66 hjort's hydkographic-biological studies 



(4) The Copepod Calanus finmarchicus ( = Cctochilas scptentrionalis 



is rarely found in water of low salinity, but is characteristic of 

 North Sea water and bank water having a high salinity (above 

 33"5 per thousand). It occurs in company with the Diatom 

 Coscinodiscus. 



(5) The Copepod Pseudocalanus elongatus {=Clausia elongata) 



flourishes in bank water of high salinity (i.e., above 33 per 

 thousand). In the Salter waters it is found along with Calamis 

 finmarchicus ; in the fresher waters with Paracalanns iw.'t'vus. 



(6) The Copepods Centropcigcs hamatus and Ilcditcmora longicornis 



were only found in waters of low salinity (Baltic current). 



(7) Radiolaria were only found in Baltic water and in bank 



water having a salinity below 33 5 per thousand. 

 In formulating these generalisations from Hjort's data, I must be 

 understood to have considerably exceeded Hjort's own cautious and 

 reticent attitude. Nevertheless, I think it desirable to generalise his 

 results, not for the purpose of basing any conclusions upon them, but 

 in order to present them in a form which will at once suggest points 

 for further examination, 



111, Fisheries, 



1. The West Coast Spring Herring Fishery. — The spring herring 

 fishery on the west coast of Norway is due to the annual " spawning 

 migration," and takes place in the months of January, February, and 

 March, Formerly the fishery extended over a much more extensive 

 area than at present, viz., from the Naze to Christiansund ; but now the 

 fishery is practically limited to the neighbourhood of the mouth of the 

 Hardanger fjord. The spawning grounds are the shallow banks lying 

 around the groups of islets and rocks in this district, bounded by the 

 60-fathom line, and covered with sand and fine shells. In favourable 

 years the spawning herrings advance up to the very beach in all the 

 sounds and bays, and the roe is then found covering great stretches of 

 the bottom. 



1894 was such a year. Enormous bodies of herrings abounded close 

 inshore, and quantities of roe were obtained at a depth of only 3 to 4 

 fathoms. It will be remembered that in the spring of this year, 

 owing to a succession of heavy westerly gales. North Sea and Atlantic 

 water was found close inshore. 



It would thus appear that on the Norwegian coast herrings abound 

 close inshore for spawning purposes when the shore water attains its 

 maximum salinity for the year (North Sea water, 34 per thousand). 



This view was confirmed for the season in question by the fact that 

 early in February, when the Baltic current had rounded the Naze, and 



