catch increased rapidly from 1962 to 1965 when it 

 reached a peak of nearly 425.000 fish. It has fluc- 

 tuated greatly since then but has shown a general 

 decline. Because these catch figures represent two 

 species and are for the entire eastern Pacific they 

 might mask any significant trends in catches of sail- 

 fish on the primary grounds. Therefore we have 

 computed sailfish catches for areas 5, 6, and 9 com- 

 bined, and for area 6 separately. 



The following table shows catches in thousands of 

 fish: 



SWORDFISH 



NORTH OF 10° NORTH 



5 28.6 



5 + 6+9 53.1 



1965 



329.9 

 366.0 



173.6 

 199.7 



131.3 

 245.4 



208.9 

 359.7 



72.7 

 149.8 



100.5 

 210.1 



Catches from the pooled areas (5, 6, and 9) shown 

 in the table seem to follow rather closely the trend 

 in catches for the entire eastern Pacific. However it 

 appears that in area 6 catches have declined rather 

 sharply. For example the 1970 catch for area 6 is 

 less than a third of what it was in 1965, whereas the 

 1970 catch for areas 5, 6, and 9 combined is about 

 two-thirds of the 1965 catch from the same areas. 



Figure 18. — Relationship between catch in numbers of 

 fish, catch per 1,000 hooks and effort in millions of 

 hooks for sailfish in areas 5, 6, and 9, 1965-1970. 



SWORDFISH 



SOUTH OF 10° NORTH 



Figure 19. — Quarterly hook rate of swordfish expressed 

 as catch in numbers per 1.000 hooks, for areas north and 

 south of long. 10°N. 



The relationship between catch, effort, and catch 

 per effort for sailfish taken during 1965-1970 in 

 areas 5, 6. and 9 is shown in Figure 18. In the lower 

 panel of the figure a negative relationship is evident 

 between catch per effort and effort. This figure sug- 

 gests, as is expected, that increasing effort will 

 likely result in reduced catch rates. In the upper 

 panel no clear relationship is apparent between 

 catch and effort. Catch for the years 1956-1970 fluc- 

 tuates about some average which is independent of 

 fishing effort. This would suggest that catches 

 would not be expected to increase on the average as 

 effort is increased. 



Swordfish 



For the purposes of examing trends in abundance 

 catches of swordfish (which occur throughout the 

 eastern Pacific but are concentrated in the north in 

 area 2 and in the south in areas 9. 12, and part of 18) 

 have been divided into two groups, one north of lat. 

 10°N and the other south of lat. 10°N. The catch 

 rate may be somewhat confusing in that the longlin- 

 ers have fished at night, utilizing squid as bait, on 

 the northern swordfish grounds since 1964. Night 

 fishing also most likely takes place on the southern 

 grounds but we have no data on this. This form of 

 fishing increases catch rates by a factor of two on 

 the average. 



In Figure 19 the number of swordfish caught per 

 1.000 hooks is shown for the area north of lat. 10°N 

 (upper panel) and for the area south of lat. 10°N 



328 



