188 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



{stryl-JisMi-^^'). They may, nuder the influence of less common 

 I^hysical couditions occasionally ai)j)ear in places where they 

 are not found otherwise, and where they must therefore be con- 

 sidered as accidental visitors. 

 d. with regard to the season when these migrations take place, into 



" winter-fish" and " summer-fish," &c. 

 €. with regard to the number of periodical visits paid to a coast dur- 

 ing the year, into fish which come once a year and fish which 

 come several times a year. 

 /. with regard to the steadiness of the visits to a certain locality, 

 into 

 a, resident fish, and 

 (S. periodical fish. 

 3. Erratic Jisk, that is, lielagian fish which roam about irregularly and 

 only visit a coast accidentally.^ 



D. — With regard to the greater or less stability in their 

 PLACE OF SOJOURN, the fish may finally be divided into 



1. fish 2vhichj on account of the torjyor of winter or summer, by sucJcing 

 themselves fast to objects resti^ig at the bottom or fioating about in the 

 water, or from, other causes, are generally in a state of rest. 



2. fish which are more or less in motion, tvhich, icith many, assumes the 

 character of a regular daily motion. {Even those fish which gen- 

 erally are in a state of rest may occasionally be classed in this group.) 



35. After giving the above outline of the way in which fish may be 

 divided into difierent groups, we must ascertain what position the her- 

 ring holds with regard to these difierent divisions and subdivisions. 



The herring is most decidedly a salt-water fish, although it certainly 

 also occurs occasionally in water whose saltness is very limited, for in- 

 stance, in the northern portion of the Gulf of Bothnia; and for short 

 periods, whilst spawning or seeking food, it will also enter bays and 

 mouths of rivers whose waters contain very little salt. 



36. The herring is both a littoral and i\, -pelagian fish. When young it 

 generally stays near the coast, but begins comparatively early to follow 

 the currents of the sea and go some distance from the coast. As a gen- 

 eral rule, however, the herring is more of a littoral fish when young, and 

 a pelagian fish when older. Very small shoals of herrings may some- 

 times be altogether littoral, the individuals composing them, as far as 

 known, scarcely ever going any distance from the coast. The larger 

 shoals, however, generally spend the greater part of the year out in the 

 open sea, and the great schools are altogether pelagian in their character, 

 visiting the coast only during comparatively short periods of the year." 



°^ S. Nilsson, Fornyad underdanUj herdttcUe amfslceriarne i Bohmliii). Stockhobu, 1828, 

 p. 15. Handllnfjar rorande sillfisliet i bohuslunsla Skdrgdrden . Stockholm, 1843, p. 37. 



•^*Si. Berthelot, Oiseaux voyageurs et2>oi8sons dc passage. II. Paris, 1878, pp. 99 aud 12.5. 



" Instances are not wanting, liowever, when such pelagian herrings hare, under 

 peculiar circumstances, remained near the coast for a longer time. 



