967 



states quia' tin' umiusite of Norway". W'licii the 8iia wil- 

 ing begins, however, the .sexes uiiiigle pronii-scuously, 

 and the opei'ation i.s pert'onued mueh in the same way 

 as we have abo\'e described wiieii treating of the Gwy- 

 niads. Gislek tells in animated language how the Baltic 

 Herring then apj)roaches land in large and densely pack- 

 ed shoals, often extending more than three-quarters of 

 a mile along the coast, and always containing many 

 times more females than males. The fish tumble about, 

 and lash with their tails so violently that tlie scales drop 

 off and float to tlie surface, in company with small air- 

 biibbles whicli the Herrings emit. The sea is dyed gray, 

 and a powerful and rank smell, appreciable at a great 

 distance, fills the air. The spawning multitude does 

 not shun the net, l)ut rather presses willingly into its 

 meshes. The operation does not last long, how-ever, at 

 the same spot, "probably no more than five or six hours", 

 according to Si'xdevall, when the shoal withdraws. 

 Out at sea the spawning presents a similar sight: in a 

 confused mass, gleaming with phosphorescent light, the 

 fish toss about, near the surface when the night is dark 

 and the weather mild; deeper in the water when there 

 is moonlight and in frosty weather^ The impregnated 

 eggs sink to the bottom, and attach themselves to sea- 

 weed, stones, shells, and other firm objects, or some- 

 times cake together on the gravel or sand, or even on 

 a clayey bottom. 



The number and size of the eggs vary, as usual, 

 according to the size of tiie mother fish and their own 

 degi-ee of ripeness. Their number may be estimated at 

 about 20,000— 40,0U0 in different females; their size, 

 when they are ripe and ready to be deposited, varies 

 in the Baltic Herring'', generally speaking, l)etween 0"92 

 (exceptionally O'So) and 1 mm., in the Xorth-$ea Her- 

 ring between 1 and I'S mm.' Of the development we 

 learn from Sundevall's notes' that, "after the embryo 

 had been formed, it was seen (in August) to turn in the 

 egg seven or eight times a minute, subsequently more 



seldom, and latterly oidy once every two or tln-ee mi- 

 nutes. The hatcliing generally takes place in a fort- 

 night or a little more, but in water of a higiier tem- 

 perature, over + 20° C. (+ 68° Fahr.) for example, only 

 three days are recpiired''. As long as tlie fry retain tiie 

 yolk (fig. 242), they move in a peculiar manner. By 

 violently bending or tossing tlie body, an operation 

 repeated every second, or at somewhat greater or less 

 intervals, they work their way upwards, to the surface 

 (at least \\hen they are confined in vessels 3 — 6 dm. 

 deep), and as soon as tliey have touched the surface, 

 they keep still and sink again to the bottom, where 

 they lie for a while, and then resume this upward mcj- 

 tion. — As soon as the yolk is absorbed, which takes a 

 week's time, they commence swimming in dense shoals, 

 with a serpentine movement. The fins and the general 

 shape of the body seemed to have attained their full 

 development in tiie course of two or three months, 

 when the fish is about 36 mm. long." These remarks 

 apply to the Spring Stromniing. But so great may be 



Fig. 242. Newly liatched Baltic Herriug, 7 mm. long, taken on the 

 12tli of May, 1854. C. .7. Sundev.^ll. 



tlie difference between the summer and winter growtii 

 that the Autumn Stromniing, which develops during the 

 colder months, recjuires in the Baltic, according to Mubiu.s 

 and Heincke, 7 — 9 months to attain the said degree of 

 development', and has then grown to a length of more 

 than 60 mm. The ventral fins are developed in the 

 Spring Herring of the Baltic, according to Heincke'', 

 when the fish is only 25V2 'i^'ii- long; but in the Autumn 

 Herring they do not appear until the fish measures 

 33^/2 mm. The followdng comparison has been drawn 

 by Meyer between the growth of the Spring Herring 

 in the Baltic and that of young Trout: 



- 1. c, p. 26. 



For a description of the noisy spawning at sea, and how the Herring immediately after the operation quits the spawning-place, see 

 Gov., Val., 1. c. XX, p. 87. 



' KupFFER, Jahresb. Comm. Unt. D. Meere, Kiel 1874 — 7(5. p. 177. 



'' According to BoECK, 1. c, I'l mm. 



' Om Fiskyngels utveckling, Vet.-Akad. Haiidl., Bd. I (1855), p. 17. 



■'' The hatching takes place, according to Kupffer (1. c., p. 29), in water of a temperature between + 14° and + 19° C. within 6 — 

 8 days; according to MoBius and Heincke (Fiscli U/tts., p. 137), at a temperature of + 10° or + 11° C. in 11 days and at a temperature 

 of + 7° or + 8° C. in 15 days. 



' According to Meyer (Comra. Deutsch. Meor. 1874 — 76, p. 248), however, small Autumn Herrings 45 — 60 ram. long and of almost 

 perfect shape are found in February. 



'' Comm., 1. c. p 128. 



Scandinai-inn fiihe 



122 



