1957 



1938 



^f- 



1999 



-«- 



I960 



1961 



-rr- 



1962 



50 



100 



JO 



-i 1 — 



100 



>-!l^ 



— I r 



150 



-T^^-^f^ 1 



200 250 300 



LENSTHtcml LENGTHkml 



Figure 40. Lengths for bluefin tuna captured from the Noilh Sea ("+" on graph means less than 0.5%) 



almost two decades for which ver)' 

 few data are available. 



Length frequency data in 5 cm 

 groups for Bay of Biscay catches in 

 1949 (J Le Gall 1950) (.French 

 catches only) and 1972 (Bard et al 

 1973) and 1975 (Cort 1 976) (for both 

 French and Spanish catches) are pre- 

 sented in Figure 42. Additional size 

 frequency data, in different size 

 groups, are furnished by Dao and 

 Bessineton (1974) and Cort and 

 Cendrero (1975) 



These data indicate that age 2 

 fish are usually the most important in 

 the Bay of Biscay catches, with age 3 



the next in order, and age 1 fish oc- 

 curring episodically in recent years 

 (Dao and Bessineton l')74). Age 1 

 fish were important in the 1949 

 sample, but no data for other years in 

 the peak period of the live-bait fish- 

 ery are available There has been a 

 decrease in the importance of age 4 

 and larger fish in the catches since 

 1972 This has been attributed to the 

 entry of Japanese longline vessels into 

 the area in 1 974 and subsequent sea- 

 sons (Cort and Cendrcio 1975, Cort 

 1976), 



Much additional data is avail- 

 able for weekly (or daily) landings at 



St. Jean de Luz, the principal port of 

 the French bluefin tuna fishery, in 

 terms of fish weighmg less than 30 

 kg and more than 30 kg (Hamre and 

 Tiews 1964, Hamre etal 1966, 1968, 

 1971, Aloncle et al. 1974). Eighty 

 percent of the 1962-1972 landings 

 by weight were in the class weighing 

 less than 30 kg (Dao and Bessineton 

 1974). The percentage by numbers 

 would, of course, be considerably 

 higher 



The Spanish fishermen, how- 

 ever, take more of the larger fish 

 than the French Dao and Bessineton 

 (1974) found that only 52% of the 



