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I am sorry that we know but very little of the mortality of the plaice at 

 its various ages; but it is in itself not very likely that it should be so very 

 great at a time when the fish grows much (for instance when it is 10 — 14 

 inches), particularly as its maximum size in the Cattegat, as we know, is much 

 greater (c. 25 inches). 



Diseases we scarcely know to be among them, and if they suffered from 

 any very extensively, this would certainly have been observed by man. We 

 must rather think of other animals as the chief cause of the death of the larger 

 plaice, viz. cod, sharks, rays, anglers (Lopldus piscatorius) , halibuts, Delphinidce, 

 seals; and of these, I suppose, it is chiefly the cod and the marine mammalia 

 on which we need fix our thought, for, of the rest, Lophius and the halibut 

 have suffered much from the fishery in the Cattegat, and are not common 

 any more, while our usual sharks and rays scarcely can take plaice of 10 — 14 

 inches in great numbers. 



Now as to the cod, it is only the large codfish which may be supposed 

 to swallow such larger plaice, and in a few cod I have also seen flat- 

 fishes, but never plaice, only common dabs. This might be accidental, as I 

 have only examined a smaller number; but in Scotland much has been done 

 to clear up this question. 



In the Firth of Forth 727 cod were once examined, and in 50 % of them 

 remainders of fish were found, viz. of whiting, launce, long rough dab, 

 herring, Agonus, common dab, cod, haddock, and some indeterminable 

 remainders besides a few rare fishes, In another year 131 cod were examined 

 at the same place; in 53 % were found remainders of fish, among which could 

 be distinguished remainders of launce, Agonus, Lumpenus, whiting, had- 

 dock, goby, herring, cod, gurnard, long rough dab, and common dab — 

 but remainders of the plaice are never mentioned as found in the stomach of 

 the cod from the Firth of Forth though many plaice are living there; nor have 

 plaice been found there in any other fish's stomach — for instance in rays, 

 Lophius — so it is scarcely probable that larger plaice, on the whole, are eaten 

 by very many fishes. 



How it is in this respect with the marine mammalia, porpoises, other 

 dolphins, and the seals, I do not know for certain, all of them are great ich- 

 thyophagists, it is true, but I must suppose it is here »round« fishes that suffer 

 most, particularly from the seals. It is well known that these follow the shoals 

 of garfish and cod, but that any of the said marine mammalia particularly 

 seek the plaice is a thing I never heard of; on the contrary, it is always other 



