Students from Kenakena School, Paraparaumu, recently received a hands-on lesson from DOC, Kapiti Area Office and Greater Wellington Regional Council, about the threats of aquatic pests in our natural waterways. An aquarium filled with water and replicas of native aquatic plants and fish was set up in the classroom as an example of what a healthy native aquatic ecosystem should look like. Students then placed replica exotic fish such as gambusia, rudd, and koi carp plus a cup of sediment into the aquarium. Students soon discovered that the exotic species displaced the native fish and the koi carp stirred up the sediment making the aquarium look dirty.
Students watched as Stacy Moore, DOC Community Relations, and Kerryn Penny, from Greater Wellington Regional Council, took out the remaining native plants and replaced them with pest weeds such as hornwort and oxygen weed. “These exotic weeds are easily transported on un-cleaned boat engines or nets to clean waterways where they can quickly become established and have an impact on recreational activities and natural habitat,” Kerryn said.
Numerous North Island waterways are infested with pest fish. They cause deterioration in water quality and declines in native fish populations. Species such as koi carp are now so widespread in some places they can't be eradicated and the pristine, natural state of waterways has been lost. It is illegal to liberate any aquatic life into a natural waterbody without a permit.
Peter Warwick, Live Environments inc., showed students safe plants and fish to put in any house aquariums or ponds. “If you no longer want your pond fish or aquatic plants do not dump them in a waterway but give them back to a local pet or aquarium shop,” stated Peter.
Students were encouraged to be detectives when they were out near streams or ponds with their family this summer. “Please contact Greater Wellington Regional Council or DOC if you identify any pest fish or weeds,” stated Kerryn. Stacy Moore, DOC community relations programme manager, brought a frozen koi carp for the students to examine. “Exotic pest fish and weeds threaten much of New Zealand’s native flora and fauna. Prevention is the best tool as eradication can be expensive long term and often impossible.”