508 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



enemies to the roe must be mentioned parasitic algre, infusoria, star-fish, 

 large crustaceans, the cod, the whiting, the fiounder, and other fish. 

 The young fish are also violently persecuted by the cod, the whiting, 

 and other fish. 



As an enemy of the herring we must finally mention the so-called 

 "sea-blossoms," a kind of lover of salt water algae (Oscillator ice), which 

 are quite frequent in the Baltic, and which often force the herring to 

 seek deeper water. 6 



The herring and the small herring, although closely related, cannot 

 well live together, but must rather be considered as mutual ene- 

 mies. They keep in separate schools, and if both kinds are caught in 

 one and the same seine, as will sometimes happen, this is doubtless 

 caused by the seine's enveloping two different schools, either whole or 

 in part. 7 When these two fish meet the small herring has invariably to 

 give way to the stronger herring ; and when large herrings begin to 

 appear in the seines this is considered an unfavorable sign for the small 

 herring fisheries. The large migratory herring is considered dangerous 

 to the young herring, and when occurring in large numbers it is said to 

 chase the small herring away ; the fishermen on the northern coast of 

 Bohus Ian, therefore, do not like to see this herring make its appearance. 



After having thus briefly given an account of the food, the sicknesses, 

 and the enemies of the herring, we must make a few remarks regarding 

 its general mode of life. 



As regards its' life during thetenderest age C. J. Sundevall says : 'As 

 long as the fish still have the umbilical bag they move about in a very pe- 

 culiar way. By violent contortions of the body, which occur every second, 

 and even oftener, they work themselves up to the surface of the water 

 (at least when inclosed in vessels 1 to 2 feet deep) ; as soon as they touch 

 the surface they keep still for a little while, and then again sink to the 

 bottom. This movement is constantly repeated." "As soon as the um- 

 bilical bag has been consumed, which takes place in a week's time, the 

 young herrings begin to swim about in dense schools and with a worm- 

 like movement." 8 



When the herrings are not disturbed, they generally move in a straight 

 line or in more or less curved lines, and like most other fish, do not turn 

 round abruptly. On this peculiarity fishing with bottom-nets and fish- 

 pots is based. 



The herring is a lively fish and prefers a strong current. It has often 

 been observed to go straight against the current, which, however, may 



6 C. J. Sundevall, Stockliolms lansKgl. Hushallnlngs-Sdllskaps Handlingar. VI. Stock- 

 holm, 1855, pp. 152, 153. V. Skrydstrup, Nordislc Tidsskrift for Fiskeri, II, p. 40. 



7 Violent storms, however, may occasionally cause the small herring to mingle with 

 the larger herring. 



8 Stockholms lan» Kgl. Husliallnings-Sdllskaps Handlingar, VI, Stockholm, 1855, pp. 

 195, 196. Kgl. Svenska Vetenskaps-Akademiens Handlingar, I, Stockholm, 1858, pp. 17, 

 18. Compare also A. Boeck, Om Silden og Sildefiskerierne, Christiania, 1871, p. 14 3 15. 



