FISHERY BULLETIN: VOL. 80. NO. 2 



over 50% in several cases. The only crustacean 

 found was a partially digested penaeidean 

 shrimp, together with a myctophid, in a large 

 Photonectes sp. 



Malacosteidae 



Only 24 items were found in the 100 Malacos- 

 teusniger examined (Table 8). The most frequent 

 items were copepods; these included some small 

 harpacticoids, but most were large aetideids or 

 scolecithridids. Similar-sized Pleuromamma 

 xiphias were conspicuously absent. Two fish (86 

 and 93 mm SL) had eaten somewhat larger prey, 

 and remains of relatively large prey were found 

 only in the three largest fish examined. The inci- 

 dence of intact prey was much lower in the larger 

 of the two size groups. 



As indicated in Clarke (1974), two species of 

 Photostomias occur near Hawaii; neither is iden- 

 tical with P. guernei, the only presently recog- 

 nized species. The form designated species 1 here 

 matures at about 60 mm SL and grows to ca. 100 

 mm SL, while species 2 matures at about 120 mm 

 SL and grows to >150 mm SL. Individuals less 

 than ca. 50 mm SL cannot be reliably separated. 

 The data given in Table 6 are limited to speci- 

 mens that were analyzed after I had learned to 

 separate the species as well as possible; the text 

 below, however, also includes prey identifica- 

 tions and relative sizes from 54 other specimens 

 from earlier collections. These 54 specimens 

 were no longer conveniently available to me after 



Table 8.— Summary of stomach analyses of Malacosteus niger 

 with list of all items and remains found. 



% undamaged specimens 



Size (SL, mm) 



No. examined 

 (damaged) 



Empty 



Remains 

 only 



Intact 

 items 



24-90 44(3) 71 2 27 



91-188 56(0) 88 4 9 



SL — items or remains: 



30 Undeuchaeta plumosa 



37 Candacia longimana, Chirundina streets/, aetideid CV, cope- 

 pod remains 



61 Undeuchaeta major 



70 Oncaea sp 



70 remains of 3-4 copepods 



71 2 C. streets/, 2 U. major, Euchirella curticauda 



80 2 C. streetsi, U. plumosa, Lophothrix sp. 



81 aetideid CV 



84 Oncaea sp. 



85 Oncaea sp 



86 Lophothrix sp., Euphausia hemigibba, myctophid (10 mm SL) 



87 Sapphirina sp. 



93 Nematoscelis tenella 



96 Amallothrix sp. 



97 Euchirella sp.. remains Scaphocalanus sp. 

 101 Corycaeus sp 



110 Thysanopoda sp. remains 



111 Gaetanus kruppi, fish remains 

 188 fish remains 



I had learned to separate the species, and could 

 not be identified with certainty from notes taken 

 at the time of examination. 



Both species ate crustaceans exclusively, and 

 with few exceptions the prey and identifiable re- 

 mains were sergestid shrimps, mostly small Ser- 

 gestes spp. Two large individuals of species 2 had 

 eaten Gennadas spp., and an unidentified small 

 specimen had eaten a Nematobrachion, the only 

 euphausiid found. Aside from the Gennadas 

 occurring only in species 2, there was no evidence 

 of difference in diet between the two species. Ex- 

 cept for a juvenile shrimp eaten by a small fish, 

 relative length of prey was 15-42% of SL with a 

 median of 28.5%. 



DISCUSSION 



Vinciguerria nimbaria, V. poweriae, Valenci- 

 ennellus tripunctulatus, Danaphos oculatus, and 

 Gonostoma atlanticum and small G. elongatum, 

 G. ebelingi, and Diplophus taenia were planktiv- 

 orous, i.e., almost all prey were <5-10 mm long. 

 Clarke (1978) showed that four of these species 

 feed primarily by day, and the limited data here 

 indicated that Vinciguerria poweriae does also. 



The majority of the diets of V. n imbaria and V. 

 poweriae <30 mm SL consisted of small cope- 

 pods and ostracods. Vinciguerria nimbaria >30 

 mm SL appeared to feed mostly on substantially 

 larger prey — amphipods and small euphausiids, 

 but large calanoid copepods were not important 

 at any size. In the western Pacific, V. nimbaria, 

 apparently smaller than the smallest size group 

 covered here, were also reported to feed mostly 

 on small copepods and ostracods (Ozawa et al. 

 1977). 



Certain prey types found in stomachs of V. 

 nimbaria, e.g., Scolecithrix danae, Paracandacia 

 spp., Oncaea venusta, Stylocheiron spp., were 

 either absent or very rare in the daytime plank- 

 ton samples, but most were present at moder- 

 ately high densities within the nighttime depth 

 range of V. nimbaria (Clarke 1980). Based on 

 diel changes in state of digestion of prey, Ozawa 

 et al. (1977) concluded that V. nimbaria fed at 

 sunset and at sunrise; their evidence for feeding 

 at sunrise is indirect and equivocal. Clarke's 

 (1978) data do not preclude feeding during the 

 upward migration at sunset, but give no indica- 

 tion of feeding at night or sunrise. Thus, while 

 some of the prey types not present in the plankton 

 by day may have been taken at sunset, it seems 

 unlikely that any would remain intact until late 



298 



