THE COD FISHERIES NEAR THE LOFFODEN ISLANDS. 657 



as during- the rest of the year. As far as I kuow, it has not yet been 

 shown that there is any regular periodicty (thus causing certain regu- 

 lar herring-periods) in these causes (wind, current, and temperature). 

 Meteorologists will have to decide in how far this may be possible. It 

 is a fact that there is considerable difference in the occurrence of the 

 "herring-food" near our western coasts in summer between one year 

 and the other. Some years the sea near the coast has all through sum- 

 mer been filled with an enormous quantity of various small marine 

 animals, while in other years they have almost entirely disappeared, or 

 have only accidentally been driven near the coast by the current, quickly 

 to disappear again. The most peculiar feature of this "herring -food" is 

 the great quantity of very remarkable little animals which from the ear- 

 liest times have attracted the attention of the fishermen. These are the 

 so-called " Salper" (Salpae), little animals which are as transparent as glass 

 and float freely about in the sea, either singly or connected into lon^ 

 chains resembling strings of pearls. They are genuine pelagian animals 

 which every year are found in large numbers far out in the open sea, 

 but whose occurrence near the coast is very irregular. Years may pass 

 without a single one of these animals showing itself near the coast, till 

 suddenly one year they come in in such enormous numbers that every bay 

 and sound is filled with them. It is scarcely probable that the herrings 

 feed on these animals, but they are invariably accompanied by a large 

 number of other small pelagian animals, with which they come from the 

 ocean, and of these the " herring-food" proper (small crustaceans) forms 

 by far the largest part. If such enormous masses of "herring-food" fill 

 the bays and sounds during summer, it may be supposed, from what has 

 been said before regarding this food, that those portions of the sea which 

 are immediately outside the coast must contain a great number of the 

 same animals, and that there likewise must be a considerable number of 

 such animals as feed on these crustaceans. 



According to my theory, I therefore also suppose that the spring-her- 

 rings in such years are nearer the coast than in years when the quantity 

 of " herring-food " in the coast- waters is not so great; and I am inclined 

 to assign greater importance than is generally done to this circumstance 

 which from time immemorial has been considered as one of the "signs" 

 which indicate good spring-herring fisheries during the winter. I am 

 likewise inclined to ascribe similar causes to the decline of the formerly 

 so productive Bohuslan fisheries. At a time when owing to peculiar 

 currents in the sea an unusual quantity of "herring-food" has filled 

 the North Sea and the Skagerak, it may well be supposed that a portion 

 of the great mass of herrings coming originally from the northwest 

 may have gotten so far into this part of the sea that when the spawn- 

 ing season approached they, in following their usual southeasterly di- 

 rection, would come near the Bohuslan coast, where they spawned, re- 

 turning to this same coast in accordance with the innate instinct of all 

 fish ; and that in this way they have developed into a tribe of herrings 

 42 F 



