Archives For koura

Over summer rangers in Rotorua embarked on a series of initiatives to monitor freshwater species in the Rotorua Lakes area.

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By Emily Funnell, Technical Advisor – Aquatic and Reporting Unit

Earlier this year we carried out a survey in some of the ponds and bog tarns in Southland’s Waituna catchment.

This work was undertaken as part of DOC’s Arawai Kakariki wetland restoration programme in the Awarua-Waituna Wetlands.

Waituna wetlands sign. Photo: itravelNZ | CC BY 2.0.

Waituna Wetlands

We have always known that giant kōkopu, kōura/freshwater crayfish and other species can be found lurking in in the tarns and ponds, but we have never known how extensive their habitat was.

Freshwater crayfish/kōura.

Freshwater crayfish/kōura

In April we had a peek in a number of ponds all around the catchment, many on public conservation land, but also a few on private land.

Surveying for freshwater fish at Munroe Dam.

Surveying in the Munroe Dam

I would like to be able to say that we found these waterways teeming with fish, but unfortunately only a couple of sites fitted this description.

Giant kōkopu. Photo: Andy Hicks.

Giant kōkopu in the Waituna catchment

Giant kōkopu and other freshwater species were largely absent from most of the catchment ponds, except at the Munroe Dam and in the tarns on the southern side of the lagoon. These two sites had more giant kōkopu than we could shake a stick at, and with a good range of sizes.

Giant kōkopu. Photo: Andy Hicks.

Giant kōkopu

Unfortunately, the ponds and tarns around Carran Creek, and those to the west of Waituna Creek, were all devoid of freshwater fish. This indicates that we may have been overestimating the use of these habitats by fish—with fewer populations than we thought.

Network of bog tarns at Waituna Lagoon.

Network of bog tarns at Waituna Lagoon

So, what is the value of this information? We now know where the secure populations of giant kōkopu are in the catchment, so we can carry out more focussed investigations and management.

Cicada. Photo: Andy Hicks.

Cicada at Waituna

The beauty of these sites is that there are few threats to them in their isolated locations. With little habitat change, we anticipate that these populations will be around for a long time.

By Cornelia Vervoon, Partnerships Ranger, Franz Josef

Rangers Mirella Pomeroy and Myles Riki were out in Saltwater Forest on the West Coast last week completing the local annual mudfish (Neochanna apoda) survey.

Range Myles setting a mudfish trap. Photo: Mirella Pomeroy.

Ranger Myles setting one of the mudfish traps

They set 30 traps and caught 32 mudfish, half a dozen koura/crayfish and some kokopu – a great result!

A mudfish and a koura. Photo: Mirella Pomeroy.

A mexican standoff between a mudfish and a koura

Mudfish are under increasing threat from habitat loss, so to find them thriving in Saltwater Forest is a really positive sign.

Two mudfish in a trap. Photo: Mirella Pomeroy.

Two mudfish in one go

Mirella found out what the bigger ones have been eating:

“We caught this one mudfish, which we thought was pregnant because it had a really big belly. Then we picked it up for a closer look… and it regurgitated (“blleeerrrgh”) a juvenile kokopu into Myles’s hand.” 

A mudfish up close. Photo: Mirella Pomeroy.

A mudfish up close

You can find more information about mudfish and New Zealand’s other freshwater fish species on the DOC website.

Saltwater Forest, South Westland. Photo: Mirabella Pomeroy.

Perfect mudfish habitat – Saltwater Forest, South Westland