442 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [16] 



like, a measure wliicb may serve as a starting point. Apart from this, 

 the number of fish which, owing to their being caught during the spawn- 

 ing season, should be counted out, is fully compensated by the circum- 

 stance that we have only counted the number of fish caught by the Eckern- 

 forde fishermen, although within the same area many Kiel fishermen 

 carry on fisheries. 



This area embraces about 16 German square miles. One square mile 

 = 5,500 hectares = 550,000 ares = 55,000,000 square meters ; 16 square 

 miles are, therefore, equal to 880,000,000 square meters. If the number 

 of eggs which must be within the fishing area are distributed evenly, 

 there will be per square meter 17 plaice and 6.6 codfish eggs, therefore 

 in all 23.6 eggs ; that is to say, a quantity of eggs sujfficiently large to 

 admit of an investigation. 



There is no reason to suppose that in some other places in the West- 

 ern Baltic there are fewer fish than the number given above •, on the 

 contrary, fishermen maintain that the places referred to are overstocked 

 with fish, at least as regards plaice. If, therefore, the eggs laid within 

 this area were driven to other places, a suflicient number of eggs, com- 

 ing from the west or northeast, would take their place. It is probable, 

 however, that a current, running for a long time continuously in one di- 

 rection, would soon drive the eggs from the Western Baltic, unless there 

 are other circumstances to prevent such an occurrence. This seems to 

 be the case, and possibly makes this very basin of the sea a peculiarly 

 interesting field for observation. It seems that the floating eggs can- 

 not escape towards the north and towards the east. They cannot pass 

 through the Great Belt, because (as Meyer has shown in his observations) 

 the surface current going north through the Belt, in March, and espec- 

 ially in April, contains less than 1.8 per cent. salt. This current prin- 

 cipally comes from the Eastern Baltic, and, therefore, does not carry 

 any eggs. But if waters from the Western Baltic — containing eggs — 

 mingle with it, they begin to sink, and therefore either get in a zone 

 where there is hardly any current, or into the lower current floating 

 south, which brings them back to the i>lace from which they started. 

 At any rate, the free movement of the eggs is hindered. Only direct 

 observations, taken in the Great Belt, will show whether the movement 

 of the eggs is stopped entirely, whether more eggs enter from the North 

 Sea than those which leave the Baltic, or whether the reverse is the 

 case. Towards the east the floating eggs cannot make much progress, 

 because they would sink to the bottom, owing to the water gradually 

 losing its saltness the farther east you get. 



So far the practical results did not seem to correspond at all with the 

 observations given above; nevertheless, I felt convinced that they were 

 approximately correct. Hence in 1883 I commenced to make direct 

 observations as to the quantity of the eggs, and below I give the re- 

 sults. I fished with three nets; the net for fishing at the bottom has 

 already been described; it measured 38 centimeters in breadth; the 

 floating surface net measured 80 centimeters in breadth ; the vertical 



