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6. Determination of the race differences by means of a study of morphological 

 characters according to a uniform method. 



Denmark. 6) The study of the race differences in herrings from the North 

 Sea and the waters between the North Sea and the Baltic has been continued. 



Finland. 6) Collections of material from the various parts of the Finnish Bay. 



England. 6) A detailed examination of the data obtained in 1914 has been 

 left in abeyance. In view of the work on age determination, referred to above, 

 it was felt that interpretation of scale rings should be set on a sounder basis, before 

 the very small differences found in the race data can be regarded as definitely 

 racial in character, such differences being possibly correlated with differences of age. 



Scotland. 6) Samples from the more important localities where herring 

 fishing is prosecuted have been examined for race differences. 



7. Location of the spawning places, especially by the occurrence of the eggs or 

 newly hatched larvae. Investigation as to the nature of the bottom at the 

 spawning places. Samples of the herring spawning on the places are to be exam- 

 ined with regard to racial characters, age, composition and growth. 



Denmark. 7) The pre-war material has partly been worked up. 



Finland. 7) The spawning grounds at the Northern coast of the Finnish 

 Bay are marked out on sea-charts. 



England. 7) An intensive search for herring spawn was carried out in August 

 and September near the Longstone and on the Dogger with negative results although 

 records of "spawny" haddocks indicated that spawning took place in these areas. 



Forty positions at or near which herring spawned during last year and 

 certain previous years, as inferred from the capture at these places by trawlers 

 of haddock and cod, the stomachs of which contained herring spawn, have been 

 charted. Most of these positions lie between 56° and 53° latitude and west of 3° E. 

 longitude. They mostly coincide with or are in near neighbourhood of places at 

 which the bottom deposit contains an appreciably large proportion of stones and 

 shells; the chart prepared for a forthcoming report on the Bottom Deposits of 

 the North Sea providing the basis for comparison. The provisional inference is 

 that the presence of stones etc., influences the selection of spawning sites, but 

 more data are required to make the correlation definite. 



The character of the bottom was ascertained by the use of the Petersen 

 grab and conical dredge. 



Scotland. 7) During September, special efforts were made to capture the 

 newly hatched clupeoids and so locate the spawning grounds; Information was 

 also collected regarding the capture of "spawny" haddocks. Previous records of 

 clupeoids are also being systematically worked up with a view to the delimitation 

 of the spawning areas and the dispersal of the post-larval stages. 



