Biogeography of Whitebait spawning grounds at non-tidal rivermouths

We recently published a study of īnanga (Galaxias maculatus) spawning grounds at non-tidal rivermouths in Pacific Conservation Biology. 

Article freely available here

Non-tidal rivermouths are common on the east coast of the South island and south-east of the North Island where they are commonly associated with high energy mixed sand-gravel beaches that form perched lagoons or hāpua at the rivermouth. 

At the outset of the study the spatial pattern of spawning in these environments grounds was unknown. Some of the interesting findings were that the location of spawning was close to the rivermouth despite the lack of salt water intrusion or tidal influence, both of which are associated with spawning grounds in tidal situations. 

A downstream fish migration evidently still occurs prior to spawning events and fish movements were surprisingly rapid in response to spawning cues in many instances. Spawning events are triggered by water level changes as occurs in tidal rivermouths, but appear to be more haphazard due to their origins being rain events rather than regular tidal cycles.Geographical aspects of the spawning locations were remarkably consistent across all seven study sites in key aspects such as the position in the catchment, relationship with water changes and presence of riparian vegetation. 

This provides a solid basis for identifying and managing spawning habitat in other non-tidal rivers. Effects we recorded included spawning on flood events that resulted in spawning grounds being located some distance from the active channel. As with tidal situations this places the eggs at risk from human activities in those same zones, but potentially presents a more difficult management proposition due to these events being less predictable. Their irregular nature suggests they are less likely to be accommodated in riparian zone planning and management. Importantly, the spawning grounds are located close to the peak water levels experienced on these events, which coincides with areas that are only briefly inundated. 

Recognising and protecting these emphemeral flood-zone areas is the key to effective conservation.

Read the full article here

Beach dynamics and recreational access changes

Link to report

The report responds to a request from Marlborough District Council (MDC) for information on the coastal environment, with a particular focus on supporting the development of a bylaw to address changes in recreational use patterns that have occurred since the Kaikōura earthquake. We present a selection of information from our earthquake recovery research that has a focus on understanding the impacts and ongoing processes of change. 

Major impacts of the natural disaster are associated with vertical uplift of the coastal environment, although ongoing erosion and deposition processes are also important. Interactions with human activities are also important because they can exert strong influences on the reassembly of ecosystems which is a critical aspect of outcomes over the longer-term. 

Earthquake uplift caused widespread mortality of many coastal habitats and species (e.g., algal assemblages) that are adapted to a relatively specific set of conditions, often associated with characteristic locations in relation to the tidal range. In uplifted areas the intertidal zone has moved seaward leading to a physical widening of many beaches. This has provided greater opportunity for off-road vehicle access to the coast and has become particularly noticeable at headlands and other natural barriers that were previously impassable at high tide. Off-road vehicles pose threats to sensitive vegetation and wildlife unless appropriately managed. Achieving this is assisted by an understanding of the specific impacts of vehicle use, which in turn requires information on the location of sensitive areas. 

To ensure the best outcomes for earthquake recovery there is an urgent need to assess and respond to the new spatial patterns, and to make plans to avoid conflicts where possible.

Legacies of the Kaikōura earthquake after three years

Legacies of the Kaikōura earthquake on the coastal marine ecosystem.
A summary of observations after three years.

See article Coastal News issue 72 out now

https://www.coastalsociety.org.nz/assets/Uploads/files/CN-72-2020-7.pdf

International interest in drone surveys

It was great too see a recent article Barbara Barkhausen in a German magazine focussing on New Zealand's environment and appeal as a tourism destination.

Read the online version here:
http://www.360grad-neuseeland.de/index.php?option=com_content&view=article&id=3072:so-erholt-sich-die-natur-nach-einem-erdbeben&catid=68&Itemid=62

See more aerial images on our Feacebook page here

Recover newsletter issue 3 on Kaikōura coastal recovery

#RECOVER Issue 3 features paua tagging, whitebait surveys and seaweed recovery monitoring work from the Kaikōura coast.

Available online here https://ir.canterbury.ac.nz/handle/10092/100101

Kaikōura earthquake recovery - loss of connectivity and the necessity of a cross‐ecosystem perspective

Article just published in Aquatic Conservation: Marine and Freshwater Resources from our Kaikōura earthquake recovery work.

The Kaikōura earthquake in southern New Zealand: Loss of connectivity of marine communities and the necessity of a cross‐ecosystem perspective.
https://doi.org/10.1002/aqc.3122

Stuff article on Kaikōura whitebait

Great article by Sophie Trigger at the Marlborough Express that features our recent work investigating earthquake impacts on river mouths along the Kaikōura coast.

We were able to locate several whitebait spawning sites and made some interesting discoveries with many of them occurring on flood events. Read more about an ecological experiment to rescue eggs stranded high on the riverbank with the help of the Environment Canterbury flood management team.
https://www.stuff.co.nz/environment/112863187/kaikura-whitebait-discovery-could-have-flowon-effects

Quantifying earthquake impacts using drones

A recent Stuff article by Alice Angeloni featured our survey work using drones to map recovery processes on the Kaikōura coast.

We have completed a variety of these high-resolution surveys to investigate diverse aspects of recovery that include habitat shifts and vegetation recovery at our study sites. The sites themselves are characterised by a a variety of environmental conditions and different degrees of uplift resulting from the earthquake event. The high degree of spatiotemporal variation makes the identification of overall impact a challenging task!

https://www.stuff.co.nz/environment/121606479/drone-shots-show-marine-recovery-along-quakestricken-kaikoura-coast

Whitebait spawning in Lyell Creek Waikōau

Nice article in the Kaikōura Star on our surpise finding of whitebait spawning sites in downstown Kaikōura.

The spawning habitat in this area has benefitted from riparian restoration work in Lyell Creek / Waikōau since the earthquakes.

Whitebait spawning surveys in Kaikōura coastal rivers

This summer we've been working

to fill a knowledge gap about whitebait in streams and rivers along the Kaikōura coast. Knowing where they are is useful for recovery planning in the same areas post-earthquake as well as for restoration projects in local waterways.

Our survey programme started with fish trapping to find out which species were living in which rivers, after which we selected waterways that were suspected to have good īnanga populations. They included seven catchments close to Kaikōura (Oaro, Kahutara, Lyell / Waikōau, Middle, Swan, Harnetts and Blue Duck) as well as other sites in Marlborough. After four months of surveying we discovered at least one spawning event in all of these streams and rivers and were able to map the spawning locations including some large sites!

Recover newsletter issue 2 on Kaikōura coastal recovery

#RECOVER Issue 2 features paua population monitoring, hotspots for banded dotterels, and seaweed recovery experiments from the Kaikōura coast.

Available online here http://hdl.handle.net/10092/16796

Recover newsletter issue 1 on Kaikōura coastal recovery

#RECOVER newsletter Issue 1 summarises massive changes on the #Kaikōura coast. Available online here https://ir.canterbury.ac.nz/handle/10092/16795

Inanga ora ki te awa o Waitara

It's been great working on this project with Waitara Alive and the Ōtaraua Hapū along with Waitara High School students to better understand the health of whitebait spawning sites along the Waitara River. 

The project is comparing present day spawning site health and abundance to historical evidence collected from local kaumatua. By contrasting past with present, the Inanga Ora project team hope to identify how spawning habitat is changing, and what can be done to better protect it.

The project was funded by the 'Curious Minds' He Hihiri I Te Mahara. Participatory Science Platform.
Check out a recent update from the Venture Taranaki here

Recovery of near-shore environments from impacts of Kaikoura the earthquake

This article provides a summary of changes to the nearshore ecosystem resulting from uplift effects of the Kaikōura earthquake.

Our MBIE funded RECOVER project will be assessing initial recovery trajectories over a 130 km section of the earthquake-impacted coast.

Read more in NZ Coastal Society Special Publication 'Shaky Shores'
https://www.coastalsociety.org.nz/media/view/publications/shaky-shores-coastal-impacts-and-responses-to-the-2016-kaikoura-earthquakes/

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

Using citizen science for coastal data collection

Citizen science has come of age in New Zealand and there are a wide range of opportunities for coastal scientists and practitioners to make use of, or contribute to it.

This recent article in Coastal News provides an overview of some recent highlights and progress in this fast moving field.

Read more >>