524 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Istiompax marlina (Jordan and Hill) 



Black Marlin 



Shirokajiki "White Marlin" (Japan); Silver 

 Marlin (Hawaii) 



Distinguishing characteristics 



Nakamura (1938) has described the anatomical 

 differences between marlina on the one hand and 

 Makaira audax and M. ampla on the other, which 

 differences were subsequently used by Hirasaka 

 and Nakamura (1947) to propose the genus 

 Marlina. The principal differences are that (1) 

 the shoulder girdle in marlina is considerably 

 broader than in the other species, and the articula- 

 tion with the pectoral fin restricts its movement; 

 (2) the pelvic girdle in marlina has the two sides 

 fused together and difficult to separate, whereas 

 in the other two species the two sides of the girdle 

 are separated by a broad space and they can be 

 easily separated; and (3) the air bladder in 

 marlina consists of several layers of small cham- 

 bers, whereas it has only a single layer of chambers 

 in ampla and audax. 



We believe the differences noted here warrant 

 the retention of marlina in a separate genus; 

 however, the generic name Marlina cannot be 

 applied to this genus. In the first place, its use 

 is prevented by Zane Grey's introduction of the 

 name Marlina mitsukurii in 1928. Since he used 

 the name solely in this combination and prior to 

 1928 when such a proposal was permitted, 

 mitsukurii is the haplotype of Marlina Grey. In 

 the second place, Whitley (1931:18) proposed the 

 genus Istiompax for /. australis, new species, 

 recognized as a synonym of Makiara marlina 

 Jordan and Hill. Therefore, the generic name 

 Istiompax has precedence over Marlina Hirasaka 

 and Nakamura (nan Grey) . 



The most distinctive external characters of 

 marlina, in addition to the rigid pectoral, are the 

 short ventral fins which range in length from 

 18 to 31 cm., with an average of 26 in our speci- 

 mens, and the very low first dorsal, which in its 

 anterior lobe averages about 60 percent of the 

 greatest body depth, but may range from 50 to 

 80 percent. Many other subtle differences aid in 

 recognizing marlina at a glance. The body seems 

 compressed more than in ampla, and it appears 

 markedly heavier in the pectoral region than 



either audax or ampla because of the larger hump 

 on the back. Although marlina has been reported 

 by Nakamura to differ from ampla by having a 

 single, simple lateral line, the lateral fine is a poor 

 field character because it is difficult to see in fresh 

 specimens. 



Marlina and ampla are the only marlins that 

 appear to surpass 1,000 pounds in weight. When 

 near this size, marlina is readily distinguishable 

 because the lower jaw from tip to corner of the 

 mouth is at least half the length of the snout from 

 tip to orbit. In ampla the lower jaw recedes with 

 growth, and in very large specimens the snout has 

 the appearance of being much longer and more 

 slender than in marlina. 



The name marlina may lack priority if adequate 

 descriptions of marlins from the type localities 

 of Tetrapturus herscheli Gray (South Africa), or 

 Histiophorus breinrostris Playfair (Zanzibar) be- 

 come available. Gray's (1838) description of 

 herscheli agrees well with marlina in most char- 

 acters. In sizes estimated from his figure (pi. X), 

 the relation of the height of the anterior lobe of 

 the first dorsal to the fork length (13 percent), 

 the height of the first anal to the height of the 

 first dorsal (77 percent), the length of the ventral 

 fins (23 cm.), all agree with our measurements of 

 marlina. The height of the 20th ray of the first 

 dorsal (9 cm.) is slightly greater in herscheli than 

 marlina but the difference is not unreasonable if 

 we assume that the fin slot in herscheli may have 

 shrunk during preservation. The relation of the 

 height of the first dorsal to body depth in herscheli 

 is not like marlina, but the drawing is from a 

 stuffed specimen which may have been distorted. 

 Playf air's (1866) description of brevirostris could 

 also have been taken from a slender marlina. The 

 height of first dorsal, color, and length of pelvic 

 fin, all fit marlina but the body depth is comparable 

 to that of audax. We do not suggest changing 

 the name marlina, however, until better evidence 

 is available. 

 Color 



The name "white marlin," a literal translation 

 of the Japanese, shirokajiki, probably arises from 

 the appearance of the fish — sometimes a milky 

 white when freshly hooked. We have been amazed 

 at the whiteness of some of these huge fish as they 

 swam near the boat before they had fought hard 

 on the line. When near death and immediately 

 after death the milkiness is replaced by shades of 



