OBSERVATIONS ON THE SPEARFISHES OF THE CENTRAL PACIFIC 



By WILLIAM F. ROYCE, Fishery Research Biologist 



Since 1950 the Pacific Oceanic Fishery Investi- 

 gations (POFI), U. S. Fish and Wildlife Service, 

 has been investigating the high-seas fishery 

 resources of the tropical and subtropical Pacific 

 Ocean. These investigations have shown that 

 several kinds of tunas, particularly j^ellowfin 

 (Neothunnus macropterus), skipjack (Kats7twonus 

 pelamis), and albacore {Germo alalunga), form the 

 most promising fishery resources in this area.' 

 Moreover, these tunas are commonly found asso- 

 ciated with two other gi'oups of large fishes, the 

 spearfishes, principally the marlins, and certain 

 species of sharks. An understanding of the role 

 of both of the latter gi-oups is important because 

 they compete with the tunas for food, but the 

 marlins, in particular, are objects of gi-eat interest 

 in themselves because of their value for sport 

 along the coast of the Americas and for food along 

 the coast of Asia. 



Despite the interest in and value of the marlins, 

 these spectacular fish are little known to Ameri- 

 cans. Their habits, their wide distribution on the 

 high seas, even the number of their species, have 

 not been known. Much information has appeared 

 in Japanese literature during the last two decades, 

 but little has been wTitten in English, and even if 

 it had been, the uncertainty about the species 

 occurring on both sides of the Pacific might have 

 prevented associating the species of the western 

 Pacific with those found off the Americas. 



The spearfish problems discussed in this paper 

 include (1) a study of diagnostic characters and 

 morphological comparisons of the species, (2) a 

 decision as to the correct names, and (3) observa- 

 tions on distribution, abundance, and habits. For 

 the latter we shall use our observations and refer 

 extensively to the Japanese literature. We shall 

 not attempt a monograph, however. Observa- 

 tions on the spearfishes in all parts of the world are 



' Reports of the tuna studies, tORCther with detailed tables of the catch 

 and fishing localities, may be found In Murphy and Shomura (IB.'iSa. 

 1953b, 1955). 



Note— Approved for publication, October 1!. igsfi. Fishery Bulletin 124. 



being added to the literature so rapidly and so 

 little is known that such a treatment would be 

 premature. 



Most of our data have been obtained from spear- 

 fishes caught on longline fishing gear from POFI 

 vessels. This gear has been described by Niska 

 (1953) but, briefly, it consists of a series of baited 

 hooks 15 to 30 fathoms apart suspended from a 

 line at depths of about 200 to 400 feet. On all 

 cruises made after July 1952 (table 1) records 

 were kept of the species of spearfishes caught at 

 each station (fig. 1), and in man)' instances 

 morphometric measurements were made, together 

 with observations on sex, sexual condition, and 

 food in the stomach. Such observations were not 

 as complete as might be desired because the 

 primary assignment on each cruise was to obtain 

 information on the tunas, and observations on the 

 spearfishes were made as time permitted. 



Table 1. — The longline fishing cruises of POFI vessels on 

 which spearfish data have been collected, 1952-64 



In the collection of data, assistance was rendered 

 by many members of the POFI staff, including the 

 officers and crews of the vessels who had the 

 problem of handling these large and troublesome 



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