Date: 13 December 2012
The Department of Conservation (DOC) is conducting pest fish surveillance in Opotiki and Whakatane rivers to find koi carp and rudd; and the public are asked to report any sightings.
Koi carp and rudd have a significant effect on freshwater environments, native species and the whitebait, eel and trout fisheries.
From public appeals for sightings of koi carp some potential sites were identified. This summer we will also be targeting rudd. There is a population located within close proximity in the Whangamarino wetlands (Waikato) that pose a possible risk of transfer to the Eastern Bay of Plenty says Ranger, Biodiversity Threats Peter Livingstone.
“Koi carp spawn in spring and summer with females producing several hundred thousand eggs. While rudd are also highly productive with females able to produce up to 50,000 eggs per kilogram of body weight.”
“Rudd are often referred to as the ‘possums of waterways’ as they have feeding habits that endanger native plant species, destroy indigenous habitat, remove food sources for native fish and invertebrate species.”
“DOC staff and contractors will be undertaking pest fish surveillance, both in the urban and rural areas from this month over the Summer period.”
“Every effort will be made to contact adjacent landowners when staff or contractors are in and around waterways” says Mr Livingstone.
- Rudd are stocky, deep bodied fish with distinctive red fins and large, shiny scales that range from silver (juveniles) to pale orange (adults) in colour. They grow to about 25 cm and 500 g. They prefer ponds, lakes and slow flowing streams and are widespread in Auckland and Waikato with isolated populations in Northland, Whanganui, Wellington, Nelson and Christchurch.
- Koi carp resemble large goldfish except for two pairs of barbels or feelers at the corners of their mouth. Their colours vary, often with irregular blotches of black, red, gold, orange or pearly white and they can grow to about 75 cm. Barbels are the most obvious feature, which distinguish the carp from other species such as goldfish. Mostly live in sluggish, often weedy streams and around the shallow areas of lakes and lagoons.