6 



iuvestigations regardiDg the inplanting of plaice, wliicli has uow beeo set on foot 

 on a large scale. 



Soine few figures will explaiu better thau inany words how the matter 

 really stands. 



Over large areas of tlie Limfjord, especially in the central parts, two species 

 of predatory whelks occur in great quantities; one a large form, the common dog- 

 whelk or the »Konkylier« of the Limfjord (Buccinum imdatum), and a smaller, Nassa 

 reticulata. They are both shown in fig. 1. They have loug snouts furnished with 

 sharp teeth, by means of wliich they can tear up all the flesh they can get hold 

 of. Their mode of attacking the plaice is to guaw a hole in the skin and put 



WwS 



Fig. I. 



their snout through this hole; they then devour all the muscular tissue, leaving 

 only the skin and bones. The slow-moving whelks however cannot seize the plaice 

 when swimming freely, but when the plaice are caught in the gill-nets (see fig. 2\ 

 which always reach to the bottom, they are often so entangled or so enfeebled, 

 that they sink quite down to the bottom and lie quietly; they thus become an 

 easy prey for the whelks. In figures 3 and 4, several whelks are seen attached to 

 the plaice just brought up in the nets; the latter are dead in the first place, but 

 they are also partially devoured by the whelks and of no use as human food. 

 In fig. 3 at least 3 Biiccimim are seen and 2 in fig. 4 together with a starfish 

 (Asterias). The small whelks, Nassa, attack the plaice in a similar way and, on 

 accouot of their greater uumbers, are perhaps still more harmful than the large. 

 On the other hånd, the plaice are not so much in danger of the starfish es 

 (Asterias), as the latter ordinarily only get time to suck at them outside on the 

 skin, but they also might kill the fish. It can readily be understood, that 

 the whelks do an immense amount of harm in waters where the fishery 



