The Glenfern fence project.

Carving a 6m wide track across 2 km of very rugged terrain is a major undertaking.

The logistics involved in transporting the materials and machinery and then constructing a pest proof fence on a remote island in the Hauraki Gulf creates an entirely new dimension. From the Karaka Bay end the fence rises to an altitude of 200m over 1.2km before descending 800m to the Port FitzRoy end.

image of a digger

Digging the culvert for the stream.

The Xcluder pest fence has now been completed from Port Abercrombie to Port FitzRoy. A stock gate, two pedestrian gates and a vehicle gate have been installed to provide access at both ends of the fence.An electronic surveillance systemis yet to be completed which will notify control if a gate has been left open, the stream culvert screen flap jammed open or a breach of the fence. Earth has been spread over the skirt and the platform is being grassed and covered with manuka/kanuka slash.

The section of fence to be finished last was 130m above the stream at the base of the FitzRoy hill. A south facing slope with a gradient of up to 1:3 and tall trees on each side; this section was a challenge to the earthmoving contractors and even more so to the fencing team. The slightest rainfall made it too slippery to work on and the upper part only saw the sun, when it was out, for half an hour a day.

The fencing team needed a week of no rain with sufficient South-west wind to dry out the ground. These conditions were finally met from the 3rd of June with only a short burst of rain on the 7th so that the team were able to hand dig the poles on the 10 and finish straining, meshing and capping by the time rain arrived on the 14th. Even so they needed crampons on their boots for most of the time. The remaining work to be done is not so weather dependant.

From the stream bed the fence runs almost flat to the front gate of FitzRoy House where it curves back on itself and ends at the bridge over the main stream into the harbour. The fence also splits at this point with a branch running along the shore at high tide level to catch any rats that might get around the end of the fence and through the mangroves. A buffer zone with traps and bait stations will be created at the fence ends and along the shoreline to catch any rats that might swim across the bay or get around the fence ends.

Tony Bouzaid