Spatial effects of the Canterbury earthquakes on inanga spawning habitat and implications for waterways management (2016)

Type of Content
ReportsCollections
Abstract
The Canterbury earthquakes resulted in numerous changes to the waterways of Ōtautahi Christchurch. These included bank destabilisation, liquefaction effects, changes in bed levels, and associated effects on flow regimes and inundation levels.
This study set out to determine if these effects had altered the location and pattern of sites utilised by īnanga (Galaxias maculatus) for spawning, which are typically restricted to very specific locations in upper estuarine areas.
Extensive surveys were carried out in the Heathcote/Ōpāwaho and Avon/Ōtākaro catchments over the four peak months of the 2015 spawning season. New spawning sites were found in both rivers and analysis against pre-earthquake records identified that other significant changes have occurred.
Major changes include the finding of many new spawning sites in the Heathcote/Ōpāwaho catchment. Sites now occur up to 1.5km further downstream than the previously reported limit and include the first records of spawning below the Woolston Cut. Spawning sites in the Avon/Ōtākaro catchment also occur in new locations. In the mainstem, sites now occur both upstream and downstream of all previously reported locations. A concentrated area of spawning was identified in Lake Kate Sheppard at a distinctly different location versus pre-quake records, and no spawning was found on the western shores. Spawning was also recorded for the first time in Anzac Creek, a nearby waterway connected to Lake Kate Sheppard via a series of culverts.
Rights
Attribution-NonCommercial 4.0 InternationalRelated items
Showing items related by title, author, creator and subject.
-
Survey method for locating īnanga spawning sites at a catchment scale
Orchard, Shane; Hickford, Mike (2017)Īnanga (Galaxias maculatus) is one of five galaxiid species that provide New Zealand’s ‘whitebait’ fishery. Four of the five species are also threatened to various degrees. The management of whitebait species is therefore ... -
Cobden wetlands īnanga habitat assessment and recommendations for future management
Hickford, Mike; Orchard, Shane (2017)This short report describes an assessment of the Cobden Island floodplain area and Aromahana Lagoon shoreline. A large scale ecological restoration project has been underway since 2013 on Cobden Island. The project has ... -
Identifying inanga spawning sites in plans: options for addressing post-quake spawning in Ōtautahi Christchurch
Orchard, Shane (2016)The purpose of this assessment is to compare records of known inanga spawning sites in the waterways of Ōtautahi Christchurch from before and after the Canterbury earthquakes, with particular emphasis on information used ...