Government Must Act On Freshwater Management After Landmark Scientific Report

  • 17/06/2016

The Government is being urged to reconsider how freshwater is being used and managed after world-leading research by the Cawthron Institute revealed that taking water from rivers affects fish much more than first thought.

Didymo testing Clinton River Jan 2015The 15 year long research project by Cawthron scientists has revealed that taking water from rivers and streams reduces the amount of food the current is able to carry to feeding fish. Cawthron says this means fewer, or more slowly growing, fish. Species affected include native fish such as whitebait, along with trout and salmon.

Cawthron says its findings have global implications and its research findings have been published in the prestigious international scientific journal of the American Fisheries Society.

Fish & Game’s chief executive Bryce Jonson says Cawthron are to be applauded for producing such sound, world-leading scientific research. Mr Johnson says the results bear out what anglers have long suspected.

“It stands to reason that the more water taken from a river, the less life it is able to support”, he says.

Mr Johnson says the government needs to heed the research findings and bring in stronger water management rules and reconsider its support for intensive farming and irrigation.

“At the moment, the government is pouring hundreds of millions of dollars into irrigation as a subsidy for intensive farming and ignoring the impact this is having on the environment and fish, including native species.

“This report should be a wake-up call for the government. It has huge implications for tourism, farming and hydro-electric development and greater recognition needs to be given to freshwater fisheries,” he says.

“The present situation is becoming unsustainable. We have the unsustainable situation where irrigators are allowed to take more water from some rivers than actually exists in them. How is that helping the environment?

“And it is ludicrous that irrigators now want to take water from rivers and use it to replenish aquifers that have been over exploited. All this has a huge impact on the environment,” says Mr Johnson.

Earlier this month, Fish & Game gave the Environment Minister another report prepared by Cawthron calling into question present methods used to assess the health and life supporting capacity of waterways.

Bryce Johnson says this Cawthron report indicates there is not a strong correlation between how many fish can live in a waterway and present methods used to try and measure that waterway’s health, such as the macro-invertebrate index.

The index, or MCI, tries to assess the health of a river by measuring aquatic insect diversity.

“The earlier Cawthron report I gave to the minister’s office raises doubt over whether existing assessment methods - like measuring a river’s insect life - actually do what supporters claim.

“Fish & Game firmly believes such methods do not meet what the present legislation requires to safeguard the life supporting capacity of freshwater ecosystems.

“We expect the government to take heed of these landmark Cawthron reports and act so that future decisions on freshwater are based on this research,” Mr Johnson says.

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