Table 3. — List of fish species and families identified in 

 swordfish stomachs, showing total volume (cc) of each 

 for 1971 samples. 



Fish Total volume 



Scombridae (Mackerels) 



Scomber scombrus (Atlantic mackerel) 18.110 



Paralepididae (Barracudinas) 10.017 



Scorpaenidae (Scorpionfishes) 



Sebastes marinus (Redfish) 7.355 



Myctophidae (Lanternfishes) 3,802 



Gadidae (Cods) 



Merlucchts bilinearis (Silver hake) 3,485 



Alepisauridae (Lancetfishes) 



Alepisaurus ferox (Longnose lancetfish) 1,365 



Stromateidae (Butterfishes) 



Centrolophus niger (Black ruff) 1.005 



Balistidae (Triggerfishes and Filefishes) 455 



Evermannellidae (Saber-toothed fishes) 198 



Malacosteidae (Loosejaws) 



Malacosteus niger (Loosejaw) 160 



Carangidae (Jacks and Pompanos) 100 



Nemichthyidae (Snipe eels) 



Nemichthys scolopaceous (Slender snipe eel) 97 



Stomiatidae (Scaled dragonfishes) 



Stomias boa ferox (Boa dragonfish) 40 



Gempylidae (Snake mackerels) 



Nealotus tripes 40 



Scomberesocidae (Sauries) 



Scomberesox saurtis (Atlantic saury) 16 



Gonostomatidae (Anglemouths) 



Maurolicus muelleri (Miiller's pearlsides) 2 



Unidentified fishes 4,219 



Total 50.466 



tophum punctatum, Notoscopelus kroyeri, and 

 Benthosema glaciate. A total of 441 individual myc- 

 tophids was eaten by swordfish of all sizes and as 

 many as 80 taken from a single stomach. 



Silver hake (M. bilinearis) occurred in three of 

 four samples and is considered to be the fifth of the 

 five groups of primary importance. As noted previ- 

 ously, it did not appear in the Grand Bank sample 

 but did occur in samples from the Scotian Banks, 

 where silver hake is more common. 



The remaining 1 1 families of fishes (Table 3) found 

 occasionally in the stomachs are of unknown impor- 

 tance in the swordfish diet. One of these, the saber- 

 toothed fishes, family Evermannellidae, is of in- 

 terest because it occurred in all four samples, a total 

 of 17 individuals, yet the family has not previously 

 been reported from the area. The black ruff, Cen- 

 trolophus niger, family Stromateidae, although re- 

 ported from this region of the Northwest Atlantic 

 (Templeman and Haedrich, 1966), has not previ- 

 ously been found in swordfish stomachs. 



Squid 



The short-finned squid (I. illecebrosus), like the 

 barracudinas and myctophids, is eaten by swordfish 

 of all sizes. As many as 27 pairs of squid beaks were 

 found in single stomachs. On the average, more 

 squid were found in stomachs of swordfish caught on 

 Grand Bank and Banquereau than to the west and 

 south. 



most important single fish group recorded, except 

 mackerel, and made up 20% of the fish diet. They 

 occurred in samples from three stations, to as many 

 as 78 individuals in a single stomach. More bar- 

 racudinas (781) were eaten by swordfish of all sizes 

 than any other fish species. Many were slashed. 

 White barracudina (Notolepis rissoi) was the princi- 

 pal species involved but the short barracudina 

 (Paralepis atlantica) was also identified. However, 

 identification to species is exceedingly difficult with 

 mutilated remains. 



Redfish (5. marinus) was second in importance in 

 terms of total volume eaten but was obviously of 

 local or regional significance since it occurred only in 

 Grand Bank and Western Bank samples. Also, red- 

 fish appear to be eaten mainly by larger (over 160 cm 

 total length) swordfish. 



Lanternfishes. family Myctophidae, were next in 

 importance, occurring in three of four samples, and 

 were represented by at least three species, Myc- 



SUMMARY 



Species of primary importance in the swordfish 

 diet were squid (/. illecebrosus), mackerelfS. scom- 

 brus), barracudinas (family Paralepididae), redfish 

 (S. marinus), lanternfishes (family Myctophidae), 

 and silver hake (M. bilinearis). Fishes contributed 

 greater volume to the diet than squid, the percentage 

 contribution ranging from 78.7% to 94.0%. The vol- 

 ume of squid in stomachs was higher in samples from 

 the Grand Bank region than elsewhere. The total 

 volume of food in stomachs increased with increase 

 in size of swordfish. 



The species of fishes eaten varied with the feeding 

 area but the number of species increased south- 

 westward. Barracudinas were the most important 

 fish group, except mackerel, in all areas. The role of 

 mackerel in the natural diet is obscure because it was 

 used as bait. 



Specimens of the saber-toothed fishes, family 



140 





