hypothesis in the geographic variation proposed by 

 Penrith (1964). 



Morphological definition of subpopulations: The 

 knowledge of subpopulations is insufficient to estab- 

 lish such a definition. 



Description of morphological changes which occur 

 during growth: Ueyanagi (1963b) reports the change 

 in the length of the snout throughout growth as shown 

 in Figure 2. The relation between snout length and 

 body length shows a marked positive allometric 

 growth until the larva attains a body length of 20-30 

 mm (measured from posterior margin of eye to end of 

 central ray of caudal), then suddenly changes to a 

 negative allometric growth throughout the young and 

 immature stages. The morphological change in the 

 snout during the early developmental stages is the 

 most remarkable feature in this species. Generally in 

 the billfishes, the dorsal fin is very large and high over 

 its base during the larval stage but, except for its 

 anterior lobe, decreases in height in the adult stage. In 

 the shortbill spearfish, however, the dorsal fin is near- 

 ly the same height posteriorly even in the adult fish. 

 From this, Ueyanagi (1963b) assumes that the form of 

 the first dorsal fin of T. angustirostris, although un- 

 known in the immature stage, changes little, and that 

 the change is linear throught its life-span. 



1.32 Cytomorphology 

 No information is available. 



1.33 Protein specificity 

 No information is available. 



1 — I I I ! I II 1 1 — I I I I I II 



_l ' 



2 DISTRIBUTION 



2.1 Total Area 



Geographical distribution: The occurrence of the 

 shortbill spearfish is reported from Japan, Taiwan, 

 California, Chile, South Africa, and very wide areas 

 including the equatorial western, central, and eastern 

 Pacific, the South Pacific, and the equatorial western 

 Indian Ocean. This species is not reported to occur in 

 the Atlantic Ocean and the Mediterranean Sea; 

 howevern close relatives are present in these waters. 



According to Nakamura (1937, 1949), this species is 

 largely oceanic in distribution and does not enter 

 coastal waters. It occurs in warm waters to the east of 

 Taiwan (30-300 miles offshore). Near Japan, it is dis- 

 tributed in ocean waters south of lat. 35°N, but the 

 density is not high. 



Royce (1957) reports the sporadic occurrence of this 

 species in the central Pacific Ocean between lat. 10° N 

 and 10°S; information is based on longline fishing sur- 

 veys conducted by POFF vessels. In the Hawaiian 

 fishery, according to Royce, the shortbill spearfish is 

 one of the miscellaneous spearfishes that compose 

 only a small fraction of the total billfish catch. 



Koga (1959) states that in the South Pacific around 

 the Fiji Islands there is a tendency of slightly in- 

 creasing hooked rate toward the south between lat. 

 20° and 30°S. 



Howard and Ueyanagi (1965) mention that this pe- 

 lagic fish is dispersed throughout tropical and sub- 

 tropical areas of the Pacific and density is always low 

 except in the northwestern Pacific between lat. 15° 

 and 30°N, where the density appears to increase from 

 November through February. 



Kume and Joseph (1969a, b) report the occurrence 

 of the shortbill spearfish only in the high-seas area 

 beyond about 600-700 miles from shore in the eastern 

 tropical Pacific Ocean. 



According to Merrett (1971), T. angustirostris is ap- 

 parently more abundant during the southeast mon- 

 soon period, although this indication is due to high 

 catch rates in only one monsoon period. 



Within the area of the Japanese longline fishery 

 which extends over the entire Pacific and Indian 

 oceans between lat. 40°N and 50°S, this species is 

 caught sporadically in areas roughly between lat. 

 30°N and 30°S. The catch report form used by the 

 Japanese commercial longline fishery however, is such 

 that catch data are not available for the shortbill 

 spearfish and sailfish; these species are combined in a 

 single column of the report. This pooling of the species 

 in the catch record is related to the limitation in the 

 number of columns on the punch card used for prepar- 

 ing the yearly statistics on the Japanese longline 



I 2345 10 203040 IOO 200 400 1000 2000 



BODY LENGTH (mm) 



Figure 2. — Relation of snout length to body (eye-fork) length of 

 Tetrapturus angustirostris during growth (Ueyanagi, 1963b). 



'Pacific Oceanic Fishery Investigations; now the Southwest Fish- 

 eries Center Honolulu Laboratory, National Marine Fisheries 

 Service, NOAA. 



43 



