Introduction

Last August we were invited to be involved in a new initiative for controlling some of the aquatic pest that we unfortunately have in our national waterways. That initiative is the newly formed national aquatic pest task force headed by Anne Brow who is the national aquatic pest officer, which is a collective group of organizations that have an association with our waterways. The group is made up of DOC, NIWA, Ministry of Biosecurity, Power companies, Fish and Game, Weedbusters, Local Councils, and Hobbyist, which namely are us, the FNZAS. The reason why this task force was formed is that all the above organizations have a common goal of preserving our waterways for generations of New Zealanders in the Future. During the meetings we have discussed the affect that aquatic pest have on our waterways, Roles that different originations have on the taskforce but also some actions that are been taken to prevent the spread of aquatic pests. The main role that the FNZAS has in the aquatic pest taskforce is to spread the word about aquatic pest to hobbyist. Some of the other measures which have taken place is signage at waterways, Boat ramps being manned, Stands at boat shows, etc, Doc giving talks at schools these are only a couple of things being done.

What is an Aquatic Pest?

An aquatic pest is a fish or plant that may cause damage to our natural waterways

Gambusia (formerly known as mosquito fish)

Gambusia affinis are small fish introduced to New Zealand in the 1930’s from the Gulf of Mexico to control mosquito larvae but, ironically, they are not very good at it! Their ability to control mosquitoes has been exaggerated and they have become pests in many countries around the world. They are very aggressive fish and will attack fish much larger than themselves. This has lead to them being nicknamed "killer guppies".

Description and Life History:

Gambusia is a small fish with a greenish silvery sheen. Mature females grown to 6 cm and males to 3.5 cm. They mature at six weeks old and are unusual because they give birth to live young. This means that only one pregnant female is needed to start a new population. These features allow Gambusia populations to build up to large numbers very quickly.
What damage do they do?
Gambusia populations quickly expand to out number other species. They attack native fish by nipping at their fins and eyes and prey on their eggs. Whitebait and mudfish species are especially vulnerable to Gambusia, as they inhabit similar habitats.

Where are they found in NZ?

Gambusia prefers the shallow margins of slow flowing ponds, wetlands and streams especially around aquatic plants. They can tolerate poor water quality and a wide range of water temperatures. Gambusia is widespread throughout Northland, Auckland, Waikato and Bay of Plenty. Isolated populations have been found in Hawkes Bay, Wanganui and Nelson.
For Mosquito Control
Native fish such as whitebait, bullies and eels and aquatic invertebrates all feed on mosquito larvae. In addition introduced goldfish and tadpoles and frogs don’t cause as many problems as Gambusia and feed on mosquito larvae.
If you have got mosquito problems:
Empty containers around your home that contain water (saucers, jars, tyres, paddling pools etc) and clear your guttering.
If you have a pond make it as unfriendly to mosquitoes as possible by making the sides steep, having flowing water and planting plants around the edge to shade the water. This will improve your ponds habitat for other species that feed on mosquitoes.

Legal Designation:

Unwanted organism.

Koi Carp

Koi carp are an ornamental strain of the common carp (Cyprinus carpio) native to Asia and Europe. They were introduced to New Zealand accidentally in the 1960’s as part of a goldfish consignment. They contribute to water quality deterioration and are a serious problem in Australia, as well as New Zealand.

Description and Life History:

Koi carp resemble goldfish except that they have two pairs of barbels (feelers) at the corners of their mouth. They are highly variable in colour, often with irregular blotching of black, red, gold, orange or pearly white. Koi carp are long-lived fish and grow to about 750 mm in length.

What damage do they do?

The way that Koi carp feed stirs up the bottom of ponds, lakes, rivers muddying the water and destroying native plant and fish habitat. Koi carp are opportunistic feeder, eating insects, spawn, juvenile fish of other species and diverse range of plants and organic matter. They feed like a vacuum cleaner, sucking up everything and blowing out what isn’t wanted. Aquatic plants are dislodged in the process and unable to re-establish. Koi carp cause habitat loss for plants, native fish and waterfowl.
Where are they found in NZ?
Koi carp prefer still waters in lakes, or backwaters in rivers. They are very tolerant of poor water quality, contributing to water quality decline.
Koi carp are widespread in Auckland and Waikato. They are spreading into Northland and they have been found in isolated places in Wanganui, Hawkes Bay and Wellington. Koi carp are not thought to be in the South Island.
To help stop their spread a containment area between Auckland and Hamilton was created. In the containment area, recreational fishing is permitted, but all Koi must be killed when caught. Koi carp outside of the containment area are considered a serious incursion and control options will be investigated.

Legal Designation:

Unwanted organism.

FNZAS Involvement:

There have been two meetings of the group. The first meeting was to define a set of National symbols to help get the message about aquatic pests across to the public. This means fish and plants. We had a great meeting with input from nearly all groups being represented. We had a major influence on the symbols designed as there was some thought of using only two symbols. Initially the symbol relating to aquariums was going to be omitted but we persuaded the group it was necessary. The whole focus for the day was on defining the symbols, the slogan underneath and the list of details to help people decide what to do. See the symbols below:

The second meeting was to see what each member of the group could do to help get the message across. Some offered resource and some money. We offered resource. Our web site gets a huge number of hits each day. We will be adding these symbols to our website with the major emphasis on the fish-keeping hobby.

DOC has been actively contacting the public at boat ramps, getting the stop the spread message across. The major emphasis on draining the boat, cleaning boats, trailers and boat motors before leaving the boat ramp. Most people don’t realise how easily some of the pest plants travel from one waterway to another.

As another part of being involved in this process we’ve made contacts with the major organisations affecting the species we are allowed to keep. As a result we have to update our website. The current ‘Plant Survey’ page(s) are out of date. There are references to Noxious A and Noxious B type plants. These terms have been replaced with Unwanted Organism. The list of plants is also out of date with some plants on the list now being incorrectly classed. These changes may have already happened by the time the Aquarium World is released.

The Future:

Now we have made contact with the major organisations and these organisations are using this group as a channel to faster resolve issues as they arise, we hope to be more actively involved in future processes. Even though we are only a relatively small group, we’ve already had a good influence on the outcome of the ‘Stop the Spread’ message… Let’s see what happens.