Food of the Nehu — HlATT 
353 
TABLE 6 
Monthly Distribution of the Dominant Plankton Components in Ala Wai Canal, Honolulu, Based 
ON Routine Bi-weekly Hauls in Areas Occupied by Nehu. The Symbol xxx Denotes Great Abundance, 
XX Denotes Common Occurrence, and x Denotes Uncommon or Rare Occurrence 
ORGANISM 
JAN. 
FEB, 
MAR. 
APR. 
MAY 
JUNE 
JULY 
AUG. 
SEPT. 
OCT. 
NOV. 
DEC. 
Ghost shrimps {Leucifer 
faxonii) 
XXX 
xxx 
xxx 
xxx 
XX 
XX 
XX 
X 
XX 
XX 
XX 
XX 
Crab zoeae 
XX 
XX 
XX 
xxx 
XX 
xxx 
xxx 
XX 
xxx 
xxx 
xxx 
xxx 
Barnacle larvae (nauplii) . . 
XX 
X 
XX 
xxx 
XX 
xxx 
xxx 
xxx 
xxx 
xxx 
xxx 
xxx 
Copepods 
xxx 
XXX 
XX 
XX 
X 
xxx 
XX 
X 
xxx 
X 
X 
xxx 
Medusae 
xxx 
X 
X 
X 
xxx 
xxx 
XX 
X 
X 
xxx 
XX 
xxx 
Shrimp larvae (mysis) 
X 
X 
X 
X 
X 
XX 
X 
X 
XX 
X 
XX 
xxx 
Shrimp larvae (zoeae) 
XX 
X 
XX 
X 
X 
XX 
X 
X 
X 
XX 
X 
xxx 
Isopoda 
X 
- 
xxx 
xxx 
XX 
X 
- 
- 
X 
- 
X 
x 
Chaetognatha {Sagitta ) .... 
- 
XX 
XX 
- 
- 
X 
X 
- 
X 
- 
- 
X 
Polychaeta 
- 
- 
X 
X 
X 
X 
X 
- 
- 
- 
- 
- 
notwithstanding their continued presence in 
abundance throughout the year. Of impor- 
tance in understanding the differential selec- 
tion of food in Ala Wai Canal is the fact that 
ghost shrimps are exceedingly abundant 
there, the population density per unit volume 
being many times greater than that in Kane- 
ohe Bay. Somewhat anomalous is the ap- 
parent disregard by nehu in Kaneohe Bay of 
ghost shrimps and hyperiid amphipods which 
are available during most of the year, al- 
though in much smaller quantities than in 
Ala Wai Canal. 
In regard to the selection of food organ- 
isms, the food habits of nehu in Honolulu 
Harbor (Table 8) are quite similar to those in 
Ala Wai Canal. Nehu here depend chiefly on 
the larger crustacean elements in the plank- 
ton, with crab megalopa, ghost shrimps, and 
small palaemonid shrimps comprising the 
bulk of the food. Small plankters were taken 
incident to larger items only by a few fish, and 
these plankters constituted less than 10 per cent 
by number of all the organisms taken. The 
rather small nehu from Pearl Harbor con- 
sumed mostly copepods and a smaller quan- 
tity of crab zoeae (Table 9). An analysis of 
the plankton (unpublished MS.) indicates 
that copepods comprise the most important 
component, with crab and shrimp zoeae 
ranking second and third, respectively. It is 
apparent that nehu in this area exercise little 
or no selection among the plankters except to 
ignore organisms other than crustaceans. No 
quantitative data are available for plankton 
in Hilo Bay, but the results of several tows 
made incident to a survey of pollution in the 
bay indicate a very low population density, 
and the organisms present are comparatively 
very small in size. No ghost shrimps, amphi- 
pods, larval shrimps, or crab megalopa were 
found. The minute food items found in the 
stomachs of fish from this area were present 
in about the same proportion as they occurred 
in the plankton. The above analyses indicate 
that the nehu is definitely a feeder on the 
TABLE 7 
Monthly Characteristics of the Food Habits of Nehu in Ala Wai Canal. The Symbol x Denotes 
Occurrences in Stomach Contents 
ORGANISM 
JAN. 
FEB. 
MAR. 
APR. 
MAY 
JUNE 
JULY 
AUG. 
SEPT. 
OCT. 
NOV. 
DEC. 
Ghost shrimps {Leucifer 
faxonii) 
- 
- 
X 
- 
X 
- 
X 
- 
- 
- 
- 
- 
Copepods 
- 
X 
- 
- 
X 
- 
- 
- 
- 
X 
- 
- 
Barnacle larvae (cypris) .... 
- 
X 
X 
- 
- 
- 
- 
- 
- 
X 
- 
- 
Crab zoeae 
- 
- 
X 
- 
X 
- 
— 
— 
— 
— 
— 
- 
Shrimp zoeae 
- 
- 
- 
- 
X 
- 
- 
- 
- 
X 
- 
- 
