DISTRIBUTION OF THE PRINCIPAL SPECIES AS INDICATED BY THE CATCHES 



The longline catches made by the mothership expeditions afford a meajis of estimating 

 the spatial and temporal distribution of the species of fish comprising the catch. These catches 

 were made during several months of 1950 and 1951 over a wide area (135 E. to 179 E. long., 

 and 1 N. to 10 N. lat.). The present study is confined to the yellowfin tuna, bigeye tuna, and 

 black marlin, in part because together they comprised about 70 percent of the catch, and in 

 part because the yellowfin tuna is a species of considerable economic innportance on the 

 American market. Other species that are taken in some numbers by longlining in this region 

 are albacore, skipjack, white marlin, striped nnarlin, sailfish, broadbill, ajid sharks. While 

 the catch rates of these species have not been subjected to anjilysis, they are listed in the tables 

 of catch rates in the appendix. 



Table 3. --Analyses of variance of the catch of yellowfin tuna of the mother- 

 ship expeditions (data in table 12, appendix) 



\_l June to August, 1950 



Z_l July to September, 1950 



2/ April to June, 1951 



4/ June to August, 1951 



^/ August to October, 1951 



