New guidelines to help protect endangered New Zealand fish suggest clearing blockages in waterways - but this is only optional.
Forty-one of 57 New Zealand indigenous freshwater fish species are threatened with extinction or already extinct but despite this new guidelines are only optional.
The Department of Conservation proposal could affect thousands of dams, weirs, culverts and other blockages on rivers all over New Zealand, many of them on or near farmland - and it is unclear who will fit the bill for the costly work.
Minister of Conservation Eugenie Sage said the guidelines excluded hydroelectric dams that produced most of New Zealand's electricity, and instead applied to waterway barriers less than four metres high.
"We hope the owners of those, when they maintain them, are aware of the guidelines and look at how they can retrofit them to improve the passage for fish," she said.
Ms Sage said there was a need for fish, such as eels and whitebait, to be able to move freely between lakes, rivers, streams and the ocean in order to breed.
Despite this there was no compulsion for landowners to clear away dams and weirs, nor to remove earthworks used to catch drinking water.
New river barriers should have ways for fish to transit, and local authorities should make sure this happened, Ms Sage said.
Existing barriers should be either removed or changed.