ZOOLOGY: A. a MAYER 
211 
ECOLOGY OF THE MURRAY ISLAND CORAL REEF 
By Alfred Goldsborough Mayer 
DEPARTMENT OF MARINE BIOLOGY. CARNEGIE INSTITUTION OF WASHINGTON 
Presented Jo the Academy, February 13, 1915 
A quantitative ecological study was made of the Madreporian corals 
of the fringing reef of Maer Island, the largest of the Murray Island 
Group, which lies in Torres Straits, Australia, in 9°55' S. Lat.; 144°2' 
Long. E. from Greenwich. 
Maer Island is volcanic and has broken through an old limestone- 
bearing platform which is now submerged to a depth of 15-30 fathoms, 
and upon which the modern coral reefs of Torres Straits have grown. 
The volcanic center of the Island is surrounded by a modern fringing 
reef which has grown seaward over its outer edges from the shores, and 
is now 1800-2200 feet wide on the windward (S. E.) side of the Island, 
and only 175-780 feet wide on the leeward (N. W.) side. It is wide 
in regions exposed to the full force of the breakers, and where it is not 
interfered with by silt from the three principal streams of the Island; 
while on the other hand in regions protected from breakers or inundated 
by sand or silt the fringing reef is narrow. Hurricanes are unknown 
and thus the corals grow on uninterrupted by periods of wholesale 
destruction such as affect the reefs of the West Indies, and most parts 
of the Pacific region. 
A line running S. 39° E., and 1869 feet long, was surveyed across the 
S. E. reef flat of Maer Island. The shore end of this Hue was 1496 feet 
in a N. E. direction from the mouth of Haddon brook. Squares 50 feet 
on the side (2500 feet in area) were then surveyed and staked out at 
intervals of about 200 feet along this line; and all living coral heads grow- 
ing within these staked areas were counted. 
This reef flat is peculiar in that the water is dammed by the litho- 
thamnion ridge which extends in a narrow barrier along the seaward, 
breaker-washed edge of the flat. Thus at low tide the water over the reef 
flat becomes a marine basin about two miles long, 1680 feet wide and 
only about 18 inches deep; but the water being impounded by the Htho- 
thamnion ridge, the reef flat is never laid bare even by the lowest spring 
tides. About 3,600,000 living coral heads are found upon this sub- 
merged area. For the first 370 feet out from shore there are no corals. 
The following table gives the number of living coral heads found on each 
50-foot square (2500 square feet) at intervals of about 200 feet apart 
across the S. E. reef flat or Maer Island. 
