_ 47 — B- HELLAND-HANSRN 



have been worked out just in the same way as was done for haddock. These 

 number are denoted by the broken line in the figure. The continuous line gives 

 the distribution of weights and will be referred to later. 



For cod the curve of numbers shows a rise which reaches its maximum at 

 24 — 25 cm; and it agrees accordingly in this respect with the corresponding curve 

 for haddock. However the numbers of the different centimeter-sizes up to 20 cm., 

 as compared with the numbers centring round 24 — 25 cm. or as compared with 

 the total number, are smaller in the curve for cod than they were in the curve 

 for haddock. The fact that among trawled haddock more of the smallest sizes 

 of the fish occur in proportion to the whole quantity than is the case among 

 trawled cod, would appear to be partly due to cod being later than haddock in 



Fig. 31. Average catch per trawl-hour of different sizes of cod. Broken line denotes the relative 

 average numbers while the other curve gives the average weights. 



repairing to off-shore grounds, or in other words to cod attaining fairly large 

 dimensions while still in the littoral region. Fulton moreover asserts that codling 

 under 20 cm. escape comparatively easily through the meshes of an ordinary 

 trawl. 



The irregular depression in the curve which takes place between 25 and 

 35 cm. is due to the uneven distribution of the catches. The number falls 

 off rather sharply till about 55 cm., but descends much slower after this 

 until it reaches 95 cm.: from here onwards it again decreases rapidly, and above 

 no cm. it practically vanishes — there were not more than 9 individuals over 

 no cm. in the whole 2387 trawl-hours. 



The proportion in which the different centimeter-sizes are distributed can be 

 expressed as follows: — 



size 20 25 30 40 50 60 70 80 90 100 cm. 



number 17 46 33 20 12 7 6 5 4 2 



