356 
PACIFIC SCIENCE, VoL V, October, 1951 
TABLE 10 
Food of Nehu {Stole phorus purpureus) in Hilo Bay, Hawaii, Based on an Analysis of 20 Stomachs 
organism 
percentage 
frequency of 
occurrence 
among fish 
examined 
average 
NUMBER taken 
per fish 
containing 
THE ITEM 
percentage composition 
OF food items based 
on total number of 
organisms found 
in THE stomachs 
Copepods 
adults 
80 
9 
41 
nauplii 
55 
13 
40 
Barnacle larvae 
cypris 
80 
3 
14 
nauplii 
10 
7 
4 
Nehu scales 
30 
- 
— 
Crab 2 oeae 
5 
4 
1 
With regard to the relationship between the 
size of fish and the size of organisms con- 
sumed, it is probably a function of the abun- 
dance of organisms of various sizes combined 
with the physical ability of the fish to catch 
and ingest them. Ghost shrimps are not 
present in the stomachs of small nehu, even 
in areas where these crustaceans are abundant. 
Large fish in areas where large crustaceans are 
abundant in the plankton naturally select 
them over small crustaceans because they can 
ingest organisms of larger size and their 
nutritional requirements would probably be 
fulfilled in less time and with less energy ex- 
pended. Fish in areas lacking larger crustacean 
plankters have no choice in the matter. 
Relation of food to vigor: Fishermen are 
cognizant of the differences in the character- 
istic vigor of nehu caught in the various 
baiting areas. The small fish from Hilo Bay 
and Kaneohe Bay seem less able to withstand 
the handling and confinement required in 
catching, transferring, and transporting them 
to the tuna fishing areas than are the larger 
and more vigorous fish taken in Ala Wai 
Canal and Honolulu Harbor. While we have 
no data which would compare vigor in small 
and large fish in the same baiting area, it is 
possible that vigor is directly related to the 
size of the fish. Small herring, for example, 
are more fragile and less hardy than large 
herring because they lose their scales more 
readily. Some evidence that hardiness in nehu 
may resemble that for herring was found by 
examining the stomach contents of nehu ! 
caught in Hilo Bay. Approximately one-third' i 
of the fish stomachs contained nehu scales. | 
The shiny scales were sighted and ingested as ' | 
they were shed into the water. The taking of | 
scales would be only of academic interest if | 
it were not for the fact that Hilo Bay nehu are i 
very small, exceedingly fragile and weak, and ! 
difficult to maintain alive in bait wells. If 
these small nehu lose their scales more readily | 
than do larger nehu, as is true for herring, the j 
excessive fragility may be associated with the 
small size. Although we have insufficient evi- 
dence at present, further study on the relation 
of vigor to size and of size to food available 
may indicate the principles underlying the ap- 
parent differences in size and vigor of nehu in 
the various baiting grounds. 
SUMMARY 
Investigations into the food and feeding 
habits of the nehu, the leading livebait fish 
for tuna in Hawaiian waters, were conducted 
for five important baiting areas in Hawaii. A 
total of 222 stomachs of fish from the com- 
mercial catch was analyzed for food contents. 
A gross quantitative analysis of the principal 
plankton species present in two areas was 
made for a comparison between the food 
items consumed and the organisms available. 
Copepods, barnacle nauplii, and mysis lar- 
vae of shrimps were most important in the 
diet of nehu taken in Kaneohe Bay; ghost 
shrimps {Leucifer faxonii) predominated in 
