Prevention is key
Many of the waterways in mainland Auckland have been invaded by pest fish including Gambusia (also known as mosquitofish), koi carp, catfish, perch, rudd and tench.
Even goldfish can become pests when released into the wild. They breed quickly and degrade freshwater ecosystems.
These fish have either been accidentally or deliberately released and aquarium releases is an ongoing problem
There are no known freshwater pest fish on Aotea/Great Barrier Island, and it is a priority to keep it this way to preserve the outstanding natural values of the streams and wetlands on the island.
Pest fish cause degradation of our lakes and rivers through:
- Resuspension of sediment through feeding methods making the water murky
- Increasing nutrient levels and algal concentrations.
- Competition, with native fish species like whitebait species
- Predation of native invertebrates (koura) and fish species.
- Grazing of native aquatic plant communities
Once pest fish have become established it is very difficult to remove them, so prevention is key.
If pest fish became established in Aotea waterbodies it would be costly and logistically difficult to remove them.
Under the Auckland Council RPMP pest goldfish are listed as an exclusion species on Aotea. This means it is illegal to move goldfish to Aotea or breed and distribute them on the island. However, if you already own a goldfish you can still keep it on the island as long as it is securely contained in an aquarium or outdoor pond.
If you have pet goldfish in an outdoor pond make sure they are securely contained so they don’t get washed away into other waterbodies in a flood.
Never release pet fish into waterways.
If you are aware of any pest fish or observe any ‘different’ looking fish in the waterways around Aotea or for further information please contact the Auckland Council Service Centre 09 4290 258