TOLL and HESS: CEPHALOPODS IN DIET OF SWORDFISH 



prey studies by nonteuthologists has prompted the 

 writers to begin work on a guide to identification 

 of cephalopod remains from predatory species. 



Buccal masses were dissected from identified 

 squid remains and retained for future examina- 

 tion of mandibles. Estimates of the number 

 of cephalopods were based solely on soft-tissue 

 remains. Unassociated hard structures such 

 as free mandibles, lenses, and gladii often were 

 encountered in large numbers suggesting ex- 

 tended residence within the stomach. Therefore, 

 inventories of those remains were not utilized in 

 determining total numbers of cephalopod prey. 



An attempt was made to assess the vertical 

 migratory behavior of swordfish based on known 

 bathymetric distribution of their squid prey. 

 Other aspects of swordfish feeding ecology were 

 examined using fishing depth and hookup time, as 

 well as sex and size of swordfish specimens. 



RESULTS 



Tables 1 and 2 present frequencies and bio- 

 masses of prey in stomachs of 65 swordfish. 

 Cephalopods were the most important component, 

 both in numbers and weight. Fish remains were of 

 secondary importance, followed by crustaceans 

 (shrimp). Figures 1-3 depict frequency of occur- 

 rence of each group. Cephalopods composed over 

 909c of the contents by weight in 68% of 

 the stomachs examined. Only 9% of the stomachs 

 contained <50% cephalopod remains. Fish re- 

 mains accounted for >50% of contents in only 11% 

 of the stomachs. Fish remains were ^10% of total 

 remains in 69% of all stomachs. Shrimp remains 

 were found in only 9% of the stomachs, accounting 

 for 8% by weight in one stomach and <3% in all 

 other instances. Weights of stomach contents are 

 conservative because swordfish are known 

 to occasionally regurgitate or even evert their 

 stomach when captured (Tibbo et al. 1961). 



Cephalopod remains were found to include the 

 following species: 



Class: Cephalopoda Cuvier 1798 

 Subclass: Coleoidea Bather 1888 

 Order: Teuthoidea Naef 1916 



Suborder: Oegopsida Orbigny 1845 

 Family: Enoploteuthidae Pfeffer 1900 

 Subfamily: Ancistrocheirinae Pfeffer 

 1912 

 Genus: Ancistrocheirus Gray 1849 



Species: A. lesueuri (Orbigny 

 1839) 

 Family: Onychoteuthidae Gray 1849 

 Genus: Onychoteuthis Lichtenstein 

 1818 



Species: O. banksii (Leach 1817) 

 Family: Lepidoteuthidae Naef 1912 



Genus: Tetronychoteuthis Pfeffer 

 1900 



Species: T. massyae Pfeffer 1912 

 Family: Architeuthidae Pfeffer 1900 



Genus: Architeuthis Steenstrup 

 1857 



Species: Architeuthis sp. 

 Family: Histioteuthidae Verrill 1881 

 Genus: Histioteuthis Orbigny 1841 

 Species: H. dofleini (Pfeffer 1912) 

 Histioteuthis sp. 

 Family: Ctenopterygidae Grimpe 1922 

 Genus: Ctenopteryx Appellof 1899 

 Species: C. sicula (Verany 1851) 

 Family: Ommastrephidae Steenstrup 

 1857 



Subfamily: Ommastrephinae Steen- 

 strup 1857 



Genus: Ommastrephes Orbigny 1835 

 Species: O. pteropus Steenstrup 

 1855 

 Genus: Ornithoteuthis Okada 1927 

 Species: O. antillarum (Adam 

 1957) 

 Subfamily: Illicinae Posselt 1890 

 Genus: Illex Steenstrup 1880 

 Species: /. coindetii ? (Verany 

 1837) 

 /. oxygonius Roper, Lu, 



and Mangold 1969 

 /. illecebrosus ? Lesueur 

 1821 

 Family: Thysanoteuthidae Keferstein 

 1866 

 Genus: Thysanoteuthis Troschel 

 1857 



Species: T. rhombus Troschel 1857 

 Family: Cranchiidae Prosch 1849 

 Subfamily: Cranchiinae Prosch 1849 

 Genus: Cranchia Leach 1817 

 Species: C. scabra Leach 1817 

 Order: Octopoda Leach 1818 

 Suborder: Incirrata Grimpe 1916 

 Family: Bolitaenidae Chun 1911 

 Genus: Japetella Hoyle 1885 

 Species: J. diaphana Hoyle 1885 



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