CLARKE: DIETS OF FOURTEEN SPECIES OF MESOPELAGIC FISHES 



Table 3. — Density estimates of prey types at each of the four depths sampled. A " + " indicates presence, but with estimated density 

 <0.005 m"3. Undetermined subadult copepodite stages of copepods are designated by "C" and specific stages by "C" plus the 

 appropriate Roman numeral; otherwise, copepods are all adults (CVI). Prey types <1.0 mm long, whose densities are probably 

 underestimated due to mesh escapement, are starred. 



Prey type 



Copepods: 



Neocalanus spp. Oil, Gill 



Neocalanus spp. CIV, CV 



Neocalanus spp 



Calanus tenuicornis 



Nannocalanus minor 



Undinula vulgaris 



U. darwini 



Eucalanus spp 

 'Acrocalanus spp 

 'Clausocalanus spp. 

 ■Pseudocalanidae 



Euaetideus acutus 



Chiridius + Gaetanus spp. 



Aetideidae — C <2.0 mm 



Aetideidae— C 2,0-3,0 mm 



Aetidedae— CV, CVI >3.0 mm 



Euchaeta media 



Euchaeta spp 



Euchaeta spp C s2 mm 



Euchaeta spp, C >2,0 mm 



Scolecithrix danae 

 'Scolecithrix bradyi 

 'Scolecithicella spp. < 1.0 



Scolecithicella spp. 3 1.0 



Lophothrix spp CV CVI 



ScottocaJanus spp, CV, CVI 



Unident, Scolecithriodae./Phaennidae 



Pleuromamma xiphias 



P. xiphias CV 



P abdominalis 



P. abdominalis C 



P. gracilis 



P gracilis CV 



Centropages spp, 



Lucicutia sp,, 



Heterorhabdus papilliger 



Heterorhabdus spp. 



Augaptilidae 



Candacia longimana 



Candacia spp, CV. CVI 



Paracandacia spp, CV CVI 



Pontellidae 

 'Acartia spp 



Unident. calanoids 



'Oithona spp. 

 'Oncaea spp. >0.6 mm 



'Oncaea spp sO.e mm 



Corycaeus spp. 



Other cyclopoids 



there was a trend for higher ASV's in the larger 

 fish; about half the prey taken by the two largest 

 size groups had ASV's of 1.0 m^ or more. 



Triphoturus nigrescens (Table 6) 



A large fraction of the diet of the smaller T. 

 nigrescens were microzooplankton — mostly Oncaea 

 spp. The most frequent prey among the macrozoo- 

 plankton was P. xiphias; it and several other 

 medium to large prey types had moderately high 

 ASV's. Few prey had high ASV's and those with 

 low ASV's included all sizes. If the ASV for Oncaea 

 spp. is reduced by a factor of 4 to roughly correct 



for undersampling, it is still equal to or greater 

 than those for the medium to large macrozoo- 

 plankton. This indicates that preference for On- 

 caea by small T. nigrescens is similar to that for 

 several larger prey types. 



The microzooplankton were a small fraction of 

 the diet of the larger T. nigrescens, and the cor- 

 rected ASV for Oncaea spp. is relatively low. 

 Pleuromamma xiphias was the most frequent prey 

 species and had one of the higher ASV's. Most of 

 the other prey were medium to large types, and 

 some of these had moderate to high ASV's. The 

 largest fraction of both items and prey types, how- 

 ever, had low ASV's (Table 2). These included both 



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