~i i i — i — i — i — r 



CENTRAL 

 PACIFIC(o) 



"i — i — i — r 



SOUTH 

 _ ^--PACIFIC 



(1S°-25°S) 



\NORTH 

 PACIFIC 



Of- 35°N> 



EYE-FORK LENGTH (cmi 



Figure 10. — Comparison of pectoral fin of striped marlin 

 stocks in the Pacific Ocean. The shaded band represents 

 the area in which our data for the relations of eastern 

 Pacific fish fall. Data for South and North Pacific fish are 

 from Kamimura and Honma (1958). Data for central 

 Pacific fish are from Royce (1957). 



body depth, length of pectoral fin. length of pelvic 

 fin, and dorsal fin height are considerably shorter 

 on the average in fish from the eastern Pacific than 

 in fish of identical size from the Atlantic Ocean. 

 For striped marlin, our results indicated that 

 weight and maximum body depth can be used to 

 separate striped marlin stocks within our study area. 

 For example, a 180 cm long striped marlin landed off 

 San Diego is, on the average, about 19% heavier and 

 has a maximum body depth 3% greater than a striped 

 marlin of identical size landed off Buena Vista or 

 Mazatlan. Also, striped marlin from the northeastern 

 Pacific (lat. 20°-35°N) and South Pacific (lat. 

 18°-25°S), apparently can be separated on the basis of 

 length of pectoral fin. 



We conclude, therefore, that there are mor- 

 phometric characters that can be used to separate, 



with some degree of accuracy, sailfish and striped 

 marlin stocks. We suggest, however, that more 

 powerful techniques, such as multivariate analyses, 

 be used in future attempts of stock identification of 

 eastern Pacific billfishes. 



ACKNOWLEDGMENT 



We are grateful for the generous cooperation of 

 the staff and sportsmen at Rancho Buena Vista, the 

 Star Fleet in Mazatlan, and the San Diego Marlin 

 Club for permitting us to measure specimens. Larry 

 Coe, Dan Eilers. Douglas Evans, Maxwell El- 

 dridge, and David Tolhurst helped collect the data 

 and Brad Cowell assisted with data processing. 



LITERATURE CITED 



KAMIMURA. T.. and M. HONMA. 



1958. A population study of the so-called Makajiki (striped 

 marlin) of both northern and southern hemispheres of the 

 Pacific. I. Comparison of external characters. [In Jap., 

 Engl, summ] Rep. Nankai Fish. Res. Lab. 8:1-11. 

 KUME, S.. and J. JOSEPH. 



1969. Size composition and sexual maturity of billfish caught 

 by the Japanese longline fishery in the Pacific Ocean east 

 of 130°W. Japan. [In Engl.] Bull. Far Seas Fish. Res. 

 Lab. (Shimizu) 2:115-162. 

 MARTIN. W. R. 



1949. The mechanics of environmental control of body form 

 in fishes. Univ. Toronto Stud., Biol. Ser. 58, 91 p. 

 MORROW. J. E.. and S. J. HARBO. 



1969. A revision of the sailfish genus Istiophorus. Copeia 

 1969:34-44. 

 RIVAS. L. R. 



1956. Definitions and methods of measuring and counting in 

 the billfishes (Istiophoridae, Xiphiidae). Bull. Mar. Sci. 

 GulfCaribb. 6:18-27. 



ROYCE, W. F. 



1957. Observations on the spearfishes of the central Pacific. 

 U.S. Fish Wildl. Serv., Fish. Bull. 57:497-554. 



STRASBURG. D. W. 



1969. Billfishes of the central Pacific Ocean. U.S. Fish 

 Wildl. Serv.. Circ. 311. 11 p. 



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