>0 

 20 

 • O 



O 



30 



20 



10 



1946 



1947 



L-^?- 



> 20 



«948 





 30 



20 U l^'*^ 



10 - 



o 

 so 



20 



10 



30 



20 



10 



1992 



. 1963 



1950 



1961 



-J^ 



SO 



I 



lOO 



■^Jf- 



1954 



. 1955 



1959 



-UU 



nt 1 r 



50 100 150 200 



L£NaTH(cm) 



— r 

 soo 



150 200 



LeNGTHUm} 



250 



Figure 20. Lengths for bluefin tuna captured off Nova Scotia (1946-1959) ("+" 

 on graph means less than 0.5%) 



3C0 

 WEIGHT Ikg) 



Figure 21. Weights of bluefin tuna captured from St Margaret's Bay ("+" on 

 graph means less than 0,5%), 



1960 on) for 1947-1975 (Figure 24). 

 As the latter figure shows, the size 

 composition of the samples has var- 

 ied drastically over the years. In 1947, 

 giants were dominant, with a fair pro- 

 portion of mediums m Cape Cod Bay. 

 The mediums, mainly the year class 

 of 1943, which was also outstanding 

 in the Nova Scotia catches of 1949- 

 1950 (Mather and Schuck 1960), be- 

 came dominant in Cape Cod Bay in 

 1948 and 1949. They would have 

 been dominant in 1950 also but for 

 an apparently unprecedented inlTux 

 of small bluefin. 'I'his 1948 year class 

 remained dominant through 1957. 

 The mediums became dominant again 

 in 1958-1960, mainly because of the 

 progression of the veiy strong year 

 class of 1952 through this size cat- 

 egory. This year class was also promi- 

 nent in the 1959 Nova Scotia catches. 

 In 1961, small, medium, and giant 

 bluefin were all represented, but an- 

 other strong year class (1957) had 

 become dominant fhe progression 

 of this class made the medium group 



24 



