DISTRIBUTION OF THE BLUE AND IN THE INDO-PACIFIC

JAMES E. MORROW, JR. Bingham Oceanographic Laboratory, Yale University

ABSTRACT The distributions of blue marlin ( mazara) and black marlin (Istiompax indicus) (fishes, family Istiophoridae) are described, with detailed records of occurrences. The popular name, "Indo-Pacific blue marlin" is suggested for M. mazara. In the course of the last ten years, we have been fortunate in being able to examine fresh specimens of from most of the known centers of abundance of these fishes. Having recently returned from an expedition that took us completely around the world on this quest, it seems appropriate to publish a short note on the distribution of two . Istiompax indicus (Cuvier) Black marlin, Shirokajiki This species is well-known to anglers, who have taken it in the waters of New Zealand and Australia, off the west coast of South and Central America, and off the east coast of Africa. It is a common species in the oriental long-line fisheries of the central Pacific and along the coast of the Orient. We have examined 81 specimens and five photographs from th following localities. New Zealand (Bay of Tslands)-4; Peru-6; Ecuador-I; Central Pacific (no precise 10- cation)-9; 3°N, 171°W-l; 8°N, 169°E--l; lOoN, 1400E-16; 4"S, 132°E-I0; East coast of Celebes Island-2; Banda Sea-8; South of Taiwan-1; East coast of Taiwan-1; West coast of Taiwan -2; Off Trincomalee, Ceylon-I; East coast of Fadiffolu Atoll, Mal- dive Islands-I; Male Atoll, Maldive Islands-l (photograph); 4° to 5° N, 67° to 71°E-l; Seychelles Islands-l (dried head and pectoral fins); Muscat, Arabia-2 (1 stuffed specimen, 1 skeleton, in British Museum Natural History); West coast of Pemba Island-I; Zanzibar-l (partial skeleton in British Museum Natural History); Bazaruto, M09ambique-8; Mauritius-3, plus 4 photographs. It is thus apparent that I. indicus ranges through most of the temperate and tropical parts of the Indian and Pacific Oceans. The color of this species is quite variable, ranging, in dead speci- mens, from dark blue-black to nearly white. According to Nichols and LaMonte (1935), the pale color appears to be one of the chief diag- 322 Bulletin of Marine Science of the Gulf and Caribbean [9(3) nos tic characteristics of the silver marlin, their subspecies tahitiensis. However, LaMonte (1955) has expressed doubts as to the validity of this character and has suggested that it might be the result of glandular imbalance in individual cases. In the commercial markets of Misaki, Japan, and Kaohsiung, Taiwan, there were specimens of I. indicus of all sizes (60 to 1133 pounds dressed weight) and of all shades, from the "typical" dark blue-black to a pale dirty white. Japanese fishermen stated that this was a matter of individual variation, and that they considered all these fish to be the same species regardless of color. At Suo, Taiwan, two of the oldest fishermen gave accounts in more detail. In three languages, through two interpreters, the following information was obtained: "The fish are darker in the water, but become pale in a few hours and remain pale. They are slightly reddish in the water. If they are iced before rigor, they keep the reddish color. But if the fish is iced later, it becomes white." "Marlin further offshore are darker. Nearer shore, especially off estuaries, they are more greyish. After they are harpooned, the color becomes almost black. We club them to kill them, and then they im- mediately become the color of eggplant, which fades in about ten minutes." Personal observation of specimens of I. indicus taken on hook and line has shown that their color in the water ranges from pale blue with the appearance of a milky over-wash, to deep blue, almost black. Sometimes bright blue stripes are visible on the sides while the fish are in the water, but these have not been seen to persist after the fish has been brought into the boat. A specimen taken off Trincomalee, Ceylon appeared dark blue in the water, but changed to a beautiful deep bronze as it was drawn into the boat. The bronze color persisted for perhaps ten minutes. As the bronze disappeared, the sides turned whitish, the dorsum dark blue-black. Another individual, taken along the east side of Fadiffolu Atoll in the Maldive Islands, showed similar color changes, but faded in a matter of about eight hours to an almost uniform pale grey. On the basis of color, then, there seems to be no justification for retaining the subspecies tahitiensis.

Makaira mazara (Jordan and Snyder) Indo-Pacific blue marlin, Kurokajiki Eighty-two individuals and four photographs of this species have been studied, from the following locations: Australia-l (photo- 1959J Morrow: Distribution of Marlins 323 graph); New Zealand (Bay of Islands)--2 (photographs); Mimcora, Peru-I; Hawaii-l (photograph); Central Pacific (no precise loca- tion)-14; 3°S, 125°W-7; lOoN, 1700W-ll; 3°N, 171°_9; 8°N, 1700E-15; 8°N, 169°E-14; Off Arugam Bay, Ceylon-I; 40 to 5°N, 6r to 71°E-8; Bazaruto, Moc;ambique-l; Mauritius-I.· This species appears to occupy much the same range as does 1. indicus. Although long known to the Japanese and Chinese, and for twenty years or more to English-speaking sport fishermen, it is only recently that American ichthyologists have recognized this species. in the Pa- cific, while its presence in the Indian Ocean was noted only very re- cently. The occurrences at Ceylon, west of the Maldive Islands, at Moc;ambique, and at Mauritius are all first records for those areas. Several workers (Rivas, 1956; Royce, 1957) have considered the Atlantic and Indo-Pacific blue marlins to be identical, and indeed they cannot be distinguished on the basis of any external characters. How- ever, Morrow (1957) showed, on osteological evidence, that they are distinct. In that paper, the two forms were regarded as subspecies, but examination of more material indicates that each form should be given full specific rank. It is therefore appropriate to suggest popular, ver- nacular names. The Atlantic form, Makaira nigricans, has long been known as the "." Since Makaira mazara has now been shown to occur in both the Pacific and Indian Oceans, it is logical to follow the suggestion of Col. John K. Howard, and term this species the "Indo-Pacific blue marlin." It is a pleasure to acknowledge the generous support provided by Messrs. Wendell W. Anderson, Thomas Shevlin, Alfred C. Glassel!, Jr., and Col. Howard.

REFERENCES LAMONTE, FRANCESCA R. 1955. A review and revision of the marlins, genus Makaira. Bull. Amer. Mus. nat. Hist., 107 (3): 323-358. MORROW, JAMES E. 1957. On the morphology of the pectoral girdle in the genus Makaira. Bull. Bingham oceanogr. Coli., 76 (2): 88-105. NICHOLS, JOHN T. AND FRANCESCA R. LAMONTE 1935. The Tahitian black marlin, or silver marlin . Amer. Mus. Nov., 807: 2 pp, 1 pI. RIVAS, LUIS R. 1956. The occurrence and taxonomic relationships of the blue marlin (Ma- kaira ampla poey) in the Pacific Ocean. Bull. Mar. Sci. Gulf & Carib- bean, 6 (1): 59-73. ROYCE, WILLIAM F. 1957. Observations on the spearfishes of the central Pacific. Fish. Bull. 124, Fish. Bull. U. S. Fish Wildlife Serv., 57: 496-554.