Earthquakes cause the relocation of spawning habitat on a catchment scale

The story of how whitebait spawning sites shifted to new areas after the Canterbury earthquakes - and became exposed to new vulnerabilities.
This spatial ecology study reveals how and where we can take action to protect them.

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Using artificial habitats as a natural habitat detection tool

We have a new paper published in the journal Ecological Indicators that describes the science behind using artificial habitats (such as straw bales) to as a detection tool.

We used this approach to help identify īnanga spawning habitat in degraded waterways where egg mortality can make it difficult to find the eggs directly.

Read more here

New methods paper - Census survey approach for īnanga spawning habitat

Waterways and MERG have recently published details of a survey methodology for locating and mapping īnanga spawning sites near coastal rivermouths. 

Read more here.

Evaluation of Christchurch City Council's riparian management trial

Christchurch City Council (CCC) recently changed its riparian vegetation clearance practices for a trial period in the summer of 2016/17. While the trial has wider objectives around improved environmental outcomes, īnanga spawning habitat is directly affected by bank cutting and other forms of vegetation clearance. A survey of īnanga (Galaxias maculatus) spawning habitat was completed in April 2017 to evaluate effects of the trial.

Benefits of the trial included increasing the availability of high quality spawning habitat and the discovery of new spawning sites. The Avon/Ōtākaro supported a relatively high area of occupation (AOO) of spawning sites for a single month in comparison to other years. In the Heathcote/Ōpāwaho spawning was found at new sites including upstream of Opawa Road. However, egg production was relatively low in the Heathcote/Ōpāwaho versus the same month in previous years. This suggests a shift in the month of peak spawning activity or a possible adult population decline and requires consecutive month surveys to confirm the actual trend.

The full report is available on the CCC website here:
Response of īnanga spawning habitat to riparian vegetation management

New spawning sites found in Aromahana Lagoon in Greymouth

Dr. Mike Hickford and I recently visited an community restoration project on Cobden Island in the Grey River and nearby Aromahana Lagoon. Our main goal was to scope out a survey strategy for monitoring īnanga spawning in this area. Time was short but we did manage to find two new spawning sites. 

This is an innovative floodplain restoration project on an impressive scale. Thanks to Henk Stengs at DOC for showing us around!

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Spawning habitat maps for Ōtautahi waterways

These maps show results from two years of spawning site surveys plus two years of straw bale experiments in the waterways of Ōtautahi Christchurch. Compare them with the Whaka Inaka maps where we took all of the known sites at the end of 2015 and tested if there might be others both in the gaps and further upstream/downstream. And yes there were.

These maps are available as free downloads. There's some other maps available too ..
check them out here www.resilientshorelines.nz/p/resources.html

Case study on community-led restoration projects and climate change

A case study of three coastal restoration projects looking at community-led approaches and climate change is in the new publication "Adapting to the consequences of climate change: Engaging with communities".

Link to the article here "Community-led approaches and climate change: Perspectives from coastal restoration projects"

The aim of this new NZCS publication is to support work with communities as they adapt to the consequences of climate change. It has been written to assist coastal professionals, decision-makers and communities in preparing for sea-level rise and the associated effects of climate change.

Ngāi Tahu Research Centre seminar: earthquake recovery in Ōtautahi Christchurch watwerways

Results from our research into the effects of the Canterbury earthquakes on īnanga spawning sites in the Avon Heathcote Estuary / Ihutai catchment in Ōtautahi Christchurch. It's a story of the resilience and recovery of an iconic New Zealand species following a major disturbance. Thanks to the Ngāi Tahu Research Centre and UC Audio Visual unit the recent seminar was videoed. View the clip on U-tube here.

New report on earthquake effects

The Waterways Centre for Freshwater Research and the Marine Ecology Research Group are pleased to provide a new report on the distribution of īnanga spawning sites in Ōtautahi Christchurch. Thanks to the Engineering New Zealand / Water NZ Rivers Group for supporting this work.

Highlights include comprehensive information on changes in relation to the Canterbury earthquakes, and a summary of the key implications for waterways management.

Read more here

Comparative study of coastal hydrosystems

Over the 2016 summer we are surveying eight coastal hydrosystems for a comparative study. Four study sites are in Canterbury and four on the West Coast. The study sites have been chosen to represent a range of different rivermouth and estuarine environments and a wide range of data are being collected to characterise each site in ecosystem terms. Look out for more news from these surveys in the coming months.

Whaka Inaka project gaining media attention

Whaka Inaka: Causing Whitebait is a joint collaboration between EOS Ecology, Ngāi Tahu, and the University of Canterbury (UC). We recently receiving funding from the Department of Conservation Community Fund, and together with support from Brian Mason Trust, and businesses such as Ravensdown the project is getting underway!

Collaboration with NIWA to develop salinity models

The Resilient Shorelines team would like to thank the Brian Mason Scientific & Technical Trust and also NIWA for bringing their support to this exciting research.

An interesting though unexpected finding of this work was the discovery of a leak in the Woolston Tidal Barrage. The model calibration was excellent in the lower estuary and in the Avon / Ōtākaro. However there was a strong  anomaly between the modelled versus observed salinity datasets for the Heathcote / Ōpāwaho that have been influenced by the tidal barrage leakage. Read more about it here in the Brian Mason Trust report on 'Development of a fine-scale salinity model for the Avon Heathcote Estuary Ihutai'.

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Earthquakes cause a shift in the location of īnanga spawning sites

One of the main objectives for our whitebait conservation study was to determine if the earthquakes had altered the location of spawning sites for īnanga (Galaxias maculatus) for spawning. They are typically found in specific locations near the freshwater-saltwater interface at rivermouths. As such, īnanga spawning sites are potentially a very good indicator of change. Conversely, they may be especially vulnerable to changes that affect the availability or condition of suitable habitat.

And the answer is - yes, there has been a major shift in the location of spawning compared to all previous records!

Read more here

TVNZ coverage