Seasonal Variations in the Physical Environment of the 
Ponds at the Hawaii Marine Laboratory and the 
Adjacent Waters of Kaneohe Bay, Oahu^ 
Winifred Shui Lin Tseu 
INTRODUCTION 
Kaneohe Bay, located on the northeastern, 
or windward, side of the island of Oahu, 
Territory of Hawaii, is approximately 7.3 nau- 
tical miles long and 2.5 nautical miles wide, 
with 3.8 nautical miles fronting on the Pa- 
cific. It covers an area of 14.1 square nautical 
miles. The entrance is protected for almost 
all its length by coral reefs and has only two 
deep channels into the adjacent ocean. Within 
the bay are numerous coral reefs with channels 
30 to 60 feet deep between them. Adjacent 
to the shores the bay has broad shoal areas 
of mud or sand that usually terminate in steep 
fronts of growing coral. Numerous small 
streams flow into the bay, but none of these 
carries much water except at times of the 
extremely heavy rainfall during southerly, or 
"kona,” storms. 
Located approximately 1.5 nautical miles 
from the southeastern shore of the bay and 
0.3 nautical miles from the closest land to the 
southwest is a small island, Moku o Loe or 
"Coconut Island.” The island is about 18 
acres in area and reaches a height of 55 feet. 
Originally it was surrounded by broad coral 
flats of sand and mud, with growing coral on 
the margins. However, a previous owner of 
the island had numerous channels dredged 
to the edge of the island, the dredged coral- 
line material being thrown up to form jetties 
protecting the channels. In one area a series 
of fish ponds was constructed. The ponds are 
separated by the coral fill and are connected 
^ Prepared as partial requirement for the degree of 
Master of Science, University of Hawaii. Contribution 
No. 31, Hawaii Marine Laboratory, Manuscript re- 
ceived July 11, 1952. 
by concrete spillways into which screens can 
be fitted. The sides of these ponds which 
are almost vertical were constructed either of 
disc-shaped coral heads or of concrete. The 
bottom of the ponds is covered with a fine 
silt, similar to that covering most of the bot- 
tom of Kaneohe Bay. 
With the establishment of the Hawaii Ma- 
rine Laboratory on the island and the pro- 
jected use of these ponds for holding ex- 
perimental fish, it became desirable to learn 
of the changes in the physical environment 
in the ponds as contrasted to those in the 
adjacent waters. This study attempts to fill 
this need and, in addition, provides informa- 
tion of more general interest as no study of 
seasonal variation in inshore marine environ- 
ments has been made in Hawaii heretofore 
or, as far as can be ascertained, in other re- 
gions of the tropical Central Pacific. More- 
over, no study of seasonal variation of enclosed 
waters in Hawaii has been made heretofore, 
although ponds somewhat similar to the ones 
studied have long been used in Hawaii for 
rearing fish commercially. 
The study, as carried out, fell into four 
sections: first, the survey of the ponds to 
determine their dimensions and depths; sec- 
ond, the study of currents and tides in the 
pond area, the study of the tides being neces- 
sary for later sections of the study; third, the 
study of the meteorology— rainfall, wind, and 
air temperature— and water temperature, and 
its correlation with the changes in the ponds 
and adjacent waters; and fourth, an investi- 
gation principally of changes in the chlorinity 
and the oxygen content of the water. 
278 
