Carp (Grass) Ctenopharyngodon idella
Species: C. idella
Binomial name: Ctenopharyngodon idella
Common name: Grass carp
Ctenopharyngodon idella is a herbivorous freshwater fish species native to eastern Asia. They are a large fish and often exceed 500 mm in length, 10kg in weight, and can live for 15-20 years.They have no barbels. They are a dark bronze colour fading to a silver colour on the belly. The margins of their large scales are outlined in a darker colour.
Since Ctenopharyngodon idella has very specific breeding requirements and it was unlikely that they would reproduce in New Zealand rivers approval was given by the Government to use them for aquatic weed control. They were introduced to New Zealand in the 1960s. In New Zealand grass carp are now artificially bred on fish farms licensed by the Ministry for Primary Industries (external site). Each application to use these carp for weed control requires specific authorization.
They eat a wide range of aquatic plants and can be effective for a long period of time over large areas completely eradicate aquatic weeds.
For more detailed information visit: http://www.doc.govt.nz/get-involved/apply-for-permits/interacting-with-freshwater-species/options-for-weed-control/grass-carp/
A juvenile fish.
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