Seasonal Variations — T seu 
279 
Fig. 1. Map of Moku o Loe, "Coconut Island,” and vicinity showing stations, tide staff, temperature record- 
ers, and standard rain gauge. 
In the course of the 24 months’ investiga- 
tion, 12 stations were established, 11 for the 
first portion of the study, with the last station 
in front of the Hawaii Marine Laboratory 
added for the last 19 months. For convenience 
of reference the stations have been numbered 
as indicated in Figure 1. Stations 3 to 7 and 
11 were located in the ponds; station 2 was 
in the open water immediately adjacent to the 
ponds; station 10 on the coral flat, exposed 
at extreme low water and near the principle 
series of ponds; and station 1 in the channel 
off the island where the water is about 60 
feet deep. This last station was used as typical 
of the open water of the bay. These stations 
were visited weekly for the first 14 months 
of the study and monthly for the next 10 
months. The period during which the study 
was carried on covered the period from Feb- 
ruary 19, 1949 , to January 17, 1951. 
Three 24-hour cycles of observations were 
made to record diurnal changes in tide, tem- 
perature, chlorinity, and oxygen content. The 
dates of these three periods were selected to 
permit comparison of the different seasons. 
MENSURATION OF PONDS 
The ponds and some adjacent waters were 
surveyed to permit the drawing of charts with 
depth contours and the estimation of volumes 
and volume exchanges in the ponds. The 
surveys were made in the following manner: 
At regular intervals along the length of a pond 
or channel, the distances depending on the 
length and the configuration of the body, a 
length of line marked off every 6 feet was 
stretched across the pond. Then the observer, 
either by wading or swimming, took a sound- 
ing with a lead line at the marked intervals. 
The depths were recorded to the nearest quar- 
ter foot. Tidal readings were taken before and 
after surveying each pond so depths could 
be reduced to the zero tide line (the marine 
datum line, 0.8 feet below mean sea level in 
Honolulu) . The tidal readings throughout the 
entire period varied only about 2 inches be- 
cause at the time selected for the survey there 
was a 'Vanishing tide” with its long station- 
