_ 15 — APPFNDIX H: GARSTANÜ 



of the outer Broad known as Veno Bugt. It is also well-known from Dr. Petersen's classical 

 account ' that the Danish fishermen have been enabled to carry on a profitable industry for 

 many years by transplanting small plaice from the outer waters of the Lim Fjord, or from 

 tlie adjacent parts of the North Sea, to Thisted Bredning, taking advantage of the difference 

 in rate of growth shown by Dr. Petersen's experiments. It will be seen in the diagram that 

 the difference between the normal growth of plaice on the Horn Eeef Grrounds and that of 

 plaice transplanted to the Dogger Bank is still greater than in the case of the Lim Fjord 

 experiments. The increased rate of growth on the Dogger Bank continues for a longer period 

 of the year than in Thisted Bredning; and although the increase is not so great on the 

 Dogger Bank in the summer months as in Thisted Bredning it greatly exceeds it during the 

 later months of the year. 



The interest^ and importance of these results is unmistakable. On the one hand it is 

 fairly clear that the plaice on the Horn Eeef Grounds are unable to attain anything like 

 their maximum potential growth. They are living practically in a half-starved condition, 

 probably in consequence of great overcrowding (see below). On the other hand if these same 

 fish can be transplanted on a commercial scale to the rich feeding grounds on the Dogger 

 Bank where the population of plaice is very small, not only will the fishermen in the fall of 

 the year be enabled to increase their catch of plaice on the latter ground, but the repetition 

 of such transplantation work from year to year must contribute appreciably towards the re- 

 stocking of this once prolific but now exhausted area. One condition necessary for the success 

 of this work is that the fish should not be caught too soon after transplantation. It is for- 

 tunate in this respect that the intensity of fishing on the Dogger Bank is very low during 

 the summer months and reaches a maximum during the autumn and early spring. If plaice 

 were transplanted there during the month of May, a sufficient number would survive in all 

 probability untill the autumn months to appreciably increase the fishermen's catches. In order 

 to substantiate this statement it will be necessary to provide an approximate estimate of the 

 population of plaice on the Dogger Bank. This point will be dealt witli further on in connection 

 with the results of the trawling experiments. 



C. The vitality of trawl-caught fish 



Reasons have already been advanced above in connection with the marking experiments 

 in support of the view that tlie vitality of small trawl-caught fish is considerably impaired 

 whenever the total weight of fish caught in any haul becomes considerable. The weight of 

 the catch depends on the length of the haul and still more on the abundance of fish. The 

 relative success of the English marking experiments upon plaice on the Ameland Ground, as 



' Petersen, Keiioit of the Danish Biological Station, 1896. 



