Animal pests

Animal pests in NZ

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New Zealand has at least 22 species of introduced fish compared with 39 native fish species. Some of these fish pose significant threats to our indigenous freshwater ecosystems. Especially serious fish pests include gambusia or mosquito fish, koi carp, rudd and cat fish. Freshwater ecosystems are especially vulnerable to invasion by these pests because it is initially hard to detect them until they have reached levels where their control is difficult. Once pest fish have invaded a waterway and become established it is very difficult to remove them because they are able to spread through a whole river catchment, and control measures may affect indigenous wildlife. Pest fish can cause damage in a variety of ways such as increasing nutrient levels, re-suspending fine sediments, and promoting the spread of algal blooms. Introduced fish often further destabilise freshwater ecosystems through feeding on and removing indigenous aquatic plants and preying on invertebrates, native fish and their eggs.

For more information about other animal pests follow these links:

• Mammalian – click here
• Mustelids – click here
• Insect pests – click here
• Search for detailed pest information – click here