1901] Oplysninger om seiens vekst og aate. 19 



is situated in the belt of skerries, where the tidal current is con- 

 siderable, and I suppose that the young coal-fish has let this tidal 

 current carry up to it that abundant quantity of copepod food. 

 The said current has its biological importance not only by sup- 

 plying abundant food to the sedentary plancton eaters, but probably 

 also by alleviating the search of food for certain young fishes. 



During the months of February, March, April there is not for 

 the one year old individuals of the coal-fish much of copepods to 

 be found; the want is however in some degree compensated by 

 fish-spawn and larvæ of Cirripedia. But planctonic food is as a 

 rule so scarce, that they are obliged to cater for additional food 

 on the seaweeds. That spawn and larvæ of Cirripedia form an 

 important part of the food-supply of the young coal-fish during the 

 said months, is not doubtful. That the young coal-fish in Lofoten 

 destroy a great deal of cod-spawn I have maintained on a former 

 occasion. In quite a small stomach of Gadus virens (a little more 

 than a year old) from Bålstad in Lofoten ( 21 /4 1896) I counted 200 

 whole fish ova, as well as Cirripedia larvæ in great numbers, and 

 Tbesides a few specimens of Thalestris gibba, Keøter. 



Among plancton organisms that are consumed by the young 

 coal-fish may also be mentioned Chætognatha. In „Systematik der 

 Chætognathen" 1 ) Dr. Steodtmann states that the chætognatha chiefly 

 feed on copepods and copepod larvæ. The same author also states 

 that Leuckart has mentioned that the Sagitta bipunctata occurring 

 off Heligoland serve as food for medusæ. He supposes that chætog- 

 natha are eaten also by larger animals, e. g. by fishes. This sup- 

 position has consequently proved correct. In stomachs of coal-fish 

 from the Hjeltefjord ( 31 /io 1900) Sagitta bipunctata was tåken in 

 great numbers. 



In the stomach of older individuals of the coal-fish I have 

 tåken the following forms: 



Clnpea harengus, 

 — sprattus, 

 Mallotus villosus 1 ), 

 Ammodytes tobianus, 

 Omm a tostrephes todarus, 



*) "Wiegmann',3 Archiv f. Naturgeschichte, 58 Jahrg., 1 B., p. 371. 

 *•) This form, which makes an important food for the coal-fish off our 

 .northern coasts. I have however not seen in coal-fish stomachs. 



