THE COD FAMILY 287 



only recorded their length, and did not make a study of their 

 transformation. He put 500,000 fry, hatched on April 2/th, 

 into an enclosed pond of sea water, and on July I2th they 

 measured a little more than 2 inches in length. At this length 

 they must have completed their transformation, and thus the 

 period required for this was two months and a half. 



In October these cod measured 4f inches to 6f inches, and in 

 the' following February 14 to 16 inches. Mr. Holt found that at 

 Grimsby the critical sizes of cod in reference to sexual maturity 

 were 22 to 35 inches ; none were mature at a length less than 22 

 inches, none immature at a length over 35. No difference in 

 this respect was found between males and females. The 

 evidence available indicates that the lowest limit is not reached 

 at one year of age, but it is probably reached by some individuals 

 at two years. 



The Haddock (Gadus aeglefinus}. 



Distinguishing Characters. The barbel on the chin is very 

 short. The vent is further forward than in the cod, the first 

 ventral fin commencing below or very slightly behind the com- 

 mencement of the second dorsal. The body is narrower than 

 that of the cod. The black blotch on the side is beneath the 

 middle of the first dorsal fin. The sides and back in the fres^h 

 fish have a beautiful bronze-coloured reflection ; the lateral line 

 is black. A specimen has been recorded which measured 

 37 inches in length, and weighed 24^ Ibs., but the largest of 

 a large number measured for the Scotch Fishery Board was 

 25 inches long. 



Habitat. From the Arctic Ocean to the Bay of Biscay on 

 the eastern shores of the Atlantic, to Cape Hatteras on the 

 western side. It is not abundant in the English Channel, though 

 said to be taken there in considerable numbers in certain years. 

 Very abundant in the North Sea, in the northern part of which 

 it forms the staple produce of the trawl fishery. More abundant 

 on the north, east, and west coasts of Ireland than on the south. 



Food. The principal food in the Firth of Forth was found to 

 be crustaceans and molluscs ; the former were found in 60 per 

 cent, of the stomachs, the latter in 40 per cent. Echinoderms 



