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

197
holdfasts and those which \tlere attached t.o cOlnpsite holdfasts.
Plants in the lat.t.er
were usually lost when the holdfast mass
rotted away. whereas those with discrete holdfasts had a
chance of survival. Ten percent of all small plant.s in Area 6b were
attached to holdfasts which nr,n,r to culling had supported
four or more large plants. After about. six mont:hs all of these
holdfasts and their at.tached small
of IJ"'U."~~ \\Ii th discrete holdfast.s was low. In areas Sb
and 6b. mortali'ties of these plants over a two year .I:""",.J..u....
\'1ere 51%
and 55%
Area and the Ohau Point site were harvested a second tll~e.
Data to the and the second crops are tabulat.ed
below 9. 6} •
IV
Table 9.6
of culled areas.
(a)
Area 5b Tautuku:
crop
culled 25
October 1972
2nd crop
No. of
than 0.1 m
No. of
than LO m
culled plants (>1.0 m)
Estimated total
crop (kg)
Mean
(m)
Mean diameter (mm)
Mean stipe length
No. of plants exceeding 5 m
(m)
(length and diameter)
conceptac1es
fraction of total weight
462
135
403
445
4.5
49.0 ± 1.4
28.0 ± 1.2
15
9.2
66;82
35,6
12,,1
631
150
371
455
3.2
37.2 ± 1.4
25.0 ± 1.8
1
5.3
S3; 5~1
SB.7
e.6
(b)
Original crop
culled 2
January 1973
No. of
than 0 .. 5 m
83
Total ",'et culled (>0,5 m) 161.4
Mean length of culled
(m)
2.3 ± 0.1
Mean stipe diameter (mm)
29.4 ± 0,7
Mean stipe length (em)
16,6 ± 0.6
No. of plants exceeding 3 m
14
Longest spectmen (m)
3.96
stipe (diameter)
45
\\I'i th honey.combing
57.0
with canceptacles
29.0
fractions of total weight
/...7
2nd crop
(all plants
cleared) 10
March 1974
2.56
51.0
1.28 ± 0.1
15.0 ± 0,5
14.7 ± 0.3
5
4.03
25
29.5
10.0
4.5