Fish community responses to invasive fish removal and installation of an exclusion barrier at Lake Ohinewai, Waikato. Issue 3 (3rd July 2019)

• Record Type: Journal Article
• Authors: Tempero, Grant W.; Hicks, Brendan J.; Ling, Nicholas; Morgan, Dai; Daniel, Adam J.; Özkundakci, Deniz; David, Bruno
• Is Part Of: New Zealand journal of marine and freshwater research. Volume 53:Issue 3(2019)
• Page Start: 397
• Page End: 415
• Publication Date: 2019-07-03
• Subjects: Fish-down -- Cyprinus carpio -- shortfin eel -- longfin eel -- goldfish -- mark-recapture -- New Zealand -- pest fish; Marine biology -- New Zealand -- Periodicals; Freshwater biology -- New Zealand -- Periodicals; Freshwater biology; Marine biology; New Zealand; Periodicals; 578.77099305
• DOI: 10.1080/00288330.2019.1579101
• Languages: English
• ISSNs: 1175-8805

Abstract

ABSTRACT: Introduced common carp ( Cyprinus carpio ) are a recognised threat to New Zealand's freshwater ecosystems. In 2011, an invasive fish removal programme was undertaken in 16.8 ha Lake Ohinewai, a Waikato riverine lake. Active fish removal using netting and boat electrofishing was supported by installation of a one-way exclusion barrier on the outflow to Lake Ohinewai. The barrier was designed to allow fish passage downstream out of the lake, while preventing adult carp from moving upstream. The estimated carp population was reduced from 8, 548 fish (5, 863–12, 937, 95% confidence limits) in 2011–454 fish (251–889, 95% CL) in 2014. However, by 2016 the carp population had recovered to 2, 063 fish (1, 070–4, 328, 95% CL) with increased abundance in invasive brown bullhead catfish ( Ameiurus nebulosus ) also observed. This research demonstrates that carp populations can be reduced to low abundances in the short to medium term, but continued removal will be required for on-going control.