MANUAL OF FISH-CULTURE. 195 



spAWNma. 



The principal spawning time of the cod on the T^Tew England coast 

 is winter, but the season begins as early as November and continues 

 until April. Spawning fish are occasionally caught from October until 

 May. The spawning period for an individual fish is greatly prolonged, 

 and probably covers six or eight weeks, only a small percentage of the 

 eggs maturing at one time. The male and female cod may attain 

 sexual maturity when weighing only 3^ or 4 pounds. The ages of 

 normal fish having these weights are supposed to be three to four 

 years. 



When impelled by the spawning instinct, the cod seek the shoal 

 waters of the coast or banks in schools consisting of both sexes. The 

 female is less active than the male at this period, and probably rests 

 quietly on the bottom while discharging the eggs. There is no evidence 

 to show that the sexes are paired or in close proximity during the act 

 of spawning. On the contrary, it seems likely that fertilization is 

 generally accomplished by accidental contact of the sexual products 

 as they are swept about by the elements, having risen to or near the 

 surface as soon as extruded. 



The cod is one of the most prolific fishes. The ovaries of a 21-pound 

 fish have been computed to contain 2,700,000 eggs, and a 75-pound cod 

 has been estimated to have 9,100,000 eggs, these figures being deduced 

 by careful weighing or measuring of a known number of eggs. The 

 egg is from -^ to -^ inch in diameter, the smallest fishes having the 

 smallest eggs ; the average size may be taken as i\ inch. The approxi- 

 mate number in a fluid quart is 337,000. 



The destruction of cod eggs in nature is necessarily large. The 

 principal loss is probably through failure of impregnation, the eggs 

 losing their ability to become fertilized and the milt its vitality very 

 soon after being thrown from the fish. Incalculable numbers are thrown 

 on the shore by the waves and there die. Cod eggs are also destroyed 

 by numerous animals, including fish, birds, and invertebrates. 



COMMERCIAL IMPORTANCE AND FOOD VALUE. 



The cod is one of the most valuable of all food- fishes, and in the 

 United States ranks as the most prominent commercial fish. In the 

 matter of persons engaged, vessels enyjloyed, capital invested, and 

 value of catch, the taking of cod in the United States is more extensive 

 than any other fishery for fish proper.* The number of vessels which 

 fish wholly for cod or take cod in noteworthy quantities, together with 

 other "ground fish," is not less than 600, of over 25,000 net tons burden, 

 carrying about 7,000 men, and with a value of $3,000,000, besides which 

 there are very large fisheries carried on from boats and small vessels 

 of less than 5 tons burden. The approximate annual value of the cod 



* The oyster fishery is the most important branch of the fishing industry of the 

 United iStales. 



