(about 2450 square miles) comprised about 70 miles of coast line from 

 Talara to Zorritos and up to about 35 miles offshore. Most of the angling 

 activities, however, were conducted in the vicinity of Cabo Blanco where 

 marlin appeared to be most abundant. In addition, continued heavy seas 

 prevented the expedition activities from covering more extensive grounds. 

 With very few exceptions, no blind trolling for billfishes was conducted in 

 Peruvian waters. In Chile, baits were presented only after the fish had been 

 sighted. 



In Ecuadorian waters, 7 striped marlin were sighted during the angling 

 operations (24 days) from September 19 through October 12. Baits were 

 presented to 4 of these, all of which struck, but only 3 were hooked and 2 

 actually landed. Only 9 black marlin were sighted and baits were presented 

 to 8. Strikes were obtained from all of these, but only 6 were hooked and 

 only 1 was actually landed. All of the 4 sailfish sighted took the bait, but 

 only 3 were hooked and 2 were actually landed. No broadbill swordfish 

 were sighted in Ecuadorian waters. Blind trolling, rather than waiting until 

 the fish were sighted, was the method employed in Ecuador. Most of the 

 angling activities were conducted in the vicinity of La Plata Island. 



Of the 45 specimens of striped marlin landed in northern Chile, 41 were 

 measured and dissected. Vertebrae were obtained for age studies and the 

 gonads and stomach contents analyzed. These specimens ranged from 170 

 to 396 pounds in weight (average 255 pounds) and 2260 to 2850 mm. in 

 fork length (measured from tip of lower jaw). Of the 27 specimens sexed, 

 12 (44 per cent) were males, and 15 (56 per cent) females. All the gonads 

 examined appeared to be in a resting condition, far from the ripe or 

 recently spent stage. This would seem to indicate that striped marlin were 

 not in the process of spawning off northern Chile during the period of 

 operations of the expedition. Females were considerably heavier (average 

 289 pounds) than males (average 236 pounds). The striped marlin oc- 

 curring in the waters off northern Chile appear to be much heavier than 

 those occurring off the west coast of Mexico and Southern California. In 

 these more northern waters, specimens rarely reach a weight of more than 

 250 pounds and usually average less than 200 pounds. The reasons why this 

 species is so much heavier in Chilean waters than in the north are as yet 

 unknown, but the oceanographic and biological data obtained during the 

 expedition may throw some light towards the solution of this problem. The 

 biometric data obtained will help determine whether or not the striped 

 marlin occurring in the eastern Pacific represent one or more races or 

 populations. 



It is interesting to note that during the angling operations in northern 

 Chile, striped marlin were more interested in the bait and took it more 

 readily at higher surface temperatures and showed little or no interest when 



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