FISHES OF THE GULF OF MAINE 



203 



globule, and from 1.19 to 1.72 mm. in diameter; 

 eggs taken at Gloucester in March 1913 averaged 

 1.57 mm., varying from 1.47 to 1.72 mm. Thus 

 they average slightly larger than those of the cod. 

 The haddock egg cannot be distinguished from 

 that of the cod in early stages in its development, 

 hence the term "cod-haddock," and when they are 

 newly spawned there is even danger of confusing 

 them with the eggs of one of our commonest 

 flounders, the "witch" (p. 287), whose breeding 

 season immediately follows that of the haddock. 

 But the formation of black pigment soon identifies 

 the cod-haddock egg as such (the embryonic 

 pigment of the "witch" is yellow). 



The newly hatched larva is about 4 mm. long, 

 with the vent close behind the yolk sac and at the 

 base of the ventral fin fold, not at the margin, so 

 that it seems to end blind. It resembles a cod 

 so closely that the two would be indistinguishable 

 one from the other, were it not that the post-anal 

 pigment granules of the haddock are arranged in 

 a row along the ventral surface of the trunk from 

 vent to tip of tail, and not in bands as they are in 

 the cod (p. 188) and in the pollock (p. 216), while 

 the dorsal wall of the body cavity of the haddock 

 is densely pigmented. In water of 41° F. the 

 yolk sac is absorbed in about 10 days when the 

 little fish is about 5.5 mm. long; the dorsal and 

 anal fins are fully formed at 16 to 20 mm.; and 

 the young haddock begin to take on the general 

 aspect of the adult by the time it is 30 to 40 mm. 

 long. The arrangement of the larval pigment 

 serves to differentiate the little haddock until it is 

 about 12 mm. long. Larger fry are distinguish- 

 able from both cod and pollock by their pale 

 pigmentation, and by the greater height of their 

 first dorsal fin. 



Gulf of Maine haddock average about 6 inches 

 long (extremes, 5 to 7 inches) at the end of their 

 first year, and investigations show that the rela- 

 tionship between length and age averages about 

 as follows for larger haddock in different seas: 



Thus, American haddock grow more rapidly on 

 the whole than European haddock while they are 

 young, but more slowly when older, so that had- 

 dock on both sides of the Atlantic appear to be of 

 about the same size by the time they reach 7 or 8 

 years of age. Needier 38 has found too, that had- 

 dock also differ considerably in their rate of growth 

 in different parts of the Gulf of Maine, St. Andrews 

 fish growing faster than those of Browns Bank, 

 with Nantucket Shoals fish intermediate in this 

 respect, as is illustrated in the following table: 



Age, years 



8K 



Average length, inches 



Eastern 

 Nova 

 Scotia 



16Ji 



lWi 



21 



22.4 



24 



25 X 



According to Thompson 38 haddock on the Grand 

 Banks grow more slowly than the Nova Scotian 

 fish, averaging about 23 to 26 inches when 8 to 

 10 years old, while in the vicinity of Halifax 

 Vladykov 40 gave about 12/4 inches as the length 

 of 2 + -year-old haddock and 13M inches for 3+- 

 year-old, a rate of growth slower than for other 

 parts of the western Atlantic and perhaps not 

 typical for all years. But individual fish grow 

 at such different rates (probably due to food 

 supply) that a haddock of a given length may differ 

 by 1 or 2 years in age, or even by 3 years in the 

 case of the larger fish. Thus a Gulf of Maine 

 haddock, 14 inches long, may be 2 to 2)i years 

 old; one of 20 inches, 3 to 4 years; one of 28 inches, 

 8, 9, or 10 years old. 



An illustration of this variability is that 6 out 

 of 10 fish that were tagged by the vessels of the 

 U. S. Bureau of Fisheries and were recaptured 

 later had gained ){- to K-inch in 2 months though 

 another had not grown at all in that period; one 

 grew 2 inches in 9 months, but two others grew 

 only K- to %-inch in 1 1 months. 41 And Vladykov's 



» Contrib. Canadian Biol, and Fish., N. Ser., vol. 4, No. 20, 1929, pp. 11-20, 

 275-284; N. Ser., vol. 6, No. 10, 1930, p. 64 [295], fig. 17, p. 55 [296]. 



>• Research Bull. No. 6, Newfoundland Dept. Nat. Resources, 1939, p. 15, 

 fig. 3 and table 3. 



<° Vladykov (Contrib. Canad. Biol., vol. 8 (29), 1934, p. 7) gave his lengths 

 to the last vertebra, but we have converted these into total lengths to middle 

 of caudal fin. 



>' Schroeder, Jour. Marine Res., vol. 5, No. 19, 1942, p. 16. 



