Table 11. — Percentage taxonomtc composition of micro- 

 nekton in area 4 of figure 6, from net hauls and tuna 

 stomachs 



[29 standard nleht net hauls of 1.5-m. net (7,19! ml.); 247 stomachs ot yellow- 

 fln tuna (14,839 ml.); 1 stomach of skipjack tuna (97 ml.); asterisk means 

 <0.05 percent] 



Table 12. — Percentage taxonomic composition of micro- 

 nekton in area 5 of figure 5, from net hauls and tuna 

 stomachs 



[10 standard night net hauls of 1.5-m. net (2,470 ml.);319 stomachs of yellow- 

 fin tuna (16,256 ml.); 42 stomachs of skipjack tuna (661 ml.); asterisk means 

 <0.05 percent] 



Differences between micronekton from nets and 

 tuna stomachs were rather marked as far as per- 

 centages of fish families are concerned. Myctophi- 

 dae was the largest fish component of net material 

 in most areas, but in tuna stomachs it was general- 

 ly a small component, where it occurred at all. 

 Only in area 5 (yellowfin tuna) and possibly area 

 6 (skipjack tuna) were the percentages for tinia 

 comparable with those for nets. Leptocephali, a 

 large item in net catches in most areas, were rep- 

 resented in tima stomachs only as a negligible per- 

 centage in area 6 (yellowfin tuna) . The occurrence 

 of the gonostomatid fish Yineiguerria (wluch is 

 shown separately from other members of the fam- 

 ily because it is the only one recorded from tuna 

 stomachs) was reasonably similar in the three 

 kinds of material in tables 8 to 14 considered as a 

 whole. Stemoptychidae, Bregmacerotidae, Nem- 

 ichthyidae, Stomiatidae, Idiacanthidae, and 

 Batliylagidae were significant components of net 

 micronekton in some areas, but never of tuna 

 stomach contents (unless they occurred in the un- 

 identifiable fish remains, which have been included 



in "other fish"). Most of the families mentioned 

 in this paragraph are generally regarded as 

 mesopelagic. 



On the other hand, some significant fish compo- 

 nents of tuna stomach contents were absent or 

 scarce in net catches — Engi-aulidae, Scombridae, 

 Scomberesocidae, Ostracidae, Tetraodontidae, 

 Thunnidae, Serranidae, Exocoetidae, Coryphaeni- 

 dae, Polynemidae, Carangidae, Gadidae, and 

 Trichiuridae. These families are generally re- 

 garded as epipelagic. Engraulidae occurred in tuna 

 stomachs only in area 1, and their absence in net 

 catches for that area may reflect the fact that they 

 occur mainly in the northern half of the area, 

 whereas the net hauls were made principally in 

 the southern half; the 1.5-m. net has some capac- 

 ity for catching engi-aulids, because a specimen 

 of Engraulis mordaic was caught in area 1 in June 

 1964, after the tables in this paper were compiled. 

 The absence or scarcity of Ostracidae, Tetraodon- 

 tidae, Serranidae, Gadidae, and Trichiuridae in 



104 



U.S. FISH AND WILDLIFE SERVICE 



