Variation in Egg and Larva Production of the Anchovy, 
Stolephorus purpureus Fowler, in Kaneohe Bay, Oahu, 
during 1950-1952 1 
Albert L. Tester 2 
INTRODUCTION 
A small anchovy known locally as the nehu 
is the principal baitfish used in Hawaii for 
catching skipjack (Katsuwonus pelamis) by live- 
bait fishing methods (F. C. June, 1951). This 
baitfish, which is taken commercially by 
nightlight methods after dark or by surround 
net in the daytime, occurs in quantity only 
in a few localities on Oahu, e.g., Pearl Harbor, 
Honolulu Harbor, Ala Wai Canal, and Kane- 
ohe Bay, all of which are shallow, relatively 
turbid, and in part brackish. These bays and 
inlets appear to support separate populations 
(Tester and Hiatt, 1952). As the supply of 
nehu comprising the populations appears to 
fluctuate both seasonally and annually, it is 
of interest and importance to investigate the 
causes. One possible factor, variation in egg 
and larva production, is dealt with here for 
one population, that of Kaneohe Bay, over 
a period of 24 consecutive months in the years 
1950, 1951, and 1952. 
Pertinent information on the spawning 
habits of the nehu, nature of the eggs and 
larvae, and the larval growth rate has been 
given by Tester and Yamashita (1950), Tester 
(1951), and Yamashita (Ms.). Briefly, the 
nehu is a pelagic spawner, spawning takes 
place (in Kaneohe Bay) mostly from 10:00 
1 Contribution No. 59, Hawaii Marine Laboratory. 
Manuscript received June 8, 1954. 
2 Department of Zoology and Entomology, Uni- 
versity of Hawaii. 
p.m. to midnight, the bluntly ovoid eggs 
hatch within about 24 hours or less, the typi- 
cally clupeid, filiform larva measures about 
2 mm. at hatching and appears to have an 
initial growth rate of about 1.5 mm. per day. 
A more detailed description of eggs and lar- 
vae, including criteria for identification, is 
given by Tester (1951: 326-327). 
Previous studies on the distribution of nehu 
eggs and larvae in Kaneohe Bay were con- 
ducted by Tester (1951) in 1949 and 1950. 
In these, four general surveys of horizontal 
distribution (in September, December, March, 
and June) were made, together with interim 
surveys of horizontal and vertical distribution. 
Among other things it was found that (a) 
spawning took place in all months which were 
sampled, and no particular spawning season 
could be defined from the data, (b) the eggs 
were present at all depths but with a slightly 
greater abundance towards the surface, (c) 
most of the eggs occurred within the southern 
sector of the bay (Fig. 1), (d) within the 
southern sector, there appeared to be a con- 
sistent peak of abundance of eggs in the 
vicinity of Stations 4 and 5 (between Coconut 
Island and Mokapu Peninsula), (e) within the 
southern sector, the larvae appeared to move 
in a clockwise direction around the bay as 
they increased in size. It was recommended 
that a specific sampling program be under- 
taken at or near Station 4 to investigate in 
more detail the temporal distribution of eggs 
and larvae. The recommended program, cur- 
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