Figure 7 shows the relative strength of the different yeaf 

 classes (curve A)» From this graph it is difficult to see if' the 

 average strength has changed during the last decade. However, if 

 we simplify the original fluctuation curve by constructing a new 

 point from the media of 3 successive points we arrive at curve B, 

 showing clearly that after 1930 the strength did not rise above the 

 average of all year classes, while before 1930 only the year classes 

 1921, 1922 and 1926 were somewhat below the average© 



Apparently, therefore, during the second half of the period 

 1918=36p the egg production was not sufficient to maintain the 

 haddock stock, while during the first period the egg production 

 must have been large enough to do soo 



Now we have to establish for both periods how many eggs are 

 produced by a group of haddock which^ for instance, at the beginning 

 of their second year had a strength of 1,000 (so-called group l)o 



We know from Raitt's work (1939) how much each year class has 

 declined on the average from year to year during both periods* 

 With the aid of these numbers we could show in columns 2 and 8 of 

 table 10 how many of the 1,000 one-year-old fishes will be left 

 over at the end of each succeeding yearo Exact data on the numerical 

 ratio of both sexes are not known e 



It is assumed here that in each year class there would be as 

 many males as females and so we arrived at the numbers in columns 

 3 and 9, Raitt (1936) has also shown what percentage of females 

 are sexually ripe at different age levels (column 4), thus we can 

 establish how many ripe females were present during the various 

 periods (columns 6 and 10) » He has shown also (1933) how many eggs 

 a female delivers on the average at different age levels (column 6) 

 and from that we can establish the number of eggs produced by all 

 females of each age level (columns 7 and 11) o 



By the addition of these numbers we arrive at the number of 

 eggs whichj by various degrees of fishing, were produced by a group 

 of haddock having at the beginning of their second year a numerical 

 strength of l,000o In other words, we may say that about 17 million 

 eggs are insufficient to product 1,000 one-year-old haddock, but 

 that 34 million eggs very probably will be enough. 



Therefore, 34,000 eggs are needed to produce a single one-year- 

 old haddock. Thus, if the fish stock is not to decline and if there 

 were as many males as females, one female has to spawn 68,000 eggs. 

 This is a figure which lies between the number of eggs which a female 

 will produce at 2 years and what she will produce at the age of 3e 



