FISHES OF THE GULF OF MAINE 93 



fins have no true spines nor is there a lateral line. The anatomical character 

 separating the sea herring from the several alewives (genus Pomolobus) is the 

 presence of an oval patch of small teeth on the vomer bone in the center of the roof 

 of the mouth in the former, but even without this test a practiced eye can separate 

 herrings from alewives at a glance by the comparatively shallow bodies of the 

 former and the deeper outlines of the latter, a difference better shown in the illustra- 

 tions. Furthermore, the sharp midline of the belly is but weakly serrate in the 

 herring, while in the alewives it is saw-toothed. 



Size. — Herring grow to a length of about 17 inches. 



Color. — Deep steel blue or greenish blue on the back with green reflections; 

 the sides and belly silvery; the change from dark belly to pale sides often marked by 

 a greenish band. The gill covers sometimes glisten with a golden or brassy gloss; 

 indeed, fish just out of the water are iridescent all over with different hues of blue, 

 green, and violet, beauties that soon fade, however, leaving only the dark back and 

 silvery sides. The ventral and anal fins are transparent white; the pectorals, how- 

 ever, are dark at the base and along the upper edge; the caudal and dorsal dark 

 grayish or shading into green or blue. 



General range. — Both sides of the North Atlantic. Off the European coast the 

 herring ranges north to Norway, Spitzbergen, and the White Sea, as well as to Ice- 

 land and Greenland; south to the Straits of Gibraltar. On the American coast it 

 is known as far north as northern Labrador ; regularly and commonly as far south as 

 Block Island, though most abundant north of Cape Cod ; and it is occasionally seen 

 at Cape Hatteras in winter. It is replaced by a close ally (C. pallasii) in the North 

 Pacific. 



Occurrence in the Gulf of Maine. — The herring is probably the most numerous 

 fish in the Gulf of Maine as it is in the North Atlantic generally. To list the locali- 

 ties where it has been recorded would be to mention every hamlet along the coast 

 from which fishing boats put out, for it is universal at one season or another around 

 the whole coast line of the Gulf as well as offshore. Off most parts of the coast, 

 however, the appearance of schools of herring, large or small, is distinctly a seasonal 

 phenomenon, and inasmuch as its on and off shore migrations are intimately bound 

 up with the phenomena of reproduction and growth a brief consideration of these 

 may precede the more detailed discussion of its occurrence. 



Breeding habits. — ^o much study has been devoted to the natural history of the 

 herring by European zoologists, as well as by Moore (1898) and Huntsman (1919, and 

 unpublished notes) in our own Gulf, and by Lea ^* in more northern Canadian 

 waters, that we have very good knowledge of its breeding habits in general and of 

 its early growth. This may be briefly summarized as follows: 



It has long been known that the eggs of the herring sink to the bottom, where, 

 by means of their coating of mucus, they stick in layers or clumps to the sand or 

 clay, seaweeds, stones, or any other objects they chance to settle on. They are 

 often found massed on net warps, anchors, and anchor rodes. The eggs are 1 to 1.4 

 mm. in diameter, depending on the size of the pai'ent fish and also, perhaps, on the 

 local race of fish involved. Females — again according to their age and size — 



" Age and growth ot the herrings in Canadian waters. Canadian Fisheries Expedition, 1914-15 (1919) pp. 75-164. 



