of the location of snout in terms of the center of 

 eyes. In [/. platyptenis], the center of eyes is 

 above the tip of snout, while in [T. aiiclax]. they 

 are on a nearly same level. 



"Separation of [M. indica] from [M. mazcira] can 

 be made on the basis of the form of the pectoral 

 fin. 



"(4) Larvae over 20 mm in length: On top of the 

 criteria of Table [2], the following characters, as 

 listed in Table [3], can be applied."" 



Ueyanagi has assumed for the identification of 

 Atlantic specimens that M . nigricans will resemble 

 M. niazara. T . pjliiegeri will resemble T. angiistiros- 

 tris, and T. albidiis will resemble T. audax. In his 

 1959 paper he tentatively identified Gehringer"s 

 (1956) unidentified specimens as blue marlin and 

 some of his sailfish specimens as white marlin be- 

 cause Gehringer's illustrations resembled Pacific 

 blue marlin and striped marlin. 



EVALUATION OF 

 IDENTIFICATION METHODS 



The basic problem with the identification 

 methods used for these young fishes is that only one 

 character is used and this character is poorly sub- 

 stantiated with other characters. For example, 

 when examining Ueyanagi's tables of diagnostic 

 characters for larvae less than 5 mm in length 

 (Table 2), only one character separates each of the 

 five species considered — spearfish has branchios- 

 tegal pigment, striped marlin has the tip of the snout 

 and center of eye on the same plane, etc.: other- 

 wise, they have the other characters in common. In 

 larvae between 5 and 10 mm, relative snout length is 

 used since sailfish have a relatively long snout, blue 

 marlin a relatively short snout, and spearfish a 

 snout of intermediate length. For larvae between 10 

 and 20 mm in length the snout length and snout 

 shape are slightly more reliable. With larvae over 20 



Table 2. — Summary of the prominent diagnostic characters of istiophorid larvae less than 5 

 mm in length modified from Ueyanagi (1964). 



66 



