134 



FISHERY BULLETIN OF THE FISH AND "WILDLIFE SERVICE 



Capelin Mallotus villosus (M tiller) 1777 

 Jordan and Evermann, 1896-1900, p. 520. 



Description. — The capelin is an even slenderer 

 fish than the smelt, its body being only about one- 

 sixth to one-seventh as deep and about one- 

 twelfth as thick as it is long, and of nearly uniform 

 depth from gill cover to anal fin (except in the case 

 of females when their abdomens are distended 

 with spawn) , whereas the smelt is usually deepest 

 about its mid-length (at least if the fish is fat), 

 which gives the two species characteristically 

 different aspects. The head of the capelin is 

 pointed like that of the smelt, the mouth gaping 

 back to below the center of the very large eye with 

 the tip of the lower jaw projecting noticeably be- 

 yond the upper. The scales are minute, much 

 smaller than those of the smelt and more numerous 

 (about 200 per row on the sides of the body) ; the 

 teeth so small as to be hardly visible to the naked 

 eye, and the tongue fangs, so characteristic of the 

 smelt (p. 135), are lacking here. The outline of the 

 adipose fin likewise helps separate capelin from 

 smelt, for it is low in the former and about half 

 as long as the anal, but short and high in the 

 latter. The pectoral of the capelin is broader also, 

 usually with 15 or more rays. 



The capelin exhibits a pronounced sexual 

 dimorphism; the male has much the longer pectoral 

 fins; and the base of his anal is elevated on a pro- 

 nounced hump, whereas it follows the general out- 

 line of the belly in the female. In males, too, the 

 scales in one of the longitudinal rows immediately 

 above the lateral line, and in another row along 

 each side of the belly, are pointed, distinctly larger 

 than the other scales, and become longer still at 

 spawning time when each pushes up the skin as a 



finger-like process; they form four ridges that are 

 very evident when the fish is held in the hand. 



Color. — The capelin is transparent olive to bottle 

 green above, like a smelt, but its sides are uni- 

 formly silvery below the lateral line and the scales 

 are dotted at the margins with minute dusky 

 specks (in the smelt there is a distinct silvery band 

 on each side) ; the belly is white. Back and head 

 darken at spawning time. 



Size. — Few capelin are more than 6% to 7K 

 inches long. 



Habits} — Capelin are most in evidence during 

 the spawning season, when they come inshore in 

 multitudes along arctic-subarctic coasts. They 

 spawn on gravel or pebbly bottom, chiefly close 

 below tideline, many of them in the wash of the 

 waves in the beach; many are stranded then 

 on the beach between waves. But eggs have also 

 been reported from as deep as 35 to 40 fathoms. 

 Each female while spawning is accompanied 

 by two males that crowd her between them; 

 but she may have only one companion. 4 Spawn- 

 ing takes place chiefly at temperatures of 43° to 

 50° F. (6°-10° C.) and more actively by night 

 than by day. 



The eggs are reddish, about 1/25-inch (1 mm.) 

 in diameter, and so sticky that they cling to each 

 other like herring eggs, and to the gravel and 

 pebbles with which they are intermingled by the 

 swash of the waves. They hatch in about 15 

 days at a temperature of 50° F. (10° C). And 

 they will tolerate a salinity as low as 7 per mille, 



i Interesting accounts of the habits of the capelin and of its rate of growth 

 in Newfoundland waters have been given recently by JefTers (Ann. Rept. 

 Biol. Board Canada (1930), 1931, pp. 7-18); by Sleggs (Rept. Newfoundland 

 Fish. Res. Comm., 1, No. 3, 1933); and by Templeman (Bull. Newfoundland 

 Government Lab.. 17 (Research), 1948. 



» According to Lanman, Rept. U. S. Comm. Fish. (1S72-187. 1 .) 1874, p. 225. 



*&>& 



Figure 56. — Capelin (Mallotus villosus), Grosswater Bay specimen. From Goode. Drawing by H. L. Todd. 



