of the Fishery Board for Scotland, 



57 



sufficient, if not an abundant, supply of food. The winter spent, however, 

 seems to be more emaciated than the summer spent. 



The store of fat permits the herring to grow in length and keep in good 

 condition while the reproductive organs are ripening. Heincke divided 

 the year of a spent Schlei herring into three portions, viz. : — (1) A recover- 

 ing and fattening period after spawning. It lasts three or four months. 

 This is the main feeding-time. The emaciated body is filled up, and 

 enormous stores of fat are laid down in the abdomen. (2) The ripening 

 period of six to seven months. The herring eats much, but with a reducing 

 intensity, and the several organs ripen at the expense of the fat. (3) The 

 spawning period, which lasts about two months. The desire for food is 

 extinguished, and the instinct of reproduction completely dominates the 

 fish. 



It would seem as if there were a factor that determines the season when 

 the young fishes will leave the immature group. That is fixed by the 

 locality in which the fishes live. It is probably different for the coast 

 waters than it is for the open sea. 



After spawning, the ovary returns to a quiescent preparatory condition. 

 Food is then distributed through the tissues ; growth takes place rapidly, 

 and fat is stored up. In about six months time the fish has arrived at a 

 M matje " condition. The reproductive organ having passed through its 

 preparatory and seemingly resting condition, begins to ripen again, and to 

 make the great demand on the energies of the fish. 



The Rate of Growth. 



Fulton discusses the question of the rate of growth of the herring, and 

 gives a resume of the different opinions which have been held as to the 

 age at maturity. 



The smallest size at maturity was given by Huxley at 17*5 cm. (7 inches), 

 by Matthews as 18'5 cm. (7| inches), by M'Intosh and Masterman as 20 

 to 22*5 cm. (8-9 inches), by Cunningham as 20 to 21 cm, (8 to 8| inches), 

 and by Fulton as 24 to 27 cm. (9|-10| inches). 



Meyer found the herrings in the neighbourhood of Kiel ripe when 

 between 16 and 20 cm. in length. Heincke gives 18 cm. (7 \ inches), and 

 Jenkins 19 to 19*8 cm. (7^-7yf inches) for the same. Each local form 

 will, according to Heincke, have its own minimum size at first spawning. 



The age at first maturity has given rise to much difference of opinion. 

 Thus Huxley considered that the herring might become mature when 

 eighteen months old, while Sim and Cunningham believed that spawning 

 took place at the end of two years. M'Intosh and Masterman said that it 

 probably occurred during the third year ; Fulton assigned it to the fifth 

 year. 



For the Kiel herrings Meyer gives two years as the age at first spawn- 

 ing, while Jenkins, from a study of the otoliths, believed that this event 

 did not occur till the third year. Schneider agreed with Jenkins. 



Dahl, who investigated the rate of growth from an examination of the 

 scales, came to the conclusion that the Norwegian spring herrings measur- 

 ing from 25 to 37 cm. in length were from three to at least fourteen years 

 of age. He maintained that the herrings grew at different rates in 

 different localities — that the Norwegian herring when five years old 

 measured 26 to 31 cm., while the Lowestoft herring at the same age 

 measured 21 to 26 cm. He thought, moreover, that the small herrings in 

 the fjords grew more slowly than the herrings of the ocean. The Nordland 

 Fat Herrings are, according to this zoologist, 2 J to 4| years old, and they 

 have never spawned. Prince says that herrings 8 to 1 1 inches (20 to 28 

 cm.) cannot be less than three years old, and may be in their fourth year. 



