FISHERY BULLETIN: VOL. 80, NO. 2 



Table 7. — Summary of stomach analyses of planktivorous sizes of Astronesthes indicus and Thysanactis dentex. 

 For large prey types, the range of relative lengths in percentage of predator length is given in parentheses after 

 the count. Data for larger fishes of both species are in Table 6. 



Idiacanthidae 



All sizes of Idiacanthus fasciola had eaten fish 

 nearly exclusively (Table 6). Of the 23 fish, 15 

 were myctophids of at least 5 genera (Bolinich- 

 thys, Ceratoscopelus, Diaphus, Lamp any ctus, 

 and Triphoturus). Only one of the others, possibly 

 a stomiatoid, was definitely not a myctophid. The 

 largest prey of all sizes of /. fasciola were about 

 20% of the predator's length, but the minimum 

 and average relative size of prey were somewhat 

 higher in the small /. fasciola. The only two crus- 

 taceans found were intact, but neither appeared 

 to have been very recently ingested. No crusta- 

 cean remains were found, and the two intact 

 crustaceans were smaller than all (substantially 

 smaller than most) of the fishes eaten. Two other, 

 smaller items — a pyroosome and a copepod — 

 found in /. fasciola were not counted because 

 they showed no sign of digestion or compression. 

 Thus /. fasciola must have occasionally fed in the 

 net and may have ingested the crustaceans there. 

 Whatever the case, crustaceans are certainly a 

 very minor part of the diet. 



Melanostomiatidae 



Thysanactis dentex under 120 mm SL had 

 eaten zooplankton as well as large prey (Table 7). 

 The 43-90 mm size group had eaten small eu- 



phausiids — mostly Thysanopoda aequalis 11- 

 19% of their length— and large, pigmented cope- 

 pods — mostly Pleuromamma xiphias; however, 

 several relatively larger (15-36% of SL) fishes, 

 Thysanopoda spp., and sergestids were also 

 found. Fish 91-120 mm had eaten copepods and 

 small euphausiids much less frequently; the bulk 

 of the diet was relatively large fish and crusta- 

 ceans. With the exception of a single isopod, the 

 items and remains from fish >120 mm (Table 6) 

 included only relatively large prey: other fishes, 

 a large Thysanopoda spp., and two sergestids. Of 

 the 24 intact fishes from all sizes of Thysanactis 

 dentex, 9 were definitely myctophids of at least 5 

 different genera (Bolinichthys, Diaphus, Diogen- 

 ichthys, Lampadena, and Triphoturus), and 11 

 were definitely of other families, including 6 

 Bregmaceros spp. and 2 Melamphaes spp. Most of 

 the high values of relative size were for the slen- 

 der Bregmaceros spp. The three B. japonicus 

 from the 91-120 mm SL Thysanactis dentex were 

 45-53% compared with 11-28% for the remaining 

 fishes and large crustaceans. Among the prey 

 from T dentex, over 120 mm SL, the three Breg- 

 maceros sp. (c.f. B. macclellandi) ranged from 39 

 to 42%, while with the exception of an unidenti- 

 fied fish at 48%, the remaining fish prey were 14- 

 32%. 



There were approximately 30 species of Eu- 

 stomias in the collections, many of them either 



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