HADDOCK FISHERY £2 99 



SESSIONAL PAPER No. 38a 



rapid and practically con&tant increase in size up to tlie fourth year. The growth 

 after the fourth winter is slower than in the previous years, and after the fifth winter 

 the yearly increment is very slight. Here we have evidence that the haddock mature 

 in the fourth or fifth year of their life, as growth is probably arrested when the fish 

 begin to spawn. 



(d) ascertained weioiits of fish, and of certain organs. 



The fish were weighed " round,'' that is before splitting and cleaning. The balance 

 used weighed accurately to five grammes. The weights showed considerable varia- 

 tion, fish of the same length sometimes differing in weight by more than a hundred 

 grammes. 



The livers were weighed without the gall-bladder, immediately after removal 

 from the fish. The percentage of liver-weight to body -weight varied from -68 per 

 cent to 4-30 per cent; the average percentage for twenty-two fish was 2-25 per cent. 

 We might note that of the two extremes the fish with the smallest percentage of liver 

 was 6 years old and measured 62 cm. ; while that with the largest liver was 7 years 

 old and 65 cm. long. 



The gonads were weighed as soon as removed and graphs drawn showing the 

 average weights of the gonads for each age. The ovary is proportionately much 

 heavier than the testis except in the four-year-old fish, where average weights of the 

 gonads are equal. The variation in the per cent weight of the ovaries is very slight, 

 there being a difference of only three-quarters of 1 per cent between the largest and 

 the smallest ovary. 



(e) size of eggs in the developing ovaries. 



Eggs were taken from the ovaries (at a point beside the junction of the two 

 organs). They were measured with an eyepiece micrometer. The average size of the 

 largest eggs in the ovary was recorded. In general the eggs were -20 mm. in dia- 

 meter. In the case of a small 3-year-old fish, the largest eggs were only '15 mm. in 

 diameter. One 4-year old, and some 6- and 7-year-oM fish showed eggs -25 mm. in 

 diameter. The size of the. eggs bears no apparent relation to the size of the ovaries. 

 A very small ovary may contain larger eggs than a larger ovary. From this we see 

 that the size of the egg is probably the best criterion of the state of development of 

 the ovary. 



38a— 7^ 



