INTRODUCTION 



This is the second interim report on an investigation of the 

 deep-swimming tuna resources of the central Pacific Ocean ''fig. l)„ 

 This study is being conducted by the U„ S„ Fish and BITildlife Service 

 through the Pacific Oceanic Fishery Investigations (POFl}„ The first 

 report (Murphy and Shomura 1953) dealt with the results of fishing 

 during the period from July 195>0 to September 19f>l. The fishing on 

 which this report is based took place from January to June 1952, 



During Cruise 11 of the John R„ Manning (fig. 2), January 

 to March 1952, section lines were fished across the Equator at 180°, 

 169% and 155° W. longitude. Cruise 1 of the Charles "h. Gilbert 

 (May and June 1952) included sections at 130° and 120° W. longitude. 

 In this paper the results of fishing are discussed together with a 

 preliminary evaluation of the relation of the tuna to the environment . 



We use the vernacular names of the fishes throughout the 

 report. These with their commonly accepted scientific names are 

 as follows: 



White-tipped shark - Carcharinus longimanus (Poey) 

 Silky shark - Carcharinus sp„±/ 

 Great blue shark - Prion ace glauca (Linnaeus) 

 Bonito shark - Isurus glaucus (Muller and Henle) 

 Marlin - Makaira sp. 



Sailfish - Istiophorus orien talis (Schlegel) 



Wahoo - Ac ant hoc ybiun solandri (Cuvier and 



Valenciennes) 

 Dolphin - Coryphaena hippurus (Linnaeus) 



Yellowf in tuna - Neothunnus macropterus ( Temminck and 



Schlegel) 

 Bigeye tuna - Parathunnus sibi (Temminck and Schlegel) 

 Skipjack - Katsuwonus pelamis (Linnaeus) 



Albacore - Germc alalunga (Bonnaterre) 



Lancet fish - Alepisaurus sp„ 

 Barracuda - Sphyraena barracu da (V.albaum) 



ACKNOWLEDGEMENT TS 



Several persons contributed to the planning and organization 

 of the two cruises, including 0. E. Sette, D. L. McKernan, and 

 W. F„ Royce. Dr, Royce is also responsible for the provisional iden- 

 tifications of the sharks o The successful completion of the cruises 

 was due in no small part to the enthusiastic performance of the 

 officers and fishermen of the John R„ Manning and the Charles H„ Gilbert, 



V A species closely resembling C. floridanus Bigelow, Schroeder, 

 and Springer, anH C„ ahenea (Stead) . 



