10 

 8 

 6 



4 - 

 2 

 

 8 

 6 

 4 

 2 

 

 8 

 6 

 4 

 2 

 

 8 

 6 

 4 

 2 

 

 8 

 6 

 4 

 2 

 

 8 

 6 

 4 

 2 

 



| AMERICAN CATCH RATES (LINE IS) 

 ! JAPANESE CATCH RATES (II°S-I2°N) 



JAN 



FEB 



L 



MAR 



APR 



L 



MAY 



H 

 I 



JUN 



JUL 



AUG 



SEP 



OCT 



NOV 



1 



DEC 



m 



170° 160° 150° 



WEST LONGITUDE 



170° 160° 150° 140° 130° 



WEST LONGITUDE 



Figure 5. --Catch rates of yellowfin from the 

 equatorial Pacific (11°S.-10°N. latitude) 

 obtained by American and Japanese vessels 

 during 1954. 



When the catches were high west of the Linei 

 Islands area (around 160°W.) they were lower 

 in the vicinity of the Line Islands and conversely 

 (fig. 5). 



During the month of July 1954 Japanese 

 vessels fishing near the Line Islands area ex- 

 perienced markedly higher catch rates than the 

 American vessels. This is difficult to evaluate 

 in view of the wide variability in the very few 

 samples obtained by American vessels during 

 July. However, the Japanese did most of their 

 fishing south and somewhat west of the Ameri- 

 cans and used fabric instead of steel gear. 



Line Islands 



General: A seasonal trend can be seen in 

 the yellowfin catch rates from the vicinity of 

 the Line Islands during 1954 (fig. 6). Starting 

 with high catch rates in February, there was a 

 gradual decrease to a very low level during the 

 latter part of July, early August, and during 

 October. During November there was a slight 

 increase over the summer months, but the rates 

 remained considerably lower than those of the 

 first few months of the year. The catch rates of 

 the Japanese longline vessels based at Pago Pago, 

 American Samoa, show a similar decline (fig. 7) 

 during the early months of 1954 (Van Campen 

 1954). 



This trend in catch rates during 1954 is 

 sharply divergent from past observations, for 

 Shomura and Murphy (1955) found that the great- 

 est abundance in the Line Islands area occurred 

 from July through September during 1951-1953. 

 This dissimilarity in the seasonal trend of catch 



u> io 



o 

 o 



20 o 



o 



I 



to 



o 



- 12 O 



o 

 o 



North 



Alnlo 



FEB 

 American Cf 

 Cr I 



1 ^L 



MAR APR 



I North American Cr 2 



Alrita Cr 2 



C.H.Gilbert Cr 15 



IvlAY JUN 



J R Manning Cr 20 



JUL AUG 



Commonwealth Cr I 

 Brothers Cr 2 

 Oceanic Cr 2 



"SEP OCT NOV 



Sea Hawk Cr I 



Commonwealth Cr 2 



Figure 6. --Daily catch rates for yellowfin in the Line Islands during 1954. 



