These principles must be considered when organizing further research. 



" Blooming " of tha Sea and its Influence upon the EHstrlbution of Herring . 



The questions regarding the adverse or negative action of "blooming" (mass production of 

 diatoms and Phaeocystis ) upon herring were discussed in the works of Soviet research workers such 

 as Mosentsev (25), Manteyfel' (19) as well as in the works of foreign scientists such as Hardy, 

 Savage and Wimpenny (39, 40, 41 , 42, 43) . 



B. P. Manteyfel' (19) came to the conclusion that herring almost never occur in the intensive 

 "blooming" of Phaeocystis in the Barents Sea. In May and June, the commercial concentrations of 

 herring are found to the west and south-west from the boundaries of the "blooming" and they follow 

 these boundaries, which recede to the east. Individual schools of herring even penetrate somewhat 

 into the rear of the "blooming" zone . 



Manteyfel' believes that in the zone where the "blooming" is terminating, herring can main- 

 tain themselves in the 10-meter layer (above the zone of the descending Phaeocystis) and down to 

 70 meters (under the zone of the descending Phaeocystis ). 



The reason for the adverse effect or influence of phytoplankton upon herring has been ex- 

 plained by research workers in various ways . 



Hardy (1925), for instance, supposed or suggested that phytoplankton clogs the gills of her- 

 rings, but this supposition was rejected by further research. Many research workers were of the 

 opinion that the mass production of phytoplankton not only affects herring adversely, but also has 

 the same effect upon zooplankton. 



It is true that, during the greatest production of Phaeocystis , the zooplankton is very poor: 

 only the eggs and larvae of crustacea are encountered in the "blooming", whereas a small niunber 

 of adult crustaceans stay somewhat farther down- -below the "blooming". 



Such a composition and distribution of plankton, according to our observations, is charac- 

 teristic of the biological spring season. Consequently, when studying the phenomenon of the "ex- 

 clusion" of zooplankton by phytoplankton, one must always bear in mind the seasonal phenomena in 

 plankton . 



An intermixing of cold and warm waters, which carry with them the vernal plankton at the 

 various stages of development, occurs in the areas where the Atlantic and the polar waters meet 

 and mix with one another . 



In such regions, the interrelations of plankton and herring are especially complex. 



Here one can often encounter simultaneously the production of phytoplankton and zooplankton 

 and the feeding of herring in the "blooming". It is also possible to encounter a "blooming" without 

 zooplankton, where there are no herring. 



We conducted a number of observations in 1953 in various regions of the Norwegian Sea to 

 establish the relationship between herring and phytoplankton. The following problems or questions 

 aroused our interest: Do herring react in the same way to "blooming" caused by the mass produc- 

 tion of Phaeocystis and to "diatom blooming" and when do herring "avoid" a "blooming"? 



All the observations were carried out in April and May of 1953 on the E/S "Professor 



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