A biological study of Durvillaea antarctica (Chamisso) Hariot and D ...

V~riation in ~tanding crop with wave force has been recorded
for other large brown algae. John (1971) found that the standing
crop of Laminaria och1'oleuaa Ply. in Sp;~J.in decreased \llith increasing
...,ave force. au thors (Parke 1948, Kain 1963 and Luening
1969, 1970) hav0 dG9CribGd seasonal changes in the standing crop
of Lamina1'ia spp. and 8aaxdseth (l970a) described seasonal vaiiation
in standing CY'op of A8C!OphyUum nod-OSUYfL These fluctuations d.te
usually a:tt.1:ibut~d to seaBoliQ.l variation in gro"(.>Jth rate. Presumably
seasonality in '''diVe fo!CCG'l is also a caus:e. According 1::0 Kain
(l971b) the harve~~Hn9 of drift L. hyperboY'ea in Sri tain is mainly
carried out during wlnter when storms are most fr€qu~nt# and largest
quantities of drift plants are found.
S~nding crop measur~ments of D. antarc-tica ranged from 9.9 to
33.0 kg/m?. (5Z '" 20.7 kg/m 2 ). Only two measurements of D. wiUana
standing crop were obtained: 23.3 and 98.4 kg/m2. These values,
especiallyth~ second value for D. wi~lana, are very high relative
to standing crop me~8urements of oth@r large brown algae (Table 10.2).
Only MacFarlane IS or Mann'g measurements of the standing crop
of Laminaria longioPu/J'is aLe comparable with the values obtained
for Durvillaea. It should be pointed out that the very high value
obtained for D. u)illana was based on a relatively small sample area
(8 m 2 ) and could very well overestimate the s tanding crop of Do
willana at Tauc.uku.
necessary.
Furthll'lX" measurements of D. wiHana are
There are reI" references to the density of other large b.l:'own
algae decreasing with wave force, although Luening (1969), Kain (1971a)
and John (1971) reported that t.he numerica.l density of LaminaY'ia spp.
decreases with depth.
standing crop of D. antarctica va.ries with wave exposure and
\·Jith season. In tireas where the impact force of wave:~ is very
high values ronged from 3-5 kg/m 2 • tl/here wave force was less severe I
but still veleY strong higher values of 20-30 kg/m 2 were obtained" In
semisheltered places dominated by cape form specimens, standing crop Has
9-10 kg/m'- (Table (3.2).
Standing crop l1t Tautuku d~clined
in the second half of the
winter