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

7
the primary blade broke off.
Furthermore, they were expensive and
aroused the curiosity of the general public.
At Tautuku 25 D, 1,)1: ZJ an(/
we'Ce tagged in October 1972 and 50 ")ere tagged just south ot the
Parititahi Road Tunnel in March 1973. Of these 75 labels, 62 were
lost within l~o years. Those \'Jhich tore out of the blade we.:ce
replaced until June 1974 when a severe stonn on the South
Island east coast devastated D, hlillana beds at Ta.u'tuku and Kaikoura.
(b)
Osingthe tagging m.ethods described above, 331 D.
antarctica
were marked on First. Slope, Tautuku, in July/August 1972 a.nd 1100 B.t
Ohau Point, Kaikoura in September 1972. Although selection of marked
plants was not strictly random I efforts were m.ade to include all size
classes in the samples,
very similar (Table 2,1).
The size structure of the t.wo samples \Vas
Poin·t and Tautuku.
Size composition of marked D. antarctica samples at Ohau
Size class (m)
Ohau Point
(Septemb~r 1972)
Percentage of sample
Tautuku
(October 1972)
0.5
0.5-1.0
1-2
2-3
3-4
1
31.3
24.5
14.9
9.7
5.8
7.8
61.8
31. '7 )
29.8 )
19.8
6.4
3.9
8.4
61. 5
I t took be tween five and eight days vJ i th calm seas to census
each of these marked samples. Nine cenSllses were made at. Tautuku
betl'leen July 1972 and March 1975, and seven censuses were made a.t
Ohau Poin-t between September 1972 and November-Decemher 1974.
each census additional small plants were marked so that a size class
of srnall plants \V'as retained throughout the study period.
'rhe 50 "Allflex" I:CJ.gged D. wiUana at Pa:cititahi wet:e
five t.imes bet.ween Mcu:ch 1973 and December 19"15, fwd Ute 25 a·t
'J.'autuku on four occasions between October 1973 and March 1975.