same length as the pilchard on hatching. This variation is a most striking one, 

 but it is no key to subsequent growth during the larval and post-larval stages of the 

 species referred to. 



By the sixth day after hatching, the Twaite shad (Plate IX., fig. 13), according 

 to Ehrenbaum, doubles its length, being 8 '7 mm., or rather more than J inch : a length 

 which the sea-herring does not attain until about the tenth day, though the herring, as 

 above noted, is a much larger larva when it issues from the egg. The shad, like the 

 sea-herring, almost doubles its length in ten days, measuring 15-73 mm. (M inch), 

 while the pilchard is stated to be 24 mm. (2%5 inch) at that age, a measurement which 

 no doubt needs confirmation by further observation. By the twentieth day the herring 

 (Plate VIIL, fig. 2) exceeds 10 mm. in length (% inch), the Twaite shad (Plate IX., 

 14) is 2%o of an inch, and the common shad (Plate IX., fig. 19) inch> or about 

 19 mm. When double the age just mentioned, i.e., on the fortieth day, the herring 

 / is a little over half an inch long (2*69 mm.), the gaspereau is about the same length, 

 b^l4 to 15 mm. (Plate VIII., fig. 10), but the shad still exhibits remarkable growth, being 

 on the thirty-fifth day 56:95 mm. long, i.e., 2 to 2^ inches long (Plate IX., fig. 20), 

 while the Twaite shad, on Ehrenbaum's authority, is barely f inch (20 mm.) (Plate 

 IX., fig. 15), and reaching on the forty-third day a length of nearly an inch, 24 mm. 

 (Plate IX., fig. 16) . At the age of two months, or, to be more accurate, on the seven- 

 tieth day, the herring exceed ''^%oo inch (18*9 mm.), whereas the shad is now 3 or 4 

 inches long (76 to 100 mm.), while by the fourth month the shad is stated to have 

 doubled its length, being 5 to 7 inches long (125 to 175 mm.), as compared with the 



