Table 4. — Stomach contents of specimens from Theodore N. 

 Gill collections (from Gehringer, 1956). 



Size offish 

 (mm) 



Contents 



3.9 5 copepods 



5.4 Parts of 9 copepods 



6.0 3 copepods; parts of 7 copepods 



6.0 7 copepods; parts of 1 fish larva 



9.4 2 copepods; parts of 3 fish larvae (heads 1.4 mm) 



'10.1 1 fish larva, 2 4.2 mm 



10.1 1 copepod; part of 1 fish larva 



'10.3 1 fish larva, 2 4.8 mm 



'10.3 1 fish larva, 6.0 mm; part of 1 fish larva 2 



'10.8 4 fish larvae, 2 approximately 5.4 mm 



'11.3 Part of 1 fish larva (head, 3.0 mm) 



'11.4 1 fish larva, 2 6.6 mm; piece of another fish larva 



'12.3 1 copepod; part of 1 unidentified crustacean; 



1 fish larva, 2 5.1 mm; part of 1 fish larva 



'12.8 1 fish larva, 2 7.2 mm 



12.8 4 flying fish larvae, 4.8 to 6.0 mm; head of 



1 fish larva 



'13.0 2 copepods; 1 istiophorid larva, 6.0 mm 



13.0 1 flying fish larva, 4.8 mm; parts of 2 other 



fish, one approximately 6.0 mm 



'13.9 1 flying fish larva, 5.1 mm; 1 fish larva, 2 7.2 mm 



14.6 Part of 1 fish larva (head, 2.1 mm) 



15.3 3 flying fish larvae, 3.6 mm; parts of 2 flying 



fish larvae 



16.2 1 istiophorid larva (head, 2.4 mm) 



16.9 Part of 1 fish larva (head, 1.8 mm) 

 16.9 1 fish larva, 8.4 mm 



17.8 3 fish larvae, 3.0 mm, 3.6 mm, and 7.2 mm 

 18.2 1 thin fish larva, 11.4 mm; part offish larva 



20.9 Parts of fish larva 



'21.0 1 istiophorid larva, 10.2 mm 



27.4 Parts of fish larva 

 '34.5 Parts of fish larvae 



38.8 8 flying fish larvae, 4.8 to 8.7 mm; 2 fish larvae, 



6.3 mm. and 6.6 mm; parts of 3 fish larvae 



'45.0 Parts of fish larvae 



'45.0 Parts of fish larvae 



'Unidentified species. 



2 A11 fish listed under footnote 2 appear to be identical, and un- 

 less otherwise noted, measurements given are of standard lengths. 



spawning areas, it is likely that they are relatively un- 

 affected by this competition. Among the billfishes, 

 sailfish and black marlin, Makaira indica, are the 

 dominant inshore species in the Pacific (Howard and 

 Ueyanagi, 1965) and undoubtedly compete for food 

 and living space, although black marlin probably 

 utilize larger food items than do sailfish. Royce (1957) 

 examined 11 black marlin captured in the Pacific and 

 found fishes weighing up to 18 kg in the stomach con- 

 tents as well as remains from other fishes which were 

 probably too large for a sailfish to consume. 

 Dissimilarities in distribution are evident between 

 sailfish and some of the other billfishes. Kume and 

 Joseph (1969a), for example, showed that the centers 



of abundance of the shortbill spearfish, Tetrapturus 

 angustirostris, and the sailfish in the eastern Pacific 

 are widely separated. The shortbill spearfish did not 

 occur in the catches of research vessels fishing within 

 370-550 km of the coast while the majority of the 

 sailfish were caught within this limit. 



Williams (1967) noted that, "... in East Africa 

 longline catches of striped marlin were high and of 

 sailfish low, whereas the sport fishery catches of 

 striped marlin were low and of sailfish very high." 

 Williams suggested that this was partly due to the 

 different habits of the two species. Similar results 

 were obtained by Merrett (1968a, 1971) from the same 

 area, indicating that the sailfish was the most coastal 

 of the five istiophorid species present in the equatorial 

 western Indian Ocean. 



In the Atlantic, however, Wise and Davis (1973) 

 showed that during certain seasons of the year, 

 centers of sailfish abundance coincide with centers of 

 white marlin, T. albidus, and blue marlin, M. 

 nigricans, abundance. Fox (1971) also indicated that 

 sailfish and blue marlin distributions show a strong 

 overlap. 



3.34 Predators 



There is little information about predation on adult 

 sailfish. Baughman (1941a) reported on the sighting 

 by another observer of a school of bottlenose porpoise, 

 Tursiops truncatus, attacking and apparently con- 

 suming an adult sailfish in the Gulf of Mexico. Maeda 

 (1967) stated that killer whales attack "marlins," a 

 category which undoubedly includes sailfish. He add- 

 ed, however, that "marlins" are probably not preyed 

 upon to any great extent. Merrett (1968a) commented 

 that shark attacks on fishes hooked on longline gear 

 are well known, but predation on free-swimming 

 tunas and billfishes would be considerably less. 



3.35 Parasites, diseases, injuries, and abnor- 

 malities 



Silas (1967) and Silas and Ummerkutty (1967) sum- 

 marized previous accounts of parasites of scombroid 

 fishes (Table 5). Williams (1967) stated that he found 

 thousands of euryphorids (copepods, Caligoidea) up 

 to 10 mm in length on the skin of sailfish near the 

 head and caudal areas. He also recorded a heavy in- 

 festation of ascarid nematodes in the stomach of one 

 specimen. Ward (1954) listed the helminth parasites 

 Bothriocephalus manubriformis (Linton), Con- 

 tracaecum histiophori Yamaguti, and Hirudinella 

 marina Garcin as occurring in the viscera of sailfish 

 from Florida waters. Jones (1971) reported on crater 

 wounds caused by the squaloid shark, Isistius 

 brasiliensis, in istiophorids. 



Billfish are often found with portions of their bill 

 broken off. Marlins and swordfish have been reported 

 as attacking vessels and burying their bills in wooden 

 planking. Sailfish, however, are apparently not as 



107 



