104 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
eries, including a small bank in the Cattegat; while now the fisheries 
have gone down so much that the rent is only 48,000 crowns ($12,864) 
per annum. In my opinion this is caused by the circumstance that 
during continuous east winds too much water from the Baltic, which is 
not very salty, enters the fiord. It can hardly be supposed that severe 
frost should have caused the decline of the oyster fisheries, unless there 
are such undercurrents as to favor the formation of bottom-ice. The 
apparatus used in the Lymfiord for catching oysters seems to me very 
destructive, as the bow of the net has teeth instead of being smooth. 
The bottom, which is not very rocky, is therefore considerably torn up, 
and does not afford any firm hold for the young oysters. I was in- 
formed that various attempts had been made to raise oysters artificially, 
but so far without success. I think, however, that the waters of this 
large fiord must have many sheltered places where young oysters could 
be raised in large quantities. 
Broom and heather placed horizontally, in hurdles 4 feet broad and 
6 feet long, above the present oyster-beds, in places where there is the 
least possible current, would probably yield a favorable result. To 
prevent these hurdles from being covered with aquatic plants they 
should not be set till the 15th or 20th of May, as it will not hurt if they 
are overgrown with plants later. I would state regarding oyster cult- 
ure that the spawn of oysters prefers to adhere to rough, dark brush- 
wood. Heather and broom have been advantageously employed. Oys- 
ter fishing, and in fact all fishing, should be strictly prohibited in these 
places. I am confident that success will crown these efforts if they are 
made in places where there is but little current. The results would 
certainly be favorable if the hatching places were properly inclosed ; 
but this, of course, is more expensive. 
In conclusion, I would state how profitable oyster culture may be for 
a country. The Dutch oyster-beds near Jersecke in 1870 yielded a rent 
of 20,651 florins ($8,301.70), but after artificial oyster culture had been 
introduced these beds (including those of the East Scheldt) yielded an 
annual rent of 508,665 florins ($204,483.33). 
Jersecke, which in 1870 was a poor fishing village with 1,013 inhabit- 
ants, has at present a population of 2,832. Twenty- two millions of 
cemented tiles serve as spawn-collectors in the East Scheldt and on the 
Jersecke oyster-beds ; and in 1884 there were many tiles which held as 
many as 300 young oysters. The waters of the Lymfiord, in spite of 
having less food, would probably show even greater results. 
The banks in the Zuyder Zee near the Island of Wieringen, which are 
rented out by the Dutch Government for the purposes of oyster cult- 
ure, already yield an annual rent of 50,000 florins ($20,100), and this 
sum is paid for grounds which as yet have not produced any oysters, and 
which only as late as last year were supplied with mother-oysters from 
the great German oyster-beds in the North Sea. 
Norderney, Germany, February 25, 1886. 
