Aquatic pests
Unwanted freshwater pests like the invasive catfish and hornwort pose a serious threat to our rivers, streams and lakes.
Once in a waterway these pests can spread rapidly and destroy the environmental, recreational and aesthetic values of our waterways.
Find out more on the rules that apply when using the region's waterways and the need to self-certify that your vessel and trailer is free from pest weed and fish when using the region's boat ramps.
Check, Clean, Dry
If you’re moving between waterways you can help to reduce the spread of freshwater pests by using the 'Check, Clean, Dry' method. Find out how to clean your equipment correctly.
Aquatic Weed Spraying
Te Arawa Lakes Trust will be undertaking aquatic weed control operations intermittently between the 18th of May and the 30th of June 2026 on Lake Rotoiti, Lake Rotomā, Lake Ōkataina, Lake Ōkāreka and Lake Tarawera using the herbicide Diquat Dibromide, weather permitting. Aquatic weed control operations will be taking place intermittently between the 1st of August and the 30th of October 2026 on Lake Rotorua, weather permitting.
Further details of these plans including Frequently Asked Questions (FAQs) can be found on the Te Arawa Lakes Trust website.
Regarded as one of the world’s most damaging weeds as it can thrive in both aquatic and terrestrial environments.
Aquatic plant that grows in salt water and forms dense woody, creeping underground root systems.
Catfish can survive out of water for up to 48 hours, making them even more capable of invading new waterways.
Corbicula thrive in highly oxygenated freshwater lakes and rivers.
Egeria doesn’t produce seed, instead it spreads through fragments breaking off and settling in new sites.
Elodea is commonly known as Canadian pondweed and spreads through fragments breaking off and settling in new sites.
Floating mats of hornwort can grow to such large sizes that they completely shade out entire areas of lakes.
Look very similar to a goldfish except that they grow to larger sizes and have two pairs of barbels, at the corner of their mouths.
Lagarosiphon is one of the more ‘common’ oxygen weeds, made popular through the aquarium trade.
Marshwort colonises shallow waters, rapidly forming dense mats which cover waterways.
Introduced to New Zealand as an ornamental pond plant, it forms dense mats of floating leaves over large areas.
Originally from South America introduced into New Zealand as part of the aquarium and pond plant trade.
Perch originate from Europe and were introduced to New Zealand as a sports fish in the 1870’s.
Purple loosestrife is a highly aggressive invader of wetlands. It forms massive, tall, thick stands, excluding all other plants.
Rudd were illegally imported to New Zealand in 1967 and have been deliberately released progressively throughout the North Island.
Salvinia can form dense mats that cover entire water bodies, crowd out native plants, increase shade in the water and decrease oxygen levels in the water, affecting the water quality and submerged plants and animals.
Sagittaria is also known as Arrowhead because of its arrow-shaped leaves.
It was introduced to New Zealand through the ornamental aquatic trade and sold as costata.
Tench are native to Europe and were introduced to New Zealand in 1867 as a sports fish.
Water poppy grows extremely fast, outcompeting native aquatic plants and quickly forming dense floating mats.
Yellow flag iris is semi aquatic with bright yellow flowers that typically only bloom for a few days.
Be a waterway hero – check, clean, dry, certify to stop the spread of freshwater pests in our lakes and rivers.