The Sponges of Kaneohe Bay, Oahu 1 
M. W. de Laubenfels 2 
The Hawaiian Islands lie near the center 
of the north tropical Pacific Ocean. The island 
of Oahu is in the midst of these islands 
Kaneohe Bay is near the middle of the wind- 
ward side of Oahu, which side extends from 
northwest to southeast. The whole bay ex- 
tends slightly over 11 kilometers along the 
coast, but is only some 3 kilometers ( 2 miles ) 
deep. It is sheltered by extensive off-shore 
coral reefs, however, so that the water in it 
is much calmer than that of the open ocean. 
The southeast end of the bay is further shel- 
tered by Mokapu peninsula so that it is here 
three-fourths landlocked; a roughly circular 
area some 3 kilometers in diameter is thus 
especially sheltered. The present study is 
based upon collections within this latter area 
which includes the junction of latitude 21° 
26' N. and longitude 157° 48' W. 
The deeper portions of Kaneohe Bay have 
a sand bottom; practically no sponges occur 
on sand. There are many patches of coral 
scattered throughout the bay, coming up to 
extreme low tide level, thus nearly but not 
quite 1 meter below the high tide surface. 
Such masses are often more than 100 meters 
in diameter, and have a vertical measurement 
above the floor of the bay of 10 to 15 meters. 
Much of the outer or fringing area of each 
is living coral, but the bulk of each mass is 
dead coral. There are innumerable inter- 
stices, and these are teeming with inverte- 
1 Research Paper No. 9, Cooperative Fisheries 
Research Staff, Territorial Board of Agriculture 
and Forestry and University of Hawaii; Contribu 
tion No. 1, Hawaii Marine Laboratory. 
2 Department of Zoology and Entomology, Uni- 
versity of Hawaii. Manuscript received April 2, 
1949. 
brate life, including sponges. To collect and 
study this fauna, large armful-sized masses of 
coral were broken off, hauled to the surface, 
and placed on a boat where they were broken 
into small bits by means of hammers and 
crowbars. It is common to find that 5 to 
10 per cent of the surface of the dead coral, 
down in these narrow crevices, is covered 
with living sponges. These are, however, 
always thin, often as thin as paper. Such 
incrustations are difficult to detach, or to 
study in any other way. 
Much of the study of Kaneohe Bay was 
conducted at or near the island that has long 
been known by the Hawaiian name of Moku 
O Loe, but which has lately been termed 
Coconut Island. It is less than a kilometer 
in greatest dimension. Several man-made 
lagoons about 20 to 80 meters in length and 
connected to each other, and to the ocean, 
by channels that are 2 to 8 meters wide, have 
been constructed. In the channels sponges 
grow luxuriantly, and an individual sponge 
colony may quadruple its mass in 1 year’s 
growth. In the calmer waters of the lagoons 
a few scattered sponges occur, some of rather 
large size (10 to 20 cm. high), but it is 
evident that there they grow very slowly; 
individual colonies showed so little growth 
in a year’s time that it could not be measured. 
Doubtless there was some growth, but prob- 
ably less than 10 per cent increase. These 
larger lagoon specimens are probably several 
years old, perhaps even 10 years old. Larger 
sponges in the channels may be only 10 
months old. 
Field investigation was carried out approx- 
imately once a month from September, 1947, 
to May, 1948 (9 months), and again in 
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