19 



measured by uræometer on board tlie Argns; in fresher water uo eggs ure 

 to be round, ia the more saliue water they are l'ouud as it were ahvays. 

 Doubtless, tliese eggs are not all eggs of plaice, ))ut at several stations they 

 certainly are, aceording to my later determinations, and at any rate all the 

 negative results give certain information. Another map wliich lies before 

 me, based on our own investigations, in March 1902, into the oecurrence 

 of eggs in the Iower strata of water, shows, on the other baud, that eggs 

 of plaice are found in the deep water everywhere in the Belts as well as 

 in the eastern part of the Baltic Sea, as far as S. E. of Møen, under the 

 overlyhuj fresher strata. But these deeper masses of water do not, as a rule, 

 reach the shores, and they do so more and more rarely the farther south 

 and east we go through the Belts into the Baltic Sea. 



It is not my opinion that the line Cape Kullen — the Southern Point of 

 Langeland is constantly the boundary between the saliuities of c. 14,5 "/„o 

 and the Iower ones. The line raay go up or down, particularly the soutli- 

 western part of it (cmp. the tine maps of salinities in the publications of 

 "Kom. til vidensk. Undersøgelse af de danske Farvande"); but it marks 

 the territory near which we must look for this boundary line, and indicates 

 roughly the southern boundary of the territory where the fry of plaice be- 

 longing to the bottom-stage is generally iouud in large uumbers on the 

 shores (cmp. map. I, page 8). 



In the present state of things we must suppose, therefore, that the eggs 

 of plaice, which are found in the sea, presumedly, from the Skaw down into 

 the Baltic as far as Bornholm, as a rule, can go through all pelagic stages 

 to the bottom-stage, onlij ivhere the ivater at certain times can lift them np in the 

 vicinitij uf the shores and thiis carry the young Jish to the lo/v, light, snnshiny, 

 and ivarm coasts ivhich seem to he necessary for their development, ivhile those 

 which remain in the dark, cold, loiv strata of the ivater in the Baltic Sea 

 propel", evidently, as a ride, are destroyed. 



A close study, through several years, of the oecurrence of the tender 

 fry on the shores, compared with the changing hydrographic conditions, will 

 therefore, no doubt, give very interesting information with respect to the 

 growth of the stock in the various years. 



What may be concluded from the Distribution of the Fry with 

 respect to the Renewal of the Stock? 



In the Cattegat, from the Skaw to a little south of Anholt, about 10 — 15 

 million plaice are caught yearly. In the sea uorth of Zealand and around 

 Samsø as far down as north of Funen only a comparatively small number 

 of plaice is caught; for some reason or other the plaice is less common in 

 these parts. In the sea around Funen down to Femern, on the other band, 

 some more are caught, presumedly a few million plaice yearly, of more or less 



