Food and Feeding Habits of the Nehu, 
Stolephorus purpureus Fowler^ 
Robert W. Hiatt^ 
INTRODUCTION 
The nehu, Stolephorus purpureus Fowler,^ com- 
prises about 95 per cent of all the baitfish 
used by tuna fishermen in Hawaii. Despite the 
fact that this species is widely used for live- 
bait, the baiting grounds are highly restricted 
in extent throughout the main Hawaiian Is- 
lands and differ markedly in their produc- 
tivity. The most important baiting areas have 
been mapped in a recent paper which deals 
with racial segregation of nehu among the 
main Hawaiian Islands (Tester and Hiatt, in 
press). It suffices here to state that Kaneohe 
Bay, located on the northeast side of Oahu, is 
the leading baiting ground in Hawaii, pro- 
ducing, according to statistics compiled by 
the Territorial Division of Fish and Game, 
approximately 60 per cent of the total com- 
mercial catch. 
Ecologically, nehu appear to be restricted 
to sheltered coastal waters which are some- 
what less saline than oceanic water, although 
the adults live without noticeable deleterious 
effect in baitwells of tuna boats at sea and, 
on occasion, have been observed outside the 
reefs in waters completely oceanic in compo- 
sition. Inshore areas suitable for nehu are 
scarce around the Hawaiian Islands, and in a 
few of these baiting grounds the population 
density is often great. The importance of this 
species to the tuna industry, coupled with the 
fact that the supply available in these few 
areas is somewhat precarious, as evidenced 
^ Contribution No. 9, Hawaii Marine Laboratory. 
Manuscript received March 16, 1951. 
2 Department of Zoology and Entomology, Uni- 
versity of Hawaii, Honolulu, T. H. 
^ The confused generic designation of this species 
within the family Engraulidae has been discussed by 
Gosline (1951). 
by the recent decline in the nehu population 
in Hilo Bay, has indicated the need for an 
intensive study of its biology and population 
dynamics. 
Only two brief references to the food and 
feeding habits of this species exist (Hiatt, 
19Ala\ 241; 1947^: 271), but, since these do 
not treat this subject in sufficient detail, the 
present study on the food and feeding habits 
of adult nehu was undertaken. Fish from five 
different baiting areas are analyzed to ascer- 
tain if differences and similarities in food 
habits may be related to variations in their 
size and vigor. Where adequate data are avail- 
able, a comparison is made between the food 
organisms available and the food organisms 
eaten throughout the year. 
METHODS 
Collections of fish were made both through 
the cooperation of commercial fishermen and 
by the use of the fishery research vessels of the 
Hawaii Marine Laboratory and the Territorial 
Division of Fish and Game. With the excep- 
tion of the fish taken in Ala Wai Canal and 
in Pearl Harbor, most fish were caught by 
night-baiting methods, as described by June 
(1951). The fish taken in the two areas men- 
tioned were seined during early morning 
day-baiting operations (June, op.cit.). 
Fish samples were obtained from Ala Wai 
Canal and from Kaneohe Bay during all sea- 
sons of the year. Although collections were 
sparse in Pearl Harbor, Honolulu Harbor, and 
Hilo Bay, these data are included because the 
consistent year-round supply of the impor- 
tant food organisms in a particular area in 
Hawaiian waters (see Tables 3 and 6) and the 
consistency of the organisms eaten month to 
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