CANTERBURY MUDFISH / KŌWARO CONSERVATION – CANTERBURY MINE
Protecting a regional treasure
We have stepped in to help protect the critically-endangered Canterbury mudfish /
kōwaro. Lack of fencing of livestock from streams, riverside willows and other
weeds, few native plantings, sediment and nutrient run-off into streams are major
threats to its conservation.
The Waianiwaniwa valley in inland Canterbury is a major habitat
for the endemic kōwaro. The streams here become disconnected
from rivers in the lower Selwyn catchment due to seasonal
drying of the streams as they enter the Canterbury plains,
creating an environment free of predator fish species such as
eel (tuna). This catchment however, like much of Canterbury,
is dedicated to rural land use and is relatively unprotected for
On gaining access in May 2020 to a purchased 31-hectare block
of rural land, we committed to fencing 1,100 metres of the Bush
Gully Stream from livestock. We are also spraying weeds and
planting riparian native species along this stream. This is part
of a programme to protect and enhance kōwaro habitat in the
Bush Gully Stream which runs to the north of the Canterbury
mine and later joins the Waianiwaniwa River.
Other actions are to remove two stands of crack willow as part of
a wetland restoration project. We manage run-off into freshwater
from the mine, making improvements to fish passage. The intent
is to covenant 20 metres on either side of the mid-point of Bush
Gully Stream for 1,100 metres, over an area totalling 44,000 m2 or
Improving the science
We supported a survey of kōwaro populations in the Bush Gully
Stream via a University of Canterbury master’s thesis, and more
widely, the Waianiwaniwa and Hororata catchments. This work
builds on other aquatic surveys on kōwaro carried out in Bush
Gully Stream since 2006.
A further issue is uncontrolled drainages into the Bush Gully
Stream from historical underground mines dating from the
1900–1970s. We are analysing water quality and quantity
in these flows to understand how these drainages can be
managed to improve stream water quality.
A holistic issue
Nature conservation can rarely be done in isolation to be
effective. This is especially true of the kōwaro and its stream
habitat, almost all of which is degraded. This is a call for
action on landowners, farmers and foresters, mine and quarry
operators, government, iwi and local communities. We are
proud to be playing our part in this kaupapa or cause.
We are proud to be playing our part in this kaupapa to protect the kōwaro.