spring there is an apparent southward shift in the 

 distribution of sailfish, with a normally high abun- 

 dance in the 5-degree area between lat. 15-20°S and 

 long. 75-80°W. 



These current data differ from those presented by 

 Kume and Joseph (1969a) in that high abundance is 

 shown to occur all along the Panama Bight to as far 

 south as the equator. This difference is due to the 

 fact that the longline vessels did not operate in the 

 inshore areas of the Panama Bight until after 1966; 

 the study of Kume and Joseph included data only 

 through 1966. 



Howard and Ueyanagi (1965) have reviewed the 

 distribution of sailfish in the eastern Pacific based 

 on catch records from subsistence and sport 

 fisheries. Our conclusions are consistent with 

 theirs. 



As noted above, the distribution of sailfish on an 

 oceanwide scale decreases sharply to the west of 

 about long. 110°W and is relatively low throughout 

 the central Pacific. However in the western Pacific 

 they are again found in abundance around the 

 Indo-Pacific land masses. Whether the sailfish of 

 the eastern Pacific are of the same genetic popula- 

 tion as those in the western Pacific has not been 

 determined. Because of their propensity to as- 

 sociate with land masses and due to their discon- 

 tinuous distribution, it would seem useful to con- 

 sider them as separate stocks from the point of view 

 of fishery dynamics. 



As already noted, beyond about 1,000 miles from 

 the coastline catches of sailfish decrease rapidly 

 and this species is replaced in the catches by short- 

 bill spearfish. 



Though shortbill spearfish are found throughout 

 the Pacific Ocean their distribution appears to be 

 patchy and they do not appear to be highly abun- 

 dant anywhere. 



Shortbill spearfish seem to occur in the catch dur- 

 ing every quarter of the year (Fig. 10 and 12). 

 Throughout the central eastern Pacific they are 

 taken in low numbers. The only area in which they 

 appear to be relatively more abundant is along lat. 

 20°S between about long. 130°W and 90°W. This 

 center of abundance exhibits a southerly shift dur- 

 ing the southern summer. 



Swordfish 



The average, quarterly distribution of swordfish 

 taken per 1,000 hooks is shown in Figure 11, by 

 5-degree areas. These hook rates do not distinguish 





































/- — «'JUBE0 or 54HTISH 

 [%L NUU8EB Or SHOUTS .. 



tetioriSM 















\/r\ SHORTBILL SPtSfiFlSH 







[g^y j?^y FT^' fB97y 



■r Er\ / 





9 / 

 / 4 



17 / 

 / 6 



'3 ,--'' le^F 

 / 2 ^ro 



/ 4 



31 / 

 / 4 





^v 





4 / 



/ ° 



5 / 



2 / 



5 / fa^r 



31/ 



s 33 



7l s 









o A- 



6 / 



/ ,6 







6 / 



y/54 



/ 



/^ 

















13 / 



y * 













Jr\ 



o As 































/ 5 



/■'.■ 



J& 



o /: 



































o jy\ 





/': 







/£• 







































Figure 12. — Relative distribution by 5-degree area of sail- 

 fish and shortbill spearfish, 1952-1959. 



between sets of the longline made at night and sets 

 made during the day. Kume and Joseph (1969a) 

 have shown that night sets are more efficient for 

 capturing swordfish than day sets. Since night sets 

 are generally made on the swordfish grounds, at 

 least for 1964 through 1966, Figure 11 may be 

 somewhat biased because catches on the swordfish 

 grounds would be overestimated relative to sword- 

 fish catches in other areas. The bias thus introduced 

 would not likely be great enough to make a sig- 

 nificant difference in any inferences drawn from the 

 figures. 



In the eastern Pacific, swordfish are caught be- 

 tween lat. 35°N and 40°S. In the north, the best 

 swordfish fishing is found in the coastal areas be- 

 tween about lat. 20°N and 30°N. The 5-degree areas 

 adjacent to the peninsula of Baja California consis- 

 tently yield the highest catch rates in the north. The 

 principal swordfish grounds in the south are cen- 

 tered in the coastal waters from the equator to 

 about lat. 15°S, and around the Galapagos Islands. 

 From this southern area relatively consistent con- 

 centrations of swordfish extend westward in a 

 latitudinal band along the equator during all seasons 

 of the year. During the first and fourth quarters 

 (southern summer) a secondary latitudinal band ex- 

 tends westward between lat. 10°S and 20°S. This 

 could be explained by a migration of fish from the 



321 



