body is elongated (the body length is about 5.9-7.3 times the 

 body depth) and is rather thick. The snout is long (the head 

 length is about 0.88-0.99 times the length of the maxillary), and 

 its cross-section is almost round. The body is densely covered 

 with scales; the tips of the scales are pointed. Scales from 

 specimens less than 1 meter in length do not have this species 

 characteristic. There are small file-shaped teeth on both jaws 

 and on the palate. The lateral lines on the sides curve over the 

 pectoral fin and then continue in a straight line to the area of the 

 caudal fin. The head is large (the body length is 3.6-3.8 times 

 the length of the head). The eyes are moderately large. There is 

 a relatively conspicuous crest on the outer edge of the head 

 between the pre-occular region and the origin of the first dorsal 

 fin. There are 2 scutes on each side of the tail near the caudal 

 peduncle; the tail is strong and deeply forked. The pectoral fin, 

 has a pointed tip and is located rather low on the body; it is 

 shorter than the head (the head length is about 1.14-1.99 times 

 the length of the pectoral fin). The first dorsal fin begins above 

 the posterior end of the pre-opercle bone; its first few rays are 

 larger than the body depth, but as it progresses towards the 

 back, it gradually becomes shorter, ending just in front of the 

 origin of the second dorsal fin. The tip of the first anal fin is 

 pointed, large and sickle-shaped. The second dorsal fin and the 

 second anal fin are about the same size and shape. The latter is 

 located a little further forward on the body than the former. In 

 spite of the fact that the ventral fin is longer than the pectoral 

 fin in smaller specimens, the opposite is true for larger 

 specimens. The fin membrane of the first dorsal fin is dark blue. 

 The back of the body is dark blue with splotches of black on it; 

 towards the ventral side of the body, 10 or more rows of cobalt- 

 colored stripes are clearly visible. The other fins are blackish 

 brown, or sometimes a dark blue. The bases of the first and se- 

 cond anal fins are silvery-white. 



Morrow (1952a) published morphometric data on 

 49 specimens from New Zealand and later (Morrow, 

 1957) published extensive morphometric data and 

 anal ray counts on 39 fish from Peru. These data in- 

 clude standard length as the basic body length 

 measurement. Ueyanagi (1957b) presented 

 morphometric data on young specimens, 80- to 180- 

 cm eye-fork length, from the western North Pacific. 

 Royce (1957) reported extensive morphometric data of 

 25 specimens from the central Pacific using fork 

 length as the basic measurement but also giving stan- 

 dard length and eye-fork lengths for some specimens. 

 He also published more limited data on 30 specimens 

 measured by the Hawaii Division of Fish and Game. 

 Kamimura and Honma (1958) published 

 morphometric data on five characters using eye-fork 

 length as the basic body measure for 56 fish south of 

 the equator and 124 fish north of the equator in the 

 western Pacific. Williams (1967) presented dorsal and 

 anal fin ray counts of 13 specimens from East Africa. 

 Merrett (1971) gives fin measurements on about 23 

 other specimens. 



Counts have been given by several authors and are 

 shown in Table 1. 



Georgraphic variation: Geographic variation 

 appears to be considerable. Morrow (1957) concluded 

 that striped marlin from Peru and northern New 



Zealand represented separate and distinct pop- 

 ulations based on significant differences in 11 

 morphometric and meristic characters as follows: 

 average absolute lengths of pelvic fins, counts of 

 spines and rays in the first anal fin, and the 

 regressions of the following measurements on stan- 

 dard length: greatest body depth, length of base of 

 second dorsal fin, length of base of first anal fin, 

 width of base of pectoral fin, snout tip to origin of first 

 dorsal fin, snout tip to origin of second dorsal fin, 

 snout tip to origin of first anal fin, snout tip to pos- 

 terior edge of operculum, snout tip to posterior end 

 of maxillary. By a character index (CI) in which 



CI = 



pelvic length 

 10 



100 

 SL 



(Depth + Length 



of anal base + Width of pectoral base), Morrow 

 could separate correctly about 72% of the 69 speci- 

 mens from which the index was derived. The New 

 Zealand specimens tended to have character indices 

 of considerably lower numerical value than the Peru 

 specimens. 



In the western Pacific (west of long. 170°W) 

 Kamimura and Honma (1958) found a remarkable 

 difference in the lengths of the pectoral fins between 

 northern (lat. 30°-35°N) and southern (lat. 18°-25°S) 

 striped marlin. Covariance analysis of regression of 

 pectoral fin on eye-fork length showed no significant 

 difference in slope of regression but a highly signifi- 

 cant (0.01) difference in adjusted means. Also signifi- 

 cant differences (0.05) were found for both regression 

 coefficients and adjusted means for regressions of eye- 

 to insertion of second dorsal on eye-fork length. From 

 these differences these authors concluded northern 

 and southern populations in the western Pacific were 

 extremely separated. In intermediate waters of the 

 northern hemisphere (lat. 5°-25°N) all but three fish 

 had pectoral lengths clustered about the regression 

 line for the northern population. The pectoral lengths 

 of the other three fish, which were taken from lat. 5° 

 to 15°N, were close to the regression line for the 

 southern population and were presumed to have 

 strayed from that population. 



Honma and Kamimura (1958) supported the 

 hypothesis of separate north and south populations in 

 the western Pacific with the following observations: 



a) a zone of low hook-rate along the equator sepa- 



rates the populations; 



b) the main spawning grounds are widely separated 



and spawning seasons are a half-year apart; 



c) the maximum size attained is much larger in the 



southern population; 



d) adaptations of the two populations to environ- 



mental circumstances do not coincide in de- 

 tails, differing with growth stages. 



Howard and Ueyanagi (1965) extended the 



134 



