Insular Catches 



The tuna catches made at insular stations, i.e., those within 

 80 miles of land, during 1953 (table 2) were mostly yellowfin. These 

 catches suggest that this species tends to be more abundant near land 

 than in the open ocean, e. g. , an average catch of 4. 3 yellowfin per 

 hundred hooks near Palmyra Island in late January 1953, while at 

 approximately the same time (early February) catches in the open 

 ocean at about the same latitude as Palmyra (5°-6°N. ) averaged around 

 2 per hundred hooks. 



INSULAR |22 OCEANIC ( ) NUMBER OF STATIONS 



Considerably more data are available in the instance of Christmas 

 Island (2°N. , 157°W.), where there was more fishing and where com- 

 parisons can be made between oceanic fishing (on 150°W. and 155°W. 

 longitude) and insular fishing during several periods of the year (fig. 6). 



As shown in this figure, sea- 

 sonal trends for the island 

 fishing closely resembled 

 seasonal trends for adjacent 

 oceanic fishing, but in each 

 instance the island catch was 

 higher. For example, during 

 August fishing was best at 

 Christmas Island (10.9 per 

 hundred hooks) and in the 

 adjacent oceanic area (7. 8 

 per hundred hooks). During 

 January to February catches 

 were low near Christmas 

 Island (4.4 per hundred hooks) 

 and only 2.4 per hundred hooks 

 in the adjacent oceanic areas. 

 As will be shown later, at 

 least part of the higher catch 

 near islands was caused by 

 the addition of small fish to 

 the catches of large deep- 

 swimming yellowfin. 



Figure 6. --Comparison of yellowfin 

 catch rates from insular stations 

 (within 80 miles of Christmas Island 

 2°N. latitude, 157°W. longitude) and 

 oceanic stations (at 150°-155°W. 

 longitude between the Equator and 

 4°N. latitude). Data from appendix 

 tables 6-11. 



VERTICAL DISTRIBUTION OF TUNAS 



In equatorial waters the tunas are not generally taken at the 

 same rate at all depths fished by the longline (Nakamura 1949, Murphy 

 and Shomura 1953a, b, 1955). Considering all of the 1953 data, 



12 



