It might be thought perhaps as regards the dredged oysters that the 
adult group was artificial, partly caused by overfishing; hut it also appears here 
in nature that the growth is easy to observe in the young oysters under 7—8 
cm. and seldom well marked in the larger; further, reproduction begins at 6—7 
cm. in length; and lastly, from the calculation below of the small product of the 
fishery and the rich stock in the fjord, we know that so little fishery has been 
carried on during the last 23 years, either not at all or only about 1 million yearly 
that it could have absolutely no influence on the appearance of the adult group; 
at any rate not on the stock of the fjord as a whole. It might be thought that 
the fishery had some influence on the well fished banks; but even here no de- 
crease in size could be observed; for the time being only the number of oysters 
has been influenced and that only to a very small extent. The fishery hoth by 
diving and dredging is so carried on that a bank is never fished clean, only 
approximately; fishing is carried on over the whole of the fjord wherever most 
oysters are supposed to be and where the wind and weather and the convenience 
of the fishermen are most suited and suitable. On the other hand Table II shows 
that the oysters in Nissum Bredning are larger than in the other regions; and it 
has always been so, so, far as is known; here 9 and 10 cm. are equally frequent, 
elsewhere it is $ and 9 cm. 
The oysters in Table II were dredged in the period from the 9th to 20th 
April by means' of a ca. 1 fathom broad dredge, like those used by the oyster 
fishers on the banks in the North Sea; this dredge was sometimes provided with 
teeth sometimes not. After April 23rd however two smaller dredges fastened 
alongside one another, the one with teeth the other without, were used; their spread 
was thus almost over a fathom from side to side and seemed to take just as many 
oysters.. The oysters dredged at Trehuse on April 23nd were taken partly with 
the large, partly with the small dredges. 
It would be desirable to know more regarding the age of oysters at 
any definite length, but the statistical method by measurements as the Tables 
show gives but incomplete information, clearly because the growth of oysters is 
different under different conditions and perhaps also in different years according 
as these are warm or cold. Thus I have long regarded the oysters under 7 cm. 
in the Tables as containing 2 annual groups coalesced with the usual maximum 
at 2—4 cm., and I have been further strengthened in this view during this year. 
In May 1907 I was able to examine a tarred raft in the possession of a fish dealer 
which had lain in Nykøbing harbour since Whitsuntide 1905, thus from the middle 
of June 1905, and was now in the spring of 1907 taken up to be dried, cleaned 
and tarred. Two annual groups were fixed on the raft in May 1907, each numer- 
ous, one from 1906 of ca. 2 cm. in length and one from 1905 of 4-—6 cm. If 
this was the general growth in the fjord, all oysters of 7 cm. and above should 
be 3 years old and more; but I do not think that the oysters on the banks would 
grow so quickly as those on the raft or on other similar artificial objects; of this 
I have already had previous evidence. But in the estimate that the oysters of 
4—5 years old on the banks are 7—8 cm. and more I do not think we are much 
in error. To investigate the point more closely we must find a suitable method 
of marking oysters. I have heen recommended from Holland this year to try 
