The Marine Algal Communities of Stanmore Bay, New Zealand 
(Studies in Inter-tidal Zonation 1.) 
V. J. Chapman 1 
INTRODUCTION 
The main purpose of the present and sub- 
sequent studies is to obtain a picture of the 
algal vegetation on different types of shores 
in the Auckland province, and to correlate, 
if possible, the observed zonation with the 
principal features of the tidal factor. A broad 
general picture is the aim, and it is not ex- 
pected that all areas will be studied inten- 
sively. Factors other than tidal factors will 
clearly be involved, but since air exposure 
( and this includes water loss, exposure to high 
temperatures, exposure to salinity changes) 
is a causal factor and is primarily due to 
tidal phenomena it has been selected for pri- 
mary investigation. Information is also re- 
quired as to the number and location of 
critical levels on the different types of shore, 
and this is a further aspect that will be 
investigated. 
GEOLOGY 
The present study concerns Stanmore Bay, 
which lies between Red Beach and Manly on 
the north coast of the Whangaparoa Penin- 
sula at its proximal end. It is about 25 miles 
north of Auckland and is just within the 
Hauraki Gulf (Fig. 1). The sea-water is 
considerably purer than that on the south side 
of the peninsula where there is sewage and 
harbour contamination. 
The bay is backed by high cliffs which in 
the centre terminate in a narrow sand-dune 
shelf, but which at both ends come down 
sheer to the sea. The rock is the soft Waite- 
mata sandstone and erosion is progressing 
1 University College, Auckland. Manuscript re- 
ceived March 29, 1949. (Read at Science Con- 
gress, Wellington, New Zealand, May 23, 1947.) 
continually at the two ends of the bay. At 
the northern end there is an outcrop of 
Parnell Grit, which is more resistant to wave 
action. Here vertical rock faces and dissected 
platforms are to be found. 
On either side of this promontory the soft 
rock has been worn down to beach level and 
is continually being covered and uncovered 
by the beach sand. Because of this the vege- 
tation on this low beach shelf is restricted 
since sand scour eliminates all but the hard- 
iest plants, especially from mid-tide upwards. 
Towards low water mark the rock is main- 
tained free of sand and here there is a good 
covering of vegetation. 
The above type of flat shelf is to be found 
on both sides of the bluff separating Stanmore 
from the small bay immediately to the north- 
west, but the latter differs from Stanmore in 
that there are some big boulders near high 
water mark. The northwestern end of the 
small bay terminates in a steep bluff with a 
wide wave-cut platform and a large cave at 
the base. 
AREA 
The area studied included the flat beach 
shelf in the centre and northwest of Stanmore 
Bay, the northwest bluff, and the whole of 
the small bay to the northwest leading up 
to Red Beach. The cave in the second bluff 
did not form a part of this investigation. 
THE FAUNA AND FLORA 
On the sea shore, especially on rocky coasts, 
it is impossible to consider the plants and 
animals independently. In this particular area 
the dominant animals have been included 
but secondary species have been neglected 
The communities recognised belong to four 
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