Table 2. — Trophic relationships between epipelagic predatory fishes of the 



tropical waters. 



NOTE: Reading across the table, the relationships between each group of pre- 

 dators are seen (C - competitor; E - enemy; V - victim). The groups are 

 numbered uniformly in the rows and columns. 



Source: Parin, 1968, Table 13. 



3.33 Competitors 



White marlin compete with the tunas, large 

 marlins, sharks, and to some degree with lancetfishes 

 and are victimized by larger billfish and sharks 

 (Parin, 1968) (Table 2). 



Fox (1971) indicates from the Japanese longline 

 data that white marlin distributions overlap strongly 

 with those of yellowfin tuna, Thunnus albacares, and 

 blue marlin, Makaira nigricans. Wise and Davis 

 (1973) show that during certain seasons of the year 

 centers of white marlin abundance coincide with 

 those of blue marlin and sailfish, Istiophorus 

 platypterus, abundance. During the summer, adult 

 white marlin and small (2-50 kg) bluefin tuna, are 

 both abundant off the U.S. coast between Cape 

 Hatteras and Cape Cod (Farrington, 1949a). Since 

 both of these fishes feed largely on small schooling 

 fishes and squid, they must compete with each other 

 considerably. 



3.34 Predators 



Very little is known about the predation on white 

 marlin. It must be presumed that members of the 

 shark families prey on this species at one time or 

 another. When fighting white marlin on rod and reel 

 the senior author has noted the presence of mako 

 sharks, Isurus oxyrinchus. No documented evidence 

 of actual attacks on white marlin are available 

 however, although Poey (1861) described marlin on a 

 fisherman's line as becoming furious at the approach 

 of its natural enemy the shark and receiving frightful 

 wounds from its adversary. 



Maeda (1967) observed the killer whale, Orcinus or- 

 ca, attacking marlin but added that such instances 

 were probably rare since meetings of the two species 

 were most likely infrequent. 



3.35 Parasites, diseases, injuries, and abnor- 

 malities 



Parasites and diseases: Records of parasite infestation 

 and disease problems in white marlin are minimal. 

 Although both problems are likely to occur in this 

 species, few exact classifications of them have been 

 made. 



Nikolayeva and Ezpeleta (1966) examined four 

 white marlin from the Gulf of Mexico and found from 

 597 to 6,833 specimens of parasites per fish. Of the fish 

 examined, all had members of the parasite groups 

 Cestoidea, Trematoda, Nematoda, and Crustacea; 

 three had members of Monogenoidea; and only one 

 had representatives of Sporozoa and Acanthocephala. 

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

 marized the known species of trematodes, cestodes, 

 and parasitic copepods found in or on white marlin 

 (Table 3). Jones (1971) mentioned reports of crater 

 wounds caused by the squaloid shark, Isistius 

 brasiliensis, on various species of marlins. 



Injuries and abnormalities: A common injury to the 

 white marlin is the loss of part or most of its bill. The 



Table 3.— Parasites found on white marlin. 



Locality 



Parasite 



Location 

 on host 



Monogenetic trematodes (Silas, 1967): 



N.W.Atlantic Capsaloides cornuatus (Verrill) On body 



N.W. Atlantic Capsala laevis (Verrill) 

 Cestodes (Silas, 1967): 



N.W. Atlantic Bothriocephalus manubriformis 



(Linton) Intestine 



Copepods (Silas and Ummerkutty, 1967): 



W. Atlantic Gloiopotes ornatus (Wilson) On body 



72 



