A new study shows the devastating impact intensive farming is having on our native fish species, the Green Party said today.
"The majority of our native fish species are now either threatened or at risk, and intensive agribusiness is largely to blame," Green Party Co-leader Russel Norman said.
In an article published today in the New Zealand Journal of Marine and Freshwater Research, scientists have ranked the conservation status of 51 native fish to determine how threatened they are. More than two-thirds are classed as Threatened or At Risk.
Among the causes identified in the study as threatening our native fish are declining water quality, the effects of water abstraction for irrigation, and loss of habitat from changing land use, all of which are related to agricultural intensification. The two most-affected areas are Otago and Canterbury, where intensification and irrigation has been particularly rapid in recent years.
"We have a freshwater crisis in New Zealand, and this study highlights just how bad it's got," Dr Norman said.
"Our native fish are disappearing before our eyes. In some cases, there are only one or two streams left in the country with certain threatened fish species living in them. Yet there are no protections to stop these streams from filling up with pollution or being sucked dry for irrigation.
"If you don't understand the extent of the problem, ask a whitebaiter. Whitebait are the young of some of our threatened native fish, and whitebaiters all around the country are reporting fewer and fewer whitebait each season. There's no doubt that pollution and irrigation are having an effect on whitebait numbers."
Dr Norman was particularly concerned by the rapid decline of the torrent fish and blue gill bully populations, which have halved in the last ten years. These fish prowl in rapids, and are particularly vulnerable to the effects of water abstraction for irrigation, because this reduces flow and shrinks rapids. Sediment and algae from intensive agriculture also block the gaps between rocks at the bottom of streams in which torrent fish and blue gill bullies hide out.
"Once our native fish are gone, they are gone for good. For generations, kiwi kids have swum, fished, and whitebaited in our rivers. We love our rivers and our native species, and we want to protect them, but time is running out," Dr Norman said.
"Saving our native fish will require a two-pronged effort: regulating harmful activities like dairy conversions, effluent discharge, and irrigation, and beefing up protection for the threatened habitats of these species.
"Sadly we're unlikely to see either from John Key's Government with its promises of fast-tracked irrigation schemes and cuts to the conservation budget.
"John Key wants to push ahead with more and more dairy conversions and irrigation to boost GDP growth, but we can't 'balance' the environment and the economy by tipping the scales towards the economy. The environment is the basis of our clean green economy, and we need to build on this foundation rather than undermine it.
"Unfortunately, by the time this Government figures this out it could be too late for our native fish," Dr Norman said.