Protecting Canterbury mudfish
by Mike Isle
Hororata farmer John Grigg and his family have transformed their dryland sheep and “a little-bit-of-cropping” farm into a productive irrigated business. They’re also doing their bit to protect one of the largest populations of endangered Canterbury mudfish.
These endangered fish live in wetlands and slow-moving waterways. When streams dry out, they can burrow into damp mud and survive for several months until water returns. Since European settlement, much of their habitat has been drained.
Growing up on the farm, Grigg didn’t know much about mudfish until the day a farm trough dried up.
“The intake was blocked, so we’d taken it off to work out what was going on.
We opened it up and out came this unfortunately dead mudfish,” he recalls, adding that they put a screen on the intake after that.
In the early 2000s, Department of Conservation senior ranger Anita Spencer contacted the Griggs as part of a Canterbury mudfish population survey.
“I pointed her in the direction of where I thought the mudfish would be.
They set 11 traps and caught 62 mudfish around our swamp creeks; they were fairly excited about that,” says Grigg.
DOC also helped the Griggs control the crack willow that infests the wetland, drilling and poisoning some but leaving others to provide shade for mudfish habitat.
Soon an underwater electric fence, the first of its type in New Zealand, will be installed to keep predatory trout out of the wetland.