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

185
CHAPTE!~
NINE
EXPERIMENTAL ~MOVAL OF
DURVILLAEA AND IMPLICATIONS
The ra.te a,:t vlhich DuX'viUaea will reestablish itself after it is
removed is of fundEJ.mental importance to any plans to harvest. the kelp.
'l.'herefore I
the after.-effects of clearing D. antCU"dtida, and to a
lesser extent, D. 1.JYillana ... Jere followed on several eJ{perimental sites
ai.: 'l'autuku and Kaikoura. These were cleared at different seasons
so that it was possible to observe whether regrowth of DurviZZaea
vax ied wi th the time of cleari ng.
Difre:r:ent harvesting methods were used, and the effects of
these on the rate of regrowth of DurvilZaea are described.
9.2 THE EFFECTS Of HARVESTING DURVILLAEA
Before outlining some of the effects of clearing I
DurviZZaea, it
is necessary to describe the general appearance of the rock surface
immedia tely after the kelp had been removed,
At Tautuku, the newly
cleared areas all looked similar, despite the fact that they were
cleared at different seasons.
In each case, the upper third of the
kelp zone was predominantly bare rock, with scattered barnacles and
mussels (Chamaesipho columna and MytiZis eduZis aoteanus), patches of
pink, paint·-like coralline (7Lithothamnion sp _)
and cll1.i'Ops of
CoraZlina pilifera 2 • Along the upper fringe there ~"e:ce occasional
Clearing, in this case, refers to the complete removal of all
Du:Pvi Z Zaea .
2 According to H.W.JoI0nsen (pers. corom" 30 May 1975) to whom I Gent
specimens, this species could \",cll be considered as belonging to
Coral-lina pilifera Lam. 1816.
a.nd the type is an Haliptyon.
However, 'th is is a hazy entity,