Asian Paddle Crab- Invasive Marine Pest in Ngunguru Estuary

Asian Paddle Crab
Native Paddle Crab

Whats the Problem?

Asian Paddle Crabs have now established a solid population in Ngunguru Estuary (according to Northland Regional Council). These paddle crabs are highly aggresive, outcompeting our native crab species for territory and food. 

The main food source of APC's are bivalve molluscs (pipis and cockles).  If we want to give our pipi and cockle beds opportunity to recover their collapse, we need to manage this issue or face the permanent loss of the shellfish in the estuary. 

How to Identify Asian Paddle Crabs:

There is only one Native Paddle Crab of a similar size (smiley face crab), but there are key differences to help you ID an APC from our Native Paddle Crab.


ID features     Asian Paddle Crabs:     Native Paddle Crab     
Paddles:    Yes- back legs paddle shaped.   Yes- back legs paddle shaped.
Size:    Shell 10-12cm wide   Shell 10-15 cm wide
Spikes:     6 on sides of shell before eye   5 on sides of shell before eye
Shell:    No Smile   Distinct Smiley Face
Colour:Dull olive, mottle brown/orange Spotty orangey, blueish paddles
Edible:    Yes (as advised by NRC)    Yes- limit 50 per day

How to catch:

APC's are tropical crabs, more active over the warmer months.  Bait a recreational crab pot with pilchards, set at low tide along the low tide line (all along the estuary to the river mouth), leave in for 24 hours. 

How to dispatch of crabs humanely: (Northland Regional Council advice)

APC's are tropical, placing crabs in chillybin full of salt ice will put them to sleep. 

Uses for APC's:


  • Make great bait for fishing
  • Make excellent Burley
  • They are also edible (NRC advice is that the only time they would be dangerous to eat would be in the event of a toxic algal bloom, which would be advised by council, as it would render all shellfish unsafe to eat)


Community Trapping Programme:

The advice from Northland Regional Council is that the population of crabs has established in Ngunguru Estuary, and that it now is not plausible to eradicate the population . Their advice is that a community trapping programme to manage them is the only way to protect the estuary food chain and our kaimoana.

We are already working on this at school, but implore other people in the community to join us in managing this problem. The future survival of our kaimoana depends on controlling this invasive pest.

We would like to collect data on where and how many APC's are being caught, also collecting any specimens you catch in order for our students to examine them in the NRC laboratory. If you are able to help us, or have catch information, please contact




Whats in a name? Tutukaka

Our Year 2 students learnt about why our coast is called the Tutukaka Coast.

Tutu refers to the snaring of birds.  There used to be large flocks of Kaka birds here, who would have enjoyed hanging out in the canopy showing off their cheeky calls and deft moves. This coast was known for the local Kaka food source!

Recently, we have seen a few Kaka back in our village :)  These birds are currently just visitors from established populations on the Hen and Chick Islands, and Bream Head, but hopefully with all the great work happening on our coast, they may come back to stay (and not have to escape those snares!). 

Kowhai nectar and fruits and berries are a Kaka favourite. If you want to attract them to stay, why not help plant a food source for them.

Here are the Kutai 3 Kaka :)

What have our seniors been up to ...?

Rats Busted

Here is a new great app to track how your trapping is going.  It is called trap NZ.  With an account, you can record your data and map your traps in order to keep great records about how your programme is going.

Our good news in Restoring Food Chains:

Weta are using our weta hotels regularly, and sometimes they have no vacancies! We have noticed that rather than living in them permanently, they tend to come and go. The ones that are on or very near known trees that they like to feed on (such as five finger) seem to have the highest occupancy rate. We are also noticing lots of centipedes, and bugs underneath our Bug Plates.

Rats: Check out the map of our trapping data (using trap nz app)!  We have removed well over 40 rats from our school bush since our trapping started, and are looking forward to expanding our trapping programme to include possums next year. There have been 3 kaka in the school and Ngunguru vicinity in the last 2 months!  

The Kiwi Coast programme runs strong, and we are proud to be contributing our little part to habitat conservation in our Bio Region. 

Discovering Dirt

Our Year One students focus is in developing vocabulary around ecological literacy, and experiencing some of the basic concepts of what makes up our local eco-system.

Recently we have been investigating soil which has been great fun! The most interesting part is going and collecting our soil samples, then tipping them all out on the table and going slowly through them with a paint brush to see what neat things we can find :D Just like scientists, these students have been using their magnifying glasses to find teeny tiny critters! Today we found miniscule white centipedes!

We were learning about what things make up the soil. Some of the things we discovered were

Seeds, sticks, leaves, worms, bugs, rocks, bits of clay, sand, humus, topsoil, centipedes, millipedes, ants, roots and shells.

We also learn about soil types and can identify: Sand, Clay, Topsoil and Humus.

To top all our learning off, we made delicious mud cakes! We used a crunchy gingernut base for the Bedrock, a layer of soil (vanilla) topped with minerals (sprinkles), then a layer of humus (chocolate flavour) with pumpkin seeds and bugs (marshmellows). They were delicious and a great way to learn about the layers in soil.

Soil - It's Precious- Don't treat it like dirt :)



Restoring Food Chains

Thanks to all of those wonderful people on our coast who work so hard to care for our kiwi, we have a lot of these little guys cruising around! Please be careful on our roads, it might not be a possum, it might be a kiwi!

The rat traps and weta hotels will be in this week!!

We continue to run the Restoring Food Chains project in our school bush.  

This year....

The year 3-4 students are the kaitiaki for our little nursery (plants are the start of the food chain).  These plants will be contributed to community conservation projects we are involved in such as the Ngunguru Hill Restoration.  If you have any spare seedlings popping up, we would love to have them to grow on to planting stage.

Our year 5-6 students are working around invertebrate classification and monitoring.  This week, our BUG PLATES will be ready to be installed to monitor our ground dwelling invertebrates, favourite kiwi food such as worms (annelids) and millipedes (myriapods).  Also our WETA HOTELS are finished and will be put in place this week. We have 5 five star hotels, and many bamboo hotels which we hope will provide sanctuary for our tree weta, and allow us the opportunity to study them close up. These students are also making a food chains display for our earthEd board outside the library. Watch this space....

Our year 7-8 students continue with our rat trapping, bird monitoring, weeding, track maintenance and tracking tunnel work. They will also be looking at ways to keep reptiles safe from those pesky pests by designing habitat for our skinks and geckos. 

You will be pleased to know its all paying off, the year 7-8 students heard kiwi in the bush during their night connecting with their environment on survivor camp!




Building Relationships

Last week, some of our Year 7-8 students, Miss Hope and Matua Rod attended a meeting up at Tutukaka Landcare Coalition.  This was a very special meeting focused around community conservation. It was attended by the CEO and some of the board of directors of WWF (world wildlife fund), Reconnecting Northland and the Kiwi Coast! Aswell as a very special visitor, Barney the kiwi! 

This was a fantastic opportunity for those students to meet people who support and/or run large environmental action projects, and get a taste of what possibilities are out there for our young people to get involved in around kaitiakitanga.

Click here to read all about the fantastic organisations that are working hard to protect kiwi, and the role that our students have in that on our coast!




earthEd 2016 Waterbased Habitat

2015 trappers with kiwi for release on our coast! Thanks Kiwi Coast!

earthEd: Education in, about and for the health of the Earth

earthed: To feel grounded and connected to our people and place


2016 is all about water! The links between land and sea, and the interconnectedness of all living things within our eco-system.

The habitat of focus are

Year 1-2: Eco-system Exploration

Year 3-4: Freshwater

Year 5-6: Estuary

Year 7-8: Open Ocean and Offshore Islands

We as the 'human habitat' are an integral part of this eco-system, and we can easily affect positive change for our local environment.   If you would like more information on how you can become involved in earthEd at Ngunguru School, and in community conservation, please email