Biological consultant Charles Mitchell was commissioned by the Western Bay of Plenty District Council to review the restoration project being done by environmentalist Peter Ellery on the lower Kaituna River.

Mr. Mitchell said the project was valuable as a practical management example of how to restore whitebait habitat in the Western Bay of Plenty and across New Zealand.

"Western Bay of Plenty District Council is fortunate to have someone like Peter to keep this project going. How to extend this work and capitalise on the results to maximise benefits for regional whitebait fisheries needs to be considered," Mr. Mitchell wrote.

"It takes someone dedicated and focused like Peter (Ellery) who has spent his own time trying to unravel what inanga actually prefer for habitat and how to achieve this practically."

The project is in its eighth year and was started by Peter and Kim Young from the Department of Conservation after the site was identified by Mr Mitchell as an inanga spawning area. Initially starting with borrow pits, the project has added more habitat for adult whitebait by establishing a network of interconnecting ponds along the banks of the Kaituna River.

In the last 60 years, whitebait volumes harvested from the Kaituna River have plummeted. Originally up to 20 tonne were taken annually but for many years now fewer than 100 kilograms have been taken from the river and a total annual catch as low as 60kg has been recorded. The decline is largely due to the depletion of the wetland and nutrient run-off from farmland.

Mr Ellery has dedicated years of his voluntary labour to nurturing the Kaituna inanga fishery so that the adult fish have more habitat areas. By increasing the habitat, spawning potential is increased thus boosting larvae numbers. These larvae then move out to sea on the flux of the tides, grow into whitebait and return to the river to become inanga and repeat the life cycle.

The project gained national recognition in 2009 by being published in the NZ Journal of Natural Sciences.

In his report, Mr Mitchell noted the adverse environmental situation restricting the scope of the project.

The "treeless, barren Kaituna Flats show what has been lost in terms of whitebait habitat in this river alone. The Flats are criss-crossed with drains that are filthy, stagnant, low in oxygen and lack fish passage past the pump stations. The area of borrow pits is minute in comparison."

Mr Mitchell has several proposals for other areas that could support native fish through the use of fish passes and the redesign, shading and aeration of farm drains.

My conclusion is that the best possible value of this site (the Borrow Pits) and the ongoing support that Council is giving to continue this project, is to develop practical methods to manage and enhance the whitebait habitat.

Peter Ellery agrees and says he has learned a great deal about inanga habitat requirements from the small dedicated fish habitat he describes as a mini-wetland.

"While inanga can survive in all sorts of dubious habitat, it seems that their most preferred and most productive is off-river, open water wetland ponds with some current flow.

"My ongoing inanga trapping data shows an ever-increasing population of inanga, smelt and many other fish including good numbers of eels in these ponds but that data also shows that the fish can be literally crowded out by excessive aquatic weed growth, yet numbers replenish after de-weeding.

"Increasing our whitebait fishery is going to require as much ongoing management as initial creation of the habitat.

Peter says that Council has been pivotal to the project's success, providing native plants, weed-spraying contractors and digger time to remove aquatic weeds.

Council's environmental development manager Glenn Ayo says the project shows what can be achieved with dedication and commitment to hard work and the worth of volunteer support.

"Many people talk about the decline of the whitebait fishery and hundreds of fishers take from the Kaituna River every season. But active and consistent kaitiaki (caretakers) such as Peter Ellery have been pretty thin on the ground and could be counted on one hand.

"If I have one message for local people it would be – we cannot do it without you – it's your backyard, how about giving Peter a hand to make it happen."

For more information contact Glenn Ayo at Western Bay of Plenty District Council, email glenn.ayo@westernbay.govt.nz

The whitebait that gets past fishermen's nets becomes this fish and she needs more kainga (habitat) - the Kaituna project is making this possible.
Photo taken by Pete McGowan