Table 2.— Summary of the prominent diagnostic characters of istiophorid larvae less than 5 mm in length (from Ueyanagi, 1964). 



Table 3. — Diagnostic characters usable in distinguishing the istiophorid larvae more than 20 mm in standard length 



(from Ueyanagi, 1964). 



'This range is estimated from a small number of materials examined, so it seems to become somewhat wider with an increase of 

 materials. 

 2 Lateral line pattern is not yet ascertained. 



Beebe (1941) reported that they primarily eat 

 copepods. Voss (1953) identified the stomach contents 

 of his specimens and found predominantly copepods 

 and fish larvae. Gehringer (1956) also identified the 

 stomach contents of his specimens and his results are 

 shown in Table 4. 



In summary, sailfish less than 10 mm long generally 

 eat copepods, while fish larvae predominate in larger 

 sizes. 



3.3 Adult Phase 



3.31 Longevity 



De Sylva (1957) stated that natural mortality is un- 

 doubtedly high, pointing out that off Florida the sport 

 fishery is dependent upon 1- and 2-yr-old fish. Mather 

 et al. (1974) has recorded the recovery of a tagged 

 sailfish that was at liberty for more than 4 yr. The fish 



was estimated to weigh 21.3 kg when tagged, which 

 according to de Sylva would be about a 2-yr-old. This 

 specimen, therefore, was at least 6 yr old when recap- 

 tured. 



There is no information available for the Pacific or 

 Indian oceans, although Koto and Kodama (1962) 

 found that the growth rate of sailfish in the East 

 China Sea is similar to that of sailfish in the Atlantic. 



3.32 Hardiness 



Adult sailfish are probably adaptable to relatively 

 large changes in their environment and in their ability 

 to utilize different food items. 



3.33 Competitors 



Although sailfish probably compete with many of 

 the large pelagic scombridlike fishes for food and 



106 



